Tulle-gypsum part 2: first tests

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All the materials arrived so I started some tests. I did some 10×10 cm test pieces, as well as wrapping a glass bottle. Some early thoughts while the test pieces aren’t even fully hardened yet:

  • This shit is messy! No way will I be able to do 5 gram test pieces; at least that much material is stuck to my hands every time I put it on the tulle fabric
  • I made some calculations errors. 50 grams of gypsum gets me about 3 pieces of double layer 10×10 cm, not one. This is good. If I want more texture, of course I could use more
  • It sets quite slowly, I was still able to put some texture into it about 1½h after mixing. I think even for larger pieces I can just mix a single batch without having to worry too much about the setting time
  • I think my fabric is not ideal. The tulle is a tad too “open”, it doesn’t absorb the gypsum material as nicely as the gossamer used by the guy in this video. Still, that doesn’t seem to matter so much – it spreads out easily after applying the layer
  • I’m not sure yet how much top layer I will need. The texture of the tulle fabric comes through in spots where I don’t have much material on it, I don’t know how bad that would look when it’s set. Perhaps it’s fine after wet brushing
  • Colour:
    • The gypsum plaster material is not pure white, it’s actually a nice beige even if I don’t add pigment
    • The brown is great. Mixed at 4% it gives a warm light brown colour, at 8% it’s not much darker though
    • The black pigment is not as powerful as I had hoped. Mixed at 4% it gives a light cold-ish grey. Also, a little granular – doesn’t mix as easily as the brown
    • It is possible to put a pigmented layer directly onto an unpigmented one, and unless the first layer was very thick it won’t mix through much. This saves some pigment
    • I haven’t tried painting yet. With how the pigments are working, I think I should aim for a nice light brown base colour, wet brushing with a dark colour and perhaps some dry brushed highlights
  • Thinking of how to use this material for our festival decorations:
    • The original idea is to make trees. Depending on how strong it hardens, I think it will work!
    • Perhaps we can also use it to make 2D mascots, which we currently saw out of thin plywood. This material is easier to do indoors (no loud/dusty sawing)
    • 3D mascots and objects other than trees could be possible too!
    • If it’s strong enough with thin layers that still let through light – perhaps make a really cool lamp shade?

Next up:

  • Testing colour
    • Getting the main colour right: testing a few different percentages of brown, as well as mixing in some black with the brown
    • Getting some brushes
    • Trying some diy dark paint/paste out of the black pigment
    • Wet brushing dark (shadows)
    • Dry brushing light (highlights), e.g. with corn starch
    • Perhaps adding some green flocking powder or some other way to simulate moss
    • For fun: trying my blue and red pigment powders
  • Testing texture
    • How thick should the second layer be?
    • Wet on wet, or second layer onto dried first layer?
    • Different techniques of applying bark texture
  • Testing construction / backing
    • Different backing materials (paper towel, paper, cardboard, plastic..): how strong is it?
    • Trying 3D shapes: how strong is it?
    • Vaseline to go backing-less?
    • Making “hinges” for folding tree design

To be continued.

Ferrocement but it’s tulle-gypsum: materials ordered

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Found this video, I think he’s a theatre decor making teacher. He uses gossamer fabric drenched in drywall joint compound, about two layers, to make a hard shape, and quickly makes texture on top of it using excess drywall joint compound. Awesome. Looks much easier than the papier-mâché clay options I looked at before.

Ideas for making bark texture:

  • Using an icing bag to make stripes of bark texture, like this guy did with ferrocement
  • Using a roofing nail to make “valleys” for the bark texture
  • Perhaps use a silicon mould with some sort of release spray to make bark texture
  • Just folding the fabric into little vertical ridges

Colouring ideas:

  • Dark base coat, dry brush highlight on the ridges
    • Could use dark pigment in the mix so I don’t need a base coat and damaged pieces aren’t so visible
    • Just dissolve iron oxide pigment into thick paste and dry brush that directly onto wet project?
    • Perhaps some white (TiO2) pigment to make even brighter highlights
    • Black pigment in layer mix, brown pigment in extra “ridges” mix. Or just sprinkle some on the leftover mix used for ridges and barely even mix it in for some organic variation?
  • Light base coat, wet brush darker colour into ridges
    • Iron oxide brown in mix
    • Dissolve carbon black into paste and wet brush onto wet project, wipe ridges
    • Perhaps some extra dry brushed highlights

Other ideas:

  • Flexible mixing container so dried gypsum is easy to remove sounds like a good idea
  • Create a “folding” tree with a backing like this
    • Score the backing material (cardboard?) to allow bending?
    • Use same tulle fabric as backing material, no additional backing needed? Idea:
      • Use vaselined ground sheet, drape first layer of tulle on
      • Tape together with masking tape; tape lines are where the folds will be
      • Paint masking tape into dark colour, or just use narrow duct tape
      • Build up layers onto tulle, in between and perhaps slightly onto the tape lines
      • Whole thing should detach from groundsheet when set and should bend on tape lines
    • End product
      • 200×36 cm half round tree? (folds and stores as 100×60 cm, 4x 15 cm sides, should weigh about 4.3 kg)
      • 200×24 cm full round tree? (folds and stores as 100×80 cm, 8x 10 cm sides, should weigh about 5.7 kg)
  • Alternatively, a different tree design that stores flat, e.g. two shapes that intersect like a cross when seen from above
  • Alternatively, a tree design that nests for easier storage
    • Half cylinder tree trunks built using my big plastic pipe as a mould
    • More complete tree-shapes that nest like how clam shell pools nest. Would need to build a good mould to make sure they nest well
  • Tree limbs
    • Form around pool noodle or piping insulation
    • Broomstick
    • Use actual branches as base
    • Rolled/scrunched up craft paper
    • Shapes out of aluminium foil

Ordered:

  • Tulle fabric – 0.3×91 m
  • Carbon black pigment – 1.25 kg should also last a while. Recommended to mix in at 4.8% with concrete, up to 9.1%. I don’t need very black, and gypsum probably needs less pigment than cement, so it should colour 25+ kg of gypsum
  • Iron oxide brown pigment – 0.45 kg. Probably not as potent as the carbon black, might still try mixing in with the gypsum, or I could just dry brush it on as a thick paste made with just water
  • Gypsum, I ordered “Gyproc Blokkenwand Stuc” which is a gypsum plaster that can also be used as a block glue, it sets in about 2.5 hours (45 minutes working time) and is suitable for thin layers up to 5mm. Sounds ideal. Comes in 10 kg, or 25 kg which only costs 19% more. However, I don’t have much space to store things, so I got the 10 kg. If it works very well I can always get a bigger one later.
  • Flexible mixing vessel 25 liters

Total cost €55.57. Assuming my projects will need two 2mm layers, the gypsum will make 3m² worth of projects, the fabric and black pigment should last at least 7m².

Next up:

  • Picking up ordered materials and some cardboard
  • Making space and putting down plastic groundsheet
  • Testing:
    • Tulle layers: 10×10 cm pieces with 2-3 layers of tulle onto vaselined cardboard. Use about 50 grams gypsum, 42.5 mL water
    • Pigment/colour: bunch of 3×3 cm pieces using 5 grams of gypsum and 4.25 mL water each, plus different amounts of pigments. Use milligram scale & weighing boats – 7 mg accuracy gives about 15% relative error at 1% pigment, I’m ok with that.
    • Texture: 30×30 cm pieces, should be about 350-500 g each
    • Folding design: 45×60 cm piece with a horizontal & two vertical folds. Should weigh about 1 kg
    • Non-flat surfaces: try on a pool noodle or something similar

To be continued.

Papier-mâché clay

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I was looking at some compounds our lab is throwing out, saw calcium chloride and sodium sulfate, and figured those react to make gypsum. This brought me back to an old papier-mâché clay project idea I had.

Goals:

  • Create 3D forms, e.g. fake tree bark / branches
  • Somewhat fireproof
  • Somewhat strong

Traditionally papier-mâché clay uses PVA glue, drywall joint compound (mostly gypsum) and paper to make a paste that can be shaped like regular papier-mâché but becomes much harder and stronger. I think I didn’t continue with the project before because the PVA glue got prohibitively expensive for larger projects. Now I’ve found some projects using cheaper glue, e.g. from flour/cornstarch or cooked flour. Here‘s another even simpler recipe with just flour, drywall compound and paper fibre.

Actually the first recipe is already all I need. I could add some pigment powder (e.g. iron oxide) to the mix to make it browner, so it requires less painting. This should work (video). Painting: perhaps only some darker paint in the ridges, I think using the technique in this video.

If my lab is really discarding so much calcium chloride and sodium sulfate, maybe I could make my own gypsum. However, gypsum is cheap, so it’s probably not worth it. In the interest of finishing the project, I guess I should buy drywall joint compound (snelgips). If it sets too fast, I could add a bit of citric acid (maybe 1-2% of gypsum weight) to slow the setting time.

I could use the potato starch that my lab is throwing out (expired 15 years ago), but again, starch is cheap – corn starch is like €3 per kg.

I’ll need:

  • Papier-mâché clay ingredients
    • Flour
    • Cornstarch
    • Gypsum
    • Paper or cardboard – pressed cardboard apparently works well, I could save some from the lab
  • Aluminium foil
  • For small batches:
    • Bowls
    • Second hand hand mixer
    • Base/armature out of cardboard
  • For larger batches:
    • Buckets (have)
    • Paint mixer on electric drill (have)
    • Base/armature out of PVC or wood

I could even make a tree sculpture out of the large 20cm diameter pipe that I have. Perhaps something like this. These much smaller sculptures are also very nice.

First I should make a small test batch, and also check if it is indeed fireproof!

Here‘s a recipe with just powdered joint compound and gossamer fabric instead of paper. It’s not really papier-mâché clay any more since there is no cellulose fibre, however it looks even easier, lighter, quicker to use. Hmm. Gossamer fabric is cheap (€1-2 per m, 1.4m wide),

To be continued.

CR box continued

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Some thoughts.

Ikea Starkvind is an EPA12 filter, comparable to MERV18, >99.5% filtration efficiency of particles 0.3 µm and up. This is way overkill. Most CR boxes are constructed with a much less restrictive MERV12 type filter, which is maybe 25% efficient at 0.3 µm. I mainly want to filter dust, pollen and mould spores, which are >3 µm, and I want to use PC fans so I want a non-restrictive filter so I can make use of the high air flow. Even for smaller particles, it would make sense to use a less restrictive filter with a lower filtration efficiency if it means it can move more air; 100 m³/h at 60% has a better clean air delivery rate (CADR) than 50 m³/h at 90% efficiency.

Judging by the measurements by Rob Wissman, the Ikea Starkvind is so restrictive that it needs more than twice the filter area for the same flow compared to the MERV12-13 Filtrete 2200 filter. So perhaps I should look at a different filter.

I looked at the different filter types available in the EU; the EN779 standard from 2012, and newer ISO 16890 standard. I think M6 (old standard) or ePM10 >60% (new standard) would be ideal, comparable to MERV11-12. However one class higher; F7 / ePM1 >50%, comparable to MERV13; is easier to find. That’s still 5 classes lower than the Ikea filter so should still offer much less resistance. Perhaps a class lower (M5 / ePM10 >50%) would still suffice.

A single 287x592x48 mm M5 panel probably offers about the same resistance as 4 Ikea Starkvind panels. I think that should work well with 5x Arctic P14 fans. Assuming fans performing at 60% max, and 50% PM10 efficiency, that’s about 185 m³/h CADR or about 3.6 clean ACH in the room. Or I could use 2x 292x292x48mm F7 panel with 4x Arctic P14, assuming again fans performing 60% max, and assuming 90% PM10 efficiency, that’s about 267 m³/h CADR or about 5.1 clean ACH. Enough space to expand to more fans and/or filters if needed.

Those seem like better filter choices than the Starkvind. Also, I received some feedback that I didn’t think of: I should probably reverse the flow so it doesn’t pull in dirty air right over my face when I’m sleeping. I guess inflow from the top, out from the front would be ideal. Back to the drawing board, I guess.

CR box using Ikea filters and pc fans, with integrated planters: designing out loud

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I’ve been reading up on Corsi-Rosenthal Boxes, a relatively quiet and cheap kind of air purifier. The idea is to use off the shelf filters, but instead of a loud high static pressure fan on a single filter, using multiple filters so that the air resistance is low enough for quieter low static pressure fans. They’re typically made with MERV filters, but those are not readily available in Europe, so instead I could use Ikea brand EPA filters, or perhaps automotive particulate filters.

One rough rule of thumb says use about 4x the fan area in filter area. I think they mean filter dimensions, not total unfolded filter area. If I use 3x Ikea Starkvind filters (37x29x4cm), that comes to about 4x 14cm PC fans or 5x 12cm. I assume the 14cm fan option is quieter for the same airflow so I’ll go with that.

I don’t have space in my room for a free standing box, and the only place where a wall mounted box makes sense is above my headboard where I was planning to put a plant shelf. So I’ve designed something that combine a CR box (with 3x Starkvind filters and 4x 14cm fans) with two small planters that fit 9x9cm square nursery pots:

This is a “traditional” CR box approach with the 4 fans mounted together at the top, and the planters just hanging on the wall separately. I think the box sticking out of the wall looks a little weird, but I think this would be the most efficient option. Still, I don’t like it, so here’s another design:

This one has the filters neatly mounted side by side, and the four fans on the top have two planter trays interspaced. This option is quite slim and has everything integrated. I think it would look nice with some vines trailing over the filters, although I should take care that they don’t grow into the fans.

One thing to keep in mind is that this is right over my head when I’m sleeping, so it needs to be very quiet. So another option is to design a “sound maze” by having the air flow around a baffle, and sound proofing the surfaces (drawn here in lavender):

To keep the design somewhat narrow, it’d use 5-6x 12cm fans instead of 4x 14cm. An added benefit is that the plant tray runs the whole width, and plants are less likely to get into the fans:

As a soundproofing material I’d use either cotton (low VOC) or sheep’s wool, which actually absorbs VOCs and is better with moisture. Perhaps use old wool blankets.

Quick budget calculations: €38.99 for the plywood, €35.97 for the filters, €24.79 for the fans, so about €100 in materials excluding sound proofing and a fan speed controller.

For fan speed control, I’m thinking of an ESP32 or Raspberry Pi controller, maybe also to log some sensor data and/or control lights in my room.

Some calculations. SergioCoscolin looked at a box with 2x Starkvind filters, and tested 3x Arctic P12 fans versus 5x the same fans. Results:

FansCADRCADR/fanCADR/fan airflow
3x P12143 m³/h48 m³/h51%
5x P12173 m³/h35 m³/h37%

Either 5 fans is running into diminishing returns for 2 filters, or perhaps the dual direction output is less efficient.

Let’s assume my design is a little less efficient because of the extra air path from the baffle, so let’s take the 70 m³/h per filter of the higher efficiency solution above, but assume a 40% CADR-per-fan-airflow. Since I’ve got 3 Starkvind filters, I’m aiming for 210 m³/h CADR (4 air chances per hour in my room), so 525 m³/h total fan airflow. That’s 5x P12 fans or 4x P14 fans on full speed.

I like the “dampened” design, but it’s quite big and I don’t like the 45 degree angles. Also, the filters in plain view will get dirty. Perhaps I could hide them. Here’s a simplified design with the filters behind a mesh covered front inlet slit:

The inside is also simplified, with only right angle plywood. I haven’t drawn in any damping material but I think it could still fit. The front panel would need to hinge open, to be able to access the filters and fans, and it also clamps the filter in. This version uses 4x 14cm fans.

Next up I should do some static pressure calculations. The designs with baffle don’t make much sense if the added static pressure requires many extra fans to compensate the loss in airflow. In that case I’d probably just use a more airflow-efficient design with better fans, or just run at a lower speed.

Here’s a simpler more airflow efficient design with the 4x 14cm fans just pointing straight out the top. Air comes in through a mesh in the bottom. The bottom panel hinges to be able to access and clamp the filters.

Ok, one more design. This is the above design expanded with a “hat” so I could include a baffle. The air comes in the bottom and goes out the front over the plants. I think this is the least flow impeding baffle design, and it has the added benefit of being able to put stuff on top of the thing.

Oops, I forgot to draw in a flow diverting corner piece in the top right in this side view. Anyway, I think this is a pleasing design, especially if I use some of the same felt I used on my headboard as the top layer damping material.

I guess I could use the same mesh material used for the bottom opening in the top too, to prevent the plants from growing into the fans. Maybe attach both of the mesh pieces with little magnets, like an insect screen.

I could install GU10 downlights into the bottom panel. There’s enough space, and I don’t need to worry about the fittings leaking air since it’s before the filter.

I’m happy with this design! I guess I’ll skip the static pressure calculations.

Note to self: don’t use PVC pond liner to make the plant tray watertight; use something lower VOC like EPDM or PE. I think I might still have some 250 µm PE sheet.

Heat recovery ventilation, continued

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Humidity in my room is really starting to be a problem with all the plants I’ve got, and I haven’t even started up my active hydroponics systems or moss poles.

In a previous post, I looked at heat recovery ventilation to remove humidity without losing or gaining too much heat. I wrote that a ductless in/out “recuperator ventilation” system would be easiest/cheapest. Some thoughts:

  • Efficiency is low, closer to 50% than the claimed 80-90%
  • Decent units start around €300. Would be cheaper to just heat more and open the window in winter, or run a dehumidifier, though those wouldn’t solve hot & humid summer problems
  • DIY would be difficult, because of the fan; most modern fans (including PC fans) can only run in 1 direction
  • Soundproofing is difficult

So I’m going back to a counterflow heat exchanger idea. I previously looked at using a Stork heat exchanger unit, or perhaps repurposing only its core. However, that would be way too big for just my room, so I’m looking at making a smaller heat exchanger myself. I would still like it to be as efficient as possible. Main things that influence efficiency:

  • Surface area of heat exchange
  • Thickness of material
  • Thermal conductivity of material

Maximum surface area is dictated by shape/construction of the exchanger and static pressure performance of the fans. To improve the other variables, I should use a material like copper aluminium, that is as thin as possible. I’m thinking aluminium foil like this DIY design that uses stacked panels clad in aluminium foil, or this design that uses 0.5mm aluminium sheeting folded in a zig-zag pattern.

I really like the aluminium foil panel design, but I should take care that condensation does not cause issues e.g. with mould, so I don’t think I should mount the foil on wooden frames. Perhaps something 3D printed could work. I would also use thicker industrial grade foil instead of household foil.

I should think about the space that is available, and how I can fit the core, insulation, fans, filters, perhaps a sound baffle etc. into that. Ideally have the two outlets as far apart as possible to prevent short circuiting, both inside the room and outside the window.

Here’s a first sketch of a compact unit using a 50x30x12cm core, clad in 4cm insulation and surrounded by a plywood shell that fits in the window opening. One 140mm fan would be mounted near the ceiling on a 220x54mm duct, while the other would come out sideways by the window. Or perhaps I could mount both fans on the housing and/or run the duct further out. The core would be made of 16 panels, each constructed out of 7.5mm PVC U-profile with slits for passing the air in between the foil.

To be continued.

Idea: chalk/phone/water bottle bag

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I have an idea for a bouldering chalk bag in my head. I’m writing it down so I don’t forget.

It’s basically the triangular shaped “Jr.” chalk bag from pofzak.com, except the base is rectangular (so a little wider), and there’s a cutout for a water bottle in the middle against the back. Perhaps a carry handle on the water bottle side. For the closure, I’m thinking of using the same system used for drybags so the water bottle is not in the way. Edit: like the Organic Climbing “deluxe chalk bucket“, perhaps even with magnetic closure.

Want:

  • wide chalk bag, able to stick in both hands
  • carries water bottle
  • carries phone
  • carries small first aid things
  • carries nail clippers, nail file, callous block
  • carries brush
  • easily pick up everything at once

Next: paper/cardboard mockup

Another exercise evaluation

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Bouldering is going great. I’ve been steadily progressing and I’m now projecting 6Bs and 6B+s – flashing most 6As and even flashing some 6Bs. This is a big jump from my evaluation in April and I didn’t think I’d ever get this far.

My planned exercises aren’t going too well, but that’s ok. I do still occasionally do stair climbing cardio, but it’s mostly the 30 minute bike rides (and back) that have been improving my stamina. Besides that I haven’t done much exercising lately.

Points of attention:

  • Elbow: I’m starting to feel my elbow again, if I don’t work on my antagonist forearm muscles I feel like I will get tendonitis from the muscle imbalance. Or maybe since it’s mostly my right elbow, it might also be mouse RSI worsened by climbing. Anyway, wrist roller seems to immediately make it better, so I should do that.
  • Clavicle: I have some mild pain in my right acromioclavicular (AC) joint, but not from bouldering; I always get this when I do pushups. Again it might be mouse arm RSI, worsened by exercise. I think I should strengthen my rotator cuff and work on scapular control. Probably my shoulder stability is my most limiting factor in bouldering at the moment. Instead of pushups I could do band chest press, which is a bit more controlled.
  • Core: has been getting stronger from just climbing lately. Could use some extra exercises, but no longer as big an issue as it was in April.
  • Finger tendons: my finger strength has been steadily increasing without issue despite not doing any specific exercises. I’m a little worried that extra finger strengthening would be too much because I already boulder 2-3 times per week, so I’m no longer doing hangboarding.

I’m thinking about doing an antagonist muscles & shoulder health exercise routine after every bouldering session, because then I’m already “in the flow”.

  1. Warm-up
    • Broomstick dislocates
    • Wrist roller
  2. Main circuit (repeat 1-3 times)
    • Band face pulls with Y-raise
    • Band chest press
    • Band external rotations left/right (optional)
    • Band Paloff press left/right (optional)
  3. Cool-down
    • Wrist roller (optional)
    • Broomstick dislocates

New exercise goals

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I’ve had a bit of a break from exercising, but I’m almost back at my normal level of fitness. Let’s re-evaluate my goals.

Frequency goals

  • Go to the gym 1-2x per week (shorter bouldering session + StairMaster cardio session)
  • Go to an actual bouldering gym 1-2x per week (longer bouldering session)
  • Breathing exercise 1-2x per day – Buteyko breathing, Wim Hof, whatever
  • Short home exercises on non-gym days – any of these routines
  • Aim for 6 active days and 1 rest day per week

The first two I’m already doing. I’m starting with breathing exercises today, I think I should work on making that a routine before I pick up home exercises again.

Body parts I want to work on

  • Improve big toe muscles (abductor hallucis and flexor hallucis longus), both strength and neuromuscular awareness. I need to work on these to improve my posture chain and prevent foot/ankle/knee/hip pain and injuries. For instance this exercise
  • Finger tendons. I’m scared of injury so I’m very careful with these, which means that they’re most often the limiting factor in my bouldering sessions.
  • Forearm antagonist muscles. Climbing strengthens some specific grip muscles in your forearms, and I’ve noticed that if I don’t work on the antagonist muscles as well, I eventually get elbow issues.
  • Core strengthening. Working on this has improved my climbing much more than I thought it would.

Fitness tracking goals

I’m really not a fan of apps, but for bouldering, Toplogger is great. I would like to use it more consistently. Unfortunately my local gym is not on there, but the actual climbing gyms I go to are. I want to use this to track my climbing level.

Besides that, I want to use some sort of habit tracker for the following things:

  • Breathing exercises: when, how long
  • StairMaster: when, how long, how many steps
  • Bouldering: when, where, how long
  • Exercise: which routine, how many circuits, exercise specific things

Since I don’t like apps, and I always forget spreadsheets, I’m thinking of doing something on this website. Perhaps I can use a WordPress plugin or write something myself. To be continued.

Patches (by Margaret Rucker)

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I wear a silken flower on my shoulder,
An orchid made of velvet and of lace,
Because a hard wind, driving through my garden,
Of its carousals left relentless trace
In broken stems and darkened leaves. This autumn
I wear a silken flower in their place.

My marble god lies broken in the garden,
But I will patch him till he looks like new,
So people will not guess that he is shattered,
A lifeless Eros made of stone and glue.
And since I’ve learned to patch, you needn’t love me
If but for a while you will pretend you do.

by Margaret Rucker, unpublished during her life (1907-1959). Her scrapbook was rescued from a garbage bin by Chicken John Rinaldi, and some of her works were published in a book and concept album about her by Jason Webley and friends in 2014.

Interior (by Dorothy Parker)

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Her mind lives in a quiet room,
A narrow room, and tall,
With pretty lamps to quench the gloom
And mottoes on the wall.

There all the things are waxen neat
And set in decorous lines;
And there are posies, round and sweet,
And little, straightened vines.

Her mind lives tidily, apart
From cold and noise and pain,
And bolts the door against her heart,
Out wailing in the rain.

by Dorothy Parker, first published in 1926

Veganistische volkoren vruchtgevulde vlaaitjes

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Weet niet of je het echt vlaaitjes kan noemen, maar het allitereert zo lekker.

De vulling kan van alles zijn, bijvoorbeeld kersentaartvulling uit een potje of zelfs rijstepap. In dit recept maak ik ze met peer-gember-vulling. Als je een beetje opschiet kan je ze in drie kwartier maken, inclusief baktijd.

Het recept voor de bodem komt van AI, maar het idee van een simpele voorgebakte bodem met whatever vulling en kruimels bovenop heb ik in Zweden geleerd.

Bodem

Verwarm de oven voor op 180 graden Celsius.

Vet de bakvorm in. Ik gebruik een muffinvorm, kan vast ook met van die enkele vlaaivormpjes.

Kneed een mooie bal deeg van de volgende ingrediënten (recept voor 6 kleine taartjes):

  • 120 gram volkorenmeel
  • 70 gram margarine
  • 30 gram suiker
  • 2 eetlepels water

Snelste methode: verdeel het deeg nu in 6 ongeveer even grote balletjes. Plet elk balletje tot een mooi rondje in je handpalm. Bekleed hiermee de bakvorm.

Netste methode: rol met een deegroller de grote bal deeg uit tot ongeveer 3 mm dik, en steek 6 rondjes van ongeveer 10 cm uit met bijvoorbeeld een kommetje. Bekleed daarmee de bakvorm.

Bak de bodems (zonder vulling) 10 minuten voor in de voorverwarmde oven, vergeet niet een timer te zetten.

Vulling

Terwijl de bodems voorbakken kan je de vulling maken.

  • 2 peren
  • stukje gember
  • 2 eetlepels water
  • suiker naar smaak
  • kruiden naar smaak: kaneel, kardemom, nootmuskaat
  • beetje volkorenmeel om in te dikken

Was de peren, snijd ze in kwarten, snij de steeltjes en kernen eruit, en snij ze vervolgens in dunne plakjes. Kook in een klein pannetje op matig vuur, met wat water. Voeg suiker en kruiden toe naar smaak.

Snijd de gember in kleine stukjes, doe die door de perenprut die als het goed is nu langzaam kookt. Laat nog even mee pruttelen. Niet erg als het wat waterig is geworden, indikken komt later.

Kruimeldeeg

  • flink handje haver
  • wat margarine, misschien 20 gram
  • schepje suiker
  • schepje volkorenmeel

Mix haver/margarine/suiker in een kommetje tot de haver wat samenklontert tot kruimels, gebruik eventueel wat meel om beter te kruimelen of je handen minder plakkerig te maken.

Bodems vullen

Haal de voorgebakte bodems uit de oven.

Haal de vulling van het vuur en dik in met wat volkorenmeel, totdat het niet meer zo vloeibaar is.

Vul de bodems met de vulling, ik stamp het zelf altijd een beetje aan zodat er meer vulling in gaat. Bekleed met het kruimeldeeg.

Doe ze in de oven, zet een timer voor 15 minuten. Genoeg tijd om de boel weer op te ruimen, de vaat te doen en misschien een dansje.

Klaar!

De makkelijkste manier om ze uit de muffinvorm te krijgen is er een snijplank op te leggen en de boel op z’n kop te keren. Als je ‘m goed ingevet had, kan je de vorm er dan zo af halen.

Plant shelves

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I have some nice wood boards from an old project that I would like to reuse for 2 projects:

  • Windowsill planters in my bedroom
  • Plant shelf / planter on my office desk

Right now I have my windowsill plants in plastic balcony planters. Needless to say, those planters are not very nice to look at. And my office plants are getting in the way, so they could use some shelves.

Board plans:

  • ~106 cm board: office shelf left
  • ~101 cm board: office shelf right
  • ~101 cm board: office shelf middle + 22 cm (window left) + 15 cm (window right)
  • ~133 cm board: 70 cm (window left) + 63 cm (window right)
  • ~106 cm board: window left
  • ~101 cm board: 15 cm (window right) + 22 cm (window left) + leftover

Office shelf plan has gotten a little bigger (but simpler) than my previous idea: just a board in each window, connected by a diagonal board in the middle, supported by a beam under it.

It’s just resting on the window frames. I measured it well so I could wedge it between the leftmost and rightmost window posts which means it feels solid. :) KISS meant that I actually found the motivation to make & finish it, instead of overthinking but not actually making anything.

Next up: rightmost windowsill planter for my room. It looks simple enough, but getting it to fit on a 14 cm windowsill when the nursery pots are 11 cm square and the wood I want to use is 2.5 cm is a bit of a challenge.

Ventilation & air quality

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I might need to ventilate more, but I would like to keep the heat in.

Some ideas:

  • CO2 sensor & humidity sensor to know when to ventilate. I must still have a breadboarded project somewhere based on Operame
  • Automatic window opener, perhaps based on this project?
  • Heat recovery ventilation. The room I’d like to ventilate would require 25-72 m³/h. Some ideas:
    • Something like a used Stork WHR90 (€100) unit could work, but it’s very large. I could mount the outdoor inlet and exhaust on a panel behind the wooden folding “window” already in the room. Should probably duct one of the indoors connections of the unit to the other side of the room to prevent short circuiting.
    • A smaller heat exchanger with separate fans would likely be sufficient, and would be much smaller and easier to mount. Also, perhaps can be quieter, especially if mounted in an insulated box. However, it would likely be less efficient and probably more expensive.
    • Something along the lines of this project or this one
    • A heat recovery ventilation system using a single vent, with heat recovery material inside, blowing in/out alternately. Sometimes called “recuperator ventilation”. Less efficient, but simplest solution. A new unit can be had for about €150 but should also be the easiest to DIY, because the core doesn’t have to exchange heat through space, only over time. Ventilation (in/out) regime and thermal capacity should be matched carefully for highest efficiency, which means that throttling might not be possible. Commercial units use a ceramic core and roughly 70+70 second cycles. I guess instead of throttling, I could control the amount of cycles it does per hour based on the ventilation requirement. And/or use multiple temperature probes to control cycles? Ceramic cores are available: for instance this hexagonal one, and I wonder if this ceramic catalytic converter core substrate is suitable but might clog up too fast.
    • To keep in mind: outside-to-inside noise reduction by installing a noise filter on the vents? And or acoustic insulation on the wooden window to lower fan-to-outside noise?

So far, the single fan “recuperator” seems the most viable option. Perhaps with a 12V case fan, and the whole thing encased in an insulated box mounted to the wooden window. And some filters. Or perhaps two units together in the box for a low/high flow option. Can even set it to just blow into the room at night on very hot days.

First, get a CO2 sensor working.

Chelating calcium?

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I was looking at chelators to solve the calcium sulfate solubility problems for a more concentrated 1-part fertiliser. I’ve found that apparently some organic acids can complex calcium, specifically citric acid, but also others such as malic acid and lactic acid. I’ve already got malic acid that I could try. I would have to change the rest of the composition a bit – I’m specifically using ingredients such as urea phosphate to bring down the pH already. Also, I wonder if organic acids are a good idea for long term pH stability – I wonder if the acids breaking down in the plant’s water reservoir causes pH drift. Lots of things to test. Or I could just order an actual chelator like EDTA.

To be continued.

Miniature orchid in a bottle

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I bought a cute little orchid at a plant meet, it’s an Acianthera sonderiana. Apparently they grow easily in Sphagnum moss, kept very moist, with low light. It’s an epiphytic species that in the wild (Brazil) grows on branches of trees in cool moist forests. I asked the seller and he said it would be great in a terrarium, so I’m trying a bottle terrarium. I’ve got a few discarded laboratory reactor bottles, I think a 1L one would be a good fit. I only just managed to get the little orchid through the GL45 mouth.

I used some Sphagnum at the bottom (I hope it will come to life again), some lichen covered grape vines, and some pieces of moss from our balcony. I like how it turned out, I hope the orchid likes it too because I don’t think I’ll be able to get it out again!

I’m also trying a few small vining aroids (a Rhaphidophora species and a Monstera species) with some Sphagnum in a 500mL and in a 2000mL lab bottle. I hope they take.

Bouldering: evaluation after about 1.5y

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My goals in climbing are having fun, being social, keeping fit and conquering my fears. Getting better at bouldering is not a goal for me in itself, but that does help keep it fun, it’s pushed me to become more fit than I’ve ever been, and harder routes can definitely bring new scary things to conquer. I’m pretty proud of how far I’ve come already.

My strengths in bouldering are probably my reach and flexibility, my leg strength and my shoulder strength. My core and biceps are however relatively weak, and I’m still not very good at route reading. I like boulder problems with only a few very big moves, and routes where I can take my time to find an efficient beta more statically. I struggle at overhanging routes that require constant strength, and other routes where I can’t take my time e.g. with awful crimps or slopers.

  • Level I usually get on the first try: up to 5A+
  • Level I usually manage eventually: 5B+
  • Maximum level I’ve climbed: 6A+, but maybe higher? I mostly climb at a gym without grades

During a bouldering session (typically 1.5-2.5h) I spend almost all my time on problems that I think I would be able to do after one or perhaps a couple of tries. I spend maybe only 10% of the time on problems that are quite overhanging or have difficult crimps/slopers, mostly because it’s less fun to do things you’re less good at.

I tend to avoid very crimpy routes specifically, because I’m worried of overloading my finger tendons. Most sessions my fingers start to feel sore before my larger muscles do, I guess because I climb slowly and try not to rely on my biceps. I injured my fingers when I started out (the typical beginner injury) and have been careful with them since. I make sure that I’ve been climbing easy holds for at least half an hour before I do anything crimpy, and now I know when to give my fingers a rest.

I haven’t injured anything else yet, but I do feel that I should take extra good care of my elbows and knees. I’ve been starting to feel a little pain in my elbows the past few months since I started bouldering more/longer. The elbow pain is a constant 1 (barely noticeable) on a scale from 0 (nothing) to 10 (so painful I can’t think) and doesn’t get worse with use – in fact when I’m warmed up from bouldering is the only time it goes back to a 0. The physiotherapist couldn’t find or recommend anything, but I think maybe it’s from muscle imbalance from all the hanging. I’ve been doing wrist roller exercises for a few weeks now and it seems to be improving things.

My knees are sometimes a little bit more painful but I don’t think this is from climbing. My hips are usually rotated too far back, probably because of my weak core, which means my knees don’t align well with my feet when I squat if I don’t concentrate on that. Also, I notice that I tend to lock my ankles a bit when I feel stressed, which puts extra stress on my knees when I walk. I try to strengthen my knees by doing more walking and doing single leg squats, but taking extra good care that I keep everything aligned, core and glutes tight, ankles relaxed. My knee pain is usually around 1 out of 10, sometimes none, sometimes up to a 3 out of 10 if I didn’t take care of my alignment and ankles. But it’s never gotten worse from climbing.

They’re building a new bouldering hall close to where I live. I’m looking forward to going to an actual bouldering hall more often, instead of the gym where I go now. Our gym is still a great place, with regular new problems, it’s cheap and it’s close by, but it would be fun to have more choice in routes and to have clearer grades so I can track my progress better.

Workouts, updated

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Evaluation of previous post, after 2 weeks:

  • I did 7 workouts (4x #1, 3x #2)
  • They’re way longer than I thought: about 10 minutes per circuit instead of 10-15 per 3 circuits
  • I think I want to split things up a bit more, so I focus on fewer exercises and still get 3 reps into 10-15 minutes. Maybe go to 5 instead of 2×2
  • I care most about core, so I want to keep doing that multiple times per week, but I think it’s fine if I only do pushups and squats once per week
  • Hanging training (e.g. scap pullups) will have to wait, because I only have a hangboard ledge and it would require a lot of finger warmup first. Also I don’t feel ready for hangboard training yet. Maybe I’ll attach a pullup bar or something later

Routine 1

Routine 2

  • Shoulder pass through – straight
  • Push ups
  • Wrist roller

Routine 3

Routine 4

  • Shoulder pass through – alternating
  • Wrist roller
  • Elevated pistol squats

Routine 5

  • Shoulder pass through – straight
  • Banded Paloff press, left
  • Banded Paloff press, right
  • Face pulls

Workouts

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Last week I did my first pistol squats. A few years ago I trained a squat progression specifically to get to pistol squats, but I wasn’t consistent enough and never actually managed them. I haven’t really done workouts since, but I’ve been going bouldering more frequently – maybe 5 hours a week on average now.

It’s not just my squat that has gotten stronger – my grip strength and pulling strength has too. However, I’m noticing some elbow pain that might be due to muscle imbalances. And I think my bouldering will plateau soon if I don’t work on my core strength and shoulder strength and mobility.

I’m thinking of doing about 4 short workouts a week, on Monday, Tuesday, Thursday and Friday morning before work. I would like to split them into two routines that I alternate.

Routine 1 (Monday & Thursday)

Circuit:

  • Shoulder pass through – straight (for shoulder mobility)
  • Push ups (antagonist training to counter all the pulling from climbing)
  • Wrist roller (antagonist training specifically to combat elbow pain, also good for grip strength)
  • Elevated pistol squats (to make the training more fun)
  • Scapular pull ups (for shoulder mobility & strength)

Routine 2 (Tuesday & Friday)

Circuit:

  • Shoulder pass through – straight (for shoulder mobility)
  • Plank shoulder taps (core)
  • Shoulder pass through – alternating left/right (for shoulder mobility)
  • Banded Paloff press (core)
  • Face pulls (shoulder strength & mobility)
  • Reverse hyperextension (core)

~10-15 min for 3x circuit

Continued fertiliser troubles

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V8.9 take 1

Mixing order:

  • 4.675 g calcium nitrate in about 90 mL water -> dissolves fine
  • 6.273 g urea phoshate added -> slightly milky, almost entirely dissolved?
  • 8.646 g ammonium sulfate -> partially dissolved, very milky
  • Water added to ~200mL -> still very milky (250 mL would have been 500:1)
  • Water added to ~400mL -> still milky (500 mL would have been 250:1)
  • Water added to ~800mL -> still milky (1000 mL would have been 125:1)

I guess I’m no longer getting calcium phosphate precipitate due to using urea phosphate, but I still get calcium sulfate precipitate.

I guess I should’ve added the other salts first, to prevent calcium sulfate precipitation. With more nitrate in solution, there would be less chance for the calcium to bind with sulfate.

V8.9 take 2

Mixing order:

  • 11.13 g potassium nitrate in about 90 mL water -> takes a while to dissolve, but does dissolve ok
  • 2.334 g calcium nitrate added -> dissolves ok
  • 2.635 g magnesium nitrate added -> dissolves ok
  • 3.317 g urea phosphate added -> dissolves ok, slightly milky but no precipitation after a minute
  • Water to ~200 mL
  • 4.322 g ammonia sulfate -> dissolves ok!! Very slightly milky but no precipitation after a minute
  • 0.935 g trace elements -> formed some chunks, but after breaking up dissolved ok

Success! It’s only a 250:1 solution but at least there’s no precipitation any more. This is the most concentrated 1-part hydroponic fertiliser I’ve made so far.

V8.9 take 3

  • 22.26 g potassium nitrate, 5 g calcium nitrate, 5.274 g magnesium nitrate in about 200 mL water -> dissolves ok (I dropped half the calcium nitrate, put most back but added half a gram to compensate, ughh)
  • 6.273 g urea phosphate added -> dissolves ok, slightly milky but no precipitation after a minute
  • 8.64 g ammonia sulfate -> dissolves ok!! Very slightly milky but no precipitation after a minute
  • 1.872 g trace elements -> again some small chunks but dissolves ok

However, after a few minutes precipitation does start to form. 500:1 is too much, I guess 250:1 is the best I can do with this amount of sulfate.

What’s next

250:1 is already nice, it’s more concentrated than GT Foliage Focus which is 150-200:1. However there are more concentrated products such as Canna Floragro and Dyna-Gro Foliage-Pro (both around 800:1). Liquid Gold Leaf (500:1) is the only one with significant amounts of sulfur, though – I wonder how they do that. Maybe a chelator.

For V9 I will look at either lowering sulfate concentration to get to 500:1, or using a different form of sulfur. I could get some biosulfur (mostly S8), I wonder how soluble that is.

Edit

Shit, even the 250:1 eventually started precipitating out something. Probably calcium sulfate. Back to the drawing board.

L-Arginine conditioner, continued

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Ran out of the previous batch that I made (50g). Findings:

  • Spreading in hair instead of on brush first works, not sure if it’s more even but it feels like I have more control how much I put where
  • Putting more on front locks helps with frizz – that’s the part of my hair that gets frizzy e.g. from being wind blown
  • Still figuring out exactly how much to put where, but in any case my day 3 hair is less frizzy and more curly than my day 1 hair used to be
  • Putting a little too much in will give a bit of a gel cast feel, it does scrunch out a little bit. I don’t like it on day 1 but it gives great day 2 hair

New batch. Same as before, but with Xanthan gum added to hopefully thicken it more.

  • 6g L-Arginine HCl
  • 69g conditioner
  • 3 drops (~0.2%) essential oil
  • 0.15g (0.2%) Xanthan gum

It didn’t really thicken it up much. Maybe I didn’t use enough, or maybe Xanthan gum doesn’t work very well any more 10 years after its manufacturing date. To be honest the creme was a nice consistency already without it so I don’t think I’ll use it again.

Lab stand cart for distillation setup

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I want to build some sort of cart, or something with wheels to put all my distillation things on so I can easily roll it out of the way. It should permanently hold my big lab stand to hold the biomass vial, and under that I would like it to house a 10L jerrycan and a smaller lab stand to hold the heated mantle and boiling flask. Also, somewhere to put the controller/power for the cooling loop pump. Something like this, with caster wheels under the corners:

I want to make it out of leftover pieces of wood. I would need:

  • 4x 44x44x400mm horizontal
  • 4x 44x44x338mm vertical
  • 2x 69x44x362mm horizontal, at the bottom
  • 2x ~12x150x412mm sides
  • 1x 12x312x450 bottom
  • 1x 12×150+x450 backplate

I can get all of that out of scraps, yay! Let’s get building!

Edit: done! I don’t remember the last time I went from conceptualisation to finishing a project in one afternoon. It’s nice to finish something for a change.

Next up: figuring out all the connections on my random collection of glassware that I want to build a distillation setup from.

Headboard finished

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I finished the headboard and I’m happy with how it turned out. :)

Things I learned:

  • Wood glue doesn’t work very well on foam, but regular craft glue is fine. I guess spray glue would’ve been best, though.
  • A blunt bread knife doesn’t work very well for cutting this sort of foam. However, fabric scissors worked really well and I got nice straight cuts.
  • I cut the foam slightly oversized and pressed it into the frame, and didn’t glue it against the backboard. While this worked, I think it would’ve been better to cut it to size and glue it so it can’t bulge or come loose later.
  • Now I’ve got the thing behind my bed, I think it would’ve looked better if it were some 30cm wider, so it continued all the way to the wall. Maybe I will make a small separate piece to fill that gap. I have plenty of felt left. Or maybe I’ll make something out of wood, like a tall corner shelf/night stand.

Two propagation racks

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I salvaged an aluminium drying rack for glass tubes. I already had some salvaged lab glass tubes and long bottles that I wanted to make racks for, and they fit nicely in the holes. However, I didn’t have enough of the bottles to fill it up, and it was too tall for the reaction tubes. So I drilled out the little rivets, sawed one of the plates with holes into two, and made the thing into two racks to fit both the tubes and the bottles.

It was nice to work with rivets again, I don’t have much experience with those. It shows if you look closely – the one in the back has four different sizes of rivets – but I learned in the end.

I’ll use these for propagating plant cuttings. They fit perfectly in the windowsill :)