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 :)

Headboard foam

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I salvaged some foam from work that I might use to make a headboard for my bed.

It’s four 70x50x3cm pieces of firm foam, and two 70x33x3cm pieces of softer foam. I want a headboard that is at least 140x80cm so I guess I could just use two firm ones on the bottom and two softer ones on top. Then the two remaining firm ones could make a ~120x50cm back pillow for my bean bag sofa. I think I have enough felt material for both projects.

I have zero upholstery experience though, so I guess I should do some research first.

Essential oil distillation

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Another thinking-out-loud post.

I have inherited a 500mL round bottom flask and heating mantle from my lab. I’m trying to see what I would need to make it into an essential oil still.

Option 1a: simple distillation, 250 mL capacity – 29/32

Option 1 is the cheapest

  • Round bottom flask 500 mL 29/32 €0
  • Elbow 75 degrees 29/32 €8.34
  • 14/32 stopper €0
  • Jacketed straight condenser 200 mm 29/32 €16.85
  • Receiving adapter 29/32 €8.60
  • Separatory funnel 250 mL €13.18

Total: €46.97

Option 1b: simple distillation, 250 mL capacity – 24/29

Same but 1 size down

  • Round bottom flask 500 mL 29/32 €0
  • Elbow 75 degrees 29/32m to 24/29m €8.14
  • 14/32 stopper €0
  • Jacketed straight condenser 200 mm 24/29 €6.86
  • Receiving adapter 24/29 €8.87
  • Separatory funnel 250 mL €13.18

Total: €37.05

Option 1c: simple distillation, 250 mL capacity – 19/26

Same but 2 sizes down again, needs adapter

  • Round bottom flask 500 mL 29/32 €0
  • Adapter 29/32m – 19/26f €6.80
  • Elbow 75 degrees 29/32 €6.45
  • 14/32 stopper €0
  • Jacketed straight condenser 200 mm 19/26 €12.67
  • Receiving adapter 19/26 €8.60
  • Separatory funnel 250 mL €13.18

Total: €47.40

Option 2a: reflux distillation, 250 mL capacity – 29/32

This one is the most simple option; a reflux separator with a condenser, straight onto the flask.

  • Round bottom flask 500 mL 29/32 €0
  • Reflux separator 29/32 €28.99
  • Jacketed Dimroth condenser 300 mm E.L. 29/32 €30.36

Total:

Option 2b: reflux distillation, 250 mL capacity – 24/29

Same as before but reduced to 24/29, i.e. thinner separator & column

Total: €56.60 (200 mm) / €65.67 (300 mm) / €67.76 (400 mm)

Option 2c: reflux distillation, 250 mL capacity – 19/26

Same as before but reduced to 19/26, i.e. thinner separator & column

  • Round bottom flask 500 mL 29/32 €0
  • Adapter 29/32m – 19/26f €6.70
  • Reflux separator 19/26 €29.61
  • Jacketed Dimroth condenser 300 mm 19/26 €30.42

Total: €66.73

Option 3a: reflux steam distillation, 500-2000 mL capacity – 24/29

This one is the maximum I can do with my 500 mL heating mantle, although I could possibly fit a 2L chromatography flask too. Reduced to 24/29 better to keep 29/32 for easier filling/emptying? Reduce reflux separator and Dimroth condenser?

  • Round bottom flask 500 mL 24/29 €12.86
  • Some sort of reservoir
    • 500 mL round 24/29 €19.63
    • 1000 mL round 24/29 €27.78
    • 2000 mL round 24/29 €41.14
    • 500 mL globe separator €18.11
    • 1000 mL globe separator €26.66
    • 500 mL globe separator 29/32 €21.51
    • 500 mL straight column separator 24/29 €25.61
    • 500 mL straight column separator 29/32 €29.40
    • ~500 mL straight column 24/? (50×300 mm) €32.59
    • ~1000 mL straight column 24/? (70×300 mm) €41.00
    • Wait a minute, I have an awesome big ~1.8L glass reservoir that is the perfect shape! It’s just missing the DN100? lid. The lid on its own is more expensive than all the other options though. Maybe use a temperature resistant funnel? Print a PETG lid and line it with PTFE baking sheet?
  • Reflux separator 24/29 €27.92 €32.90
  • Jacketed Dimroth condenser 300 mm 24/29 €29.43

Total:

Option 3b: as above, but I’ve put more thought into it

Putting a stopcock between the boiling flask and the reservoir is a bad idea. It’ll clog up with plant material. Also, I want the biggest diameter reservoir opening possible, to make it easier to fill/empty/clean.

  • Round bottom flask 500 mL 29/32 €0
  • Reservoir
  • 29/32 option (€68.05)
    • Clevenger apparatus 5mL 29/32 €37.76 don’t trust
    • Jacketed Dimroth condenser 300 mm E.L. 29/32 €30.29
  • 24/29 option (€69.60)
    • Adapter M29/32 F24/29 €7.33
    • Clevenger apparatus 5mL 24/29 €32.90
    • Jacketed Dimroth condenser 300 mm E.L. 24/29 €29.37
  • 24/29 option with thermometer adapter (€80.86)
    • Y adapter M29/32 2*F24/29 €14.80
    • Thermometer adapter 24/40 €3.79 (probably fits)
    • Clevenger apparatus 5mL 24/29 €32.90
    • Jacketed Dimroth condenser 300 mm E.L. 24/29 €29.37

Things to figure out

  • Can a Clevenger device even be used with steam distillation (refluxing through the biomass flask)?
    • Yes, e.g. 1 2 3
  • How on earth am I going to clamp such a tall installation
  • Do I want to use my jacketed column? Perhaps upside down, but how would I connect the little screw adapter into the 24/29 Clevenger? Maybe just get the cheaper shorter 200 mm Dimroth for €21.27?
  • Could I perhaps use my condenser as part of a DIY Clevenger? It has an extra port at the bottom. Would need to improvise a stopcock at the spout. This would make for a much less tall setup; it would sit next to the boiling flask / biomass vessel stack, with hydrosol overflow going up diagonally back into the boiling flask or biomass flask. Would need some sort of splitter adapter there, a hydrosol hose, a lid for my reactor (biomass) vessel, possibly an insulated metal pipe from the vessel to the condenser.. Maybe if I want a big volume, I should just hook up the Clevenger & Dimroth to a pressure cooker or other metal pot.
  • Do I need to put some sort of restriction at the top of the Dimroth condenser to limit flow/vapor loss?
  • Would a Vigreux column do something? I’m already refluxing

Option 3c

Ok I’ve decided I want the 5mL graduated 24/29 Clevenger and a Dimroth on top of it, but I think I can get away with a shorter 200mm one because of the low heating power and high efficiency of the condenser. I can ramp up the coolant pump if needed, or just add another condenser on top if it turns out to be too short.

Total: €109.80 (dual with stopper) or €107.37 (single, no stopper)

Option 3d

What would a 2L biomass flask cost?

Total: €126.56

Option 3e

What about the one with a bigger mouth?

  • Round bottom flask 500 mL 24/29 €12.84
  • Biomass flask: 2000 mL round 50/40 & 24/40 €49.24
  • Adapter M50/40 F24/29 €14.45
  • Clevenger apparatus 5 mL 24/29 €32.90
  • Dimroth condenser 200 mm 24/29 €21.27

Total: €130.70

Things to figure out

  • Will my 200W heater provide enough heat for a 2 L biomass flask?
    • 500 g plant material: 1 kW for 4.5 h, 6 kg of water -> 200W can do 100 g?
    • ~1 kWh/kg -> at 4.5 h, 200 W can do ~1 kg?
    • ~1.9 kWh/kg -> at 4.5 h, 200 W can do ~500 g?
    • 0.3-4.0 kWh/kg, best results at 1.2-4.0 kWh/kg -> at 4.5 h, 200 W can do ~250-750 g?
    • 250 g per liter biomass
    • Ergo, 200W might just keep up with 500 g / 2 L flask? Otherwise, just run for longer?
  • Will my 500 mL boiling flask provide enough water for the process?
    • Fill to max 50%
    • Water is refluxed
    • 2.8 L/kg -> water must be refluxed at least 6 times
    • If not enough, just add through condenser? And pre-wet biomass?
  • Do I want to spend the extra €20 on a flask twice the size?
  • Do I want to spend €100+ on new glassware when I already have used stuff? It might be toxic and I’d have to figure out connections, especially both sides of the 1.8L reactor that has no lid.. The condenser I could probably figure out now that I know the screw connections. I still want a Clevenger in any case.
  • Microwave assisted extraction or microwave pretreatment

What I have bought

I’ve bought a Clevenger (5mL graduated, 24/29 connections).

I’ll try to connect everything I already have up first. But none of those things are made to connect. There are 4 places that I’d like to be mostly “steam tight”:

  • 500 mL round bottom flask to biomass flask: 29/32 ground glass to glass hose connection. Maybe drill out a rubber stopper?
  • Biomass flask to biomass flask lid: custom clamp? Or maybe make a new lid from stainless steel or old pot lid?
  • Biomass flask lid to Clevenger: GL25 (or was it GL32?) screw connection to 24/29 ground glass – maybe a 24/29 to hose adapter, and then stick it in a screw cap with teflon ring?
  • Clevenger to condenser: put the glass hose connection of the condenser into a drilled out 24/29 rubber stopper again?

To be continued.

Fun with candle wax

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I played around with some recycled candle wax bits. I had some cheeky silicone moulds as well as a candle stick mould that I hadn’t used before, and I tried some simple toilet roll candles too.

I’ve made “dipped” candles before, but never poured ones. Couple of things I learned:

  • I probably need to put some holes in the silicone moulds for the wicks. Just putting them down into the bottom doesn’t work – the wicks float.
  • The candle stick mould with a hole for the wick leaked all the wax out on the first try. On the second try I put a few knots in the wick to close the hole, but it made it hard to get the candle out of the mould. Apparently you can use something like clay to plug the hole (see below).
  • Best pour hot into a thick-walled mould, or pre-heat the silicone, to prevent cracks at the surface where the wax instantly hardens.
  • Pour slow to fill all the details and prevent hollowing out?
  • Big candles take a while to cool down. Wait several hours before unmoulding.
  • I should take more care to centre the wicks.. and think ahead and have what I need on hand. Maybe clothes pegs?
  • Putting some essential oils in is nice.
    • Edit: but only a little bit. I added way too much

Hydroponic fertiliser mistake

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Our lab threw out some surplus potassium phosphate, so I used it to formulate hydroponic fertiliser. That was a mistake. I forgot that potassium phosphate with calcium nitrate gives insoluble calcium phosphate, which happily proceeded to precipitate. I also added some other stuff that may or may not have precipitated out, so I can’t even save the stuff by filtering out the solids and making it into a two-part fertiliser, because I wouldn’t know for sure the composition.

I do have urea phosphate, which does not react with calcium nitrate. Urea-N isn’t as good for growth as nitrate-N on its own, but at least 20% of total N can be replaced by urea without negative effect. My previous formulation using urea phosphate worked great, even though it was more diluted than it needed to be and it had some pre-mixed dry fertiliser in it. It got some algae or something in it, not much of a problem but if it were concentrated enough I think that shouldn’t have happened.

Goals:

  • Concentrated 1-part fertiliser, preferably 500:1 or even 1000:1
  • Nutrient composition suitable for leafy aroids, taking into account local tap water composition
  • Acid enough to bring down tap water pH to ~6 without extra acids
  • Ammonia-to-nitrate ratio that keeps pH relatively stable in semi-hydroponics even if all water is taken up, e.g. 3:7 or 4:6 – even if this is not ideal for growth rate
  • Preferably formulated from simple salts, no mixes or acids. Mixed trace nutrients are ok

I took nutrient compositions from literature and from commercial products, I downloaded the latest local tap water composition report, and looked up properties of various possible ingredients. I put everything into a big spreadsheet, set up goal values based on requirements, and used a DEPS evolutionary algorithm solver to optimise for the above list. This is also what I did for my earlier formulation, this time I just forgot to check if the resulting ingredients were compatible.

Newest formulation to test: urea phosphate, calcium nitrate, potassium nitrate, magnesium nitrate, ammonium sulfate, trace elements. Starting with 250 mL 500:1, and will try more or less diluted depending on how that goes.

I’m a little worried about forming calcium sulfate, but at low pH (from the urea phosphate) I think it could work? Actually, I should calculate the amount of calcium sulfate that could be formed, and compare it to the solubility. Solubility is about 0.24 wt% at room temperature. At pH=2.5 solubility is only improved by +12%, although high salt level can improve solubility by about 3x. Even in pure HCl you can only get 1.8 wt% calcium sulfate in solution. I guess I could use a chelator like EDTA to keep more in solution if needed (about 4%), but that’s an expensive way to go. Maybe this is why the commercial 1-part formulations don’t have much sulfur and/or calcium, except perhaps Liquid Gold Leaf which I think has a chelator.

Actually EDTA isn’t all that expensive. I should research that.

Or maybe I should just accept a lower ammonium/calcium/sulfate concentration to get a more concentrated 1-part fertiliser, or keep with my low concentration fertiliser.

Glassware drying rack

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I want a drying rack for my home chemistry glassware, for drying & storing.

Maybe something modular, so I can expand my glassware collection later?

Perhaps incorporate a drip tray?

I have round wooden rods, I think 13mm and 8mm diameter, that would make nice pegs.

Maybe first find some wall space to hang it. Right now I only have space behind a door, but obviously I don’t want to smash fragile glassware every time I open the door.

Edit: lab was throwing one out, post here.

Plant shelf for lab office

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I want more plants in our lab office, but I don’t want to clutter my desk too much. I’ve already found a way to suspend some plants from the ceiling, but I also want to reuse some old / damaged lab glassware as planters and I don’t want to hang those.

My desk is in a corner with two windows overseeing the lab. Both windows have a small ledge, so I’m thinking of putting a shelf onto them. I could make it mostly out of reused wood from the lab, e.g. wood that was used for shipping some of our machines.

I think the weight on top will keep everything in place, but I want to secure the thing to be sure. I don’t think I’ll be allowed to drill into the window frames. I guess I could wedge something between the frame on the long side, so the shelf can’t move. Maybe I can use bolts in T-nuts to push into the steel frames on both sides and wedge it that way? Or perhaps a very strong magnet on both ends to make sure the thing doesn’t slide off?

Overhead stirrer

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Another fun project idea: making a DIY overhead stirrer. Something like this but simpler.

I think I already have a suitable 12VDC reduction motor somewhere, and I have spare adjustable DC power supplies (12V 2A and 12V 5A) that I could use to control the speed. I would need a chuck and something to attach the motor to my lab stand. Also, a stirrer attachment.

I can’t find my big gear motors right now, but I do have a cute little 6V 30 rpm one and a 24V 18 rpm one. Plenty of torque, but slow and I think they’re only about 3W continuous.

Ideal would be something like the one in the video, which is the larger ~15W continuous cousin of my mini reduction motors. I guess the 470 rpm one would be nice. I could easily attach a drill chuck to the 8mm shaft using a JT0/B10/B12 connecting adapter, then I don’t have to fabricate anything like the guy in the video did. I think B12 is the right size if I mainly want to use it with 6mm and 8mm stirrer attachments. Either that, or an M10 adapter with an M10 chuck.

I’m going with the M10 option. It has better reviews, it’s not missing the set screws and I like the chuck better.

For attachment, I think I will go with the very simplest option first: just clamp it to the lab stand with a lab clamp straight onto the motor. The motor would be facing sideways but that doesn’t matter. If I like the setup, I might find a better solution. Perhaps a piece of 12mm rod with two hose clamps or something.

I’ve ordered a reduction motor, M10 connector, 1.5-10mm drill chuck and stainless paddle stirrer for €25. That should be everything I need, besides the stand, clamp and adjustable power supply I already have.

Hormones

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I want to play with plant hormones. See what their effect is on growth patterns of houseplants. I specifically want to see if I can prevent epiphytic aroids from reverting to a more juvenile form when growing downwards instead of up something.

I already did some literature research. I also found this page, I want to read it with some healthy scepticism because biodynamics. But first, other projects.

Conditioner with L-arginine

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I’ve ordered some L-Arginine HCl for testing.

As a first test, I added 4 grams of it to 46 grams of store-bought SAPDMA-based conditioner. So about 8% L-Arginine HCl or 6.6% L-Arginine. The change in viscosity was immediate, it got so thick I could barely stir it. I applied it to my hair as I normally do, about 15 grams spread using a wet detangling brush on wet hair, and leaving it in.

Compared to the same conditioner without the Arginine, I feel it works a little worse as a wet detangler because of how thick it is. However, it does seem to work otherwise as intended – my curls appear stronger and more defined, without the gloss that some other products give to my hair. If I add more of the stuff to my hair, it works like hair gel, but less glossy/oily.

I will continue to test it for a few more washes, also see if I can apply it just dissolved in water as a hair mask. I want to understand better what it does before I start formulating with it.

Idea: extracting volatile oils

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I’ve saved some lab ware and equipment from the dumpster. I wonder if I can use some of it to make a distillation setup for essential oils.

Some things I want to try extracting oil from:

  • Banana peel
  • Mandarine peel
  • Ginger
  • Cherry tree petals
  • Rhododendron petals
  • Monarda didyma
  • Mentha aquatica
  • Pine/fir/spruce needles
  • Green walnut peel

I could start with putting the material straight into my 500mL round bottom flask, which is incidentally the largest still size I can use legally. However it would only fit about 250mL, so adding a biomass chamber with it would be very nice. It would be great if I could somehow use my ~1.8L reactor, it is the perfect shape, however it is missing a lid. I think my jacketed chromatography column could make a decent condenser. However none of them have matching glass fittings..

Thinking of buying a oil/hydrosol separator, or a Clevenger apparatus, to separate and reintroduce the hydrosol to the boiling flask.

Lots of things to figure out still.