Any question answered...

@NorthLondonLight and myself first visited at about Mile70 of an Imperial Hundred.
Was Summer though.

I bought a laser cutter at the weekend! Thanks for the warnings. The leather I'll be cutting is scrap from old biker gear. I think (hope) that it's all veg-tanned. After cutting it I'll be painting it, which will cover the scorched edges and perhaps deal with the smell. I need to set up the laser so the edges don't get burnt badly enough to crumble afterwards. From what I've read it's not hard. People seem to manage it. Perhaps the answer is to do multiple passes on low power.

Having said all that, if i was just cutting, a machine with a blade would be the thing. No smoke or burning. To justify the laser I'll have to do some engraving. I always go too with a new project. Maybe I'll end up selling the laser in disgust and buying a Silhouette.

Dull question. Any suggestions for sturdy plastic boxes of various sizes that don't cost a huge amount? I need something that can slide around in the back of a van all day without getting mangled.

maybe these?

Have a poke around the back a big supermarket and/or Royal Mail sorting office.

^^ +1 for euro crates - and as Scilly says, RM totes are good

Really Useful Boxes all day long.

https://www.reallyusefulstorageboxes.co.uk/

I'm already wearing a t-shirt

Yes, I gathered that, I just thought changing your shirt would probably be the optimal solution.

I always thought they were just transparent euro crates? Are they better?

In what concentration (gram/liter) would I need to dissolve the granules to get a good result?

Since I have a local anodising shop, for whom stripping existing anodising before refinishing is a normal line of business, I've never even contemplated how to do it at home 🙂

Internet opinion is that it can be done with NaOH but that's not how pros do it because NaOH actually dissolves the metal better than it does the eloxiert coating. The professional method involves hexavalent chromium, which we've already been warned about once today, so you definitely don't want to try that at home.

Brief (30s-1min) immersion in a 10% (100g NaOH per litre) solution is suggested as a successful recipe. Bear in mind that this is a very caustic solution (pH>13) which will also strip flesh, so be careful. Keep a lot of plain water on hand to rinse both the cycle parts and any rapidly disappearing body parts.

I'd worry slightly about the steel/aluminium interface as it will be difficult to clean properly to stop the reaction. The GXP axle is only pressed into the driveside crank, so it's probably going to suck your caustic solution into the gaps by capillary action. If you do decide to proceed, think about how you're going to prevent that with some sort of compatible sealant, from both sides.

I've got a glass jar with a disposable glove and elastic band acting as a makeshift lid. Contains a clear liquid. It's labelled ACID.

What's the quickest yet somewhat safest way to determine what it is?

Read the label.

Ingest, if you trip it's a bonus, what's the worst than can happen?

Terrifying chemical disasters thread >>>>>>>

Terrifying chemical […]

Can’t resist linking to Ignition!, a great read about terrifying (rocket propellant) chemicals

Oh, amazing, will have a read!

Start with your nose:
-eggy/sulphury = sulphuric acid
-vinegary = vinegar
-soapy/detergent = HF

That probably just leaves nitric and hydrochloric as your common acids you’re going to find. Chuck some copper in it. If you get bubbles, it’s nitric, if not it’s hydrochloric or a fruit acid.

Next you’re gonna want some sodium hydroxide drain cleaner from the plumbers merchants. Obvs watch out because this stuff also dissolves skin, mdcc_tester covered this earlier. Neutralise the acid with it and have a taste. Salty? Hydrochloric. Not salty but poisons you? Probably one of the fruit acids.

Foolproof method. Literally nothing can go wrong.

How complicated is the shape and how accurate do you need to be?
You can have custom leather cutter stamp things made. They look like a cookie cutter but obviously more robust.
Try https://www.cactusleatherlondon.com/our-services

I thought the range covered a bit more than euro crate sizes. Did you have a look at the link?

A cursory one before. A better one now. I see what you mean. Useful ;)

Many thanks for the elaborate answer!

Seems a lot less straightforward and more dangerous then the interwebz "chuck it in chemical solution X, watch anodising bubble off, rinse, rub, rinse, result."

I'll resort to the plain old mechanical solution of elbow grease and wetndry so I will probably end up with more flesh (callus) then less (stumpy fingers) which is my preferred alternative.

Has the political officer finally locked the Gravel thread because of the many transgressions?

#freethegravelthread

It has been released! Let one hundred flowers bloom.

I've removed the anodising from quite a few things over the years.
Most recently these cranks - https://www.lfgss.com/comments/15683861/

I used caustic soda crystals. Start small with a teaspoonful in about 250ml of water, the reaction starts quite quickly. I used a small brush to daub it onto the cranks and let it sit for 30ish seconds, rinse it off and repeat until all the anodising is gone.
Experiment with different strength solutions, I've done it a good few times and feel comfortable using a stronger solution than above that has the anodising run off almost instantly. Obviously you don't want to dissolve any parts, so rinse frequently.

Do it somewhere well ventilated, it gives off some pungent fumes. I usually do it in the kitchen by the open back door.
It's not that scary, just takes a bit of trial and error. If your cranks disappear then you know you've done it wrong.