material testing 

We're currently trying to choose the material for the sides of the akkupack project, and due to laser-cutting Aluminium being not quite expensive, but still costing a considerable amount, we're looking at alternatives.

Acrylic would be one suitable candidate, though the brand-name acrylic costs around 40€/m².

I still have some Kraftplex (pressed cellulose fiber) around and we did some very unscientific stress testing on that. It unfortunately doesn't quite make UL94.


material testing 

yes, yes. I know that UL94 is for plastics but anyways, a fun experiment.

After working it with a blow torch for I think close to a minute, it burned for a little less than two minutes and was glowing a few more minutes after that too.

Though the only affected area was the one we directly held the flame to and it didn't spread one bit further.

I think that's good enough. Oh and seeing that UL94 specifies a 50W flame, and we took like >1kW to it, we need further testing.

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material testing 

In the end it might not even be flammable at all under the standard conditions.

The only worry i still have is, that it's technically deformable with water, but just soaking it for a minute did not yield any meaningful results on the 3mm thick sample, so it might just be that this won't be a concern either.

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material testing 

@ln FR4 is not an option? Iirc there is FR4 up to 2mm available (iirc mainly for microwave designs)

@datacop @ln FR4 in this size would cost more than laser-cut aluminium

material testing 

@datacop i mean sure, but i can't laser cut it and i don't want to mill it either (FR4 dust is *nasty*). also FR4 plates are readily available but still quite expensive. And after quickly checking double the cost of acrylic it seems :(

It's really just for the housing parts of the mechanical design. Oh and Kraftplex is carbon-neutral and very easily recyclable, so there's that too ;)

material testing 

@ln full ack, basic idea was full fr4 manufacturing including silkscreen is quite easy, as long as you don't want to do it yourself. But it's definitely not the best and sustainable material.

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