BillStephenson
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Joined: Thu May 17, 2012 1:25 am
Location: SW Missouri Ozarks
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Re: Case made from milk-bottle tops

Wed Dec 03, 2014 8:51 pm

linwiz wrote:This is where I got the idea from, and his method seems to work great. I would need to have a different mold than the one he used, one that creates a hollow box the pi can fit into and one to make the lid.
http://www.instructables.com/id/How-To- ... -Easy-Way/

That's pretty cool. Should be able to machine that into something nice. I've done some vacuum forming of sheet plastics. You can do this in your home workshop too. Here's a video of a homemade machine and how to make a part:

https://www.youtube.com/watch?v=J5cvZ0kUBn0

I watched several of these videos, most who tried this had varying degrees of success. When we did this we used smaller holes and many more of them than shown in this video, and we drilled holes in the base to draw air where we needed it to form the part nicely. We also drilled holes in the mold itself if needed to prevent warps and wrinkles and to provide finer detail in the part. Some of those were very tiny, maybe 1/32". And, of course, you need to build your mold in a way that the part doesn't lock itself around it.

One can make some pretty nice custom cases for a Pi using this method.

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aTao
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Joined: Wed Dec 12, 2012 10:41 am
Location: Howlin Eigg

Re: Case made from milk-bottle tops

Wed Dec 03, 2014 9:40 pm

AFAIK HDPE must be bone dry with no (or very little) atmospheric moisture about when it is re-melted otherwise you end up with some new plastic that will not re-melt.

On the other hand, if you put it in a container with only a pipe put at the top and heat it to 350 C the gasses that come off are LPG and diesel. Use a still to recover the diesel and use the LPG to heat the process. You can get yield of up to 1 litre per kilo. HDPE produces almost no other chemicals whereas PVC will release chlorine so do not do it indoors.
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