Comments on RepRap: Blog: Polymorph and polycaprolactone

I've observed HDPE going yellow on the surface whe...

2005-12-13T15:20:48.206Z

I've observed HDPE going yellow on the surface when it was overheated. I took the colouring to be oxidation.

If the plan is to populate the world with RepRap m...

2005-12-13T14:37:15.736Z

If the plan is to populate the world with RepRap machines, we'd better consider the recycling of polymorph to be right up there on the priority list or else the amount of landfill consumed by RepRapped goods could easily exceed plastic waste from all other sources!

If the machine did indeed have a high precision nozzle which required clean polymorph - and a bulk fill nozzle that could take recycled stock (possibly including metallized stuff) - then the issue of recycling metallized parts would also be reduced because you could always lay down a thin 'guaranteed clean' insulating layer of fresh polymorph from the high precision nozzle before laying down fresh metallized tracks.

The bugbear is little particles of non-plastic cru...

2005-12-13T01:56:41.423Z

The bugbear is little particles of non-plastic crud in the recycled stuff clogging the nozzle of your extruder. It's bad enough keeping 'em out with new plastic granules.

Mind you, if we're using a large deposition nozzle for bulk filling or moulding, we can tolerate more impurities.

I've reused Polymorph a lot and it goes "Old Underwear" grey but retains plasticity. One batch went yellow. Not underwear - Polymorph.

Vik :v)

My own experience in working with polyethylene sug...

2005-12-10T15:00:43.756Z

My own experience in working with polyethylene suggests that you will lose some of your polymer to oxidation. Much of that oxidation might be curbed with more careful heating processes than I had, though.

As well, I expect that painting conducting strips onto parts will present some problems in segregating polymer and conducting material in the recycling process.

So after you lose interest in something you made, ...

2005-12-10T13:35:55.196Z

So after you lose interest in something you made, you can just re-melt it back into feedstock.

If that works well, a 20km sack could last almost indefinitely...presuming you are making things of a disposable nature and that they remain clean enough to produce a sufficiently unpolluted feedstock.

Should be.

2005-12-10T04:05:07.956Z

Should be.

This stuff is recyclable though - right?

2005-12-08T23:32:27.333Z

This stuff is recyclable though - right?

I think that polycaprolactone, polymorph and frien...

2005-12-07T17:48:25.486Z

I think that polycaprolactone, polymorph and friendly plastic are all essentially the same thing, despite slight differences in the FTIR shown on the wiki. We sincerely hope that 25 kg would run a RepRap machine for quite a while, including making several other machines...

Okay Adrian, reading your twiki on CAPA 6800 I und...

2005-12-07T15:37:00.310Z

Okay Adrian, reading your twiki on CAPA 6800 I understand that this is the material you want to unify work on for this iteration of the project. If that's not so I need to know.

I talked to Solvay's US agent in Houston just now and he is sending me a 5 kg sample. That should last me a while if I'm careful.

Jeff Neidinger in Houston gave me a price range of $5.30-3.50/lb for CAPA 6800. That means that a single, 20 kg sack will cost something like $234. That's a bit steep compared to something like polypropylene, but not outrageous.

This looks like a really good material. :-)

I've contacted the NZ distributor and I'm attempti...

2005-12-07T01:03:20.693Z

I've contacted the NZ distributor and I'm attempting to arrange samples and bulk product at this end.

Vik :v)