After milling quite a stack of parts out of a 4kg Sheet of Delrin, I still have 3kg of Delrin left over, only now it is mostly saw dust. Since this stuff costs over 15 Euros per kg, I was wondering if I can melt it and form it back into a new sheet. It is a thermoplast after all, right?
Any experiences? Any suggestions?
If your going to try and melt it do it outside. Aparently the noxious smell is not harmfull, but it will empty a room as quick as tear gas. Control of temperature is important -it only smells nasty when it gets too hot. Burn a couple of bits of swarf with a cigarette lighter and you'll get the idea of how bad it smells.
Regards
Kevin
Its Formaldehyde gas, and the effects are pretty much identical to tear gas, as Kevin said. Its highly flammable too, so a bit of care would not go amiss. A bucket of water to quench a burning lump of delrin into is highly recommended.
The melting range for it will be somewhere in the region of 170-200 degrees C, and you won't degrade it at these temps, but if you go much above 210> or it starts to look like caramelised sugar then hold your breath and put it in the water.
Peter
Thanks for those two great mails. I will be very careful and control the temperature. I don't want to ruin my "black gold" or my health ;-D
DONT do it!! I have worked in plastics for over 20 years, as someone has already said the gas is formaldehyde and very powerful and toxic! Delrin is a trade name for Acetal, the material is also known by at least 3 scientific names (polyformaldehyde, polyacetal and polyoxymethaline) When it burns it gives of a blue flame and not much gas, but when the flame is extinguished the resulting surge of gas may render you unconscious! Many times i have needed to identify a polymer and usually set a tiny piece alight on the end of a knife blade etc which is then sniffed, each polymer type has a unique odour. Even a tiny fragment of acetal will bring a rush of tears and have you gasping for breath. Try this with a TINY sample and you will see what i mean. It should only be melted in a confined space i.e. a moulding machine or extruder barrel.
Regards, Pete
Matthias Melcher wrote:
I was in a moulding shop where acetal has been used to purge the barrel and then left overnight, the next morning when the barrel heaters were turned on the effect was severe watering of the eyes and burning down the throat. The department was cleared for quite a while whilst the extraction system purged the room. Not nice at all.
Mart> DONT do it!! I have worked in plastics for over 20 years, as someone
Now, guys, you start to scare me. Can I use Delrin in a consumer product at all under these circumstances, or do I need to switch to a less dangerous plastic? I use this to create modified enclosures for R/C servos. My clients are hobbyists... .
Under the controlled conditions of a moulding machine where temperatures and cooling etc are at the correct limits you have no problems but when you over cook the material and allow it to gas off thats the problem.
Mart> Camp>> I was in a moulding shop where acetal has been used to purge the
Hello again,
Acetal is very stable and not toxic when in its natural COLD state. I well remember moulding the internal parts for Soda Stream fizzy drink makers from it. You customers are under no danger, unless one of their models busts into flames ;-) but then the fuel tanks are much more of a concern i would suggest! Acetal is also used for gear sets and a bearing material because of its natural oily/saopy feel. It is used in thousands of everyday items.
Pete
Matthias Melcher wrote:
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