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How to make your own Delrin

Barry

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Nov 9, 2014
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shropshire
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Barry
To make your own delrin round square or flat
you need a metal dish a burner or stove when the boss is out
Plastic milk bottles with HDPE triangle with No 2 stamp
A wax candle
Break the candle in to the pot and melt next cut the plastic and add as much as you can get in and keep stirring keep adding the plastic it will go thick and keep adding the plastic have your moulds ready tubes or squares pour and leave to set
because you used wax you can use as moulds for resin and it will not stick and you can put it on the lathe and turn to knobs try it
 

paulm

grave manibus faciendum
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Sandford
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Paul
Barry, are you trying to get me in trouble with the CMM? I'm going to have to have a go... thanks :thumbs:
 

bellringer

The Young one
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Surrey
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Alex
Delrin is not hdpe delrin is nylon it is a trade mark name of DuPont it acetal it a form of nylon the two of them are slightly different


Sent from my iPad using Tapatalk
 

Lons

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Alex is "mostly" right!

Melting HDPE with wax will not make it into Delrin, which as Alex says is just a trade name, it will still be HDPE. Delrin is basically Acetal though there can be minor chemical differences between brands.

Acetal is a much better engineering plasic than HDPE with different properties. Both can be machined easily but Acetal is harder than HDPE and can be machined like soft metal to close tollerances so often used for gears and fixings. If anyone is throwing away an old WC cistern, the hard plastic fittings are often acetal for example and sometimes useful material to keep.

HDPE is a prefered plastic in the food industry for containers due to its' light weight, acetal is about a third heavier, its' flexibility v strength and low water absorpsion which is why it's used to make milk bottles. From memory BTW HDPE is very resistant to glues and therefore would make excellent cones and bushes without the need to mix with wax. Acetal is more hard wearing and lasts longer but not really a problem if you're making your own.

That's from memory so hopefully is accurate :thinks: but I still have some spec sheets somewhere from my time in the plastics industry. Strange how I can remember the detail but have no idea where I put the literature, Must be early onslaught I guess. :nooidea:

Edit: Delrin / acetal is not nylon either! Nylon has very different properties and can be more difficult to machine accurately however a major difference is that it is hydroscopic and absorbs moisture which makes it dimensionably unstable. (still ok for cones though).
 
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Penpal

Grand Master
Joined
May 26, 2013
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Location
Canberra AUSTRALIA
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Peter
Its cheap and available and quick to access over here so I prefer to buy in handy shapes ready to go anytime. Just my take have fun.

Peter.:thumbs::thumbs:
 

TK woodman

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May 12, 2014
Posts
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halifax
First Name
Tony
I believe HDPE gives off toxic fumes when heated over 170 c - so I would never heat it on a stove
 

Lons

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Bob
I believe HDPE gives off toxic fumes when heated over 170 c - so I would never heat it on a stove

Where did you read that Tony? I'd be interested to know as it contradicts my knowledge of HDPE properties.

HDPE is porobably one of the safest plastics out in general use and though all plastics will leach fumes when heated (PVC is probably one of the worst), you would have to heat HDPE to at least 200c and even then it's doubtful it would be an issue.
From memory, it doesn't really melt at the temps we would use, it just goes sort of jelly like when it can be compressed and sticks to itself. Burning any plastic materials however constitutes a potential hazard. I haven't tried yet as I'm still collecting milk bottle tops, but have no concerns about heating it to make pen blanks.

It's a long time since my 10 years in the plastics distribution industry and I've forgotten much of my product knowledge but this has stirred my interest enough to do some research. My opinion as above is based on that and will likely be outdated but I doubt very much if the basic product chemistry has changed.

I think the biggest problem for most people seeking information is that unqualified "experts", especially on youtube state something as if it was a fact and it's just accepted as accurate.
 

TK woodman

Graduate Member
Joined
May 12, 2014
Posts
500
Location
halifax
First Name
Tony
Where did you read that Tony? I'd be interested to know as it contradicts my knowledge of HDPE properties.

HDPE is porobably one of the safest plastics out in general use and though all plastics will leach fumes when heated (PVC is probably one of the worst), you would have to heat HDPE to at least 200c and even then it's doubtful it would be an issue.
From memory, it doesn't really melt at the temps we would use, it just goes sort of jelly like when it can be compressed and sticks to itself. Burning any plastic materials however constitutes a potential hazard. I haven't tried yet as I'm still collecting milk bottle tops, but have no concerns about heating it to make pen blanks.

It's a long time since my 10 years in the plastics distribution industry and I've forgotten much of my product knowledge but this has stirred my interest enough to do some research. My opinion as above is based on that and will likely be outdated but I doubt very much if the basic product chemistry has changed.

I think the biggest problem for most people seeking information is that unqualified "experts", especially on youtube state something as if it was a fact and it's just accepted as accurate.

I think it was something i was told through H&S at work years ago and just took on board - I've never melted HDPE or researched it but it would be interesting to know if I was give correct infomation
 

Lons

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I can't edit my last post as more than 15 minutes but this is what I tried to add.

Just done a quick google 'cos I have to go out. The contradictory info out there is eye opening but there are credible reports which I intend to look at when I get time. For anyone interested, here are a few links though one of them looks solely at the release of estrogenic chemicals.

http://msdssearch.dow.com/Published...fety/pdfs/noreg/233-00577.pdf&fromPage=GetDoc
Identifying Poisonous Plastics
How To Recognize the Plastics That Are Hazardous To Your Health
http://www-tc.pbs.org/strangedays/pdf/StrangeDaysSmartPlasticsGuide.pdf
 
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Lons

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Northumberland
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Bob
I think it was something i was told through H&S at work years ago and just took on board - I've never melted HDPE or researched it but it would be interesting to know if I was give correct infomation

Makes sense Tony.

It's 20 years since I was in the industry and employers generally played safe and declared all plastics hazardous, usually because they couldn't be bothered to research the products. I spent much of my time "educating" architects and end users to order the correct material for specific projects.
 
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