Acetal Copolymer or Delrin

[cspyy]

i just made a big order from them and got some 3/8" and 1/4" delrin rod. well i got it in and its brown. the type i ordered is only offered in opaque brown.

so im going to order some more stuff and found the black except that there are two types: acetal copolymer and delrin.

*this is off of mcmaster carr.
Length48" | 5' Acetal MaterialAcetal Copolymer: Less porous and absorbs less moisture than Delrin, so it retains its shape better in humid environments. It is also wear resistant and offers excellent chemical resistance.
Delrin: This material combines strength with good chemical resistance. It has low moisture absorption.

delrin has a better operating temp @ -40*F/+185*F
acetal is +32*F/+132*F


their description makes acetal copolymer sound better but the operating ranges are not. Plus they are both the same price @ $0.82 ft.

which would be better for links?

 

[Ced RC]

I would stick with the Delrin, it is also an Acetal based resin, so it probably has a similar chemical composition as the other stuff you mention, but considering that acetal copolymer has a minimum operating temp of 32, that tells me it probably becomes brittle at the lower temps. Delrin was developed by DuPont way back when, they were trying to make a light weight material to use in place of metal.

 

[Offroader5]

Here's an excerpt of mine I pulled from my Widow WK build.....

"Well, there really is not a "fake" Delrin. It's all acetal, Delrin is just a trade name for the Dupont version of acetal. The difference between acetals' themselves is that they can be a homopolymer or a copolymer.

Delrin brand is a homopolymer, which gives slightly higher impact & tensile strength, is harder than the copolymers which means less coefficient of friction, and it can handle more heat. Other brands like Ultraform and Celcon are copolymers which have better stability...meaning they expand and contract less.

Then there's the blended acetals like Techaform which is impregnated with PTFE (Teflon).

So, in the capacity of using it to build RC chassis and other small fab parts associated with them, it's not really going to matter if you get the "non Delrin" acetal...especially since the actual difference between the homo and co polymers is only like 10%.

I feel like such a nerd....I think I have done wayyy too much research on acetal"

 

[TIMZKRAWLER]

that's an excellent explanation ...thanks ...i learned something today

 

[chip cross]

Here's an excerpt of mine I pulled from my Widow WK build.....

"Well, there really is not a "fake" Delrin. It's all acetal, Delrin is just a trade name for the Dupont version of acetal. The difference between acetals' themselves is that they can be a homopolymer or a copolymer.

Delrin brand is a homopolymer, which gives slightly higher impact & tensile strength, is harder than the copolymers which means less coefficient of friction, and it can handle more heat. Other brands like Ultraform and Celcon are copolymers which have better stability...meaning they expand and contract less.

Then there's the blended acetals like Techaform which is impregnated with PTFE (Teflon).

So, in the capacity of using it to build RC chassis and other small fab parts associated with them, it's not really going to matter if you get the "non Delrin" acetal...especially since the actual difference between the homo and co polymers is only like 10%.

I feel like such a nerd....I think I have done wayyy too much research on acetal"

I work at a Dupont plant and didn't know that.:lol:

 

[cspyy]

thats good, i think im just gonna go with delrin since it handles the cold temps better and its the same price.

thanks for the response and good info 8)

 

[Yawzer]

I've been ordering delrin and other rod from "www.indplastic.com" - they have every size imaginable - both rod and sheet and send it right away - check them out.

 

[David H]

Has anyone used delrin to make there own chassis? Following a guideline of a popular chassis, like the NN, with any success?

 

[Offroader5]

Has anyone used delrin to make there own chassis? Following a guideline of a popular chassis, like the NN, with any success?

I used 3/16" thick black acetal to make the prototype Widow chassis. Holds up great and is easy to work with.

 

[toy4crawlin]

As much as I like details those details are Worthless

Acetel Flex's A LOT
Delrin is stiffer, almost like aluminum

I'm using Delrin

 

[Offroader5]

As much as I like details those details are Worthless

Acetel Flex's A LOT

Those details are the facts...plain and simple.

And no acetal does not flex A LOT. I have both copolymer acetal and Delrin brand acetal here in like thicknesses in sheet form, tube form, and solid rod form and the difference between them in stiffness and flexural strength is hardly noticeable along short distances like skid plates, chassis plates, short links, etc.

I agree that the homopolymer (Delrin among others) is a bit more rigid and does have added strength over the copolymers, but it's not like it's a huge night and day difference....especially in the capacity of building RC parts/chassis.

If you'll be buying 1/4" solid rod to make links that are 6 to 8 inches long...then yes, buy the Delrin, it will be more stiff along the length of that thinner material. Why you'd use that small a diameter for that long of a link, I don't know...but it was just an example.

On the other hand, if you buy 5/16" or larger to make links that are only 3 to 5 inches long, then why does it matter if the material is more stiff....the link isn't long enough to be affected much by flexing.

Really the bottom line here is, if you want to play it safe in strength and the cost is the same, then buy the Delrin (homopolymer)...but usually the homopolymers are a bit more expensive then the copolymers.

Just my 4 cents....