Which type of delrin is best used for links and why?

[Nova's Ark]

Which delrin is best used for links and why?

Apparently there is several types of delrin. There is plain delrin, glass filled delrin, PTFE filled delrin, and acetal copolymer delrin.

Is one type more stiff than another?
Does one break easier?

In checking with McMaster-Carr they offer all the types listed and I am wondering which is best used for link material. Thank you for any help

[EeePee]

Acetal. Flexible, especially at longer lengths (like 6 foot), but when made in to a shorter link length they are quite stiff, but will flex when forced. I know acetal can break, but I've seen links bent almost in half and spring back without an issue many times. Not lying.

The key is to get the right diameter to match the stiffness required for the length you're using.

[Nova's Ark]

All of the delrin listed are made from Acetal so it does not get specific enough. I called McMaster-Carr today and they recommend the plain black delrin rod such as this:

http://www.mcmaster.com/#8576k13/=2rdyr2

However, this delrin seems much more flexible than the previous delrin links I had bought pre built from a member here on RCC.

Also, in JeepinDoug drill bushing thread, he is recommending using the acetal copolymer delrin:
Link Drill Bushing


That is why I am asking which one is best and why.

[Offroader5]

First off...you have it backwards. Acetal can be Delrin...but not all acetal is Delrin. Here's an explanation I gave in one of my build threads way back...so rather than retype it all...I'll just paste it here

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've found that at least with McMaster...you figure out first what diameter and color you want, then your choices are slimmed down automatically on what composition the product is. As an example...they may have a PTE impregnated acetal...but it may only come in a certain diameter and one color like brown or something

[Nova's Ark]

Originally Posted by Offroader5

First off...you have it backwards. Acetal can be Delrin...but not all acetal is Delrin. Here's an explanation I gave in one of my build threads way back...so rather than retype it all...I'll just paste it here

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've found that at least with McMaster...you figure out first what diameter and color you want, then your choices are slimmed down automatically on what composition the product is. As an example...they may have a PTE impregnated acetal...but it may only come in a certain diameter and one color like brown or something

Dude, that was awesome. That is exactly what I needed to know. When I called McMaster, they really didn't know and couldn't give me concrete answers and me being a newb I didn't know any better either. All I knew was that there are several different threads here on RCC in several different sections and they are linking to the McMaster-Carr website and almost every different thread linked to a different delrin rod.

So I guess it really doesn't matter what type of delrin rod you get?
They are all pretty much the same?

[EeePee]

Yeah there ya go.

Since Grainger is local to me I started here: http://www.grainger.com/Grainger/wwg...=26&submit.y=8

Looking for white and 5/16th I found this: (Edit, won't link)

Rod Stock, 150, Acetal Homopolymer, White Color, Diameter 5/16 In, Length 6 Ft, Diameter Tolerance +0.003/-0.000 In, Length Tolerance +0.125/-0.000 In, Min Temp Rating 32 Deg F, Max Temp 180 F, Tensile Strength 11,000 PSI
Grainger Item # 2XMP4
Price (ea.) $2.89
Brand DELRIN

[MTHead]

Yes, but don't be fooled by "Acetron" which is also a copolymer. There are a lot of places that try and pass that off as "Acetal". It will still work for link on a 1.9 or 2.2 but pushing it for a Super.

[Nova's Ark]

Originally Posted by MTHead

Yes, but don't be fooled by "Acetron" which is also a copolymer. There are a lot of places that try and pass that off as "Acetal". It will still work for link on a 1.9 or 2.2 but pushing it for a Super.

That is a concern of mine because I am making new links for my Super. I am assuming this is OK since it says it's acetal:
http://www.mcmaster.com/#8576k15/=2rf90b

[MTHead]

Originally Posted by Nova's Ark

That is a concern of mine because I am making new links for my Super. I am assuming this is OK since it says it's acetal:
http://www.mcmaster.com/#8576k15/=2rf90b

Yep, that's the correct stuff.

With McMaster you need to make sure you see either Homopolymer, or Delrin to get the strongest stuff, because the use the "Acetal" name for the copolymers also, that is when you'll get a stick of Acetron, been there done that...

[Lonewolf]

This whole scenerio can be said for most of the plastics world. And new ones being made up everyday. With technology as it is now they can hybrid all sorts of different composite materials. Many times rubber is added as well as different fibers... Styrene is very much in this also.
Most times it will be a general use material that may or may not have been recycled. At our company we recycle 90% of our scrap plastic.
For certain jobs where we buy black haircell styrene we buy from the same company and when he drops off we give him our scraps from the job before. Our distributer will hold all his scrap for us and remake sheets for us. They regulate how mant times thre mmaterial is recycled and how much virgin material needs to be added to matial quality specs.
This recyleing can go on for up to 4 "generations" After that it breaks down in quality and is then cycled into other less demading materials....

Yes plastic can be recyled like alum.....And sometimes will bring higher returns....per pound. Tho I would guess they would require a minimum weight...

Dave


Didnt mean to hyjack but kind of add some info on the plastics world.
Dave

[Nova's Ark]

Originally Posted by Lonewolf

Didnt mean to hyjack but kind of add some info on the plastics world.
Dave

You definitely did not hyjack the thread. Thank you for posting that useful information.

[Crawln Coles]

Originally Posted by EeePee

I've seen links bent almost in half and spring back without an issue many times. Not lying.

The key is to get the right diameter to match the stiffness required for the length you're using.

When have you seen links do that?


When I order from Mc-Master I pick the size first then I usually get the plain just because I didn't know what all that other stuff was!

Thanks for the info guys

[Lonewolf]

In many cases materials are altered to fit a need....
OK makeing a material more stiff usually but not always will make it more breakable and visa versa. With that being said there are many varients of most plastics.... Best guess is to start in the middle and go from there, unless you are privy to more info that suits your needs...

[JeepinDoug]

Originally Posted by Nova's Ark

All of the delrin listed are made from Acetal so it does not get specific enough. I called McMaster-Carr today and they recommend the plain black delrin rod such as this:

http://www.mcmaster.com/#8576k13/=2rdyr2

However, this delrin seems much more flexible than the previous delrin links I had bought pre built from a member here on RCC.

Also, in JeepinDoug drill bushing thread, he is recommending using the acetal copolymer delrin:
Link Drill Bushing


That is why I am asking which one is best and why.

McMaster-Carr's online catalog always gets me all screwed up. I corrected my thread to reflect the correct part number that I always order (order number 8576K12) for 5/16".

[tom@vp]

X2 acetal is the name of the material, delrin is a brand name of acetal. just use regular acetal or delrin, no glass fill...

Originally Posted by EeePee

Acetal. Flexible, especially at longer lengths (like 6 foot), but when made in to a shorter link length they are quite stiff, but will flex when forced. I know acetal can break, but I've seen links bent almost in half and spring back without an issue many times. Not lying.

The key is to get the right diameter to match the stiffness required for the length you're using.

[fixed13]

Wow, great thread, I learned all this stuff a while back when I ordered some Acetal for chassis and links but I would not have been able to make it understandable for others to read.

THIS SHOULD BE A STICKY!!!!!!!!

I could have used this thread back then instead of sounding like an idiot when I called the local plastic supply houses. I settled on the plain old Homopolymer Acetel "Delrin" and have used it for chassis and links for 2.2s and 1.9s and have no flex or breakage issues to date. I figure even if it does not last as long as metal it is so easy to work with, cheap to buy, and performs so well on the rocks, I can just make new parts.

[Ripperfi]

Man Im bummed. Wish I would have checked the site first before buying 8ft of acetron rod. Bought it locally and told the guy I wanted delrin. I was too excited when I got there to ask, is this acetron the same as delrin? Acetron is acetal and delrin is acetal but acetron is not delrin. This compares the two: http://www.alro.com/DIVPlastics/plas...ct_acetron.htm

If your wanting to make links, I would go with the homopolymer delrin over the copolymer acetron. The copolymer is very flexible, has a memory effect (warps) and just feels softer.

[Cycleeric]

Would this be ok for making some chassis braces from? After reading this thread I think this may be what I need

http://www.grainger.com/Grainger/items/1NLP7

[Stick King]

great thread. thanks for the info

[kineteks]

FWIW, we use quite a bit of Delrin & acetal copolymer & though Delrin can be thought of as marginally stronger in some applications it has historically had some issues with voids in the extruded shapes (rods in this case). We have only experienced this in larger diameter rods but because a void would obviously make for a weaker link I always use acetal for my crawler links....