Playtime With Delrin: Bronze Replacement

chips&more said:
It looked like natural colored Delrin, machined like it, but didn’t hold up in use like it. So I did some homework. Found out that when you put a flame up to Delrin chips it will give off a smell similar to formaldehyde. This plastic I have does not do that.
Click to expand...
IIRC, chips or shavings of nylon smell a bit like burnt hair when lit. Polyethylene-family plastics (including polypro) burn readily with little smell. PVC tends to give off a sharp odor (from the chlorine). Both nylon and PVC will sink in water. Polyethylene/polypro will float. These are "first approximation" field tests I recall from my engineering days.
 
Here is the actual "playing with delrin" the movie
if you got nothing better to do for the next 9:33, have a look!:D


thanks for watching and subscribing!
 
i had some more playtime with Delrin last week,
there was a machine part damaged by an operator in a hurry, the emergency quickly got handed to me to pull a miracle from my bag of tricks
the picture below is a chute that deposits large chunks of meat into a chamber for automatic slicing and then portion control by weight
the chute was dropped and chipped away, i had to somehow make the chute function again in a hurry
here is my repair...
IMG_2490.JPG

i cut off the fractured end and made an end cap from 3/4" delrin instead of the 5/8" thickness supplied from the factory.
i located and bored a hole for an oilite bushing, and laid out the pin and bolt placement
i used .250" SS roll pins and 1/4-20 x 2" SS flat head machine screws to draw the unit together and give torsional strength too.
the end result was a repair that was way stronger than the original manufacture!

thanks for looking!
 
That's just where some of the properties take a nose dive, typically. Can't say from memory which property in particular changes with that material at that temp, but I'm sure there are some graphs available that show tensile and yield, etc, at various temps.
 
Ah that makes sense, so the table only works in between those temps. Still, 50 deg.F is not that cold.
 
Humm, I don't see Teflon listed even though it's considered a thermoplastic, It will handle temperatures from about -40 degree F to around 325 degrees F if filled with things like glass fiber, carbon, and a few other fillers used. Only problem at higher temperatures if pressure is involved, it will creep on you. There's another good thermoplastic, if you can afford it, is PEEK. I've done some pretty high temperature/pressure testing with this material in years past fantastic results.
 
Teflon is hydrophilic to a degree and is not suitable for all applications, but is great for a lot of things.

I too like PEEK (polyetheretherketone) Works up to about 500°F IIRC. Structurally stout, electrically a good insulator and dimentionally stable. I have some on hand now in a few sizes and even tubing. Much cheaper than a piece of large solid round only to bore away. It is make by compression molding in custom tubes at a great savings over solid. I used to make some relatively large PEEK parts, and it is a little nerve wracking, when you have to buy the material, because as Ken says.....it ain't cheap.
 
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