Anyone Ever Cast Hard Rubber Parts?

[hddennis]

I'd like to recreate rubber snubbers for my Maxwell front axle. I thought I'd make a wooden replica and cast hard rubber copies but I don't know what or where do I get the materials needed?

 

Howard Dennis

[hddennis]

Boy, do I feel dumb! Apparently I was looking into this 6 years ago, I either work VERY slow or I'm getting Alzheimer's or both.

Any new technology since then?

Howard Dennis

http://forums.aaca.org/topic/128443-casting-hard-rubber/

[keiser31]

Barry Wolk in the "Restorations" section of the forum had some parts vulcanized. You should ask him. look under "Assembly thread, 1942 Lincoln Zephyr Club Coupe".

Edited July 23, 2015 by keiser31 (see edit history)

[nickelroadster]

You can get rubber in many different shapes and cut it with a bandsaw.  I have cast some rubber parts with Devcon Flexane (A two part urethane rubber with a hardness additive) but it is very difficult to judge how much hardness additive to use to come up with a particular shore hardness.  I have had better luck buying a chunk that can be cut with a bandsaw and then finished off on a bench sander.

[Gary_Ash]

Once you get the rubber, it has to be bonded to the metal plate.  Real vulcanization takes tooling to clamp the uncured rubber in place while it's heated and cured.  I have successfully used Pliobond cement for bonding rubber-to-steel without heat.  Put a coat of Pliobond on each part, let it dry.  Put on a second coat, let it get tacky, assemble the parts, and clamp for about a week to let the solvent escape.  I have only used the "real" Pliobond, not the newer stuff with green "VOC compliant" label, don't know if that also works.  Get the parts well aligned before you touch them together because the glue line will not slide!  Try a dummy piece of rubber on steel for practice.

 

Making a rubber bumper is a lot of work.  Call Then and Now Automotive in Weymouth, MA (781-335-8860) and see if they get new ones for you or make them to order.  Also check with your local truck spring shop because they might find something close enough in standard parts. 

 

In principle, you should replace the U bolts holding the axle and springs together when you take the bumpers out because they have already been stretched (at least) once.  Eaton Detroit Spring can make you some nice new ones. 

[hddennis]

Thanks Guys, Nickelroadster came the closest to what I actually need. There is NO steel involved, just a shaped rubber block held on by 2 leather straps.

[keiser31]

Sorry, I thought it was one of those with the steel base plate anchored by the "U" bolts.

[Friartuck]

I've used Flexane in making door rattle bumpers. This large axle bumber, I would make a wooden pattern, make a mold out of plaster of Paris (cheap and easy) and use lots of mold release on the wood pattern, perhaps even a coating of petroleum jelly (Vaseline):

 

http://www.secondchancegarage.com/public4/door-bumper-3.cfm

[Rusty_OToole]

When cutting out rubber parts, sometimes it helps to freeze the rubber. Dry ice will freeze it real hard.