Heat capacity of A-arm rubber mounts
Heat capacity of A-arm rubber mounts
(OP)
This may be more of a materials question, but figure with it being car related I may get an answer here...
Does anyone know the heat capacity of the rubber mounts used in the typical A-arm? I'd like to know if the mounts can handle the heat produced during a powder coating session. These sessions typically push 400-500F for 8-10 minutes, but I don't want to degrade the mount. The mounts are an integral part of the component, so removing it before powder coating is not an option.
Does anyone know the heat capacity of the rubber mounts used in the typical A-arm? I'd like to know if the mounts can handle the heat produced during a powder coating session. These sessions typically push 400-500F for 8-10 minutes, but I don't want to degrade the mount. The mounts are an integral part of the component, so removing it before powder coating is not an option.
Dan - Owner
http://www.Hi-TecDesigns.com 





RE: Heat capacity of A-arm rubber mounts
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RE: Heat capacity of A-arm rubber mounts
I was leaning towards a vulcanized rubber, as well, though I questioned the durability of reheating it. At least one source (Wikipedia) gives contradicting info... in one spot it lists the vulcanization process as taking up to 8 hours, followed in the next sentence as saying tires are cured for 15 minutes at 150C. It also makes mention of thermosets degrading or burning if reheated, though it's unclear if it's specifically talking about thermoset plastics in specific or cross-linked materials in general.
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Heat capacity of A-arm rubber mounts
Rubber is not my area of expertise, but a few of the major players used to be DuPont and Bayer, and an Italian company and a Yugoslavian company whose names I cannot recall. DuPont should be able to provide actual data.
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RE: Heat capacity of A-arm rubber mounts
There are many types of rubber, natural and synthetic, and EPDM rubber, and other types such as silicone and HNBR (hydrogenated nitrile) are inherently more heat resistant than natural rubber.
Regarding the time of the vulcanization process, it can vary depending on the vulcanization (cure) system, whether it's sulfur cured or peroxide cured, and the thickness of the part. Some injection molded rubber parts can cure in a minute at 400F, for example, while a thick part might take the 8 hours mentioned above at a lower temp such as 250-290F.
Hope this helps.
Tom Jablonowski, TSE Industries, Inc.
www.tse-industries.com
RE: Heat capacity of A-arm rubber mounts
RE: Heat capacity of A-arm rubber mounts
Thank you for clearing it up. As I said it was not my area of expertise.
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RE: Heat capacity of A-arm rubber mounts
RE: Heat capacity of A-arm rubber mounts
Rod
RE: Heat capacity of A-arm rubber mounts
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Heat capacity of A-arm rubber mounts
RE: Heat capacity of A-arm rubber mounts
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Heat capacity of A-arm rubber mounts
Rod
RE: Heat capacity of A-arm rubber mounts
won't chroming embrittle your parts,particularly mount bolts? Seems counterproductive for appearances sake.
Yours,Ed
RE: Heat capacity of A-arm rubber mounts
If you have different requirements and are prepared to trade of durability and noise and vibration isolation for more exact suspension location, the other materials might suit your specific purposes better.
Like Rod says, acetal (Delrin is a DuPont trade name for acetal) is a good choice for a very hard (relative to rubber) bush.
Depending on service conditions, nylon (Zytel), acetal, PET, polyurethane of various hardness, HDPE, cross linked PE and UHMWPE and PTFE (Teflon) can be used. Each has it's own merit and weakness regards, degree of compliance, fiction properties, heat generated an heat tolerated, wear in clean conditions, wear in dirt and grit, self lubrication, compressive strength, cold flow etc. etc. Also each may be provided with various additive and filler packages suc as PTFE, graphite, molybdenum Disulphide, carbon fibre, aramid powder, silicone oil.
Generally, Polyurethane is best where more compliance is required, Acetal is best where minimal compliance and best compressive strength is required, nylon 66 is best where significant heat is generated and reasonably high compressive strength is required, PTFE is best where minimum friction is required, but compressive strength and cold flow is not an issue and UHMWPE is best where temperature and load is low, but the environment is dirty.
Most can be obtained as bar stock that can be machined and PU can be obtained as liquids parts A & B which can be mixed and poured into a very simple home made mould.
Regards
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RE: Heat capacity of A-arm rubber mounts
My corona is just coming up to a quarter of a million miles. The only bushes to shag out (technical term) have been the shocker end bushes.
Cheers
Greg Locock
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RE: Heat capacity of A-arm rubber mounts
Does that mean for your use the OE bushes are not garbage.
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RE: Heat capacity of A-arm rubber mounts
OEM rubber will depend on the type of rubber as indicated by Tom. How to find out what rubber they use is another question. I guess test on rubber bushes from arms damage beyond repair that you might get from salvage yards.
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RE: Heat capacity of A-arm rubber mounts
Pat, thanks for the list... when it comes time to work on the A-arms I'll look further into some of those materials. Thank God I have access to the machine shop :)
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Heat capacity of A-arm rubber mounts
The chromed frame on this Ed Roth show car allegedly failed repeatedly just getting trailered from show to show.
He later commented he did not know he had to bake chrome parts.
Still.........