MrPolak Samba Member
Joined: June 20, 2004 Posts: 1336 Location: AG ,atnaltA
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Posted: Mon Jul 21, 2008 7:27 pm Post subject: The DEEP, DARK secret of fiberglass exhaust wrap. |
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Well, I bought some exhaust wrap, but not to wrap my exhaust, mind you. I needed to shield some not-so-hot parts from the hotter-than-H parts. I've read reports of exhaust headers rusting very quickly after application of fiberglass exhaust wrap. Why? The stuff soaks up water like a sponge and holds it. Yes, I just tested it. So you can imagine what happens over night when the dew point drops, no? Yes. The doom of all bare steel, moisture, gets sucked up against the headers.
It seems that sealing it against moisture would be the correct way to install the wrap, which can be done by applying the appropriate and expensive sealant.
No problem for stainless steel headers, right? Maybe not so, since the wrap causes the temperature of the headers go up, which may be too much of heat stress for the metal to handle. And that might be another DEEP, DARK secret in itself. |
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coolwind57 Samba Member
Joined: February 17, 2008 Posts: 79 Location: S. Indiana
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Posted: Tue Jul 22, 2008 4:16 am Post subject: |
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I'd seen this time after time when I owned a ceramic coating business. There would be rust and pitting on the section of pipe or headers that were once wrapped. It was interesting to note that you could easily identify which section of the header had once been wrapped with this stuff--even after we ceramic coated it.
Wrapping also commonly causes thermal fatigue, especially bad around welds. Stainless, in particular was kinda bad about this. One really has to really be careful when welding stainless and a lot of the cheapo headers and exhaust components would come apart at the welds when these import kids decided to wrap their stuff.
I've heard of steam coming up from under the hood in rainy conditions...can you imagine the thermal and chemical dynamics going on under the wrap?
Good ceramic coating allows for proper "recooling" of you system once you shut the engine down...wraps do not. Based upon my experience in the industry, I'd NEVER use wraps. _________________ 1983 Vanagon Diesel L
NA 1.6, 5-speed Manual
Burning Waste Vegetable Oil, baby!! |
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