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Rust proofing the exhaust [message #281137] Tue, 30 June 2015 21:01 Go to next message
werewilfs is currently offline  werewilfs   United States
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Registered: July 2012
Location: Rappahannock County, VA
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Not sure if this is even possible or worth it. I acquired a new to me complete exhaust system from a GMCer who recently upgraded his. Mufflers and tail pipes. Very solid but has a bit of surface rust. I'll be replacing my system which has a couple of pregnant mufflers and a very rusted (almost all the way through) tailpipe. Any good way to rust proof the pipes and mufflers while I have them out that will last or is this a lot of work for very little reward type activity?

Thanks as always.


Jared & Stefanie Kohl Rappahannock County, VA 1973 Painted Desert "Onslow"
Re: Rust proofing the exhaust [message #281140 is a reply to message #281137] Tue, 30 June 2015 21:43 Go to previous messageGo to next message
Dennis S is currently offline  Dennis S   United States
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werewilfs wrote on Tue, 30 June 2015 21:01
Not sure if this is even possible or worth it. I acquired a new to me complete exhaust system from a GMCer who recently upgraded his. Mufflers and tail pipes. Very solid but has a bit of surface rust. I'll be replacing my system which has a couple of pregnant mufflers and a very rusted (almost all the way through) tailpipe. Any good way to rust proof the pipes and mufflers while I have them out that will last or is this a lot of work for very little reward type activity?

Thanks as always.


I would think wire brushing and sanding off the surface rust and then hi temp exhaust paint. Will it add to life expectancy of the system? Maybe yes -- but it is more fun installing clean parts!

Dennis


Dennis S
73 Painted Desert 230
Memphis TN Metro
Re: Rust proofing the exhaust [message #281147 is a reply to message #281140] Tue, 30 June 2015 22:46 Go to previous messageGo to next message
Justin Brady is currently offline  Justin Brady   United States
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Location: Bell Buckle, TN
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+1 wire wheel it cleanish and then use a rust converter like Rust-Mort and then paint.

Justin Brady http://www.thegmcrv.com/ 1976 Palm Beach 455
Re: Rust proofing the exhaust [message #281150 is a reply to message #281140] Tue, 30 June 2015 23:37 Go to previous messageGo to next message
werewilfs is currently offline  werewilfs   United States
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Registered: July 2012
Location: Rappahannock County, VA
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Agreed... but the $900 for a new system is just not in the CFO's budget right now. Need to use what we got.

Jared & Stefanie Kohl Rappahannock County, VA 1973 Painted Desert "Onslow"
Re: Rust proofing the exhaust [message #281162 is a reply to message #281137] Wed, 01 July 2015 07:29 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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Jared,

There is a problem here.
Most exhaust systems rust from the inside first.
To fight this, avoid starting up and running the coach short hauls. If the weather is cold, this is even more important. The condensed water always contains acids and is very corrosive.
So, if you drive the coach to someplace about 100 miles away (every weekend), the exhaust system will last a long time.
It really does take about 10 miles of significant load like highway driving to clear the exhaust system of condensate.

Most paints are only good to about 350°, the exception being the heat resistant paint used on steam piping and even that starts to get problematic much over 500°. I don't even know were to buy it. When I needed any in my former years, I would just steal it from work.

Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
Re: Rust proofing the exhaust [message #281163 is a reply to message #281137] Wed, 01 July 2015 07:41 Go to previous messageGo to next message
lqqkatjon is currently offline  lqqkatjon   United States
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Registered: October 2010
Location: St. Cloud, MN
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I just purchased a can of this to paint up the tubes on my used dometic fridge I am installing:

http://www.amazon.com/Rust-Oleum-248903-Automotive-12-Ounce-Degree/dp/B003CT4AKC/ref=sr_1_1?ie=UTF8&qid=1435754344&sr=8-1&keywords=rustole um+high+heat

I was pretty impressed with the 2000 degree label.

But I think Matt is correct, it will still rust out depending on the elements it is exposed to, either from the inside or outside.



Jon Roche 75 palm beach EBL EFI, manny headers, Micro Level, rebuilt most of coach now. St. Cloud, MN http://lqqkatjon.blogspot.com/
Re: Rust proofing the exhaust [message #281172 is a reply to message #281163] Wed, 01 July 2015 08:33 Go to previous messageGo to next message
Justin Brady is currently offline  Justin Brady   United States
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Registered: April 2015
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There are plenty of high heat paints that will easily stand up to an exhaust.
That rustoleum Header paint is good stuff. It wont hold up on headers (they get too hot, the 2000 degree rating is optimistic) but for an exhaust system it is far more than adequate.
Rustoleum also makes a "grill Paint" that's for barbecue grills, I use it on exhaust all the time and it hold up great.

VHT makes a line of exhaust and header paints as well that is really good stuff. It really hardens on there when it's cured (when the exhaust gets hot it will cure and be pretty bomb proof)

Matt does make a good point about rusting from the inside out, but the rust on the inside is already there and nothing you can do about it. If you paint the outside you cut your rusting problem in half. It will still eventually rust out unless you go stainless, but it will give you many years of service before doing so.


Justin Brady http://www.thegmcrv.com/ 1976 Palm Beach 455
Re: Rust proofing the exhaust [message #281217 is a reply to message #281137] Wed, 01 July 2015 17:52 Go to previous message
JohnL455 is currently offline  JohnL455   United States
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Registered: October 2006
Location: Woodstock, IL
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Yes it's not just the water inside that makes it rust. Those combustion byproduct are witches brew of corrosion producing compounds

John Lebetski
Woodstock, IL
77 Eleganza II
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