RTV as muffler patch?

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pishta

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My old truck muffler has a few holes right where the pipe comes into the case, I cant wrap it so I thought maybe Ultra Copper RTV would fare well enough on the muffler to plug the holes. Would it last or would the muff get too hot? Its about 12" from the cat and another 12" from the Y pipe. The hole are smaller than welding rods, the one crack is about 1" long. Id hit it with my MIG but I bet Ill burn right through that thin wall of rust that I call a 32 year old muffler. Any luck with that muffler patch in a tube?
 
Man, mufflers are cheap. Replace the thing.
 
Do you really wanna advertise that you're that cheap?
 
Could use this "opportunity" to test the heat limits of fiberfix. :p
 
hell yeah, I'm cheap. I drive this truck like never now I got a company truck and it wont smog with a few pinhole exhaust leaks. Less money I put into this, the more I got to play with my Mopar. Ill let you know what works.
 
Go to the parts store and buy some good quality muffler and pipe wrap. I just used some on my Aunts old Suburban that just sits mostly. She did'nt want to spend money replacing parts. It comes with some thin metal that you wrap,and comes with an impregnated bandage ( with I don't know) that you wrap around that. And they give you mechanics wire to secure the bandage with. Worked real good , and this was on a pipe to converter joint that was 3/4 the way open. Surprised me ! I usually won't use Snake Oils
 
Silicon bronze 1/16 wire and a small oxy acetylene tip.
It will weld rusted thin metal at a lower temp so it won't blow away on you.
 
Easy to use and rust won't pop away as bad as using brass.
 

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I've used RTV for collector gaskets, so "I guess" it will stand the heat. You will have to grind down to some clean metal, and wait probably "a couple of days" for it to fully cure. "It's worth a try."

My "hated Olds" has a huge big sheet metal wrap around the muffler. If I remember right, the muffler for that damn thing is not my idea of 'cheap'
 
Well if you just gotta be cheap then yeah I am pretty sure the red high temp RTV will hold up. lol
 
I've used JB Weld to repair marine manifolds leaking water into the manifold, and filling a cylinder,, ergo, when the engine ran,, it had to keep exhaust outta the coolant.. worked for a season till I got new manifolds..
 
OK guys, ultra copper RTV (best stuff?) is good to 700F (shows bead on header flange!) and the black stuff is rated for 400F-500 intermittant, No good. I took temp of pipe into muffler and it was 470 with just 10 minutes of stop and go errand running on side streets, cat was over 500. Muffler case was 270. Im out of copper so Im going to get the muffler patch in a tube, good for 1000-1500F intermittant and cheap at $3.50. The Muff is $47 but its all welded so I cant just unbolt a flange. The muff is in good shape (weighed a ton when I took it out at last repair, full of rust??) except for the small leak at the pipe head. shop wanted $90 so I figure Ill just deposit $85 into the Mopar fund :)
 
oh yeah, 2 part epoxy I saw was rated for 300F, fast stuff was only 160F. dont know what JB is off hand...but I heard its not the best for exhaust.
 
JB Weld SteelStik

Continuous temp 250° F
Intermittent 300° F

Neighbor just repaired his y-pipe with it. Say's it works great.
 
I can relate and am a cheaper bastard. Sometimes you spend days fixing something right then an idiot totals your whole vehicle. Repairs are a moving target.

There are epoxies good to 750 F, but usually just industrial supply and they are more brittle. Silicone is good to ~600F, but doesn't usually stick well, so better as a gap filler. I think the muffler patch material is a ceramic, similar to "furnace cement". I think you can buy it to secure wood stove woven gaskets. It is like pottery glaze, an aqueous solution of oxide powders, similar to fine mud that dries hard. Like glaze, it needs to "fire" to drive off the water (hydrates). Otherwise, it will dry hard but eventually pit as atmospheric moisture attacks it (little of that in the OC). But, it will also fall off like mud, so needs fabrics to hold it. Those are usually woven fiberglass (~1000 F) or alumina (~3000 F).
 
The liquid I bought was the big tube with the screen patch, Didnt use the patch but the stuff was very thin, applied and smoothed it over as a bead, takes 4hrs to dry, they say to heat it up after 4 hours to cure, ill just idle it for a few minutes. so far so good. brace is holding firm and patch is setting up. trial start was butter smooth with no leaks.
 
OK guys, ultra copper RTV (best stuff?) is good to 700F (shows bead on header flange!)...

Yes. I work on exhaust nozzles for jet fighters. We use a high-temp RTV to seal many components (although nothing directly exposed to the 1200° exhaust gas). Only problem is, I do not think it'll adhere to rust... so you'll need to clean the rust off.
 
Or, you could just........

[ame="https://www.youtube.com/watch?v=y8TBE-VhRTY"]Drilled holes in muffler - YouTube[/ame]
 
I've used hi-temp RTV to fix muffler and exhaust pipe holes as well. But I've only done it as a temporary fix. Needless to say, if it rusted through, the rest of it isn't too far behind.

I've used aluminum sheetmetal in conjunction with the RTV. Where possible, I pop riveted the metal over the hole & RTV. I've also used the threaded hose clamps to hold it in place, where applicable, as well.
 
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