Suggestions for repairing pinholes in muffler?

[brock911]

Greetings from Canada, all the best for the holidays and health in 2015.

I'm preparing my muffler for re-paint, after a media blast I noticed 3 very small holes approximately 1/8" diameter.

Looking for some suggestions to repair these pinholes, epoxy, muffler cement, brazing of some type or welding?

Maybe you have experienced this issue or can recommend a fix?

As all ways your help is appreciated.

Regards,
Mike

[mreid]

Pinholes are usually a sign that it is rotting from the inside out. That means that the metal is very thin and will be almost impossible to repair. Your best and safest approach is to replace it. If that's not possible, brazing may be your only option, but will not last long as other pinholes will develop. Welding will blow through and expose all of your woes.

[Oh Haha]

Which of your cars has the holy muffler? If it is the 912 a used one would be MY choice for fixing the issue.

[brock911]

Thanks for your input Mark, I realize it may be futile but I'm hoping because the holes are small enough it may be salvageable?

Regards,
Mike

[Cattler]

+1 on replacing. I wouldn't think repair would be cost effective.

[brock911]

Originally Posted by Oh Haha

Which of your cars has the holy muffler? If it is the 912 a used one would be MY choice for fixing the issue.

Hello Wayne, it's the 66 911.

[tharbert]

Short term: How about a short pancake head screw and some epoxy? You'll never be able to weld it.

[mreid]

Sorry, Mike! It gets too hot for epoxy to last very long. If you can braze it yourself, that is really the only cost effective temporary solution.

[jmpowers]

I'd guess that it once you put enough heat to braze or weld it you will create a bigger hole than you started. Looking at JB Welds site this product might work?

Good luck

[The cap'n]

Ahhhh, the ever lurking JB Weld myth raises its ugly head.......

The Cap'n

[jlex]

High temp silicone with a metal screw?

[Quicksilver]

Braze it and just watch it.
That also gives you the luxury to keep an eye out for another muffler to show up at a good price.

[brock911]

Thanks for all the input, upon closer inspection it appears there is one hole.

The muffler has what looks like an outer wall of metal as well as an inner wall?

Only one small hole looks like it is right through and the metal all around this area appears quite solid to a good poke with a sharp awl, is this just wishful thinking?

There doesn't look like any rust in the area at all. I will post a couple of images later when I get home, not that anyone will be on their computers on Christmas eve.

Once again thanks for the help.
Mike

[porsche930dude]

Id just weld it up. Sounds like a pretty small area that water collected. chase the holes around till they are gone grind it smooth

[911pcars]

Originally Posted by Quicksilver

Braze it and just watch it.
That also gives you the luxury to keep an eye out for another muffler to show up at a good price.

+1. I would add a metal patch with multiple holes for brazing. That should add some structural strength and extend its life a little. Gently bead blast for paint prep, but don't spend a bunch on making it look presentable.

Sherwood

[gamin]

Post #2 mreid nailed it. I had same problem with 70 muffler. The muffler is indeed rotting from the inside. I absolutely believe replacement is the best option. If it is the original 66 muffler just think of how much service you got out of it.

[brock911]

One more question, I'm planning to try brazing the pin hole for repair because I feel the area around the hole is solid enough to withstand the heat, this could simply be wishful thinking but I believe worth a try.

However, before I attempt this I was wondering if a rivet would work?

Thank you for your opinions,
Regards,
Mike

[patz]

50 years? Probably due for retirement.

[The cap'n]

Brass doesn't like vibration, which is pretty substantial in that area, and it requires a squeeky clean base in order to adhere well. Keep that in mind.

The Cap'n

[911pcars]

Originally Posted by brock911

One more question, I'm planning to try brazing the pin hole for repair because I feel the area around the hole is solid enough to withstand the heat, this could simply be wishful thinking but I believe worth a try.

However, before I attempt this I was wondering if a rivet would work?

Thank you for your opinions,
Regards,
Mike

Pop rivets to plug a pin hole? Try it.