Topic: High Heat version of Bondo for Exhaust?

[YogiBear]

Im working on a 4 into 1 exhaust for my CB500. It has some dents on the bottom and a slight dent on the outside of the muffler at the end. Im wondering if theres something out there that's the equivalent of bondo that I could use on the pipes? It would obviously have to stand up to high temps. 

[MasterChief750]

i would use a welder as i am not aware of any type of high heat bondo

[YogiBear]

i would use a welder as i am not aware of any type of high heat bondo

You think welding would work on such thin metal like the tubes? It doesnt have to be bondo, I just used it as an example. Something like bondo, ya know?

[Alan F.]

No there's no filler for exhaust pipe dents like bondo.  As masterchief1112  said, if you were to have the dents filled with weld or braze, you could grind and sand the area smooth thus filling the dent.  If the pipes are too thin, then they're probably rusty inside and not worth the effort.

[MasterChief750]

a good welder can weld pop cans together without burning through, i cant but the man who taught me can, it would need to be the lowest heat possible so as to not burn through but someone should be able to fill weld them for you.

[754]

Its called brazing rod, Steel filler rod, and if its far enough back.. maybe solder...

 Why dont you try to massage out the dent?

[Ichiban 4]

There are high heat epoxy type products out there in the market place.  Devcon used to make an aluminized product..that you could repair crank cases and cylinder heads with.  [By "high heat" I mean up to around 500 degrees F].  Excepting for the head pipes..I don't think most rear pipes/mufflers get even to 500 F.

One problem with the Devcon..other industrial type products..as mentioned is 1.) they're hard to get in small quantities (like less than a gallon??) and 2.) they're usually quite expensive.  It's been years since I've priced that stuff..but way back when..a gallon of that stuff was well over $100.00 per gallon.

May be..as others have mentioned here..that brazing or silver soldering (by a skilled welder) may be your easiest..cheapest bet.  Don't think regular lead-tin solder would hold up on an exhaust pipe BTW.

Good luck,

Ichi

[Retro Rocket]

One problem with the Devcon..other industrial type products..as mentioned is 1.) they're hard to get in small quantities (like less than a gallon??) and 2.) they're usually quite expensive.  It's been years since I've priced that stuff..but way back when..a gallon of that stuff was well over $100.00 per gallon.

I use to use Devcon to fix brake master cylinders on bikes that had been dropped and i could buy it in a tube, never had to buy it in bulk here in Aus.

Mick

[Gordon]

I used a product called "muffler mender" that I got at the auto parts store on a hole in the #3 muffler on my 550 over two years ago and it's still holding strong.  I don't know how well it would work as a dent filler, but as long as the bonding surface is sufficiently clean and roughened I don't see why it wouldn't hold at least as long.   

[754]

 I used Devcon fillers on fibreglass on a fairly regular basis a few years back.
 It came in a box about 4 x4x 5 inches, which had 2 containers inside, it is pricey though. We used it a lot on fibreglass overlay drilling templates, used on Western Star truck bodies at the factory..

 But on exhaust, I would try to pop out the damage, if you can post a pic , I may be able to tell you how to fix..

[bucky katt]

try thin layers of jb weld. i did this for a vw exhaust collector on a merged exhaust on a 65 beetle years ago and it held for many years.

[MaaseyRacer]

try thin layers of jb weld. i did this for a vw exhaust collector on a merged exhaust on a 65 beetle years ago and it held for many years.

I used JB Weld to fix a crack in my old Honda's transmission case while I was coming home from a road trip.  It held for two weeks while I was sourcing replacement parts.  I am sure it would have held longer, but I did not chance it. 

[YogiBear]

Well, I guess ive got options to explore now. Thanks guys. 

[country joe]

My grandfather used to use the muffler mender stuff (He was too cheap to buy new mufflers) with good results. If you got the surface sanded and cleaned good, it should stick. After it dries, sand it into shape by hand. A power sander might overdo it. I have a similar problem to yours. I've got a '78 550 with a good 3 inch long dent in one of the sides of the exhaust. I'm bobbing this bike, so what i am doing is cutting the mufflers off right where they start (which I was going to do anyway) drill a hole in the dent, then use a slide hammer and pull the dent out a little bit. I would then weld up the hole, sand and paint the pipes heat paint black, then use some of that black heat proof pipe wrap. That should fix it up nice. Anyway, that's what I'm doing to mine just trying to throw you some ideas.