I need to reduce the size of my pitts muffler to make it fit in the engine cowl. when I cut it I will have a hole to fill. I would like to get some aluminum stock shape it and then use alumiweld and a torch to resolder (weld) it back together. Has anyone ever used alumiweld and torch to fill back in the void?

Yes, but you have to be very careful due to the heat distortion that may result from use of the torch. You need to accurately jig the part to keep it from "walking" out of shape. A better solution might be to have a friend with a TIG set up weld it up for you. There's less heat spread over the area to minimize warping the part. If you go the Alumiweld route, practice on some scrap before you attempt the final job.

My experience with Alumiweld is that its melting point is too low for effective use on exhaust systems. Find a local weld shop that will do TIG. They'll probably just fit it between jobs or have someone thats learning the process do it for you. Make sure you tell them you don't want any pores in the final weld or you'll eventually have an oily mess inside the cowl from leakage through the weld.

Brad

In other words Brad you're saying that one will not get the required penetration for the weld because the Alumiweld will melt and burnoff before the base becomes hot enough to accept the weld? Good point. TIG is the better way to go.

Mike

I have been able to fix one muffler with alumiweld, but not another. There is a definite technique to learn to use it. You can make a large area of damage trying to make it work in this case due to the nature of the base material and the heat required to make this work. The second muffler I just had to flat out replace. Alumiweld works more like a solder, and you need to "rub" the stick to make the metal stick correctly. It does work, but TIG would be better.

Thanks guys. Has anyone had a welder do this for them and what did they charge you?

I went to a weld shop to get the stinger rewelded on a 50cc gasser canister, and he charged me $35. Was done in two hours.

As far as penetration of the base material, as mentioned, alumiweld is basically a solder - there is no penetration. But what I was referreing to was that the Alumiweld just melted off and the repair failed when the exhaust system got up to temperature. Alumiweld actually melts around 750 F I believe. Alumiweld is great for low temp applications (boats, brackets, piping, valve covers, etc) but not so good for high temp applications like exhaust systems.

Brad

I used a welding shop to replace the pipes on a couple of mufflers, this was an independent shop and the guy charged me $10.00 a muffler welding on both pipes.

Price will be all over the place. $10 per pipe at one shop, $35 at another... I have a friend who does all types of welding, but his primary business is auto repair. If a small job like this comes in, and he has the TIG stuff out and ready to use, he does it for a lower price than if he has to shuffle a lot of things around.

OMG, I was just going to buy a new muffler ($60) because I neede two pipes in mine. Now to the weld shop I will go. That is why I love RCU