| Repairing Aluminum really isn't all that difficult if you take
your time and prepare it properly. Virtually anyone with a propane torch and some aluminim
welding rods can get the job done. I will walk you through the process and explain how to do it properly.
Remove the muffler from the engine and wash the muffler inside and out to remove flamable residue. Warm soapy water will normally be sufficient. Sometimes you may need to clean the inside of the muffler with carb cleaner first then use soapy water. You don't need it spotless, you are just trying to get rid of flamable residue that will ignite while welding. Things you MUST and MUST NOT do (1) You MUST have a super clean welding joint. (2) You MUST pre-heat the parts to be welded (3) You MUST use a stainless steel brush to prepare the surfaces (4) You MUST NOT apply heat directly to the welding rod.
Since the broken stinger was lost, I removed the remaining one and will replace both. You'll notice the welding area is buffed. You must use a stainless steel brush to do this. A regular steel or brass brush will contaminate the aluminum and it won't weld. The tubes to be welded on must be just as clean using the same method. It's best to support the part(s) in a clamping device like a vice or screw clamp. In this case, I used a vice to hold the muffler and a small C clamp to hold the tubes in place. OK, let's weld it together.First pre-heat the entire muffler with the propane torch up to somewhere around 600 degrees. This isn't critical, as you are merely keeping the muffler from drawing the heat away from your area to be welded. Once its good and hot, concentrate your torch on the area to be welded constantly moving the torch along the weld line. Follow behind the torch with your welding rod keeping the rod out of, and away from the torch flame. If the surface is hot enough the welding rod will flow in to the joint, if not back up with the torch and heat it up more but keep the torch MOVING! If you leave the torch in one spot too long you risk melting your muffler. Remember, the welding rod MUST flow from the heat on joint NOT THE TORCH. If the rod melts from torch heat, the aluminum WILL NOT BOND the parts together. Also, do not use too much welding rod on the joint, use just enough to make the bond. You CAN re-heat the welded joint but be very careful! Re-heating can melt the entire area. Once the parts are welded together, let the muffler cool off naturally... DO NOT cool it fast. This will temper the joint and it WILL break.
This is what a strong weld joint looks like. You'll notice the weld is slightly convex. This is because the joint was hot enough to make a good bond. Because the aluminum welding rod melting temperature is about 600 degrees lower than the metal to be welded, you can "clean up" the weld with heat if you like. This really isn't necessary but it will make the joint look better. The way you do this is to re-melt joint and use a stainless steel wire or rod with a point on it. Use the stainless steel rod to move the melted aluminum around to where you like.Again, be careful as you could easily melt the entire area. After the item has cooled off check it to be sure the bond is good. That's all there is to it! Now go fix all those broken mufflers you have laying around! |
