welding aluminum??? Would JB weld hold?

[Ryan_V]

I need to tack a few pieces of aluminum back on my aluma trailer after re-wiring the whole works. I have a Lincoln arc welder. (ac-220) I bought some aluminum rods for it that say they can be used with ac. I tried to tack the pieces on, but can't get a sufficient arc. I tried to practice on an old aluminum ladder, but can't get an arc. the package says they should be used with 80-140 amps. I went up to 150 amps and can't get it to arc enough to lay a bead or tack a piece.

anyone have any ideas?? or am I going to have to take it to a welding shop to have it done?

[Papa Grump]

You have to have the area completely clean of any residue/flashing/ corrosion . Go to the parts store and get a 240 grit flapper wheel to put on your drill and get everything cleaned up, including your ground. DO NOT use a wire brush or anything else that has been used on steel, as it will contaminate the alumninum.

[Eric Wettschreck]

Papa Grump is spot on.

I'm a certified welder and I'll tell ya, aluminum is by far the hardest metal to weld. Aluminum itself melts easy, but the oxides that coat it melt at a lot higher temp. It has to be clean, very clean, and when you think it's clean you need to clean it some more.

You can use a wire brush just as long as it's stainless steel and has never seen carbon steel at all, ever, never. Once you have things clean, use some electronics cleaner to remove the remaining residue.

When welding aluminum you have to go hot and fast. I know this sounds wrong as aluminum melts easily, but don't forget the oxides. Hot and fast, remember to go hot and fast.

[Ryan_V]

Wow, I'm not so sure I'm going to try and tackle this myself anymore. I don't want to burn a hole in my new trailer. I guess I'll have to find someone to do it for me. I just don't trust my limited welding skills enough. I was thinking that since it just needs to be tacked, I could do it, but I'm thinking not now!!

[Ryan_V]

What about JB weld...would that hold enough?? I'm just thinking this through in my mind on how I could finish this thing.

any thoughts on JB???

[BoxMN]

I tried some Aluma-Weld sticks on a crack in a thin boat hull once... ha, was I stupid I ended up warping the sheet hull, and I ended up sandwhiching it between two alum plates and rivots to fix it. It is ugly, but water tight!

I learned then (I should have known) that the rookie that I am should not mess with stuff I am not good at. Big lesson, practice on friends stuff haha

The JB that I used once did not hold, but I think that was because it was flexing and breaking the JB. But I could have applied it wrong too.

[Eric Wettschreck]

Instead of welding it have you thought of just bolting a doubler plate over the area? Could make things a lot easier.

JB weld may or may not work. I hate the stuff. But that's just me.

[ozzie]

jb weld steel has done great for leaks on my boat....stuff hardens and can be sanded down hard to work with though

[CarpKing921]

I'm with ozzie JB does a fine job for me. My Pops once put an anchor thru the hull of a rental and used JB to patch it up worked great but not sure for how long.