Welding Aluminum Tubes

[samo_ott]

I have a couple of leaks in one of my pontoons. I have a MiG and just bought a spool gun for it and an Argon tank. But I've never welded aluminum before. Just other metals. So my question is, does anyone have any hints to do it correctly? Unfortunately it's also along the bottom seam so it will be upside down... Sigh... So once the snow goes I'm going to tackle it. I also plan to practice on some scrap aluminum first but was still hoping for any pointers... thanks...

 

[fishinaddict]

Re: Welding Aluminum Tubes

Its not easy. Best advice is when you see the medal start to puddle you better stick the wire to it or it will blow out. Its all about timing. Its certainly in a class of its own.

 

[slasmith1]

Re: Welding Aluminum Tubes

If your set on doing it yourself I would strongly suggest getting some scrap aluminum of the same thickness and practice until you are confident in your skills.

 

[Mike722]

Re: Welding Aluminum Tubes

If you do find that you are making it worst, stop and take it somewhere or practice more. It will be easiler and cheaper for them to fix small holes over larger ones.

I tried fixing a canoe and after about 15 mins knew I was in trouble. Took to the welding shop and they fixed for $25 bucks.

 

[J JACKSON]

Re: Welding Aluminum Tubes

i have used a spool gun many times. if you can weld with a mig upside down you shouldn't have much trouble but use the chart on the welder to find your heat range/wire speed. another problem with aluminum is it doesn't glow like steel before you blow a hole in it it just disappears. so practice up first and make sure its clean before you start. and dont try to weld a big section at one time try 1/4 to 1/2 inch spots and allow it too cool

 

[buckeyboy]

Re: Welding Aluminum Tubes

Tigging with filler rod would be my preference, seams need to be extreemly tight//

 

[tashasdaddy]

Re: Welding Aluminum Tubes

Steve, 5150abf , would be the one to ask, he does it professionally. for Bennington.

 

[derekpfeiffer]

Re: Welding Aluminum Tubes

Best advice is practice in the same postion you're gonna be welding in with the same thickness of material. Also make sure its very CLEAN use like acetone and a stainless brush to clean the spot first. But miy prefrence also like someone else has stated would be to use a TIG outfit.

GOOD LUCK

 

[5150abf]

Re: Welding Aluminum Tubes

Here I am, MIG is not the best way to do it but it can be done.

First of all remove the plugs from the tubes or you will have drill a vent hole in them, as you weld pressure builds up in the tube and will blow out the weld, if you have to drill a vent hole do it on top of the tube and seal it with some 3m, don't think you can fill that hole with a mig, an 1/8'' hole is fine.

Second, clean the spot to be welded really good, sand paper or scotch brite will work, no liquid solvents as they will get sucked in to hole and comtaminate the weld, if it is a crack use a razor blade to clean inside of it.

Start your weld beside the leak and work over it, if you start right on the hole it will just blow out and I would just zap it as opposed to holding the trigger and trying to get it all at once, so start moving as you pull the trigger,move over the spot and release the trigger but keep moving the gun,this will help eliminate fisheyes, do this 2-3 times then cool it down with a wet rag, make sure you get all the water off before welding again, water is worse than oil to a weld.

Welding upside down is no big deal and the seam is pretty thick, start about a 1/2 before the crack and go a 1/2'' beyond it, again release the trigger but keep moving the gun, the problem with a mig is it is hard to not leave a "fish eye" which is a pin hole.

You said you were going to practice which should help, work on moving the gun before and after you pull the trigger and get to where you don't leave a fish eye, maybe drill a hole and try to fill it, cut a slit with a hack saw and fill that.

If the welder sounds like bacon frying or crackling, it is too cold, it should be a nice hiss, ideally the best aluminum weld is a spray transfer, the wire actually breaks into a spray 1/8'' or so before it hits what is being welded just like a spray can of paint.

A common mistake when practicing is your practice peice gets too hot, so use several peices or cool it down after a couple welds.

If you have any more questions feel free to pm me, as TD said I have been in a pontoon weld shop for 21 years so I can probably answer any questions.

Good luck

 

[samo_ott]

Re: Welding Aluminum Tubes

Thanks all. As I said, once the snow goes (and there's a lot here) I will be tackling this. Once last question, how how I determine how thick the aluminum is? Oh and also, I will not need vent holes as it already has them.

 

[5150abf]

Re: Welding Aluminum Tubes

You don't say what kind of boat but generally tubes are .080, some are .090 or .100 but that is rare.

 

[samo_ott]

Re: Welding Aluminum Tubes

It's old and I'm not even sure of the make. Will post a pic soon.

 

[samo_ott]

Re: Welding Aluminum Tubes

This is what my 20'er looks like. But I'm not even sure that the sides are the original sides so probably not too easy to ID it! And as you'll see in my other post, it needs furniture!

 

[tashasdaddy]

Re: Welding Aluminum Tubes

the sloped railings reminds me of an old tracker.

 

[flycaster]

determine manufacturer

determine manufacturer

You should be able to take the HID to the department where you register your boats and they should be able to tell you the manufacturer and year of manufacture

 

[5150abf]

Re: Welding Aluminum Tubes

And those are U tubes, depending on what year it is they may be filled with foam, CG regulation that all U tubes be filled with flotation foam which a welder wouldn't like at all.

 

[samo_ott]

Re: Welding Aluminum Tubes

There does not appear to be any foam in them. How I know this is I had to stick a hose in to pump em out when they leaked. And half the boat sunk when the worst side filled up. Thus if there's foam there it's not doing a good job!

Just out of curiousity, why only are U tubes filled with foam?