Aluminium Welding

[daedong]

I know this question has been asked many times but I am still confused. I wish to build a small aluminum boat about 5 to 6 metres I have looked at kits and plans and they all recommend MIG welders in the 250amp range. I have just ordered a 200amp AC pulse TIG. Will this do the job?

I do have a 220 amp MIG but have never welded aluminum. I Understand it is easier to weld aluminum with a TIG is this true or not. Should I set my MIG up for aluminum and start to practice or wait and master the TIG.

Mastering Tig takes an awfull lot of skill - but it also is very neat and produces a very acceptable penetration weld in the hands of a capable operator.

Mig on the other hand is not nearly as neat as a GOOD tig welder can produce - but is very acceptable for boat building purposes you describe.

I built mine with MIG.

Not ALL Mig welders feed aluminium wire well - you need for example a different insert inside the feed line.

You also use argon gas.

You need to practise a fair bit to get it right.

There are special techniques for Mig in aluminium.

50% stitch backwelded and regular rotation from port to starboard side to avoid warping hull lines..inducing hull twist etc.

Fillet welds for transom etc..

Lots of cleaning / grinding and re welding but end result is a good boat!

You can do it with MIG.

You can do it with TIG but will take much more "experience" believe to produce a better result than MIG.

Mig worked for me - practice practice practice.

Cheers!

[daedong]

trouty

Did you have much experience with the mig before you built your boat? Did you build it from scratch or by a kit.

[wingsails]

I agree with Trouty, Taught myself mig then went to tech for more info and tig is SLOW and after seeing my friend use a tig to build an offroader radiator tank which took nearly 10 hours and a full bottle of argon (here that AU$ 120), I am sure could have done the same job and polished it up in 2 hours and a 1/10 th of the gas. Mig for me even if you do get a glitch it doesn't take long to cut out and redo. I find it easier to weld ally than steel now but maybe more practise

[stonebreaker]

Since you've already got the mig welder, I'd look into buying a spool gun or even dropping the big money and buying a push-pull setup. Then take a welding course at your local trade school to learn how to do it right. As mentioned, mig has the advantage of being LOTS faster than tig.

I didn't have that much trouble learning to tig aluminum, but I had a good teacher. It does take some time to learn, however, and you have to learn to scrub every bit of anodizing and surface oxidation off the aluminum or you get a bad weld.