Help me weld 16g steel without blowing through it???????

[Slurpee]

Hello,
First of all I am rookie! I have welded a few projects previously that I thought turned out pretty well and have held together.
I'm trying to modify a gas tank for my motorcycle project. The tank it self seems to be about 18g and the piece of steel I am using to do the modifications is 16g. I am having a heck of a time getting a nice weld on it. I am constantly punching through the 18g tank material and then turning around and not getting good penetration.

I have 4 settings on my Miller Cricket. I have tried 1 and it didn't have enough juice it seemed to keep an arc going. 2 works the best but is still punching through regularly. 3 and above just blast right through.

Currently I am on 2 with a wire speed of around 45 (just under half the potential top speed. I am using gas at a flow rate of 10.

The other issue is I seem to be getting a few holes and porousness in my welds. What kind of machine settings and weld techniques work best when welding thin steel?

Please help!!!!..... if you don't I might be leaking gas out of my tank and blow up, and my death would be on your shoulders! HA HA!
Thanks

 

[tayash]

Your Welding Very thin material of about 1mm So the stop start technique should help with blow through and it's more forgiving at higher settings.
http://www.mig-welding.co.uk/thin-metal.htm

Also if your welds are very pourous you should check you don't have an in line leak some where.

Hope this Helps

 

[Rubber Duck]

Before trying to weld on the gas tank I would be inclined to practice A LOT on some similar material and make sure it is fully purged of vapours!

Before you go BOOOM

 

[tayash]

Good point!

 

[Slurpee]

The gas tank is in 2 pieces so I'm not too worried about going boom. I'll take a look at the start stop technique and hopefully that will get me there.

 

[d c]

what i did when butt welding a louvred vent in my bonnet (hood) was to use the start stop technique and struck the arc on the thicker of the two pieces and drifted across to the thinner parent metal.
i practised on the piece cut out of the bonnet, 1mm and a bit of scrap the same thickness as the vent approx 1.5mm.

 

[Slurpee]

Do any of you stop start users know if it will give me a solid bead that will hold gas? As this is a gas tank I need it to be able to hold liquid, does this method provide a solid bead after grinding and sanding?