[stomper]

I have a millermatic 210 with a spool gun using 100% Argon. I am modifying the motor mount transom on the motor pod of my pontoon boat, getting rid of the wood and replacing with aluminum. The motor pod is made up of 1/8" aluminum and I want to weld 1/4" to it. I have been practicing a bit but I have been having some issues. My welds look good but the starts are not nice and they are not fused in, (for lack of better words) like the rest of the weld. Looks like a cold start. I have the welder set for a good spray transfer. what could I be doing wrong. Also welding 1/4" to 1/8" should I be concetrating on working the puddle more to the thicker material to reduce the chance of burning through the thinner stuff. Also it seems that I have to move realy fast when welding aluminum as compared to steel. Is this normal with aluminum or do I have the settings wrong.

[noddybrian]

Hi - your going to have some limitations welding with a spool gun on ally so don't expect perfection - unless you have a synergic set or torch mounted control for the power source you are limited to settings that work once running a weld , so starting on a cold piece of material that is thermally very conductive initially the weld is going to be cold / only real solution is to pre-heat the start point with a torch just prior to weld - once your welding the heat will travel in the ally & build up so you do end up going faster and faster - this is quite normal - you are quite right when welding dissimilar thickness materials to concentrate slightly more on the thicker part - in my experience spool on is fine for repairs on trailer bodies & seems strong if done with sufficient heat but it's rare to get good looking welds except possibly with synergic - a long time ago I used a Cobra push / pull set up that also had wire speed trim & power souce remote voltage control on the torch - that could put down a real nice looking weld - but cost more than a good Tig - only advantage was speed - but Tig will always look best with a good operator.
Good luck with the project.