welding 1.5mm box???

[moggyjnr]

hey all, quick question regarding the welding of 40x40x1.5 box. been using a sealey mightymig 130xt and getting different welds, to the point where sometimes it burns through . think this is due to a slight gap maybe? tried mucking about with the settings, max power number 2 and feed on 3 seems to work good.

had issues with the gas flow too as there is no flow meter, just a valve. i've joined the box at corners with a 45 degree angle and has to fill part of the join with weld. once flap disced its looks pretty good.

any advice overall??

cheers Moggy

 

[Jan]

On the surface you might expect that a 130 amp welder should go low enough to work on sub 2mm materials, but that doesn't always follow. I don't know about your MightyMig, but a lot of similar sized/rated boxes cannot go below 30 amps, which is a bit high for 1.5mm. Doable, but difficult for the beginner. I can only suggest you use the lowest setting and fine tune the amperage/voltage with the wire feed control. After that it's merely a matter of practice, practice, practice.

 

[norlander]

if you have a gap on 1.5mm you will probably blow a hole, 40mm is a short run and the workpiece will heat fast by the end of the run -if you have mitred the corners the run may be abit longer but still the same effect-and the gap will cause the edges to blow away.
So what I do is pulse or stop n start on gaps or if I think the last couple of mm will blow.So a series of joined tacks is possibly a better way to put it, in fact its the same technique I use for vertical and hole filling sometimes.

 

[moggyjnr]

Ok guys thanks, multiple tacks is the way forward. Works well. Almost finished the job and looking good

 

[normspanners]

One problem might be your earth, if you set up settings to account for a poor earth for one run, then the lead arcs and cleans the clamp/metal and you get a good connection for the next weld, then your power will be too high.
making agood earth connection is vital for consistent welds