Plug welds.

[SmashingPunkFan]

Plug welds in the trunk pan and braces... I couldn't get any of them to stick to the frame.

The new pans, perfect penetration,  the old frame rail was not phased.

I have a Hobart handler 140,  machine set to 3/35ish. Single pass of Sem weldthru primer.


Any help would be amazing

[cdr]

on mine I had to use a small sand paper roll & remove the primer at each hole.

[Pete in NH]

Hi,

I too, would try cleaning off the primer in the weld areas. Also, remember the floor pan must be in tight contact with the frame rail at the weld area.

The frame rail is a much heavier gauge metal than the floor pan and it will take more heat to weld/melt it than the thinner floor pan metal. You may need to turn up the energy from the welder, allow more time to make the weld or try the trick of pre-heating the frame rail a bit with a torch. I would try pre-heating the frame rail a bit,  turning up the welder heat too far might risk burning the thinner floor pan metal.

[green69rt]

I also have a Hobart Handler 140.   I would guess your wire speed is too slow.  I use a wire speed of 45 with a current setting of 2.  For a current setting of 3, I use 50 or 55.  And yes make sure the very center of the plug weld is shiny metal to get the initial spark to take.  

Edit:  forgot to say that I use .023 wire.

[tsmithae]

As said, remove the weld-thru at the location of the plug weld.  Also, what size holes are you drilling?  I found stepping up one size on my drill bit greatly increased penetration on the framerail.  I think I went from a 5/16 to a 3/8 and that helped a lot for me.

[hemi-hampton]

I use a little hand held spot sandblaster to sand blast the weld thru primer out of my plug hole I'm welding. Then I got nice clean metal around my hole. Make sure the frame rail is nice clean metal & not rusty at all. And like said before you might have to turn up the heat a little for better penetration of the thicker steel frame rail. Good Luck. LEON.

[SmashingPunkFan]

Great success!  Switched up to a 3/8 drill, and held the weld dead center for about 5-8 seconds then filled surrounding areas.

Had it set to 3/28-30ish

They held, and I couldn't be happier.

[Troy]

I have a slightly bigger welder but any time I'm welding to a rail I use a setting that's slightly hotter than what I'd need for the rail thickness. The thick rail will act like a heat sink so you have to get it to melt first! Using a setting for sheet metal thickness won't even make it warm. But it looks like you figured that out!

Troy

[SmashingPunkFan]

I have a slightly bigger welder but any time I'm welding to a rail I use a setting that's slightly hotter than what I'd need for the rail thickness. The thick rail will act like a heat sink so you have to get it to melt first! Using a setting for sheet metal thickness won't even make it warm. But it looks like you figured that out!

Troy

Thanks Troy.
I checked under the frame immediately after the welds,  and the heat was visible through to the other side.
I think the trick was stepping up to a 3/8 drill,  it allowed the puddle to build with more heat longer before filling it all the ways up.
I'm just so happy,  I've had all my amd metal for 4 years,  and the welding in process is underway now.

[tsmithae]

Glad to hear that helped! The new process you are using sounds very similar to what I do and I get real good penetration with it.