Frame Rail Welding Help

[mike357]

I have been working on the 86GT frame rail installation and have hit a wall with welding the thick frame rails to the thin floor pan. A lot of spatter / popping and ugly "earthworm" welds with one blow through and then I stopped. I know I need to have the welder (LINCOLN mig - pro 135) set so I get good penetration to the thicker rails. Welder settings I have been chasing are 5 - 6 on wire speed and C arc setting + gas. Attached is a picture of the frame rails when I started cleaning up some of the proud contact points keeping the rails from sitting flush to the floor. It only took a few small grinding attempts to get them to fit very tight to the floor.

Problem: The rails are much thicker than the floor pan. The rails are like 1/8 " thick. I cleaned and ground to bare metal the floor where the rails will be welded along their length. "Then", A possible contributing factor to my welding issue is "After" I cleaned the floor and rails to bare metal I sprayed the areas to be welding with Eastwoods Weld through primer...It looked lie a good idea to help control spatter. Spatter, pops and ugly welds that I'll be grinding off until September!


I would appreciate your advise on the weld problem. Note; not so easy lying on your back either!

Thank you

[mudgepondexpress]

Concentrate the heat on the rail then angle back to the floor, a kind of stitch pattern. If welding something like this I usually set up a practice piece to get the settings and pattern down, You have to set the head to penetrate the rail, then use your pattern to transfer it to the floor. If there is a lip, you should drill holes and plug weld it first. Plug welding is much easier to do with dis-similar thickness metal.

Good luck
Kenny

[michaelg10]

Drill holes in the floor pans and plug weld from the top. You wont burn through the floor pan that way while ensuring a good weld. No need to stitch weld if you space them every inch or so, like the factory.


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