8 replies to this topic

[pete l]

Hi all,

 

I'm replacing the box section that the front seats bolt to. I've got the old one off, cleaned everything up, zinc primered it all. And started welding it in. I'm plug welding, 7mm hole in new panel.

 

I scrape away the primer through the hole and wire brush it down. I've tried everything and can't get a good plug weld each time I weld, sometimes it's fine then the next one will be pants, it'll splatter when I start the weld. 

 

When I try on scrap metal (the old box section) my welds are great, everytime too, but when I get back to the car, it's rubbish. I've even welded a new earth plate on the new panel.

 

I don't know what I'm doing wrong or if the old floor metal is contaminated or of bad quality.

 

So, to all you good welders out there, (Neal  ) help me please.

 

Pete.

[gaspen]

Did you spay zinc primer on the scrap metal also?

 

Personally I hate zinc primer because it's splatter. You need a clean metal surface for welding. There is no paint or primer that withstand to the heat of welding.

 

After welding you can use primer to protect the metal from corrosion until it painted. 2K primer, seam sealing, and wax oil after paint will prevent your car from rusting.

[Ben_O]

Doesn't sound like a primer problem.

I'd be looking to see if the new panel is clamped tight enough to the floor where the holes are that you are using for your plug welds.

If there is any gap, you will get problems.

 

Hope that may help

Ben 

[sonikk4]

If it’s splattering that sounds like the metal you are welding the crossmember to is either contaminated or rusty.

OR what is your wire like on your spool?? Is that starting to corrode?

[pete l]

Thanks for the replies.

 

Yes I used the same primer on the scrap metal and it didn't cause any problems.

 

Ben, The top panel isn't clamped to the floor, I have nothing big enough to clamp it down. But it is touching, not sure if that means there's a gap.

 

Neal, the floor is clean and rust free and cleaned with 90% alcohol.

 

I've ran out of wire and gas, just been to buy some more.

 

Pete.

[sonikk4]

Thanks for the replies.

 

Yes I used the same primer on the scrap metal and it didn't cause any problems.

 

Ben, The top panel isn't clamped to the floor, I have nothing big enough to clamp it down. But it is touching, not sure if that means there's a gap.

 

Neal, the floor is clean and rust free and cleaned with 90% alcohol.

 

I've ran out of wire and gas, just been to buy some more.

 

Pete.

 

Pete, if there is a gap then that must be clamped down so have a look on ebay and buy yourself some 5/32 skin pins (they are blue) or use some small self tapping screws to pin it all down with.

https://www.ebay.co....SIAAOSwvrxhDQf9

 

This is a mixture of 1/8th (yellow) and 5/32 (Blue) Some people will say use cleco's, however they do not have good clamping force. BUT there are Cleco butterfly clamps which is what i use on my builds. Now these do clamp properly. However trying to find them outside of Aviation is not that easy. However i have found some 1/8th ones.

 

https://www.ebay.co....UAAAOSw4h1f39tl

[pete l]

So the panels have to be really tight together ? how tight is tight ? I'll have to try it and see how it goes, I do have some of these clips somewhere.

 

Thanks Neal.

[GraemeC]

As a temporary fix, try using a wooden hammer shaft to push the panel down hard whilst you try to weld.

[sonikk4]

So the panels have to be really tight together ? how tight is tight ? I'll have to try it and see how it goes, I do have some of these clips somewhere.
 
Thanks Neal.

Tight as in full contact with each mating surface.