6 replies to this topic

[jackclancy]

Hi all. I was attempting to weld in a new rectangular patch to the Mini floor earlier. One side of the patch was totally fine, but when I switched to all the other sides - the car bodywork just kept melting and creating holes. I had to get a bit creative with it, managed to sort of botch it in the end, but I know there's probably a simple reason this is happening. I turned the welder down to its lowest power and it still happened. 

 

If anyone could help that would be great!

 

Thanks

[Avtovaz]

there could be loads of reasons with out sounding unhelpful! But posting a pic is always the best thing. 

 

It does sound a bit like the one side was on good metal , and the others had rust in them that made it thin maybe. Did you "dot" it or try to seam weld in in one go?

[jackclancy]

I sort of managed to do it by welding an absolute tonne (if that makes sense). Ended up with quite large lumps. I would try and weld the two bits together and then a hole would form, then I was having to sort of fill the holes in. I.e not just spots. But I was attempting to do spots yes!

 

The car body isn't rusty at that point!

 

Its all welded in now and dont have pics of it mid progress. I can get a pic tmrw!

[jackclancy]

I hasten to add this was my first time welding haha!

[sonikk4]

So was it a cut out and you welding in a repair patch  (butt welding) or just laying a patch over??

 

If it was the first, what was the gap like all around the patch you were welding in?? Too big a gap and it will be an utter nightmare unless you have a copper backing piece.

Too small and the weld will pucker up creating high spots. 1mm gap is a nice width.

 

Laying a patch over, ideally pulse welding will see you through nicely, however this is all dependant on your power setting and wire speed.

 

What were you welding with, MIG with gas or gasless?? Gasless takes time to master, gas is more forgiving but like anything correct metal thickness, cleanliness of the metal is paramount. And a very good earth as well for your earth clamp, shiney metal is your friend here.

 

And of course power level and wire speed.

[bikewiz]

As sonikk4 says using a copper backing plate will help with blow through.

 

Try practicing on some scrap to get your settings right before you go at the car.

Edited by bikewiz, Yesterday, 10:07 PM.

[68+86auto]

Cheap welders have too high of a minimum voltage to easily do thin steel. My welder is designed specifically for welding car panels so has a very low minimum current.