penitration problem

[GSP]

Hi I am new to the forum and learning how to weld. While working on an old car restoration, I decided to ask for some help on trying to repair the end of an inner sill. The piece I posted is a practice piece that I have cut long ways to show the inside and the back of the weld.

The pieces are dirty, but when I do the final weld I will not be able to get to the inside of the pieces anyway. My problem is I cannot get penetration 80% of time. I have the welder on high amp and 6 on the feed.

Thanks Steve

 

[Misterg]

Hi, and welcome.

Are you trying to make 'plug' welds? . If so, try making bigger holes (7 or 8 mm say).

 

[BrokenBiker]

What welder are you using? Car repair panels should rarely need high voltage settings unless you are using a very small welder

 

[tom2207]

welcome to the forum

You cant weld rust ,,, you need a silver line / edge all the way round , for that sort of job I would be drilling a 10mm or 12 mm hole and welding the back plate and work my way out to the front edge ,,,, but its looking like you may be lacking power ,,, good that youve started on something that isnt the car though ,,,,

 

[Erie Fred]

What welder are you using? Car repair panels should rarely need high voltage settings unless you are using a very small welder

Listed welder is "Sears" ..... they sold the little 120vac lunchbox MIG welders.
I don't recall ever seeing a 240 vac version (like Hobart/Miller/Lincoln)

 

[GSP]

The project car is a 1955 tr2 if you guys are car people. Anyways I am re-attaching on the car the last few inches of the inner sill. I chose to use some 20 gauge black plate steel, the metal has a thin coating of something black ,probably a common coating for this stuff.

I cut 2 pieces of the 20 gauge about 16 inches long by 3 inches wide and inserted them into the inner sill from an opened end. Previously, I drilled 6 holes in still, so I could weld the 20 gauge to the sill from the outside.

I welded 4 of the holes up and thought I was doing well with penetration, but when I went to weld the last 2 holes the weld did not penetrate, but looked good on the outside. There is a difference with last 2 holes because I forgot to remove the black coating and could not get to it. Oh the holes size was 5/16.



Some of my thoughts are did I have the weld too high or is that posible

Could the black stuff stopped the weld cold? Every spot in the area was red hot as I was welding

Should I spend more time in the new piece or the old piece when welding?

I appreciate in any put, idea or whatever.

Thanks

Steve

 

[Blobber]

We like cars! Start a thread in the projects section
The metal still looks rusty? Certainly whatever coating won't help the welding

 

[Misterg]

I chose to use some 20 gauge black plate steel

Could the black stuff stopped the weld cold? Every spot in the area was red hot as I was welding

YES!

The black is mill-scale and needs to be removed before welding. You might find getting it off enough of a PITA to scrap the black steel and get some cold reduced / bright steel sheet instead.

 

[BrokenBiker]

if you are using a low powered welder, the only option is to weld on clean, shiny metal. rust, mill scale, paint, primer, galv spray etc will all hinder penetration unless you have the power to burn through it and mig isnt really the way to go for that sort of thing.

clean it all back and you should see better results