Sill Welding - The Thin Metal Technique?!

[onenastyviper]

Hi huys, thanks to reading this forum () I can now stick two bits of metal together ().
Welds look clean and I am getting good 'penetration'.
I am using a clarke 160TM together with a bottle of Argoshield light and practicing on small squares of 1mm thick mild steel and I can use the thin metal technique. I only get the odd small pin hole when I try to weld over a tack but I think I have to grind them down some more. The only problem is that with such small pieces, they distort and 'cup' upwards with the weld bead.
That's the background now my question, I am practicing so that I can weld my car - it has some rust holes on the bodywork and on the sill.

From what I read, MOT structural welding must be continuous, does this mean that I cannot use the 'thin metal technique' to patch the rust hole?

PK

 

[BChild]

From what I read, MOT structural welding must be continuous, does this mean that I cannot use the 'thin metal technique' to patch the rust hole?

PK

Thin metal technique still results in a continuous bead of weld

As opposed to 4 tacks in each corner and then a big dollop of under seal

 

[onenastyviper]

Good to know, I was getting a bit worried about how can I weld the thin metal together without using the method.

Thanks :happy:

 

[scotclayshooter]

Is that what i call trigger welding? On then off just before it burns through and on again just before it cools.
Setting the clear delay on the mask a bit longer than normal works great rather than going clear black all the time.

The joys of learning to weld on 80s Fords!
I remember tying to do a battery tray on my XR3i it was welded around the repair panel off the car and siliconed in place! Looked good and was secure LOL

 

[Chickenjohn]

another quicker alternative is what I call the "short seam thin metal technique".

You can tack the repair piece in, then add more tacks till they are 1/2 inch or 1cm if you are Euro apart. Then run short seams between the tacks. This is possible on thicker structural steel, i.e. 1mm, 1.2mm such as you find in sills. Don't forget to weave! A tiny wiggle during welding across the join between the two pieces makes the weld look a lot nicer and (I think) spreads the heat so you don't blow through as much.

If you do have small pinholes left in the weld, just fill them with more weld and grind down.

 

[onenastyviper]

How much do I have to worry about the paint and other stuff on the other side of the sill panel?
Cleaning it to shiny metal is easy on the outside but internal access for around the patch area will be difficult...

 

[Chris Stevens]

How much do I have to worry about the paint and other stuff on the other side of the sill panel?
Cleaning it to shiny metal is easy on the outside but internal access for around the patch area will be difficult...

Welding patches on sills is very easy, but most beginners have to face using very poor Chinese MIG sets, that generally are running .6mm wire, which makes things rather more difficult.

To weld a sill patch successfully, you need to clean base metal very carefully (wire wheel on an angle grinder is the best thing to use), and make sure the edges of the patch extend well beyond the corroded area.

Then using 1.5mm MS sheet cut your patch to the correct size, clean up the patch front and rear adjacent to where you will be welding, and tack weld it to the rotten sill.

Next step is to fully weld the patch to the sill, and using the 1.5mm patch material makes this easier, as heat can be directed into the patch, which makes welding faster and reduces possibility of burn through.

All patch repairs can be carried out in pretty much the same way, but it does help to use .8mm wire if you have a welding set that has the power to run this properly.