How to prep freshly welded/repaired metal ?

I'm going to be handing my mk1 into a local welder/fabricator to cut out rot and replace with new metal/panels for the following areas:  rear beam mounts, inner sills, Both outer sills and finally drivers and passenger side (inner and outer) arches.

Although his welding is really good, he isn't exactly a panel beater or sprayer so I was wondering what are the best  steps to treat fresh metal…. I had the following in mind.

1) Zinc Primer the repaired area
2)Seam Seal joins and any  open seam welds
3)top coat ( I was told never to leave bare primer as this absorbs moisture which attracts rust.. I woundn't be able to afford a  complete respray after the big bill for welding so any top coat i.e rattle can shoud be fine?)

Any hints or tips would be greatly appreciated..thanks in advance!
 

Sounds about right.

If you can add a polyurathene sealer after the Zinc Primer this helps with the moisture absorption problem as the Zinc Primer is there as an anti rust protector type thingy.

Seam sealer can be used although the old skool way is to use lead. There is a guide in the guide sections. It's extremely well written and very informative! (ok I wrote it, so it's probably not that good, but does give an idea!)

You'll also need to add a few layers of primer and sand this back until it's smooth (use around 600 grit for this bit)

Then top coat in your colour of choice.

Then depending on if your car is a metallic or not:

Metallic - DO not sand the metallic paint but apply clear coat as another coat to the colour you've applied. Allow 15 minutes for a flash time between coats. At least 2 coats of colour and 2 coats of clear.

Non Metallic - Sand if desired between coats of colour (around 1000 grit) then clear if required (you can sand between coats for a really smooth finish)

Then once all dried (at least 4 weeks) rub down with 2000 grit and plenty of water and use a machine polisher to bring out the shine with different compounds.

That ended up being far a far longer post than I was expecting!  

Good luck

Ian

Just re-read your post to make sure I was answering correctly!

the above will work fine for the arch repairs. Don't use seam sealer on the outside!

For the underside Zinc Primer and seam sealer.
Then a couple of coats of primer, then an underseal of some sort. POR 15 do some good ones as do Eastwood (avalaible at Frost Restoration) or a shulz or some sort of Truck Bedliner also works well.

I've used Raptor bed liner on the underside of my restoration and it seems to be on there quite well. Doesn't like fuel though!

Ian

Etch primers always good for bare metal .
Sealant where it needs it. And stone chip in a cans ok for sills
You can buy 2pack in aerosol cans now and the finish is amazing.
Also they will mix your colour to body code.
In northants we use Sayers paint supplies