Best use of Seam sealer, weld thru, etch primer etc.

[mrbodly]

Hi all

Going to be replacing the inner and outer sills on the van, I'll be doing a thread with photo's etc.

Now I don't want all that work to be in vain so I am after advice on the best products to use and where/when to use them, when it comes to rust proofing.

Is weld thru primer just for spraying the areas to be welded or can it be used to spray the whole repair area, rather than buying etch primer as well?

I assume seam sealer goes on after welding prior to primer. For instance where the inner and outer sill are spot welded together is it best to use sealer on the outside of seam as well as inside?

Is waxoyl the best option for spraying the internal cavities?

Apologies for the newbie questions but this will be my first stab at body repair. Any advice gratefully received.

Cheers
Myles

[mrbodly]

Also, do I need to use Vactan? I'm going to try and chop out as much of the rust as possible.

[boatbuilder]

Weld through is just for areas to be welded i.e. between the spot welded seams. Paint sometimes doesn't stick well on top of weld through primer because it's mostly zinc.
Seam sealer can go on bare metal or on top of a decent primer for example epoxy, doesn't really matter which way you do it.
Waxoyl or dinitrol or dynax is what most people use.
Vactan not needed if you're cutting out the rust.

[ZsZ]

I found that the seam sealer is better on primer. Always found some rust under it, when I put on bare metal.
I think the best if you get etch primer, filler, etc. matching together from the same brand. Had bad experience using filler/painting over Zinc spray and mixing 1 component paint with 2 component.
Waxoyl is not sold here so I dont know how good it is, but I am using FluidFilm and Motip together and seems OK since two years.

[waltraud]

I use dynax s50 in cavities, it is a better designed product than waxoil and im pretty sure it has won awards like practical classics for its corrosion resistance.

[Plasticman]

cut out remove as much as you can, then blast then vactan, then where you will be welding clean it up and weldthru, after welding blast something like rustoleum rattle can primer there is one that works well here(if yoiu dont have spraying gear) and use an airline with a windy gun end to blow it right in,
let it all dry and carry on with whatever you are doing ,when all finished filling /undercoating etc add seam seal and remove excess with spirit wipe, leave to dry then paint
mm