[chas350]

Hello, 1st post here other than welcome area.
I am doing some repair on my 98 full size van. I replaced the lower quarter section from the drivers door back to wheel arch today.
I used SEM copperweld on the lap area, my first time using weld thru coating.
Boy did I have trouble mig welding that seem! It acted like I was using no gas on dirty metal, all bubbly and porous. I even ground down and tryed to repass over with soso results. Maybe I sprayed on to much? I thought it was dry enough. Anyhow I can't get behind this with a dolly to planish the weld and then scrink disc. So I need some body filler, I have a can of Rage, but the weld is full of pin holes. Should I prep or use something different to seal these first? Or maybe an all metal type filler that has alum in it?
I dont want the filler to start to bubble or some thing in 2-3 years.
Dont have a lot of experience with these newer fillers. My last resto was 18 years ago.
Any help would be apreciated much!

[BMM]

Typically you need a bit more heat to burn through the Weld-Thru, might help.

Duraglass (Fibre Reinforced Filler, Duraglass is technically a brand name I think) would be what you need. It's waterproof to prevent moisture coming in from behind.

That said, how big/plentiful are these pinholes?

[chas350]

They range from a pencil point down in size.
Some area's were impossible, for me, to weld proper, while others were not bad. I tryed extra heat/speed but it burned thru to quickly. This is not my 1st time welding, and acts like my gas is off or its windy. Or dirty metal/rust.
I was able to reweld some of it after grinding down and it looks decent. But its not working in other areas. I can't keep doing this while trying to keep it cool enough not to warp.
Thanks

[Countilaw]

as long as your weld is solid and continuous you can use a filler. But, is your is not solid the lenght of the weld, the filler will eventually crack through the paint.

So don't try to cover a bad seam weld with filler.

Frank

[BMM]

Precisely. If the weld is not strong, you're whoped. Now, the pinholes, I'd Epoxy it, then lay on some Duraglass. After that, you can move to regular fillers, just make sure the Duraglass is in nice and tight.

Being its a big ol van, I don't imagine you're going for a showcar appearance, so you could skip the Epoxy before filler, but alot of people here recommened it.

[sunsetdart]

You could also try Metal to Metal.........but I don't know about it sticking to anything but an epoxy primer or bare metal. You may have to bet the area free of the weld on primer.

[chas350]

BMM, what kind of epoxy? are you talking primer? or repair/adhesive type stuff?
what do you think about the metal type filler?

thanks for the replys

[chas350]

Ok, I stopped by a local autobody supply and they also said to use like an everglass type product. So the majority rules right? That settles it!
Thanks for the help, i am going out to the shop not to finish prepping and apply it.
later
chas

[baddbob]

If you want the best chance for long lasting success, apply two good coats of quality epoxy primer then do your duraglass work over it the next day. And you will also need to apply some kind of corrosion protection to the inside of that panel along the seams and weld areas especially-rust has already started to form in these areas as the weld was cooling-so stop it now! A cavity wax type spray works good in these areas like 3M's Rustfighter.

[BMM]

Or Fluid Film! Its cheap, but does a good job at getting into where it should.

Good to hear youre working on it!

[chas350]

BMM "Or Fluid Film!" quoted
Who makes this? Do I need a special application gun? lastly where can I get it?

Badbob, is the 3M stuff expensive? I need an undercoat gun? I know I can get 3M locally but fear it being 3M its gonna be expensive.

How about the Transtar expanding foam? It claims to seal and waterproof?

I did spray on rubberized undercoat to the entire back side of the new panel.

I sand blasted the existing inner panel and adjoining areas and undercoated this also. Excepting the seam overlap and plugweld areas were I used that blasted copperweld. I think the recomended 2 medium coats was to much!

Im sure any heat from welding/grinding probably didnt help the undercoating

I did use the everglass lite over the clean steel, and got my 1st coat of Rage over it. So its probably to late to epoxy primer it

Badbob, should I grind and sand blast it and eprime now? or just go on?
This is my work van So Im not going after the show type job, BUT I do drive this all winter with salt/sand on the roads and want it to last.

So......darnit, now what do I do

[chas350]

ttt please

[adtkart]

If I am reading this right, you sprayed undercoating on the pieces before you welded it? If that is the case, that may very well be part of the problem with your welding. Undercoating on bare metal does nothing for rust protection. It is more suited for a sound deadner than rust protection.

Looks like you should have ask questions before you did this project, as you have some issues to fix now.

Aaron

[MAUSS]

If I am reading this right, you sprayed undercoating on the pieces before you welded it?

No, he used SEM Copperweld - a weld thru primer... not undercoating.

[adtkart]

I did spray on rubberized undercoat to the entire back side of the new panel.

If there was undercoating in that area, then it will contaminate the welds. The heat will melt it, and then it is attracted to the heat/welds.

Aaron