Welding seam protection

rustover

rustover

Member
I'm currently working on fitting the crossrail to the Camaro. I've had to cut the piece in a few places and weld back together. As far as the weld seam goes I have finished both sides (front/back) and have checked for pinholes in the dark with a bright light and didn't find any. I have sanded and re-sprayed the epoxy on the backside. Once installed it will be up against the trunk pan and inaccessible. At first I thought I might also put some seam sealer over the weld on the back side, but after applying two coats of epoxy I think it's good and nothing else is needed. What do you guys think? The other red is weld through primer and I just removed about a dime size around the plug weld and then scuffed the epoxy in the other areas and applied the weld through.

I also had a little left over and brush painted it over the weld seam on the front side. There was a couple of places that the metal shrunk along the seam and you could barely see a hint of the weld seam. Once installed I will sand and respray the front. The back will be repainted when the car is on the rotisserie after the tail pan is welded. I also plan to use the transtar cavity wax.

Its a lot of work, but I'm trying to make it very difficult for it to rust again. Do you guys have any other suggestions. Thanks. Russ









 
Given that it is highly unlikely this car will ever see road salt I think you are good to go.

Don
 
Looks good to me. Like it has been stated it probably won't see the nasty elements but if you want you could flood the seem with epoxy the best you can or use a cavity wax and flood it with that if you wish.
 
throw away any weld through primers and stick with the good stuff, epoxy.

I blast both parts, epoxy them, prep my holes, them assemble. I clean out epoxy from the adjoining panel by the use of a squared off drill bit or endmill. I weld happily away at a high heat setting, and its about as good as one can get. Any more grinding than that is removing more than you need.

Another gentleman on this site and others has a BEAUTIFUL walk through of this process, with pictures and everything. Anybody have a link?

Marty
 
Marty Comstock said:
throw away any weld through primers and stick with the good stuff, epoxy.

I blast both parts, epoxy them, prep my holes, them assemble. I clean out epoxy from the adjoining panel by the use of a squared off drill bit or endmill. I weld happily away at a high heat setting, and its about as good as one can get. Any more grinding than that is removing more than you need.

Another gentleman on this site and others has a BEAUTIFUL walk through of this process, with pictures and everything. Anybody have a link?

Marty
Click to expand...
I pretty much only use epoxy now as well.
 
Thanks guys. I have seen that process on Robert's thread. I have tried just the epoxy and I must be welding it too hot because I always cause the epoxy to catch fire and this lifts it in certain areas. It's something I need to experiment with and dial in.
 
Looking at the pics in the order you have them I was thinking you cleared the metal raw for welding and then was going to do something. That would be the best way to do it, don't use weld thru primer because I feel that is a waste of time and do sent do anything. Clean the metal about an inch away from the intended weld area and weld, then flood with epoxy the best you can then if you would like you could use cavity wax spray and flood again but the Epoxy will hold off rust best.
 
rustover said:
Thanks guys. I have seen that process on Robert's thread. I have tried just the epoxy and I must be welding it too hot because I always cause the epoxy to catch fire and this lifts it in certain areas. It's something I need to experiment with and dial in.
Click to expand...
let it burn, when you prep it to re epoxy, anything with no adhesion will go bye bye. Anything burnt inside the seam, well, nothing will handle that, so your epoxy is now protecting it better than anything possible.

I have never used the term "I welded it too hot" anyway ;-)
 
I was under the impression weld thru primer reacted to the heat of a weld and just flowed the copper coating. Has anyone ever tore apart an epoxy or weld thru primer to make a comparison? Im not saying one is better than the other, I honestly do not know but it would be a logical assumption that weld thru primer is more suited to a weld than epoxy primer? No?
 
Outlaw;n82121 said:
I was under the impression weld thru primer reacted to the heat of a weld and just flowed the copper coating. Has anyone ever tore apart an epoxy or weld thru primer to make a comparison? Im not saying one is better than the other, I honestly do not know but it would be a logical assumption that weld thru primer is more suited to a weld than epoxy primer? No?
Click to expand...
Almost nobody here thinks so, I have my own opinions but on this I keep it to myself.
 
I have seen personally no benefit to using weld thru primers in fact there have been times that it caused the weld to look like chicken s--t and rust began just as fast as though it was left raw, creeping between the 2 panels. Once I seen that I sword off that stuff not to mention I highly doubt anything can survive the heat of molten metal (the weld puddle) and the heat around it (it does kinda get warm).

So with that my position is to address the issue with Epoxy flooding as best you can after the welding is completed. Prepping like what was done in the pics (except for the weld thru primer) then flooding after welding would be a good way to do it. Everybody has their own way to address it and that's close to the way I would do it.
 
There is no way that any weld through coating has the adhesion and corrosion resistance epoxy does. The shop I work in, they used it until I showed them (they overused the hell out of it) that it scrapes off with so little pressure it isn't funny. They thought it was good stuff, sprayed it everywhere, then epoxied over top of it. If you were able to put it EXACTLY where it may melt, and no further, Id try it. Till then, I epoxy, and let the heat do what it does. Good marketing doesn't always make a good product.
 
The places where I use weld thru, Im not sure I could ever "flood" with epoxy. If I can get any epoxy to it, I would definitely use that method over weld thru.
 
Thanks to all the replies guys. I really appreciate it. I'm going to experiment on using just the epoxy. The weld thru is not cheap, so saving money is always good. Any idea on a cure time for epoxy before plug welding? I know some of it will burn away.
 
You will still want to clear out where the weld will go, like using a wire wheel on a drill to clear the plug hole after fitting. It would be safer to wait until dry, think safety first.
 
I thought this was interesting. 56 chevy 1/4 panel to trunk channel seam tinned by the factory. It is definitely original.

cd3a8186-883e-474f-a8cf-1841aeda8c99_zpsciiew8fm.jpg
 
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