So, I am choosing to completely weld the seams where the Rear Deck filler meets the quarter panel. My question is, do I need to fill the low spots with another weld, or filler? What would you all suggest?
Seam sealer! :yes:
When you say rear deck panel you mean the panel that extends to both quarters that the rear glass sits if that is the case I wouldn't keep filling that with weld the more heat you put on it the worse distortion is going to be. I would fill the rest with short strand fiberglass.
Just another thought if you keep grinding into the adjacent metal you make it super thin and worhtless
Do not use fiberglass. Eventually it will delaminate and rust will appear.
Short strand fibreglass is stable as hell and I've never seen it come off/deteriorate in the 30+ years I've been using it. Regular cloth or mat fibreglass? Well, that's a different story. The first stuff we saw in the 70's and 80"s was called Tiger Hair. It was and is waterproof and much stiffer than regular old bondo. And, it's in those grooves on my car, so I guess we're both taking our chances, eh? :cheers:
Can't he just continue to weld it closed as long as he welds it slowly / a little bit at a time, to keep it cool? Then file it flat?
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Welded properly, there would not be the low spot(s) like in your picture. The panels should have been butted together and the weld would have filled and built up above the seam. There would be no low spot after grinding.
I'll be doing the same job soon. How big was the gap when you started?
Its just not necessary to completely fill that seam with weld
With the rolled edges at the quarter and deck filler, there is quite the gap to fill with a quick weld (to avoid too much heat) to fill. I can definitely make additional passes to build it up, but don't want to risk any distortion.
Once the panels were clamped and welded together (before filling the seam with weld) I held a straight edge across the top and would say that the gap was about 1/4", reducing down to nothing. If you looked at a profile of the gap it would be like the drawing below.
If I'm doing the same the same fill job, I'm thinking of silicon bronze filler on top of weld. How compatible is the silicon bronze with paint and body material?
Quote from: jimynick on May 17, 2020, 07:17:44 PM
Short strand fibreglass is stable as hell and I've never seen it come off/deteriorate in the 30+ years I've been using it. Regular cloth or mat fibreglass? Well, that's a different story. The first stuff we saw in the 70's and 80"s was called Tiger Hair. It was and is waterproof and much stiffer than regular old bondo. And, it's in those grooves on my car, so I guess we're both taking our chances, eh? :cheers:
Fiberglass resin does not expand and contract at the same rate as sheet metal and will eventually delaminate. At this stage of the OP's repair I recommend using a two part epoxy preferably JB Weld. JB Weld works great as a body filler and has the tendency to self level making it easier to finish the work. JB Weld expands and contracts at a similar rate as the sheet metal. I have used it with great success. :yes:
I would be more concerned about body flexing! that is why i suggested seam sealer. :alan2cents:
Quote from: IRON MAN on May 18, 2020, 11:00:59 AM
JB Weld expands and contracts at a similar rate as the sheet metal. I have used it with great success. :yes:
Were you the one working on my 73 back in the day? It ended up with what looked a lot like JB 1/4-1/2" thick for two feet all over where the passenger rocker got bashed in. That repair was there for a long time and it was hard to find. The metal repair work was horrible but the mud work was really good.
I wouldn't hesitate to fill that shallow seam with good quality reinforced filler. There isn't much flex in that area and with the two panels fully stitched, they aren't going to be able to move relative to each other. Either way, its likely to get a light coat of filler even if you were to weld it all and grind it down. You will never work that area flat with the flange seam under it.
I'm curious about the brass brazing. Would that work well?
Would the paint adhere to the brass the same as the metal around it?
Quote from: cuda hunter on May 18, 2020, 01:56:40 PM
I'm curious about the brass brazing. Would that work well?
Would the paint adhere to the brass the same as the metal around it?
Yes, the brass must have all the flux removed and be clean. heat warp-age could happen if not careful. Etch primer, serfacer primer, fillers will adhere to the brazed area. They make a set up to MIG weld instead of using a torch now. :alan2cents:
Quote from: gzig5 on May 18, 2020, 01:13:32 PM
Quote from: IRON MAN on May 18, 2020, 11:00:59 AM
JB Weld expands and contracts at a similar rate as the sheet metal. I have used it with great success. :yes:
Were you the one working on my 73 back in the day? No, not me. I live in the SF Bay Area.
Quote from: gzig5 on May 18, 2020, 01:13:32 PM
Quote from: IRON MAN on May 18, 2020, 11:00:59 AM
JB Weld expands and contracts at a similar rate as the sheet metal. I have used it with great success. :yes:
Were you the one working on my 73 back in the day? It ended up with what looked a lot like JB 1/4-1/2" thick for two feet all over where the passenger rocker got bashed in. That repair was there for a long time and it was hard to find. The metal repair work was horrible but the mud work was really good.
I wouldn't hesitate to fill that shallow seam with good quality reinforced filler. There isn't much flex in that area and with the two panels fully stitched, they aren't going to be able to move relative to each other. Either way, its likely to get a light coat of filler even if you were to weld it all and grind it down. You will never work that area flat with the flange seam under it.
I agree both edges of that seam were they meet at the top have a gentle roll that is slightly raised it will be a tough area to blend in without skim coating the deck into the quarters and down the trunk.
Convertibles don't have that seam present. What did the factory do for them?
Quote from: larry4406 on May 19, 2020, 03:25:28 AM
Convertibles don't have that seam present. What did the factory do for them?
Lead I would think. Like the roof seam and rockers to the quarter. That is another option. Brazing is going to put a ton of heat in the panel unless you are very experienced. The least chance of warpage would be to MIG it or lead. Either way, there is going to be filler, no way around it. It's not a terrible thing if done well with quality products.
Quote from: larry4406 on May 19, 2020, 03:25:28 AM
Convertibles don't have that seam present. What did the factory do for them?
Whatever they used for that, didn't last, all my convertibles (had 3) cracked there.
Again, :yes: BODY FLEX.
Ok, it looks like I am leaning toward the seam sealer option. Now for my next question, is it sandable?
You might want to add something to the paint to make it more flexible if you have a softer material underneath, as you would for rubber bumpers Otherwise the paint might crack where the body flexes. But I'm not an expert on this. Just some thoughts.
Modern clear will flex to a point. Axalta FKA Du-pont dose not recommend using flex agent. 3M urethane will stay pliable with grease and wax remover applied over it. use a cloth or your finger to trowel it. most body shops do it that way. So to answer your question no you can't sand it. :alan2cents: Even after seam sealer is set up, app lie a little grease &wax remover to it and it will soften back up. I would prime the bare metal then seam sealer applied. :alan2cents: