I didn't find it difficult but that's me. I cut both panels at once and that leaves a perfect gap for welding...

What if you overlap, plug weld and hold in place with clecos, then do a seam weld on the bottom an grind smooth? No lip, overlap on the inside to make it simple and then either seam weld the inside or seam seal after plug welding...?

That would work and be strong but it is twice the welding so twice as much heat and or time. Your welder is son or son in law? ask him what he thinks. I suspect the butt welds would be child's play for anyone who welds for a living. I actually find the welding to be the easy part it's the grinding that seems like work...

, he loves grinding... It is an art form to him.

I too like the idea of no seams. Butt welding is not difficult I suppose but the possibility of pinholes concerns me. Especially if you are spot welding in a ring over and over versus a straight seam.

That is what the skim coat of fiberglass is for...knock it down, prime it. Perfect...

I remember you posting that. Good advice.

I've been butt welding mine except where the floor pan welds to the rocker panel. Half the welding and grinding and no overlapped seams to eventually collect moisture. I have more trouble with patience (letting it cool) than I have either type of joint.

I've been butt welding mine except where the floor pan welds to the rocker panel. Half the welding and grinding and no overlapped seams to eventually collect moisture. I have more trouble with patience (letting it cool) than I have either type of joint.

Ditto,

Hate waiting. I use compressed air to help cool things down but I still hate the waiting

 Patcon

  When cooling the weld with air do you notice any warpage? I realize the weld probably adds enough stiffness to prevent much warpage. The reason I ask is the other day I was working on my hood when my neighbor came over and asked me if I had ever shrunk high spots with heat and compressed air? He has restored a 52 Pontiac and a 54 Studebaker, both look good. He explained the process, heat it with a torch (not too hot) and control the shrinkage with compressed air. I don't have the courage to try it. Especially on the thin sheet metal of a Z. Z hoods are thicker than some of the other panels but I'm not going to experiment on a reasonably straight hood.

 Curious if you've tried it or even heard of it?

Since this topic has been revived I'll use it to ask a question that I haven't seen addressed in any of the floor threads I've seen.  I have two reinforcement pieces welded to the inner rear underside of each floor panel.  I outlined them with blue tape in the picture.  There is also the reinforcements for the transmission support.  

 

So what do you do with these?  Cut through them?  Separate them and re-weld?  Cut around them?  Remove and replace them with new?

 Depends on the condition of the sheet metal of the body, the doubler and the surrounding area. If there is a possibility of rust between the layers, They should be separated and treated or replaced. I've replaced and added a few doublers (fish plates) on mine. 16g galvanized sheet metal with zinc rich primer on the body is my choice. In lieu of those options, a good rust converter should be used. I'm going to be using Ospho on the rest of mine. Wish I had looked into it previously. I don't mind rinsing some areas with water but I can't bring myself to use water to rinse the seams out. Ospho, it appears, can be left to dry.  

 Patcon

  When cooling the weld with air do you notice any warpage? I realize the weld probably adds enough stiffness to prevent much warpage. The reason I ask is the other day I was working on my hood when my neighbor came over and asked me if I had ever shrunk high spots with heat and compressed air? He has restored a 52 Pontiac and a 54 Studebaker, both look good. He explained the process, heat it with a torch (not too hot) and control the shrinkage with compressed air. I don't have the courage to try it. Especially on the thin sheet metal of a Z. Z hoods are thicker than some of the other panels but I'm not going to experiment on a reasonably straight hood.

 Curious if you've tried it or even heard of it?

Mark

 

My brother has his own body shop and has been at the trade for about 30 to 35 years.

I watched him straiten and smooth both the hood and roof on my Z prepping for paint.

The roof was dented due to being sat on some where in a previous existence and the hood he just got fussy.

He used the heat  and just worked the metal that way.Using expansion and contraction and a little impact here and there.

That is something you will not see today but he spent about 10 hrs just working on the metal before he skimmed it and started blocking everything.

With him it is pride in his craft plus he didn't want his big brother to pout

The roof is really good but the hood is amazing how absolutely straight it turned out.