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Discussion Starter #1
I am part way in to this install. Old channel removed only a rough cut on the dash, well below the new flange. Question- is a lap joint reasonable here? or make a finish cut on the dash and butt weld?

Lap joint is stronger, but may possibly leave a place for rust, all though with a butt weld it is difficult to back paint the new seam.

Any advice is appreciated.

Dave
 

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I am part way in to this install. Old channel removed only a rough cut on the dash, well below the new flange. Question- is a lap joint reasonable here? or make a finish cut on the dash and butt weld?

Lap joint is stronger, but may possibly leave a place for rust, all though with a butt weld it is difficult to back paint the new seam.

Any advice is appreciated.

Dave
I think this would be a personal choice and why no real responses. Butt welds can be better in some instances, but you have to know what you are doing and know how to stitch weld so as not to warp things. Assume you have all your dash wiring & components removed, so painting underneath should not be an issue. A trick I use is to paint the bare surfaces or joining surfaces you are welding with high heat barbecue black used on outdoor grills. Let it dry as you normally would before welding. Seems to hold up pretty good under high heat and minimizes the amount of paint burned off. I would think you could get up under there to remove any of the loose & burned paint and scuff up the metal for paint. I like the Rustoleum rust reformer and I am also liking the spray can spray on bed liner that seems to put a hard cover coat on things not seen or black anyway.

If you over lap, again, clean/neutralize the rusted metal, and go with the barbecue black where they will over lap. Draw the pieces together with a few pop rivets, then stitch weld to keep heat down. Pull the pop rivets and weld up. Again, I might go with the spray can bed liner to seal up and coat the underside. Top side, if concerned about any seams or imperfections, I don't think I would use plastic filler, but something a little flexible like the fiberglass filler, or heck, might even get stupid and smooth over a coat of JB Weld on the entire seam and then sand smooth after drying. I sometimes use some non-conventional fixes that seem to work pretty good - and its my car and I won't be selling it anyway.

So there are some options if you have not already finished up by now. :thumbsup:
 

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Discussion Starter #3
Thanks for the input. I think I will use the lap except on the 6 to 8 inches near the A pillar and transition to a butt weld so the windshield resting surface is back to original. Because the dash metal is so flexible, it will readily tuck in under the new windshield channel.
Thanks PontiacJim
 

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Thanks for the input. I think I will use the lap except on the 6 to 8 inches near the A pillar and transition to a butt weld so the windshield resting surface is back to original. Because the dash metal is so flexible, it will readily tuck in under the new windshield channel.
Thanks PontiacJim
OK, sounds like it will work. The key is to get it right for the windshield. I often think, "It took this many years for it to rot out, I know at my age I probably won't be around to see it rot out a second time, so do I need to make it perfect or just good enough to last my life out?" LOL
 
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