Roof bracing sealant question

Beechwood45789

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So I have my roof skin on my 69 super bee all fitted up, screwed in place and ready to go. There is a fair sized gap between the braces and skin. I am using 3m NVH between the two pieces. My plan was to use the port a power to push up the braces to meet the skin so the sealant isn't bridging a gap. But after doing a dry run and seeing the braces come back down after letting off the port a power I'm nervous that when the sealant sets up and I remove the jack, the braces will pull down creating low spots in the roof. So I need a second opinion before I proceed, do I just bridge the gap with sealant or push up on them and potentially risk waving out a 900 dollar roof skin?
 

Beechwood45789

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Hell nevermind I have a better idea. Take the roof skin off, jack the braces up to bend them to where they need to be, then test fit the roof again. Duh. I'd delete this thread if I knew how.
 

4406bbl

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The braces and skin should not actually touch 100%, the nvh fills the gap and stops the vibration/ print thru to the outer skin.
 

Beechwood45789

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The braces and skin should not actually touch 100%, the nvh fills the gap and stops the vibration/ print thru to the outer skin.
Yep thank you sir. I had probably a 3/4 inch gap where I was wedging a shrinking disc in there trying to save the old roof skin. Loosened my set screws and raised my braces to almost touching, now I'm sealed up and welded out, right as rain.
 

rich hourigan

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Thanks for recommending the 3M product, The project car im working on has the loose roof skin to roof bracing thing happening. I was wondering what product i should use... i do have a question... would you apply this product to the whole length of the roof bracing or just stitch it in where the big gaps are present.. thanks Rich
 

4406bbl

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Either way, ideally you could shim the roof with a cedar shim slightly, one area at a time to get a little in where the factory daubs are to restick those, then add a little more elsewhere. Nvh will not expand or shrink like some other adhesives so you are pretty safe no matter what you do.
 

Bighouse

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Take a look at “anti-flutter” foams. SEM makes quite a few. It’s a soft-expansion and will not upset the position of the outer panel.

Some products can push and pull and create more work. This does not have to be such a strong adhesive, more of a fill and stabilize product.
 

zyzzyx

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I used the SEM product for the underside of my hood and it's a similar product. Works great and I was glad I
had a friend with a bodyshop that I could borrow the gun from instead of buying one! Just remember to block
the roof with a board because no matter what you do, there will be low spots and high spots! This is a pic of my
68 GTX with no work done to the roof. Notice the low spots where the braces are!!!!!
DSCF8651.JPG
 

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