[JimmyL]

What is the best way to fill in a roof insert so it will not leak or crack?

 

[lowROLLERchevy]

what sort of roof insert are we talking about ? what kind of car ?

 

[JimmyL]

36 coupe, orig metal roof, that had rubber around it, I have tack welded it in. To weld it in solid would be take too long and may warp it and I don't know how to lead it in. I have heard of some stuff called tigar hair. Just wanted to get some advice on what would work.
Thanks Jimmy

 

[BodymanDave]

You should weld as much as you can stand then use a fiberglass reinforced filler over the welds. Tiger hair is a fiberglass reinforced filler but the hairs are real long. Get a short strand or pulverized strand fiberglass reinforced filler...it's easier to work with. Then do the finish mud work with regular bondo/filler. If your working on a 36 Ford I just finished one and have a follow along on this project on my website. Might give you some ideas or help...Dave

http://www.autobodyoldcars.com

 

[lowROLLERchevy]

any time you do a filler panel like that you want to weld it in as much as possible. you want any flexing that the panel will do, to be transmitted right thru the weld and into the next part of the panel... if the flex stops AT the weld, the surrounding filler will crack

the best way to do the welding is to use spot welds to start, get the panel tacked in very well all the way around, then use slightly longer welds to start connecting the dots

use a blow gun to cool each weld after you do it , and jump around ... from 12 oclock to 6, then 3 and then 9 oclock ...

3/4 welded is the least i would recomend, fully welded is always the best

 

[adtkart]

Jimmy..... You said that wwelding it completely will take too long. It will take more time to re-do it when it cracks, and IT WILL CRACK. If you can tack weld it, you can completely weld it. Just take your time and go around doing little areas at a time.

Like the old saying. "If you don't have time to do it right. How are you going to have time to do it over"?

 

[troy-curt]

Hammer the welds as you go and weld it solid.

Troy

 

[MARTINSR]

Weld it solid or very near solid (quarter inch gaps MAX) or it WILL crack, period.

 

[BodymanDave]

I weld all my stuff solid I don't even leave a pinhole but I see some weird stuff. I repaired a 56 Chev that took a light hit in the rear. Shoved the bumper into the right Qtr. Here's the strange part..someone had put a replacement Qtr. bottom on the car at one point. They had tack welds around 6 inches apart,maybe 10 tacks or so down the whole panel.No kidding. Needless to say the replacement Qtr. popped loose. I knew the owner of the car and had seen the 56 numerous times and there was no cracking going on before the wreck. NOW don't do what I am describing.Weld stuff up solid. Just one of those strange things ya see when restoring old cars.

 

[troy-curt]

By welding solid there is less chance of moisture contaminating the joint.

Troy

 

[MARTINSR]

You are right on Troy, less chance of moisture (zero actually if it is totally solid), less chance of cracking, less chance of everything bad. Welding it solid is the best way by far.

Jimmy, I don't know if that is a 36 Ford but if it is, for goodness sakes weld it complete. Any nice 1936 car deserves it, but 36 Ford is one of the most beautiful cars ever made. It certainly deserves the little extra time to do it right.