Crack Repair
Thread Starter
Instructor
Joined: Aug 2004
Posts: 142
Likes: 1
From: Minnesota
Crack Repair
I've read Lars & Butch's Tech Tip on Paint/Repair, but am looking for more detail in how to repair stress cracks like in the pics below. Does one need to sand all the way THROUGH the panel before building back up, or just sand the crack into a "V", or what? I want to make sure these cracks don't show up again after slaving over this paint job for so long...
Any info or links would be appreciated!
-=Boston!=-
Any info or links would be appreciated!
-=Boston!=-
Instructor
Joined: Jan 2004
Posts: 242
Likes: 0
From: Manchester Mi
getting mine repaired and the stress cracks in mine he is cutting out and re-glasssing, body man claims if he doesn't do it this way it will only be a temporary fix and they will show back up in a year or so
Drifting
Joined: Oct 2003
Posts: 1,426
Likes: 1
From: VetteMOD
St. Jude Donor '05-'07
I am interested in this also. I have a spider crack in my hood from some numbnutz put too tall of an intake on it and the aircleaner wingnut spider cracked the hood.
Also, my car was apparently hit in the front and the aluminum headlight door was bent. The door was bent back into place but the bend was too sharp and the resultant crack in the aluminum eventually witnessed through the paint.
Shouldn't these types of stress cracks be "V" cut as suggested and filled with an epoxy/glass mix (regardless of fiberglass or aluminum)?
Also, my car was apparently hit in the front and the aluminum headlight door was bent. The door was bent back into place but the bend was too sharp and the resultant crack in the aluminum eventually witnessed through the paint.
Shouldn't these types of stress cracks be "V" cut as suggested and filled with an epoxy/glass mix (regardless of fiberglass or aluminum)?
Racer
Joined: Nov 2000
Posts: 415
Likes: 0
From: mauriceville texas
You must stop the crack or it will come back. You can drill a hole at either end and grind the entire crack out. Take a full coke can and wrap sand paper around it. this will give a nice channel to lay the new glass. Then you can build it back and sand down. this works great on bodyseams. I am in the process of doing this on a 71 vert now. It works. and is forever. I learned this little bit of info from Mike (trackdog). He came to my shop and showed me first hand. He is outstanding with bodywork maybe he will get in on this. Robert
Drifting
Joined: Jan 2005
Posts: 1,389
Likes: 9
From: Seabrook Texas
St. Jude Donor '05
I have a hairline crack that is about 3 inches long on the passenger fender and runs to the inside of the hood. how should that be fixed if you can not drill 2 holes? Thanks for the help.
Melting Slicks
Joined: Oct 2001
Posts: 3,025
Likes: 12
From: Pleasant Grove AL
The cracks should be V'ed at about a 30 deg angle and cut down more than half way through, but not necessarily all the way through. Either stop drill as previously suggested, or simply extend the V past the ends of the crack a half inch or so. If it's a small crack, it can be filled with short strand fiberglass filler, if larger, it needs the long strand stuff. On the larger cracks you can buy long strand filler, commonly known as "Tigerhair", or you can use resin with chopped up glass mat. After you have worked that down to contour, youstill need a thin layer of body filler or glazing compound over the fiberglass. Do not paint or primer directly over the glass. After this, a layer of 2K primer is best, but I don't think you can get that in a spray can. There are some urethane primers you can get in a spray can, if that's what you are using. Check at your paint supply store and ask what they recommend to go over FG.
If you have one of the newer cars with SMC panels vs the older GRP panels, be sure the resins you are using are compatible.
If you have one of the newer cars with SMC panels vs the older GRP panels, be sure the resins you are using are compatible.
