Stopping cracks?
Thread Starter
Melting Slicks
Joined: Jun 2009
Posts: 2,709
Likes: 3
From: Savannah GA
Stopping cracks?
If the rear of my 1977 were steel, I would drill a hole in the "running" end of a crack to "stop" it, then weld, grind and fill. Is there any advantage in stop drilling a crack in SMC? Thanks!
Thread Starter
Melting Slicks
Joined: Jun 2009
Posts: 2,709
Likes: 3
From: Savannah GA
I suspect if I suggested I intended to paint my car with Glidden Evermore Super Semi-Gloss house paint there would be many responses. Has no-one here an opinion on how to avoid crack propogation on a fiberglass/ SMC body panel?
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
Cracks do not propagate in fiberglass. Its a myth. No holes needed.
Pro
Joined: Apr 2008
Posts: 541
Likes: 0
From: Wichita Kansas
Well, it seems everyone is right on this one.
I spoke to my boat glass guy who also builds and repairs fiberglass parts for factory "stock" race cars. He said that IF he were trying to stop a crack from running in glass, he would drill the end of it. But, he would only see the need to do that if it was going to be some time before he was going to properly repair the piece. Essentially a short term measure to keep is from getting worse until a proper repair can be made.
He agreed that after a proper repair, there is no need to have the end of the crack drilled out beforehand. He said that after the proper repair techniques are performed, the crack "no longer exists" because the repair process has rebonded all of the area that was cracked. He described the proper procedure as "V"ing out the cracked area to a width of aout twice the thickness of the piece and ending beyond both ends of the crack approximately the same distance as the V runs on each side of the crack. Then glass and resin (epoxy) the prepared area. Once done, the crack "no longer exists". Hope this is helpful.
I spoke to my boat glass guy who also builds and repairs fiberglass parts for factory "stock" race cars. He said that IF he were trying to stop a crack from running in glass, he would drill the end of it. But, he would only see the need to do that if it was going to be some time before he was going to properly repair the piece. Essentially a short term measure to keep is from getting worse until a proper repair can be made.
He agreed that after a proper repair, there is no need to have the end of the crack drilled out beforehand. He said that after the proper repair techniques are performed, the crack "no longer exists" because the repair process has rebonded all of the area that was cracked. He described the proper procedure as "V"ing out the cracked area to a width of aout twice the thickness of the piece and ending beyond both ends of the crack approximately the same distance as the V runs on each side of the crack. Then glass and resin (epoxy) the prepared area. Once done, the crack "no longer exists". Hope this is helpful.
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
Well, it seems everyone is right on this one.
I spoke to my boat glass guy who also builds and repairs fiberglass parts for factory "stock" race cars. He said that IF he were trying to stop a crack from running in glass, he would drill the end of it. But, he would only see the need to do that if it was going to be some time before he was going to properly repair the piece. Essentially a short term measure to keep is from getting worse until a proper repair can be made.
He agreed that after a proper repair, there is no need to have the end of the crack drilled out beforehand. He said that after the proper repair techniques are performed, the crack "no longer exists" because the repair process has rebonded all of the area that was cracked. He described the proper procedure as "V"ing out the cracked area to a width of aout twice the thickness of the piece and ending beyond both ends of the crack approximately the same distance as the V runs on each side of the crack. Then glass and resin (epoxy) the prepared area. Once done, the crack "no longer exists". Hope this is helpful.
I spoke to my boat glass guy who also builds and repairs fiberglass parts for factory "stock" race cars. He said that IF he were trying to stop a crack from running in glass, he would drill the end of it. But, he would only see the need to do that if it was going to be some time before he was going to properly repair the piece. Essentially a short term measure to keep is from getting worse until a proper repair can be made.
He agreed that after a proper repair, there is no need to have the end of the crack drilled out beforehand. He said that after the proper repair techniques are performed, the crack "no longer exists" because the repair process has rebonded all of the area that was cracked. He described the proper procedure as "V"ing out the cracked area to a width of aout twice the thickness of the piece and ending beyond both ends of the crack approximately the same distance as the V runs on each side of the crack. Then glass and resin (epoxy) the prepared area. Once done, the crack "no longer exists". Hope this is helpful.
