Fiberglass/SMC repair tutorial?
10-22-2010, 06:34 PM
#1
Resident moron
Thread Starter
Fiberglass/SMC repair tutorial?
Hey guys,
I have some damage in one of my fender liners that I'd like to repair, and I'd also like to figure out how to mini-tub my car.
I believe I have the appropriate materials: fiberglass mat and tape, SMC-appropriate resin and filler - all from Evercoat.
What guide did you guys use to learn the basics of fiberglass/SMC repair? Since these are both fender liner repairs, I don't really care how it looks so my amateur skills shouldn't be too big of a deal. I just want it to hold up and be functional.
Thanks!
Dope
I have some damage in one of my fender liners that I'd like to repair, and I'd also like to figure out how to mini-tub my car.
I believe I have the appropriate materials: fiberglass mat and tape, SMC-appropriate resin and filler - all from Evercoat.
What guide did you guys use to learn the basics of fiberglass/SMC repair? Since these are both fender liner repairs, I don't really care how it looks so my amateur skills shouldn't be too big of a deal. I just want it to hold up and be functional.
Thanks!
Dope
10-22-2010, 07:31 PM
#2
Melting Slicks
I seem to recall reading a thread on DYI minitubs. It had everything documented with pictures. Now we just have to find it.
Found it. http://tradezone.com/vette/tubing.html
I surprised at the lack of in-depth information on the web for repairing SMC. So far, this is all I've found of any value.
Found this. Just basic info, but it's a start.
http://www.saabce.com/Media/PDF/Plas...Procedures.pdf
And this.
http://www.hex.co.uk/tds/fusor/RP301...0procedure.pdf
Here's some very good info for various types of epoxy repairs. Some techniques may not be exactly the same for SMC.
http://www.westsystem.com/ss/use-guides/ Check out the video where they sawed a kayak in half, epoxied it back together and then torture tested it.
Found this on another forum. It has a few good tips, and cautions.
"The DIY needs to know that most 'fiberglass' found on automobiles in roughly the last 15 years or so is not fiberglass but SMC or Sheet Molded Compound.
SMC can NOT be repaired with fiberglass resin or automotive body fillers primarily because the expansion and contraction of SMC when it heats up in the sunlight is much greater than fiberglass. SMC resin is basically glorified/higher quailty fiberglass resin but it must be repaired differently. If you repair a hole in SMC with a non-SMC compatible filler or resin the repair will butthole (assuming the repair feathers out in the first place) around the perimeter of the repair typically the first day it sees 110 degree heat radiating off the Wal-Mart parking lot and its much more likely and noticeable on darker colors. The funny thing is once the sun goes down or the car is pulled into the garage the butthole can totally go away until it see sunlight and heat again.
An easy way to tell SMC from fiberglass is SMC will be smooth on the backside of the panel while fiberglass you can feel the raised chopped glass.
Remember too on an SMC repair whether you use SMC resin or SMC filler you want to have a nice shallow 20 degree bevel (50 grit 3" grinder will do the trick) along the entire top-side perimeter of the repair for the resin/filler to not only bite into but to expand and contract with.
I have good luck with Fiberglass Evercoats SMC fillers and resins along with UPOL's SMC filler which sands very easy and was priced right.
Assuming you have a hole (say in a Sea Doo hull) and are panel bonding a backer plate for reinforcement behind an SMC panel once the adhesive cures, grind away any and all excess adhesive that oozed through the backer panel and OEM panel. If you want some added insurance and havew the time apply a coat or two of epoxy primer and wait overnight before applying SMC filler.
Duramix has and always will be my TPO/SMC/Metal bonding favorite (even if 3M owns them now:barf: :barf: ) because its liquid urethane but to each his own.
Also, NEVER wipe raw (sanded/ground/opened) SMC with any solvent (like wax and grease remover or paint thinner) or water! If you do your odds of having adhesion problems are great. The only thing you EVER want to clean raw SMC with is clean compressed air.
When I first got into this business the Corvettes were busting power steering lines and in return they were spewing fluid all over the backside of the hood. One of the brace would delaminate from the hood opening up an area of raw SMC. The PS fluid would get into the raw/open SMC then it was game over for any and all paint adhesion. GM warranteed this hoods to the tune of $1400 (just for the SMC hood) in the earlier 90's because paint would no longer stick to them. I did have some shops that would set the hoods right-side up in the sun and attempt to sweat the ps fluid out over time in order to reuse the hood again and make some money but the odds usually weren't in their favor. "
__________________
Found it. http://tradezone.com/vette/tubing.html
I surprised at the lack of in-depth information on the web for repairing SMC. So far, this is all I've found of any value.
Found this. Just basic info, but it's a start.
http://www.saabce.com/Media/PDF/Plas...Procedures.pdf
And this.
http://www.hex.co.uk/tds/fusor/RP301...0procedure.pdf
Here's some very good info for various types of epoxy repairs. Some techniques may not be exactly the same for SMC.
http://www.westsystem.com/ss/use-guides/ Check out the video where they sawed a kayak in half, epoxied it back together and then torture tested it.
Found this on another forum. It has a few good tips, and cautions.
"The DIY needs to know that most 'fiberglass' found on automobiles in roughly the last 15 years or so is not fiberglass but SMC or Sheet Molded Compound.
SMC can NOT be repaired with fiberglass resin or automotive body fillers primarily because the expansion and contraction of SMC when it heats up in the sunlight is much greater than fiberglass. SMC resin is basically glorified/higher quailty fiberglass resin but it must be repaired differently. If you repair a hole in SMC with a non-SMC compatible filler or resin the repair will butthole (assuming the repair feathers out in the first place) around the perimeter of the repair typically the first day it sees 110 degree heat radiating off the Wal-Mart parking lot and its much more likely and noticeable on darker colors. The funny thing is once the sun goes down or the car is pulled into the garage the butthole can totally go away until it see sunlight and heat again.
An easy way to tell SMC from fiberglass is SMC will be smooth on the backside of the panel while fiberglass you can feel the raised chopped glass.
Remember too on an SMC repair whether you use SMC resin or SMC filler you want to have a nice shallow 20 degree bevel (50 grit 3" grinder will do the trick) along the entire top-side perimeter of the repair for the resin/filler to not only bite into but to expand and contract with.
I have good luck with Fiberglass Evercoats SMC fillers and resins along with UPOL's SMC filler which sands very easy and was priced right.
Assuming you have a hole (say in a Sea Doo hull) and are panel bonding a backer plate for reinforcement behind an SMC panel once the adhesive cures, grind away any and all excess adhesive that oozed through the backer panel and OEM panel. If you want some added insurance and havew the time apply a coat or two of epoxy primer and wait overnight before applying SMC filler.
Duramix has and always will be my TPO/SMC/Metal bonding favorite (even if 3M owns them now:barf: :barf: ) because its liquid urethane but to each his own.
Also, NEVER wipe raw (sanded/ground/opened) SMC with any solvent (like wax and grease remover or paint thinner) or water! If you do your odds of having adhesion problems are great. The only thing you EVER want to clean raw SMC with is clean compressed air.
When I first got into this business the Corvettes were busting power steering lines and in return they were spewing fluid all over the backside of the hood. One of the brace would delaminate from the hood opening up an area of raw SMC. The PS fluid would get into the raw/open SMC then it was game over for any and all paint adhesion. GM warranteed this hoods to the tune of $1400 (just for the SMC hood) in the earlier 90's because paint would no longer stick to them. I did have some shops that would set the hoods right-side up in the sun and attempt to sweat the ps fluid out over time in order to reuse the hood again and make some money but the odds usually weren't in their favor. "
__________________
Last edited by Greg_E; 10-22-2010 at 09:24 PM.
