Another body repair thread...
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Another body repair thread...
I know there are many threads on the topic, but every one of them has confused me.
I need to make some repairs on my 77. None of these will be on exterior painted surfaces - all on underlying areas of SMC fiberglas. There are two types of problems I need to fix:
1) cracks and missing sections
2) separation from underlying metal structures.
For the cracks and holes, I obviously need to use fiberglas mat and an SMC-compatible resin. What kind of resin should I get? Evercoat (which is what my local body supply carries) has an epoxy resin and an SMC resin. Which one works better? Should I look for a shop that carries a different brand of materials? I know that the older polyester resin isn't compatible with the 77 materials.
For the areas of separation, what is a good bonding agent? I only have to re-bond about 8" of one fender along the door opening, and about 4"-6" at the bottom of one door. Would regular epoxy be appropriate, or is there a specific bonding agent that would work better? If I need to get something specific to automotive use, what can I get in a small quantity at a reasonable price?
I need to make some repairs on my 77. None of these will be on exterior painted surfaces - all on underlying areas of SMC fiberglas. There are two types of problems I need to fix:
1) cracks and missing sections
2) separation from underlying metal structures.
For the cracks and holes, I obviously need to use fiberglas mat and an SMC-compatible resin. What kind of resin should I get? Evercoat (which is what my local body supply carries) has an epoxy resin and an SMC resin. Which one works better? Should I look for a shop that carries a different brand of materials? I know that the older polyester resin isn't compatible with the 77 materials.
For the areas of separation, what is a good bonding agent? I only have to re-bond about 8" of one fender along the door opening, and about 4"-6" at the bottom of one door. Would regular epoxy be appropriate, or is there a specific bonding agent that would work better? If I need to get something specific to automotive use, what can I get in a small quantity at a reasonable price?
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
Either
http://www.lordfulfillment.com/upload/DS3374.pdf
or
http://www.westsystem.com/
or equivelant.
Shop at boat wholesale suppliers
Shop at boat glass suppliers
fillers can be added to stiffen the consistancy.
Both are epoxy for smc, poly, or metal
http://www.lordfulfillment.com/upload/DS3374.pdf
or
http://www.westsystem.com/
or equivelant.
Shop at boat wholesale suppliers
Shop at boat glass suppliers
fillers can be added to stiffen the consistancy.
Both are epoxy for smc, poly, or metal
Melting Slicks
Joined: Jul 2004
Posts: 2,577
Likes: 2
From: Long Island New York
According to Lars' Corvette Body and Paint Basics on www.corvettefaq.com all Corvettes up until 1982 were FRP. SMC was first used in 1982 and up models.
This is what he wrote:
"Two different construction techniques have been used to manufacture Corvette body panels over the years. When the ‘Vette made its debut, the new “FRP” body was a major innovation. “Fiberglass Reinforced Plastic” was a construction method that could be used to make lightweight panels with curves and design features that could not be easily duplicated in stamped steel. The body was basically built just like a fiberglass swimming pool or a boat hull: A “chopgun” was used to blow fiberglass strands and resin into a mold that was first coated with resin to produce a smooth surface finish on the body parts. This technique was used through the 1981 model year.
1982 was a unique transition year in many respects. Fuel injection was added to the ‘Vette, and a computer was installed to manage all major engine functions. ’82 also saw the advent of a revised body panel construction. “Structural Matted Components,” or SMC panels, were thinner and lighter due to a laminate construction using more plastic and less ‘glass. This panel type is used on all of our C4 ‘Vettes, and partially on the groundbreaking ’82."
This is what he wrote:
"Two different construction techniques have been used to manufacture Corvette body panels over the years. When the ‘Vette made its debut, the new “FRP” body was a major innovation. “Fiberglass Reinforced Plastic” was a construction method that could be used to make lightweight panels with curves and design features that could not be easily duplicated in stamped steel. The body was basically built just like a fiberglass swimming pool or a boat hull: A “chopgun” was used to blow fiberglass strands and resin into a mold that was first coated with resin to produce a smooth surface finish on the body parts. This technique was used through the 1981 model year.
1982 was a unique transition year in many respects. Fuel injection was added to the ‘Vette, and a computer was installed to manage all major engine functions. ’82 also saw the advent of a revised body panel construction. “Structural Matted Components,” or SMC panels, were thinner and lighter due to a laminate construction using more plastic and less ‘glass. This panel type is used on all of our C4 ‘Vettes, and partially on the groundbreaking ’82."
Race Director
Joined: Aug 1999
Posts: 18,126
Likes: 174
From: WI
[QUOTE=I'm Batman;1559993316]I know there are many threads on the topic, but every one of them has confused me.QUOTE]
yea, I am kinda confused too.....why aren`t you asking a body work question here?? ...redvetracr
http://forums.corvetteforum.com/forumdisplay.php?f=138
yea, I am kinda confused too.....why aren`t you asking a body work question here?? ...redvetracr
http://forums.corvetteforum.com/forumdisplay.php?f=138
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
According to Lars' Corvette Body and Paint Basics on www.corvettefaq.com all Corvettes up until 1982 were FRP. SMC was first used in 1982 and up models.
This is what he wrote:
"Two different construction techniques have been used to manufacture Corvette body panels over the years. When the ‘Vette made its debut, the new “FRP” body was a major innovation. “Fiberglass Reinforced Plastic” was a construction method that could be used to make lightweight panels with curves and design features that could not be easily duplicated in stamped steel. The body was basically built just like a fiberglass swimming pool or a boat hull: A “chopgun” was used to blow fiberglass strands and resin into a mold that was first coated with resin to produce a smooth surface finish on the body parts. This technique was used through the 1981 model year.
1982 was a unique transition year in many respects. Fuel injection was added to the ‘Vette, and a computer was installed to manage all major engine functions. ’82 also saw the advent of a revised body panel construction. “Structural Matted Components,” or SMC panels, were thinner and lighter due to a laminate construction using more plastic and less ‘glass. This panel type is used on all of our C4 ‘Vettes, and partially on the groundbreaking ’82."
This is what he wrote:
"Two different construction techniques have been used to manufacture Corvette body panels over the years. When the ‘Vette made its debut, the new “FRP” body was a major innovation. “Fiberglass Reinforced Plastic” was a construction method that could be used to make lightweight panels with curves and design features that could not be easily duplicated in stamped steel. The body was basically built just like a fiberglass swimming pool or a boat hull: A “chopgun” was used to blow fiberglass strands and resin into a mold that was first coated with resin to produce a smooth surface finish on the body parts. This technique was used through the 1981 model year.
1982 was a unique transition year in many respects. Fuel injection was added to the ‘Vette, and a computer was installed to manage all major engine functions. ’82 also saw the advent of a revised body panel construction. “Structural Matted Components,” or SMC panels, were thinner and lighter due to a laminate construction using more plastic and less ‘glass. This panel type is used on all of our C4 ‘Vettes, and partially on the groundbreaking ’82."
SMC ==== "Sheet Molded Composite".
Used in 1966 Corvette
Here is an Industry resource for all types of composites that has just about any reference to fiberglass in the auto industry you can imagine.
http://www.compositesworld.com/
Corvette 1952-2004: A History of Materials Innovation
1952: EX-122 concept show car hand-built. Becomes forerunner of Corvette.
1953: Corvette unveiled in New York. Fiberglass chosen for production, which starts in Flint, MI, on June 30. First-year build: 300, all Polo White. Designer Zora Arkus-Duntov - who becomes Corvette chief engineer in 1968 - joins GM. Production moves to St. Louis in December.
1954: 3,400 built. Blue, red and black colors added.
1955: New small-block V-8 (195-hp) introduced (prior models powered by 150-hp 6-cyl. engines).
1956: Fiberglass removable hardtop introduced.
1957: Fuel injection, a U.S. first, debuts. Anodized aluminum trim bows on interior.
1958: Quad headlamps introduced.
1962: Aluminum radiator replaces copper.
1963: Sting Ray version introduced.
1965: Disc brakes replace drums.
1966: First sheet-molded composite (SMC) used for front body panels and hood.
1970: Plenum and instrument panel support panels switch to SMC.
1971: Rear quarter and end panels switch to SMC.
1973: Soft front bumpers to meet federal 5 mph (8 km/h) impact standard, add 35 lbs (16 kg) and 2 ins. (5 cm) to length.
1974: Duntov, who developed Corvette into high-performance car, retires.
1975: Plastic fuel-tank bladder bows.
1976: "Last" convertible built. Returns in 1986.
1978: In 25th year, 46,776 built, with starting price of $9,351.89.
1981: Assembly switches to Bowling Green, KY, from St. Louis, where last '82 was built. No '83 model, as plant shift takes place. Fiberglass-reinforced rear leaf springs debut.
1984: One-piece, lift-off SMC roof panels with massive rear glass introduced.
1986: Aluminum cylinder heads and antilock braking systems added.
1989: Airbags and 6-speed transmission introduced.
1992: 1 millionth Corvette built on July 2.
1993: Rear inner panels molded from recycled SMC, an industry first.
1994: National Corvette Museum opens in Bowling Green. Leather seats become standard for all models.
1997: All-new, fifth-generation model bows with major suspension components fabricated from aluminum. High-tech hydroformed steel used for driveshaft "tunnel." Windshield frame and IP supports switch to aluminum.
Advertisement
1999: Rear "tub" and front floor panels switch to lightweight balsa composite. First fixed-roof hardtop since '68 debuts.
2000: Lightweight titanium debuts for Corvette Z06 exhaust system.
2003: An estimated 35,000 models will be built, pushing 50-year output to more than 1.3 million.
2004: Carbon-fiber hood introduced for Z06, cutting weight in half.
Source: GM, Chevrolet and industry sources.
1952: EX-122 concept show car hand-built. Becomes forerunner of Corvette.
1953: Corvette unveiled in New York. Fiberglass chosen for production, which starts in Flint, MI, on June 30. First-year build: 300, all Polo White. Designer Zora Arkus-Duntov - who becomes Corvette chief engineer in 1968 - joins GM. Production moves to St. Louis in December.
1954: 3,400 built. Blue, red and black colors added.
1955: New small-block V-8 (195-hp) introduced (prior models powered by 150-hp 6-cyl. engines).
1956: Fiberglass removable hardtop introduced.
1957: Fuel injection, a U.S. first, debuts. Anodized aluminum trim bows on interior.
1958: Quad headlamps introduced.
1962: Aluminum radiator replaces copper.
1963: Sting Ray version introduced.
1965: Disc brakes replace drums.
1966: First sheet-molded composite (SMC) used for front body panels and hood.
1970: Plenum and instrument panel support panels switch to SMC.
1971: Rear quarter and end panels switch to SMC.
1973: Soft front bumpers to meet federal 5 mph (8 km/h) impact standard, add 35 lbs (16 kg) and 2 ins. (5 cm) to length.
1974: Duntov, who developed Corvette into high-performance car, retires.
1975: Plastic fuel-tank bladder bows.
1976: "Last" convertible built. Returns in 1986.
1978: In 25th year, 46,776 built, with starting price of $9,351.89.
1981: Assembly switches to Bowling Green, KY, from St. Louis, where last '82 was built. No '83 model, as plant shift takes place. Fiberglass-reinforced rear leaf springs debut.
1984: One-piece, lift-off SMC roof panels with massive rear glass introduced.
1986: Aluminum cylinder heads and antilock braking systems added.
1989: Airbags and 6-speed transmission introduced.
1992: 1 millionth Corvette built on July 2.
1993: Rear inner panels molded from recycled SMC, an industry first.
1994: National Corvette Museum opens in Bowling Green. Leather seats become standard for all models.
1997: All-new, fifth-generation model bows with major suspension components fabricated from aluminum. High-tech hydroformed steel used for driveshaft "tunnel." Windshield frame and IP supports switch to aluminum.
Advertisement
1999: Rear "tub" and front floor panels switch to lightweight balsa composite. First fixed-roof hardtop since '68 debuts.
2000: Lightweight titanium debuts for Corvette Z06 exhaust system.
2003: An estimated 35,000 models will be built, pushing 50-year output to more than 1.3 million.
2004: Carbon-fiber hood introduced for Z06, cutting weight in half.
Source: GM, Chevrolet and industry sources.
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Thread Starter
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
yea, I am kinda confused too.....why aren`t you asking a body work question here?? ...redvetracr
http://forums.corvetteforum.com/forumdisplay.php?f=138
http://forums.corvetteforum.com/forumdisplay.php?f=138
2) because the pros over there would confuse me even worse.
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Batman, there are guys less than an hour drive from you that have LOTS of hands on working with all types of glass. Theirs all floats, but hey, glass is glass. SMC or FRP, those guys have been in it.
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
These repairs don't need to be pretty, they just need to stay put. It's all hidden stuff.
Le Mans Master
Joined: Nov 2004
Posts: 6,434
Likes: 0
St. Jude Donor '07
Pro
Joined: Apr 2006
Posts: 733
Likes: 1
From: Coquitlam British Columbia
Batman one other thing you might watch for when working with your SMC panels and "epoxy" I would use an epoxy compatible Fiberglass mat, as I understand the mat threads are bonded in a different manner than fiberglass mat used with the poly resin.
ikwhite
ikwhite
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
I still need a suggestion for rebonding small areas of fender and door panels...I'm sure with the 3M stuff I'd have to buy 10x as much as I need at a price that would curl my hair.
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Drifting
Joined: Jan 2006
Posts: 1,944
Likes: 22
From: Yooperville MI
Unfortunately, when doing bodywork yourself you will often buy more product than you need, whether it be supplies or paint, seems to come with the territory. But as justification, you are still saving money by doing the work yourself.
In case your car has been unknowingly repaired before, you will know that you have SMC if both sides of the panel you are working on is smooth. If one side is smooth and the other is rough and you can feel strands of fiberglass, you have found a FRP part that might part of a bad previous repair.
Chopped strand mat is the same for polyester or epoxy resins and comes in different weights or thickness. Most epoxy resins sold at local paint stores perform about the same so the Evercoat you mentioned is fine. If you go to the West Systems web site, http://www.westsystem.com/ they have an on line user manual that is very descriptive on using epoxy resin for making parts and repairs. Well worth reading.
Adhering/reattaching smc to metal surfaces and adhering smc to smc can be done with a lot of products mentioned such as 3M Automix SMC/Fiberglass Panel Adhesive for around $35. This is good stuff. It does require a special application gun that costs about $70 but I've heard that used guns show up on ebay now and then. Hope this helps.
In case your car has been unknowingly repaired before, you will know that you have SMC if both sides of the panel you are working on is smooth. If one side is smooth and the other is rough and you can feel strands of fiberglass, you have found a FRP part that might part of a bad previous repair.
Chopped strand mat is the same for polyester or epoxy resins and comes in different weights or thickness. Most epoxy resins sold at local paint stores perform about the same so the Evercoat you mentioned is fine. If you go to the West Systems web site, http://www.westsystem.com/ they have an on line user manual that is very descriptive on using epoxy resin for making parts and repairs. Well worth reading.
Adhering/reattaching smc to metal surfaces and adhering smc to smc can be done with a lot of products mentioned such as 3M Automix SMC/Fiberglass Panel Adhesive for around $35. This is good stuff. It does require a special application gun that costs about $70 but I've heard that used guns show up on ebay now and then. Hope this helps.
Pro
Joined: Apr 2006
Posts: 733
Likes: 1
From: Coquitlam British Columbia
Chopped Matt
My research into the subject has shown otherwise that not all chopped matt is the same. In some chopped matt the individual fibers that make up chopped strand mat is held together by an adhesive binder that is designed to break down in polyester and vinyl ester resins.Chopped Strand Mat compatible for use with epoxies is stitched together, as opposed to the adhesive binders used in common fiberglass mats. I do see on the market that some companies label there matt compatible for both and presume they are fine to use. Here is a link to some epoxy matt that is stiched rather than bonded for anyone looking for this type of matt in bulk.
scroll to bottom of the following link.
http://www.shopmaninc.com/mat.html
ikwhite
scroll to bottom of the following link.
http://www.shopmaninc.com/mat.html
ikwhite
Chopped strand mat is the same for polyester or epoxy resins and comes in different weights or thickness.
