Surface Prep before Primer - Question
Thread Starter
Instructor
Joined: Dec 2005
Posts: 241
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From: Aubrey TX
Surface Prep before Primer - Question
I have sanded my '73 completly down to the fiberglass to remove the 3 layers of paint and 3 layers of primer from 30+ years of previous owners. I wanted to start with a fresh surface for new paint.
At the paint store yesterday, they said to wash the car with soap and water and then after it dried use a surface prep/degreaser/wash, I forgot the product number. My question and concern is since the fiberglass is porous like a sponge, should I wash the car with soap and water and use the prep wash??? I am concerned that the fiberglass will absorb the water and prep wash and eventually will want to evaporate in hot weather causing the primer and paint to bubble.
Suggestions Please.
73C3
At the paint store yesterday, they said to wash the car with soap and water and then after it dried use a surface prep/degreaser/wash, I forgot the product number. My question and concern is since the fiberglass is porous like a sponge, should I wash the car with soap and water and use the prep wash??? I am concerned that the fiberglass will absorb the water and prep wash and eventually will want to evaporate in hot weather causing the primer and paint to bubble.
Suggestions Please.
73C3
Drifting
Joined: Jan 2006
Posts: 1,944
Likes: 22
From: Yooperville MI
This is where some painters may disagree. I clean the bodies with glass cleaner first to remove water soluble contamination that the wax and grease remover will not touch because it is solvent based. Follow the glass cleaner with wax and grease remover to remove oils and other solvent or petroleum based contaminants.
Glass cleaner is better than soap and water because it will evaporate faster and will not leave any residue behind.
Glass cleaner is better than soap and water because it will evaporate faster and will not leave any residue behind.
Le Mans Master
Joined: Jul 1999
Posts: 9,206
Likes: 17
From: Sewell NJ
Almost any paint product you apply says you should use a surface prep like Prep Sol. If I were you I would go over the car carefully with an air hose to blow out all of the loose stuff. Then take two lint free towels and wipe the car down with Prep Sol using one to apply and the other to remove.
One other thing you should do while wiping the car down. Be very aware of all the seams on the car where the various pieces are joined together. The Prep Sol will show any cracks which should be noted for repair. If you have to repair anything use Epoxy Resin and Mat which is more compatible and stronger than Polyester Resin and Mat. Also, get good mat. I had some that I bought from the local parts store and when you compare it to what I bought from Ecklers its less than half the thickness and weight. Try to use as little body filler as possible.
I would then coat the car with a sealer or a primer sealer which is compatible with fiberglass or Sheet Molded Compound. This will isolate the body from the topcoats. Then apply however many number of coats of primer it takes to get the car blocksanded to perfection and then apply the topcoats. Good luck.
One other thing you should do while wiping the car down. Be very aware of all the seams on the car where the various pieces are joined together. The Prep Sol will show any cracks which should be noted for repair. If you have to repair anything use Epoxy Resin and Mat which is more compatible and stronger than Polyester Resin and Mat. Also, get good mat. I had some that I bought from the local parts store and when you compare it to what I bought from Ecklers its less than half the thickness and weight. Try to use as little body filler as possible.
I would then coat the car with a sealer or a primer sealer which is compatible with fiberglass or Sheet Molded Compound. This will isolate the body from the topcoats. Then apply however many number of coats of primer it takes to get the car blocksanded to perfection and then apply the topcoats. Good luck.
Advanced
Joined: May 2006
Posts: 90
Likes: 0
From: Brighton Ontario
Originally Posted by vettfixr
Almost any paint product you apply says you should use a surface prep like Prep Sol. If I were you I would go over the car carefully with an air hose to blow out all of the loose stuff. Then take two lint free towels and wipe the car down with Prep Sol using one to apply and the other to remove.
One other thing you should do while wiping the car down. Be very aware of all the seams on the car where the various pieces are joined together. The Prep Sol will show any cracks which should be noted for repair. If you have to repair anything use Epoxy Resin and Mat which is more compatible and stronger than Polyester Resin and Mat. Also, get good mat. I had some that I bought from the local parts store and when you compare it to what I bought from Ecklers its less than half the thickness and weight. Try to use as little body filler as possible.
I would then coat the car with a sealer or a primer sealer which is compatible with fiberglass or Sheet Molded Compound. This will isolate the body from the topcoats. Then apply however many number of coats of primer it takes to get the car blocksanded to perfection and then apply the topcoats. Good luck.
One other thing you should do while wiping the car down. Be very aware of all the seams on the car where the various pieces are joined together. The Prep Sol will show any cracks which should be noted for repair. If you have to repair anything use Epoxy Resin and Mat which is more compatible and stronger than Polyester Resin and Mat. Also, get good mat. I had some that I bought from the local parts store and when you compare it to what I bought from Ecklers its less than half the thickness and weight. Try to use as little body filler as possible.
I would then coat the car with a sealer or a primer sealer which is compatible with fiberglass or Sheet Molded Compound. This will isolate the body from the topcoats. Then apply however many number of coats of primer it takes to get the car blocksanded to perfection and then apply the topcoats. Good luck.
This the best method, also an epoxy primer is preferred
Le Mans Master
Joined: Oct 2005
Posts: 9,429
Likes: 44
From: Macon, GA
Originally Posted by ahoover
This is where some painters may disagree. I clean the bodies with glass cleaner first to remove water soluble contamination that the wax and grease remover will not touch because it is solvent based. Follow the glass cleaner with wax and grease remover to remove oils and other solvent or petroleum based contaminants.
Glass cleaner is better than soap and water because it will evaporate faster and will not leave any residue behind.
Glass cleaner is better than soap and water because it will evaporate faster and will not leave any residue behind.
Perfect advise...
Drifting
Joined: Jan 2006
Posts: 1,944
Likes: 22
From: Yooperville MI
Epoxy primer is the only way to go over bare fiberglass or steel bodies for that matter. Excellent adhesion and will seal loose strands of glass that may pop through the top coats in the future. Also, if the inside of your hood is bare or any other replacement parts are bare on the inside, prime the insides to keep various oils from staining the fiberglass and popping through the finish later on. A good example I've seen often is A/C compressor oil flying up and absorbing into a bare hood and causing discoloration of the top coats.
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Thread Starter
Instructor
Joined: Dec 2005
Posts: 241
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From: Aubrey TX
Thanks to All!! I appreciate you're advice.
I plan on shooting K36 next weekend. The car is completly naked including the underside of the hood and the door jams and cracks have been repaired. From that point it will be block sand and maybe re-prime. I will post pictures when I have something worthy to show.
I plan on shooting K36 next weekend. The car is completly naked including the underside of the hood and the door jams and cracks have been repaired. From that point it will be block sand and maybe re-prime. I will post pictures when I have something worthy to show.