Fiberglass matt and resin applied over paint

Anything goes in the world of fiberglass and plastic



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PostPosted: Tue May 15, 2018 8:29 pm
Hello,

I have a body repair where under the drip edges of my car's roof have started to rust and produce holes. When it rains water enters the headliner and drips onto the front passenger side floor.

After wire brushing, grinding and sanding the area to remove as much rust as possible from the exterior. I was thinking of repairing with sheet metal. However my welder is 240 AC/DC and where I'm working on my vehicle I only have 120 VAC and no 120 vac welder.

So after looking around at various body fillers I decided the next best method to repair would be fiberglass matt and resin.

The only problem is I want to treat both the interior and exterior of the rust holes with a rust preventive paint such as Chassis Saver or Miracle paint of which I have on hand.

Rust prevention paint such as these are designed to go on rusted as well as bare metal surfaces. Most work by locking any rust making it air-tight so no oxygen is able to reach the metal and rust thus help prevent oxidation that causes
iron oxide.

I have a Evercoat 637 kit with 3 square feet cloth, 8 oz resin and some hardener.

The instructions specify "Don't apply resin mixture over painted or finished surfaces, it won't adhere."

I was thinking of ruffing up the rust paint before attempting to applying the fiberglass resin with cloth, but need a second opinion as I haven't worked much with fiberglass.

I was thinking of using some body filler such as Bondo 272 Bondo-Glass Fiberglass Reinforced Filler however the holes are I think too large to use any sort of filler even if it's reinforced.

Anyway I suppose I could skip the rust paint and just apply the fiberglass resin and matt however I'm thinking moisture will more easily reach the metal increasing the likelihood of more rust.

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PostPosted: Thu May 17, 2018 3:57 pm
So they threw you over here, huh? Okay, so yeah, fiberglass has got to go on clean roughed up metal....no painted surfaces. I'm not real big on what you are trying to do because of more "where" this is at than anything else. Also, I'd probably be using an epoxy resin rather than the stock polyester stuff. Something like West Systems is going to be stronger and definitely seal the area from air/oxygen.
Honestly, metal would be much better for what you are doing but I do understand why you would be hesitant to do it......
Metal, wood, fiberglass, we work it all... www.furniturephysicians.com We can restore the irreplaceable!



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PostPosted: Thu Jul 26, 2018 7:31 am
Albert,
Use the MCU (miracle paint) with the fiberglass cloth! I've done it for many years. Coat the rusty metal with the MCU and let it get tacky but not dry. Then apply the fiberglass cloth or mat as you would normally but use MCU instead of resin.
If you let the first coat of mcu dry too long you'll have to sand it well before applying anything else and that's not a lot of fun.
Using this method I have repaired plastic spoilers, built up molds and models, completely fabricated interior pieces, and more.

This method is much better than using glass/resin on bare metal, and I would not trust the bond with resin over mcu.



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PostPosted: Thu Jul 26, 2018 7:48 am
Also, when you get the glasswork done like you want it, topcoat that mcu (I'm guessing it's black, not silver) while it's still tacky with a couple light coats of primer and it will save you from having to sand the mcu before priming.

One of my favorite mcu's...
http://www.masterseriesct.com

KBS also.

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PostPosted: Thu Jul 26, 2018 9:37 pm
Slofut, I have used KBS products, but not as you describe with fiberglass cloth.
That's a tip I will file away in my memory bank, and maybe try in the future.

How do you prevent MCUs from curing in the can once the can has been opened?
"If you can't move it, paint it." - U.S. Army

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PostPosted: Thu Jul 26, 2018 9:56 pm
Just jumping in because this is one of my favorite subjects....prolonging finish life. The best way to save moisture cured coatings is to decant your leftovers to a smaller container so it is full to the rim, displacing all of the moisture laden air you can. If you prefer to keep it in an original container I prefer to use large stainless steel ball bearings which work much better than marbles. Again you are raising the level up to the tippy top. Bloxygen can be used but is not quite as effective as it is with regular auto-oxidative style varnishes, stain, enamels.....the argon based Bloxygen is a dry gas though.
Metal, wood, fiberglass, we work it all... www.furniturephysicians.com We can restore the irreplaceable!

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PostPosted: Fri Jul 27, 2018 9:36 pm
DarrelK wrote:....... I prefer to use large stainless steel ball bearings which work much better than marbles. Again you are raising the level up to the tippy top..........

I'll try this next time, thanks. :goodjob:
"If you can't move it, paint it." - U.S. Army

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