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Refinishing a Healey hardtop...
- Thread starter Cottontop
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Rob Glasgow
Jedi Knight
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I purchased a factory hardtop two years ago and refurbished the interior this past winter. Bill Bolton provided the headliner, seals and great advice. I can't help with your request since my exterior was in great shape as purchased. Even the navy blue paint on the hardtop worked well with the Ice blue of the car.
Rob
Rob
roger_abbott
Jedi Hopeful
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Mmmm - wonder if it would be worth while to make a mold for reproduction tops, or has someone done this already? Keoke?
pan
Jedi Warrior
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Hi Tim,
I have never refinished a hardtop either, but my trade background is in reinforced plastics. I presume the top is FRP? (Fibreglass reinforced plastic).
Always remember that composite mouldings are porous (yes,even boats!). The outer surface is the only protection the material has to resist moisture invasion. Tiny air bubbles, referred to as "porosity", are always present just under the surface. Better quality mouldings are less likely to suffer but those bubbles are still there.
A common mistake when refinishing components made of this material is to completely remove the gelcoat. When this is done the glass fibre filaments are exposed. This is a bad practice and is not necessary. The reason this is done is usually because the gelcoat had many cracks. It is far better to spend the time in the tedious task of opening out the cracks and filling. If the top is in good condition, do not use an aggressive sander to prepare for paint. Doing this will expose those tiny air bubbles mentioned above. All that is required is thorough washing with a mild solvent, e.g. white spirit to remove any wax, then scuffing with a pot scourer. A high-build primer is recommended.
I have never refinished a hardtop either, but my trade background is in reinforced plastics. I presume the top is FRP? (Fibreglass reinforced plastic).
Always remember that composite mouldings are porous (yes,even boats!). The outer surface is the only protection the material has to resist moisture invasion. Tiny air bubbles, referred to as "porosity", are always present just under the surface. Better quality mouldings are less likely to suffer but those bubbles are still there.
A common mistake when refinishing components made of this material is to completely remove the gelcoat. When this is done the glass fibre filaments are exposed. This is a bad practice and is not necessary. The reason this is done is usually because the gelcoat had many cracks. It is far better to spend the time in the tedious task of opening out the cracks and filling. If the top is in good condition, do not use an aggressive sander to prepare for paint. Doing this will expose those tiny air bubbles mentioned above. All that is required is thorough washing with a mild solvent, e.g. white spirit to remove any wax, then scuffing with a pot scourer. A high-build primer is recommended.
OP
Cottontop
Jedi Warrior
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Cottontop said:
Many thanks to those who responded.
When I first asked the question, I had a 50 year old 4-seater hardtop with 3-4 layers of primer and different colors of paint and hand size areas of bare fiberglass.
Within the bare areas and extending under the paint layers are a meriad of spiderweb and other cracks. These cracks appear to be limited to the gel coat and not seem to extend down into the fibers.
I was seeking an answer as to how to remove the multi-layers of primer and paint so that I might repair the cracks and refinish the surface.
Not wanting to use stripping chemicals, as they melt the gel coat and would contaminate any newly applied resin, and knowing that spot sanding would probably overly scollop the surface, I resorted to my old tried-and-true method of using a heat gun and a sharp edged putty knife.
I have now removed nearly all of the paint and primer with no nicks or damage to the surface. My plan is to route out all of the cracks with a 1/4" ball-burr and high speed air motor, then to apply several layers of long-chain (high strength) resin to the surface, forming a new gel coat.
I'll then apply several new layers of glass cloth and resin to the INSIDE of the top before spraying the entire inside with expandable foam. The closed-cell foam will not only supply insulation, but structural strength as well.
Primer and paint is fairly straight forward. I will be re-painting the car at the same time.
After contouring the inside surface with a sanding block, I'll install an overhead "swivel lens" dome light and an adhesive backed headliner.
That should keep my A/C in and the Texas heat out.
Thanks in advance for your thoughts/comments ?
Tim
pan
Jedi Warrior
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Hi Tim,
The procedure you descibe should provide you with an effective & lasting repair. The foam interior lining would be improved with a light skin of 'glass to form what is called "foam sandwich construction" but, for a sports car hard top it might be a bit of overkill!
The procedure you descibe should provide you with an effective & lasting repair. The foam interior lining would be improved with a light skin of 'glass to form what is called "foam sandwich construction" but, for a sports car hard top it might be a bit of overkill!