varnish repair

[shellback]

My mahogany speedboat has 12 coats of carefully applied Epiphanes and has looked great for three years, however, at the end of last season several cracks appeared in a number of places. Can I lightly sand through the affected areas, scuff the whole surface and recoat?

[Art Read]

I'm no expert at maintaining varnish, but what you suggest sounds plausible. If you've got a varnished mahogany runabout and don't already have it yet, I'd suggest that Rebbeca Whitman's book "Brightwork" would be a sound investment. I suspect our hosts sell it right on their on-line "store" on the home page. She describes the technique for what you're up against in great detail.

[Ian McColgin]

You can repair varnish if there's been no serious change in the wood color. Unfortunatly, it often happens that the wood changes color over time under the varnish and when you sand to wood you may well create a fresh wood surface of a slightly different color.

So, firstly, try not to sand too deeply.

Best practice is to work a little too hard and do all your bring down sanding with 220, so you don't take too much off. Make a gentle bowl in the varnish - you end up sanding a lot around your problem.

When you apply new varnish with each coat, do not go out to the good varnish. Leave a sanded perimeter so you can see where you're working. Each new coat should cover somewhat more area than the one before - evenly filling that shallow bowl.

Build up enough coats in the repair area, then finish sand and varnish the whole piece.

G'luck

[John Blazy]

Good explanation of feathering and even buildup, Ian. Y'always endup topcoating the wholething that's fer sure. If I got a scratch in my furniture, I used to call them $300.00 mistakes because you had to respray the whole thing for one little scratch. If the cracks are simple stress / shrinkage cracks, what about the "doping in" method where you syringe in some thinned down varnish into the cracks where the solvent may soften and re-seal them? Just a thought. That way you don't have to sand out too much, but you still want to topcat again- JB

[ 01-14-2003, 02:37 PM: Message edited by: John Blazy ]

[Classic Boatworks - Maine]

Are the cracks along seam lines?

[shellback]

The cracks are not all along the seams, just random. And thanks for the thoughts. I'll try the sand a 'bowl' and fill in layers technique. Because there is a good base to start with there are no spots where it has gone through to discolor the wood.