how can you tell when the varnish is gone and other repair tips?

I am doing a repair to my coaming lip on my west river 180 (same coaming design as the chesapeake line) which i cracked during rolling practice.

i was getting out of the boat and bracing behind myself with a paddle that apparently was on the coaming lip and when i put my weight on the paddle, it cracked the top layer (the lip) and pulled part of it away from the coaming riser pieces (which were not damaged).

its an older boat and i apparently never glassed the coaming lip/inside of the risers) but just put epoxy over it and than varnish over the epoxy.

the approach i am looking to take is 1) to sand the varnish off the coaming lip, 2) fix the crack/re-attach it to the coaming risers with some cabosil-thickened epoxy, 3) glass the entire coaming lip/inside edge of the coaming....and 4) fill coat and varnish.

my question is, without sanding all the way back down to the wood on the coaming lip, is there a reliable method that tells you you are through the varnish and into the epoxy.  how do you ensure there is no varnish on the old epoxy prior to the reglassing effort?  is there a chemical test, a heat test or some way to confirm you won't try to put epoxy over varnish?

many thanks in advance for your help.  any other comments on the repair approach welcome as well.


3 replies:

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RE: how can you tell when the varnish is gone and other repair tips?

Wipe the area with a rag soaked in denatured alcohol. If it slides smoothly, you're in epoxy. If it's tacky or sticky you're in varnish.

BTW, it sounds to me as if the problem may be more the lack of a fillet under the lip (on the outside) rather than the lack of glass on the inside of the lip. Do you have a nice fat fillet there to smoothly transfer the stress from the lib to risers?

Good luck witht he repair,



RE: how can you tell when the varnish is gone and other repair tips?


thanks for the observation about the fillet on the underside of the lip/riser.  the answer to that is No.

this is an area that i considered when trying to sort out this repair.... but could not figure out how i could be sure i got the varnish off the underside of the lip/riser so i would know i am getting a good bond on any new fillet.  any ideas on how to go about that?

the other idea i was thinking about was to take a quarter to half inch off the lip width (looks like i have almost 1 inch overhang) so there would be less overhang/opportunity for leverage if you accidently put downward pressure on the outside edge of the coaming.

appreciate your thoughts on that as well.


RE: how can you tell when the varnish is gone and other repair tips?


I think that if it was me, I'd actually just order a new set of risers and lip from CLC, use a chisel and sandpaper to remove the old one and rebuild a new one. I'd also use the plastic sheet/finish off-boat method.

That way I wouldn't have to worry about the varnish, it'd have minimal impact on the existing finish and sanding and filleting would be much easier.

As far as trimming the lip,how would that impact the spray skirt/cockpit cover staying on?

Good luck,




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