Sanding Mistake Memorialized Under Fiberglass

In my hast to fiberglass over an inlay on my Passagemaker forward seat, the color difference between the area on the front seat where I had lightly sanded and the area immediately surrounding where I sanded much more to smooth epoxy didn’t register as a problem. Now it’s painfully obvious, see pic (

Will this darken with exposure to sun or should I write it off as practice and just flip it  over on the other side and start over?

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RE: Sanding Mistake Memorialized Under Fiberglass

   Not sure if it will darken, but your decision is do you want to go boating soon?


RE: Sanding Mistake Memorialized Under Fiberglass

Ouch...That does stand out more than you'd think just a difference in sanding would provide. Sorry to see this especially since you seemed to absolutely nail the install. 

I have not noticed any darkening on my PM's epoxy in the sun and it has probably 60 hours of direct sunlight on the seats. My understanding is that darkening epoxy is usually a indicator that there is insufficient UV protection of your finish.

I'm going to say that the varnish had more of an effect on the color of the of the wood than any other factors. You maybe able to soften the difference with careful and clever application of your finish. As I am exclusively a freshwater guy I used Interlux Schooner only on my hull and used good 'ole Minwax Helmsman spar varnish on my seats and bulkheads. I also used the spray version for inside my compartments which may or may not have been necessary. 

I may have been late in my last reply to your other post but if you do end up re-doing your inlay on the opposite side I would double check the need to fiberglass the seat with CLC customer support. I think the instructions to put this under glass applies to kayaks and other craft that have glass decks. It might save you some real time.

Also, at the end of the day the level of finish needs to be something you can live with. You will be your hardest critic. I named my boat "My Bád" because I feel like I hosed up the finish and it has many, many blemishes. Everyone who sees the boat loves it. Don't fall into the trap that if your bright work isn't absolutely perfect that it needs to be painted. Go bold, go bright.

Kindest regards!

RE: Sanding Mistake Memorialized Under Fiberglass

Regarding suggestion to not fiberglass forward seat. I contacted CLC to get their thoughts on it. Here is their response. Ironically, I didn't have any problem with bubbles. I wish I only had that problem.

"You raise a great question. In this case, I'd definitely fiberglass over the inlay. That forward seat may see lots of use in the future and you want to protect the inlay as much as possible. 

That said, fiberglassing over an inlay presents its own unique challenges. You're definitely going to have to contend with some air bubbles. I've 'glassed over numerous inlays and no matter what I do, I always seem to end up with a few of those little buggers. 

Carefully excavate the bubbles out with an Exacto knife, fill them with epoxy, and keep going with your fill coats. You'll be thankful down the road."

RE: Sanding Mistake Memorialized Under Fiberglass

i am impressed with your cleverness to recognize you could simply turn the piece over and take another wack at it.

that said,    why not give it another go.  i don't think it would take that long and you would know to avoid the mistake again.

i have had a similar experience but noticed it and addressed it prior to the epoxy hardening....and was able to stop, sand the whole piece and restart.

in my case, the wood had been exposed to the sun for a while while the project sat and the sanding basically re-exposed fresh wood. so i expect over time it may have worked its way to a uniform finish but i didn't want to wait to see what would really happen.

so why not do it the way you want.....a lot of set-backs you have to live with....this one you have a clever hide:)


RE: Sanding Mistake Memorialized Under Fiberglass

So I found the correct answer and it is to use a heat gun to remove fiberglass ( ). It took me about 20-30 minutes to pull up fiberglass in sheets about 6 in wide. It came up very easy once heated. In total, I’m about 1.5 hours into it and I estimate I have about another 30 mins of sanding to be ready to re-fiberglass it. This time all of the surface sanded equally.

RE: Sanding Mistake Memorialized Under Fiberglass

   Nice one! Sounds like you are moving right along! Thanks for the update.


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