Epoxy mistake

 I was fiberglassing the deck of my shearwater hybrid and I had not realized the epoxy left in the bottom of my container was getting hot (tall yogurt container and I was holding from the top). As soon as I started to squeegee it I could tell something was wrong. I tried to work it off the deck but alas it was a lost battle. It appears that it did not fully fill the weave(first coat) so I'm left with weave pattern lines under a very shiny part of the deck. What can I do? Here is a link to the pictures... Glass mistake https://imgur.com/a/yw5C3fL

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RE: Epoxy mistake

This affect the entire deck or just a smallish portion?

Got a heat gun? (Hair dryer won't work... trust me.)

Tough to admit making a mistake but it's not insurmountable. With heat and time you can soften the epoxy enough the cloth can be pulled up & away. Practice with the heat gun so that the epoxy softens enough but doesn't begin to bubble. Work over fairly small areas while keeping the gun's nozzle moving constantly with one hand, the other with pliers for a good grip on the warm, saturated cloth.

What's left behind needs to be evaluated carefully for how well vs. how poorly it's bonded to the wood underneath.

Worst case is scrape / sand it away, start over. Be careful to mix each batch in a new, clean container, or one that's been used but the epoxy's cured hard enough to be peeled out leaving an almost 'good as new' surface. (Honestly I'm skeptical of reusing containers like this as they always seem to have small bits of hard epoxy I miss just waiting to get put into a fresh batch. Fine if your mixing filleting stuff, not so much when it's a finish coat, terrible set-back if it's the cloth-saturating one.)

Good luck with your error; come back with pics of your successful rehab please!

RE: Epoxy mistake

   It's a space of about 12 inches by 22 inches. The rest of the boat came out perfect. Would I need to pull the entire deck glass up or just the small spot? Can I aggressively sand down the area I messed up and just lay new glass there?

RE: Epoxy mistake

You can sand it off if you prefer, but it will be a lot more work and you have to be very careful as you approach the wood. On the other hand, with the heatgun you have to be very careful that you do not cause damage beyond the area that you wish to remove. A combination of heatgun for the bulk removal and sander to clean up the edges might work best.

You do not need to remove the entire deck glass, just the damaged area. The new patch should overlap 2 inches onto the good glass on all sides.

1. Mask off the  area to be patched with clear wide plastic packing tape.

2. Cut the patch so that it extends to the middle of the tape in all dimensions.

3. Apply it and wet it out, then wait until it cures to the "green" stage - no longer tacky, but it's still flexible like a piece of stiff leather.

4. Gently peel it up off the tape.

5. At the point where the tape ends, make a small nick with a razor blade and gently start pulling the excess glass up. It should tear at the line where the packing tape ends.

6. Immediately remove the packing tape so that it won't leave a residue, then wait a day or more for the epoxy to harden so that you can sand it.

7. Lightly sand the edge with #220 paper and it will be ready to have the weave filled. The patch should end up invisible.

Here's the process on my WD12 when I was overlapping the deck cloth onto the pre-glassed hull.

Masked with packing tape.

"Green" glass peeled off the tape

Peeled glass being torn off. If the tear doesn't follow the edge of the tape, restart it with a razor.

Torn edge sanded, ready for weave fill and finish.

Good luck,




RE: Epoxy mistake

Do what Laszlo's outlined, you'll be fine. 12" x 22" is a reasonably sized area to practice the techniques needed. If the rest of your deck came out fine, the repairs will too.

RE: Epoxy mistake

   Thank you all so much. I used the heat gun and a small blade to remove the glass. Sounds like next step is sand down the area and clean up the edges right? https://imgur.com/a/X8LO3A0

RE: Epoxy mistake

   Here is the deck all cleaned up and sanded down. Just have to wait for later in the day to start the glass process again so I don't have any out gassing issues. https://imgur.com/a/oflc2Ja

RE: Epoxy mistake

Looks good.



RE: Epoxy mistake

hi tempest170,

if not too late, in order to ensure you get a clean repair, i would recommend you wipe the surface down with denatured alcohol (you can do this with a denatured alcohol soaked white paper towel), prior to putting on the new epoxy/glass.

when you wipe it down with denatured alcohol, you will quickly get a perspective if the glass that you have sanded will wet out clear or not. 

if you still see 'white" when the denatured alcohol is wet....you need to do a bit more sanding to get to clean glass/epoxy area.  

if under alcohol, it looks clear, you now can proceed with confidence that the new epoxy/glass you will be putting over the repair will be clear and blend in as if nothing had ever happened.

the important part you are assessing is the 'good glass' that you sanded (that now looks hazy white),,,,and you are just confirming, prior to the new epoxy, that it will wet out clear and the repair will disappear.

if it is not clear when wet with denatured alcohol, it will not be clear with the new epoxy.

anyway, just a tip on how to ensure repairs are never noticed.




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