Glassed the deck of my Guilemott double strip built recently and there are a number of white lines running almost the length of it. See photos.
I’m assuming this means the cloth got stretched or damaged before I wet it out.
Wondering if anyone has any ideas for fixing this. I am thinking about glueing a thin strip of sandpaper to a bit of timber to allow me to sand out the lines. A bit worried about what it will do to the strength of the deck if I sand through the glass a couple of long thin lines though.
Hi Anthony,
i have done layups for 30 some years and can’t claim to have seen something like that.
when i look at the picture closely, the line is not oriented along a particular thread…and it appears on the line….that the cloth is dry/not wetted out. .did something scratch or drag a line across the weave after wet out but prior to it curing?
if the cloth, prior to wetting it out, is not contaminated, it should wet out clear even if a thread has been pulled….did you notice the lines when wetting out/applying the cloth? if not, when did you notice it?
i am assuming if you took some denatured alcohol and applied it to the surface, that you still see the line. if denatured alcohol makes it go away….then you can make it go away by applying epoxy.
i would hold on sanding it out until we hear how you respond to the questions above…
Hi Howard. Thanks for the advice.
the line was there when I wet it out with epoxy. I’m confident it’s not from being scratched. I feel pretty confident I wet it out thoroughly too.
It didn’t disappear when I put a fill coat over it, and doesn’t go away with alcohol.
Hi Anthony,
thanks for the confirmations.
i suspect that there was some kind of contamination in the glass.
the only other explanations i can think of would be that along the line, there is some other reason that the epoxy got pulled/pushed away from the glass leaving it dry/not fully wetted out. this could be becuase something got pushed down hard against the wet glass pushing the epoxy out of the glass leaving it dry….or that under the glass, there is something with the substrate (wood) along the line that made it pull the epoxy into the substrate leaving the glass dry (this can happen along a wooden seam for example). but there is no obvious evidence in the photo for this….
so where i think you are is: option 1) moving forward and ignoring it as long as the current white line is fully embedded in good epoxy. or option 2, sand it out, as you mention, but patch it.
the advantage of option 1 is you finish quicker and get to go kayaking. the downside of option 1 is the line will probably fail sooner than not having that defect requiring you to patch the glass inevtivably. but sooner could be the a season or two on the inside or as long as five to six seasons or more if the boat is treated nicely (stored dry and out of the sun).
option 2 is sand it out….but you do need to patch it (put another piece of glass on top and feather it in). in my view, these lines are two long to simply sand out as you would be cutting too much glass strands perpindicular to the path of the scratch with no strength replacing it if a patch is not put in place. the patch in this case would be 2inch wide X however long the scratch is that you sanded out….then you fare it in. the advantage of option 2 is you patch it and you are done as if this never happened. the disadvantage is adding three to five work sessions to fix it – a session or two to sand out the old scratch, one session to patch. another session to do a fill coat on the patch, and one to two sessions of sanding to fare it all back in.
fwiw, i have experience on option 2 in the boat in the picture below. on its maiden voyage i accidentally paddled it over a piece of rebar sticking out of concrete blocks along the shoreline where i was paddling…. putting a five foot scratch through the epoxy and deep into the glass……as if somebody dragged a knife down the bottom of the boat. the five sessions got done in about an elapsed week of time…and then nobody knew anything had ever happened.
if it were me, i would probably do option 2 . but you can also go option 1 if you want to kayak sooner rather than later and do option 2 during the off season if you have one. in that case, i would avoid the varnish step …until i completed option 2.
i hope this is helpful. we have a couple other strip builders who may weigh in….
h
That’s a beautiful boat Howard!
Thanks very much for the tips.
I reckon I’m going to end up sanding and patching. A large part of me just wants to leave it, but I’m sure I’ll be more happy If I fix it.
It seems from the picture that the lines are on the bottom of the hull. Assuming you built this boat to actually paddle it, it is crazy to try and fix. These boats get scratched quite easily and the lines will be lost after a few years of use.
Agreed I wouldn’t worry if it was on the hull David. They are on the deck though.
Sorry, I definitely did not understand that was the deck. I still wonder if it is worth the risk that the patch will not blend in perfectly.
