Thread: Fiberglass putty... need advice

G'day Seatime, welcome to the forum.

It sounds as if you are going to do gluing and what I know as filleting - but it may not be that. Can you describe the construction method and possibly tell us the name of the design? Any details may help someone here give the right advice.

For filleting material when building a ply kayak I used epoxy thickened with sawdust or sanding dust (this is OK if bought or collected clean - don't use floor sweepings). There are other commercial fillers, including things to make it less dense (ie lighter) but these are not essential. The advice I had on adding the thickener was to keep adding until the mix is the consistency of strawberry jam - and I've found this works well.

If you haven't sourced epoxy yet then be sure to buy a marine grade. Hopefully PAR will post here soon - he's only a couple of states away and may be able to put you onto a good source. Check out his epoxy primer here:
PARyachts: Epoxy Tips & Tricks

If you do a google search on "filleting boat seams" or similar you should find some other tutorials and youtube videos that may help too.

Good luck with it and do post some photos here if you can. We like pics

Welcome to the forum.

Thanks Bob (well at least one guy has visited my site ), though Tennessee is a considerable distance (700+ miles from me), supplies and materials can be shipped about anywhere.

I'd second the previous comments about needing to know what you're trying to do, the building method, possibly the actual set of plans you're working from etc. There are lots of "putties" and Lowe's/Depot doesn't have anything that's really marine suitable. They do have some moderately applicable sealants, but these are mostly just polyurethanes (caulk), which are different from what I suspect you need.

Most of us make our own from epoxy. Though I've recommended wood flour previously, I don't any more, except as a color matching agent. Unless the wood flour is exceptionally fine and a particularly dense hardwood, it tends to let the goo run out of the fillet or joint as the exotherm process heats up. This said, I do use mahogany (or appropriate species) dust to color repairs, which helps hide things, but this is more art form than practical. In fact, it's much faster to use a pigment if just trying to match color.

In any case, tell us what you're building and be a bit more specific about stuff, so we can be too.

THANKS FOR GETTING BACK FELLAS
...I AM BUILDING A STITCH AND GLUE PRAM 7'8". I NEED TO FILLET THE SEAMS BUT DONT WANT TO BUY THE EXPENSVE EPOXY THATS OUT THERE. I HAD HOPED YOU GUYS KNEW OF SOMETHING CHEAP THAT WOULD DO.

HERE SHE IS:

Originally Posted by PAR

Welcome to the forum.

Thanks Bob (well at least one guy has visited my site ), though Tennessee is a considerable distance (700+ miles from me), supplies and materials can be shipped about anywhere.

I'd second the previous comments about needing to know what you're trying to do, the building method, possibly the actual set of plans you're working from etc. There are lots of "putties" and Lowe's/Depot doesn't have anything that's really marine suitable. They do have some moderately applicable sealants, but these are mostly just polyurethanes (caulk), which are different from what I suspect you need.

Most of us make our own from epoxy. Though I've recommended wood flour previously, I don't any more, except as a color matching agent. Unless the wood flour is exceptionally fine and a particularly dense hardwood, it tends to let the goo run out of the fillet or joint as the exotherm process heats up. This said, I do use mahogany (or appropriate species) dust to color repairs, which helps hide things, but this is more art form than practical. In fact, it's much faster to use a pigment if just trying to match color.

In any case, tell us what you're building and be a bit more specific about stuff, so we can be too.

PS....I meant to say epoxy wood putty instead of just " epoxy " in my reply. This feature (messages) site is not working properly.

THX

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If that is a taped seam build (stitch and glue, etc.) then you have to use thickened epoxy in the seams and the fillets. The only reason stitch and glue builds exist, is because of the abilities of epoxy. In other words, if it wasn't for epoxy, this build method wouldn't be viable.

Again, it's time to get specific about your needs and what you're doing. What brand of epoxy are you using, what design are you building, where are you getting your fillers?

That looks to be a Mertens design and his site is a good place to get materials. Use their "Marinepoxy" instead of the name brands, as it's just as good at 1/2 the price.

The cost of epoxy for a project like that will be modest. You'll need maybe a gallon if you're frugal, maybe a gallon and a half if you're like most novice builders. Basicly less than $100 if purchased at Bateau.