Cheap fiberglass and epoxy or alternative

[Elias_Fleishman]

I recently started constructed a small 8' sailboat out of crappy 1/2" homedepot plywood, it's not even as good as lauan stuff im pretty sure it's pine. Anyways the entire hull will be constructed from pine because it's what I have left over from when my parents had our porch built and I'm trying to save some dough so I can start my I550 build. The hull will be by no means watertight on it's own(there is a 1" gap that runs down the center of the hull that will be covered by a 1"x1/4" pine slat) so what fiberglass and epoxy resin would be cheapest for me to buy or what alternatives do I have? Im not trying to make something spectacular just something to hone my skills before I start on my I550 build.

[PAR]

If you're going to hone skills, epoxy use is a major one you'll need on an I550. Use Marinepoxy from bateau.com. It's stable, the cheapest going and the slow is about as non-blush as practical. It's really the only reliable gap filling adhesive that will help. If the plywood is as bad as I think you have, you'd be well advised to fully coat the panels of this little contraption of yours. 1/2" plywood is hugely oversize for an 8' sailboat, so who's design is this?

[Elias_Fleishman]

It's a design I've had in my head for a while I'm only using 1/2" because it's what I had laying around. What about glassing the entire hull?

What about the thick epoxy and medium hardener from here:http://www.shopmaninc.com/epoxy.html

[gonzo]

It probably is not worth it. If you tape the seams it won't leak.

[PAR]

Okay, if 1/2" CDX plywood (or whatever) on an 8' dink is good for you, then why bother with goo. It's clearly not an heirloom build so treat it as what it is. Squeeze some polyurethane sealant into the seams and hope for the best.

[Elias_Fleishman]

Originally Posted by PAR

Okay, if 1/2" CDX plywood (or whatever) on an 8' dink is good for you, then why bother with goo. It's clearly not an heirloom build so treat it as what it is. Squeeze some polyurethane sealant into the seams and hope for the best.

whoa there pump your brakes man!!

this isn't just some 8' dink its my first build and when i do things i like to them right even if it is just my first time doing it. i want this boat to last as a testament to my craftsmanship not just fall apart and rot away under my deck.

any ways if you want to see some pictures and explanation of whats going on check out my blog: I550chrystal.blogspot.com

[gonzo]

Your last statement contradicts the thread you started. Cheap and heirloom can't live in the same room.

[Elias_Fleishman]

its not supposed to last forever but 10 years might be nice and i never said that i didn't care about the boat. of course i want to be a good why else would i be spending every single spare hour that i have working on it. seriously as soon as i get home from school i got to my back yard and start working on it and i don't stop till its too dark to see.

[PAR]

I have a several small craft designs, including more then one sailing dinghy about that size and none require 1/2" plywood planking. Most do have a reinforced transom if using an outboard, but 1/2" planking is way over the top as far as a reasonable and justifiable planking scantling. Is this your design? What's the PPI?

[Elias_Fleishman]

Well it all started about 3 days ago when I was bored in math class. I knew it might take a little while longer than I first expected to get the money together for my i550 and since I'm such an impatient teenager I got to thinking. I remembered that we had a couple of sheets of ply wood just laying around so I decided that I was going to use them to make a boat. So the next class, which happened to be engineering, I made a 3d drawing of my boat on inventor. I did not want to have to make any joints on the panels so I decided to make the boat only 8'. From there I knew my basic hull shape so I got to cutting the bottom panels. From then on it has been kind of a design as you go thing but I always have a mental picture so no biggie. It's actually Turing out better than I expected.
The reason I have used 1/2" plywood is because I have more of it than 1/4" and the 1/4" is in really bad shape. I literally have not spent a dime on this boat only time everything that I have used so far was just lying around.

[PAR]

In other words, you haven't a clue where this is going to float at (depth or trim angle), right? So, what's your engineering experience telling you about how this might turn out? Can you post a drawing or two, with some dimensions?

[SamSam]

There was a guy on another forum that was always making floatable objects cheaply because he had no money. He was big on cloth and paint instead of fiberglass and resin.

[PAR]

Yea, I've seen these types, but their methods don't hold up and they can't substantiate their techniques with material properties data, making you wonder about the whole process. In other words, comparative peel strength characteristics, with their paint and cloth methods, would go a long way toward some level of acceptance.

[lewisboats]

Hope you pump iron...I suspect that thing will weigh a ton (or feel like it does). You could try PL Premium as a glue and use epoxy as a sealer. Tape the seams, seal with a coat or two and paint. I wouldn't expect it to last more than 4-5 years if stored covered and raised off the ground outside, a few more if you keep it inside and keep up on the coatings. Is that treated ply? if so then up the lifespan by a couple of years in each case. You will probably get tired of lugging it before it craps out ( I know I would). Personally...if I were building it I would cut my costs, use PL Premium for the glue, one of the PL caulking adhesives as a caulk, Polyester resin and glass for the outside of the seams. Use it until it falls apart and build something else. Out of pocket would be less than $50.

[Elias_Fleishman]

That's the best fix I've heard yet I think I'll go with the polyester and pl.

I never saved the drawings. I would basically draw up the frames and loft them all together to get a basic idea of the shape. The plywood is also extremely warped so it has a natural curve that I couldn't measure.