i just purchased a large 80% wool blanket and plan to experiment with it on a 10' foam drift pram i am building. Im going to saturate/soak a smaller piece first with water based polyurethane to see what happens. if it works like i think it might, ill do the bottom this way over a sealed 2" foam bottom, and then an frp panel and maybe apply the final layer of epoxy graphite up to the water line.
my understanding is that the graphite adds no structure but rather very small particles of graphite to "shed layers" easily creating the "slipperiness". I have also seen people use welding blankets and other such materials.
you may wish to look up "basalt fabric" also. i saw a youtuber stab a 1' square polyester layed up test panel of this compared to the equivalent of fiberglass and the basalt was clearly stronger/impenetrable.
Im designing my floating tub with the idea that its a boat thats meant to be used and beat up. i building this prototype with the intent to perfect a jig for easy speedy layups of a very cheap and lightweight boat. this way i can think of it as disposable or easily repairable.
The first layer of fabric i used on the interior 1" side panel cores was just fabric "weed mat" applied with epoxy. seems good enough for what im after. I'm still using some internal wood frames to carry the load so i dont need so much fabric and epoxy. i also tried glidden gripper primer/paint. worked awesome. i used it to compare adhering the fabric to the transom and bow. it held as good/better than the epoxy did to the foam on the sides. dried much faster and costs less than half.
i also bought some sheets of flat smooth FRP(fiberglass reinforced plastic) panels from home depot. thought that might make a rugged boat bottom layer as well. the panel are only 30 bucks each. prolly a lot easier and cheaper than laying up our own. i plan to encase the entire outside of boat in this panel as the "final finishing coat".
well, now we see how she goes.
to me this is the fun of building our own boats. we get to work through our own ideas lol
best of luck with the completion of your project!
Thats an interesting idea, my question is won't the FRP panel most likely be a non epoxy product and so not bond well to epoxy?
hi bennet. not sure. maybe thats a good reason to try some FRP adhesive like titebond fast grab to adhere the outer layer frp panel to the epoxy fabric layer?? that stuff is way less expensive than epoxy(13$gal) and is made to spread so it may be perfect for the application?? plus no mixing ; )
it might not even need the epoxy graphite bottom if this works out well over the wool fabric/composite? bottom covered in frp. should be plenty slippery??
maybe i'll try both 5200, and the frp adhesive to attach the few frames on interior to the outer layer frppanel? i guess i'll need to test some scraps to find these answers.
thanks for the response as it got me to consider the frp adhesive over the epoxy, which makes sense for a lot of reasons!
Im also now considering comparing 1 part epoxy acrylic garage floor sealer as an option for saturating the wool fabric bottom.
so many ideas.
JC, if you decide to go with two layers of cloth, I would wait until the first layer is almost cured, just still a little tacky. Then you can put the second cloth layer on and orient it easier. If you lay second layer of cloth on the first wet epoxy coat, it is very messy and virtually impossible to move or adjust it once it's on as it will immediately start soaking into the wet epoxy, if that makes sense. For the finish coat, you will get the same results with graphite powder mixed in the last filler epoxy as with any Coat It type product for less money. I bought the large 8 lbs Coat It for a 16X48 bottom and there was just barely enough to finish. It comes in a gallon can, but the can is only 3/4 full, not sure why, maybe to leave room to mix. So for a 17X52 you would most likely need a couple cans.
I don't know how much better two layers of 10 oz would be than one layer of 20 oz. I'm sure they both have their merits. As far as bottom coating goes I'd recommend the epoxy and graphite for the sheer convenience. It costs basically nothing, and when you scuff up the bottom and want to make a touch up its ready to go, just mix a little epoxy and pour in a touch of graphite and paint it on.
I have three layers of 6 Oz. with Graphite in the last three coats of epoxy and after 4 years of draging it on-off the rivers (rocks, sand, deadheads, dirt banks, and timbers) it's holding up well. No Maintenance required yet.
Dorf, good news as that is what I ordered earlier in the week. Raka did not have 10 or 12 oz cloth in stock and did not anticipate ordering more soon, so 3 layers of 6 oz it is.
If you go with graphite in the bottom coats of epoxy, take the time to read the instructions on the can. Too much added is no good, makes the epoxy brittle. Guess how I know? Read my blog "Dorf's Wooden Drift Boat" (toward the end) I explain in detail what happened.
Done right it works (for me).
I agree proper mixture and application works very well. I am not saying it is super slick but it does protect the bottom of my boat from damage and is not brittle.