I was doing some fussing about with my CSC Friendship and while stepping in the tub my foot went almost through the center :eek1. (Guess the crackling noises for the last year or so should've been my first clue..) The floor had a dozen or so holes in it and I'm sure after years of being rained on & general weather the wood reinforcement has rotted away. I've been talking with a friend of mine who has done some boat hull repairs (NOT professionally) and was hoping to sound my plans off someone who may have done some similar repairs on a fiberglass tub. I'm planning on cutting the bottom out of my tub and glassing in a new section of ply. Using resin and fiberglass cloth to glue the new section in, make sure I overlap up the tub walls, and any new mounting holes get sealed with resin/epoxy of some sort so this doesn't happen again immediately. I've also been instructed to use marine ply only, otherwise you have to worry about the wood swelling when you 'glass it in. I'm also guesstimating on using 1/2" marine ply (seems a touch thicker than what was in originally), any reason to go thicker? BTW, I'm not a fiberglass wizard by any means which is why I'm throwing this out there. I know I won't produce show quality, just want to save the body so it doesn't go completely to pieces.
Being in Fl. I'm guessing there might be a few boat repair shops around. Might pay to see if any would have some marine ply pieces laying around, would hate to have to buy a 4X8 sheet! Once fixed coat the bottom, inside and out, with truck bedliner a little texture will hide lots of imperfections.
Having built a few boats, and repaired any number of which, as well as doing repairs on aircraft parts (trim tabs, leading edges, etc.), I think I'd go about it a bit different. Is this a glass over ply arrangement? If so, I'd start by cutting away the bottom skin, then get rid of the old ply. Instead of using new ply, you might also want to consider using a different core material, either honeycomb or a foam, like Kleegecell. You can cold bond that into where the old plywood was, shape it (if needed) with a belt sander, then put the finish layer of cloth over the top. If you can rig a vacuum bag, so much the better. Instead of using a polyester (which is what it was originally laid up with), use an epoxy, which has better adhesion properties, although it has very low UV resistance, so you'd have to put on a top layer of paint. The only issue with using an epoxy is that even though it will stick to the polyester, polyester won't stick to epoxy, so any future repairs will need to be done with epoxy also. A couple of hints if you've never worked with GRP: First, break down and buy a resin roller to make sure that the cloth is fully, but not over, saturated. Another is that mixing up a fresh batch of resin up when you've started, so before you start, have pre-measured amounts of resin in old beer cans (soda cans have a different coating), all set for catalyising. When you get near the end of a batch, shout out at your helper to catalyse the next batch. Oh, and wear skin protection. I did so much work with the stuff without any, if I'm anywhere the fumes anymore, I instantly break out. Finally, never forget to have a good scrub up before taking a pee, the consequences of failing to remember are such that you'll only ever do it once! :)
+1 on Pago's advice. Nothing so special about marine ply, other than it has a (mostly) void free interior.
One more thought: If there are bolt holes going through the cored area, you'll need to put solid blocks in (aluminum works well), or alternatively, after it's all laid up, but before the holes are chased through, use a spade bit or a hole saw at least twice the diameter of the finished hole, to overbore through one skin and the core, but not the other. Then put a piece of tape over the backside, and refill the area with a high density filler and redrill when cured. This way you get a lightweight, rot-proof form, but when you torque the bolts down, it won't collapse the core, and water can't infiltrate. I'm guessing the original builder failed to do this with the ply, water wicked in, and the rest is history. I could flog off a sheet of good Fijian marine ply to you, but the airmail from here would be a killer. Bugger all hard to get stamps to stick on it as well.
This is exactly what I was looking for, thanks so much Pago! I'll stick with the ply, just 'cause the size I need could easily be someone's scrap/remnant and the bottom of the tub is flat so no special shaping will be necessary. (I'm assuming it was originally reinforced w/ply, I haven't got the balls to cut the bottom out of it yet.) I didn't even think about reinforcing the mounting holes either, really appreciate you making the point. Original construction had no provision to prevent crushing the glass & wood. I'm guessing the two part putty that turns to a steel-like substance (little grey/black roll, we used to call it "pinch & knead" when I still worked in a shop) should work pretty well for that. You're right about FL, I can't throw a rock in any direction without almost hitting a boat dealer/repair shop where I live. Thanks again for the insight guys, much appreciated
Don't waste your money on the store-bought stuff, it's probably polyester based anyways. Get some collodial silica (powdered sand), or micro-balloons, and mix that in with some resin to form a putty. Once you get the desired consistancy, catalyse it (it'll get a bit thinner), let it set for a minute or two for the reaction to start, then pot the hole. The filler made with the silica is harder, but is also harder to fair than the micro-balloon filler, as well as heavier...let your concience be your guide. Also, with the beer cans, keep a crooked finger under the tin as you're working. When it starts getting notably warmer, biff it, and start on a new tin, as it's starting to gel, and you won't get good penetration. One last thought: If you can't do the entire layup in one go, let everything cure through, then sand it, and clean it up with some acetone. Epoxy forms what's called an 'amine blush' on the surface, a sort of wax. If you don't remove it before you try laying on a new layer, it won't stick well. Good luck. Like lots of things, it sounds more complicated than it really is.
Go to your local WestMarine store and pick up their epoxy resin and hardner. If you want to spring for it, you can buy pumps that attach to the top of the cans to ensure correct mixing as well. Once you get this stuff, get some thin (but many layer) ply. It does NOT need to be marine ply. Cut the ply to the desired shape, and then seal the ply with the epoxy on both sides (take spreaders you would use for bondo and spread the epoxy over the wood). You will see it soak into the wood. Do 2 coats. Once this dries, the wood is VERY stiff, and completely waterproof (unless you drill holes in it). Then lay this in you tub, and level out all the sides using fiberglass mat and more of the epoxy. Then sand smooth and pain or bedliner. You will never have to worry about it again. This stuff is just tough as nails once its all set up. http://www.westmarine.com/webapp/wc...toreNum=50218&subdeptNum=50219&classNum=50220
pagomichaelh is steering you right. Forget poly resin and only go with epoxy. On a sidecar tub conventional ply is ok. Marine ply is better if you damage the epoxy and water gets to the wood it's but not needed here IMHO. 1/4" ply or whatever the original is is fine don't go with the idea thicker ply is better...it's not here. The plywood is just the backing,shape to work on. The strength is in the correctly applied epoxy not the plywood. Read, and re-read the epoxy kit instructions. Working temps are important especially the temp of the wood you're putting the epoxy on. If it doesn't stick/cure correctly you'll be very unhappy with the results and wasted a lot of time. It ain't rocket science but it is science.
the suggestion about going to WEST MARINE is sound they sell WEST SYSTEM PRODUCTS(not the same company) http://www.westsystem.com/ss/ the WEST SYSTEM EPOXY is what i used when i was teaching BOAT BUILDING to JUNIOR HIGH KIDS they, also, offer a lot of instructional materials that you can download http://www.westsystem.com/ss/fiberglass-boat-repair-and-restoration/ use their resin & hardener w/ their pumps and your measuring issues will be NON-ISSUES follow their instructions and you will be over 1/2 way home i sure wish you had posted pics of the damage, so i could speak w/ more knowledge about your project good luck sw & chili
Guys, thank you ALL for the input. I greatly appreciate the sharing of technique and do's & don'ts. Even if it doesn't come out pretty, I at least don't feel like I'm going to destroy my tub now. This weekends' agenda, supply shopping And I will share the process so you guys can bear witness to my triumph/defeat/whatever it turns out to be!
It WILL happen, but be patient... I just started getting the hack ready for the Cross FL Everglades ride and put a storage box back on the frame. This has backburnered the fiberglass tub for the immediated future. I add to that a prego wife, 18 m/o daughter, and little to no time management skills in my own garage . And a minor case of procrastination....
