well, i'm 13.5 hours into this superskipjack build, and i have the following done:
decks assembled
hull bottom, and keel
next week i'll move onto getting the hull assembled & glued with epoxy, then i have a 12 day stretch off from work and plan
at least 10 full days on it, can't wait to see how far i get! i've noticed a few little things in the plans that i'm making notes of to pass on to the stevensons but all in all, it's going well, the cockpit is HUGE for a boat this size, can't wait to get it out. it took a while to get good a cutting curves with a skillsaw, but it's a neat trick! i also have some areas where i'll need to smooth out some curves with a belt sander, but overall i like what i see so far.
as i've mentioned before, i'm doing this on a budget so i haven't used marine grade plywood, although what i am using is outdoor waterproof glue plywood. i plan to glass the entire boat, so after all the discussion i hope i get a few good years out of this hull
i'm already thinking down the road to a larger build so this one is not something i'm building to last 20 years. but i'll post a few more pics as it comes together
[attachment=1]
Lookin good man,be done by next friday at that pace....But that work area is Wayyyyy to clean
haha thats cuz i was told i could build a boat on MY side of the garage ONLY, no mess allowed!
couple of new shots now that the boats gone 3D lots of holes to fill as a result of using cheap plywood but we are glassing the entire thing. i've had a few "why the *%#* did i cut that the wrong size" moments, but so far, having a blast. also cleaning the work area every night so my wife's car will fit into the garage, but it keeps the mess under control!
the sides of the hull should go on tomorrow, then it might look like something
It's coming along real well, you could send the boatshop elfs to do a number on my place if they get bored at yours, LOL. Keep sharing the progress pics, good luck on the sides today.
Greg
It looks great! Yes: Glass the cheap ply!! That was the MAIN reason I had to re-do mine. The cheap stuff just doesn't stand up any longer. I would consider soaking it with penetrating epoxy prior to glassing, but it's probably not necc. I did mine, but then I was repairing a previously painted surface and wanted to get as much into the wood as possible, and to get a slightly better bond (given that I couldn't get ALL the paint off!)
Mike
All recent penetrating epoxy tests confirm what I've been touting for years, which is penetrating epoxy is a waste on money and effort. With the exception of some very hard to find, non-reactive modifiers, used in some industrial coating systems (epoxy) all the major penetrating formulators use solvents to reduce the viscosity of the epoxy, thus improving penetration. The Smith Brothers product is the industry leader and right on the can it tells you what you're buying, which is 37% epoxy, the rest is common solvents, some in direct contradiction to each other (some are hygroscopic, while other s are non-hygroscopic), which is self defeating chemically.
When you introduce solvents to epoxy, more then just a few percent of the volume, the physical properties drop dramatically. Just a 15% solvent dilution reduces regular amine cured epoxy by 50% in tensile strength and 60% in compression! Most every epoxy used in boat building is an amine cured product (there are actually several different types of epoxy resin).
For years the formulators of these products got away with this snake oil, but eventually got called on it with independent testing. In fact, it (the government) forced a major player to change it's name. Now, penetrating epoxies are really a marketing gimmick, though there are some very limited uses for some, very low dilution formulations (like those found at Progress Epoxy Polymers, Inc). The best part for the formulators, is they sell you highly diluted product for more then the cost a straight epoxy. This is all well documented stuff and a huge money maker for the formulators.
Back to why it's not effective. When the solvents flash off, they leave a maze of out gassed paths (the bubbles rise to the surface) through the cured epoxy matrix. This has the net result of making the surface prone to moisture gain. These out gas paths also break up the continuous skin of cured plastic, so not only is is weaker, but it's not even as water proof as regular polyurethane paint!
In the end, testing proved it's not the amount of substrate penetration, that makes things more water proof, but the quality of the coating. The two basic resins systems, used in marine grade epoxies, are 100% solids when fully cured and this is what makes things waterproof. Viscosity can be controlled with temperature (the hot on hot thing I've mentioned in other threads), so improved penetration is just technique, not product.
Lastly, if you apply a penetrating epoxy (or any high molecular pressure liquid that penetrates, like acetone) to plywood, it can't penetrate any further then the first veneer glue line, assuming it's a WPB adhesive, which makes any "serious" penetration dubious at best.
To sum up, if you use a penetrating epoxy first, on raw wood, whatever is applied over it, will be trying to stick to something that is dramatically weaker and much less waterproof then regular epoxy, so it's ability to remain stuck, is questionable. The usual result is the subsequent coatings (regular epoxy or paint) fails in sheer, because the peel strength of the diluted epoxy, tears at the bond line.
So its the epoxy that waterproofs the boat.
other then abrasion resistance
Does the fiberglass add to the waterproofing? Or is it
Just the extra epoxy needed to apply it
That adds to the waterproofing?
well it "kinda" looks like a boat
the hulls on and first coat of filling (love the way epoxy hides your mistakes!)
now i need to create some sort of jig to support me when we flip it back over so i can crawl around inside and do seats, etc.
one of the shots shows my flatter transom, as i said before, i was unhappy with the huge stress on the transom after bending it, so i went with a flatter rear deck, which created a flatter, more upright transom with a small curve to it. i've tried to stick to the plans but there are a couple things like the transom where it made sense to do what the wood wanted
anyhow more to follow:[attachment=1][attachment=2]
(08-20-2011, 03:58 PM)bob lee link Wrote: [ -> ]So its the epoxy that waterproofs the boat.
other then abrasion resistance
Does the fiberglass add to the waterproofing? Or is it
Just the extra epoxy needed to apply it
That adds to the waterproofing?
It's the quality and the film thickness of the coating that waterproofs. Diluted epoxies aren't 100% solids, so the coating can't resist moisture vapor penetrating the substrate. Straight (regular) epoxies offer the best moisture resistance. Regardless of the amount of substrate penetration, if the film thickness is sufficient, then it'll be water proof.
In short, if you use a regular marine grade epoxy (one that isn't designed to penetrate by using solvents), then you're good to go. All of the major formulators and reformulators have straight, unthinned epoxies and they all are waterproof. This would include West System, System Three, Raka, Marinepoxy, Epoxy Products, AeroMarine, etc.
Yes, 'glass fabric helps waterproof, both from adding to the film thickness, but also because the fibers themselves are inert and can't absorb moisture once embalmed in goo. With some fabrics, like Xynole and Dynel, it's purely the extra epoxy that adds to the waterproofing, but it would be rare to see a Weekender builder using these specialty fabrics.