The original boat was polyester. It doesn't bond as well as epoxy to wood, but it did hold up for quite a while.
There are two schools of though on the layering of tabbing- the way I mention and the reverse. ( I was taught that way to better avoid peel failure). We aren't building airplanes, here, we are fixing recreational boats, so it isn't as critical. But in either case the joints use fabrics/tapes of different widths to taper the joint and spread it over an area.
If you mimicked the thickness of the original transom, you are probably fine there. If the tabbing looks similar, you might be fine. My gut feel is that you only get this opportunity once, so I think if it were my boat, I would use more tabbing, and use different cloth widths to taper the thickness and stiffness.
They get into this stuff at boatdesign.net and there are crusty naval architect types there- and I am not one.
This thread there is good: (is a link to another forum ok?)
http://www.boatdesign.net/forums/fib...ion-45735.html
The attached PDF (first image for a non cored hull) and images in that thread are interesting. There they discuss bulkheads, but a transom is sort of a bulkhead, just one sided. It at least talks about tapering cloths and some of the concepts.
Quote:
Originally Posted by kiwi
Thanks FS. Good camera angles hide a lot  I had some trouble rolling out all the air pockets before resin kicked over, especially on edges with 1708. I read about FF's adding a chamfered edge where the sheet rolled over the top. I routed a round edge, but it could have been bigger. The large sheets were harder than the small stuff. But it wasn't too bad. I'm learning what my capabilities are (more like aren't). But so far I have managed not to make a cat's ass out of it.
Great advice on tabbing. I wish I learned all of that earlier. I did not lay as much tabbing as you all mentioned. Do you all recommend following up what I've done so far with additional tabbing? Does it help strengthen the joint if I were to go over what's been glassed with the tab schedule you mentioned, or is it better to always have the outer layer overlap the previous one? I plan to come back with 1708 final inner transom layer like FF did on his, and that should tie the added tabbing in?
Got any tips on how thick I should get? My transom laminate currently is, from outer skin inward:
- Original outer skin
- 1 1/2 oz mat
- thickened resin (applied with grooved trowel), squeezed by core to bed it to outer skin
- double 3/4 plywood core, with 1 1/2 oz mat in between
- 1 1/2 oz mat over the core
- 1708
- 1 1/2 oz mat
-1708
I'm using polyester resin, so maybe err on the thick side?
One last thing- while I have the cap off and have access to the deck drains that feed to the bottom of the hull, any reinforcing that you would advise adding to these? If so, how?
Thanks for all the help. |