transom glass question

[bluecat]

hi i am after some advice or pics of the best way to lay glass for an inner transom replacement?
it seems obvious one large sheet of glass will not fit along the bottom of the hull AND the sides evenly without kinking so which is the best method to lay glass so its obviously the strongest lay up
do you cut a section out in the corners to make it sit square along the sides as well?
any advice or pics appreciated cheers
the boat is 15ft and will take approx 90hp
best regards chris

[PAR]

Well, it would be helpful to know what you're doing and a few pictures would be nice as well.

Let's assume you've replaced the transom core and now are attempting to "tab" it back into the hull shell. The first question I have is how big a radius or fillet have you provided for the tabbing to lay against? Again assuming the fillet is big enough to prevent puckers in the tabbing, you'll need to cut strips of tape or bulk cloth (assuming cloth) and dry fit these along the perimeter of the inside of the transom core. You'll need several inches of overlap onto the hull shell and the core and enough tabbing bulk to keep things in place. On a boat this size, with that motor, I'd error on too much tabbing rather then too little so lets say at least 3 layers of 10 ounce biax as the tabbing.

Once the tabbing has cured and been sanded reasonably smooth, apply a regular fabric to clean things up, say 6 to 8 ounce cloth. Fill the weave and you're ready for paint.

Of course this assumes (again) that the core is well bonded to the outer skin, the inner skin (if present) is well bonded to the core, the tabbing is well bonded to the core (or inner skin) and fillets and hull shell, not to mention any other structural issues have been attended to.

As you can see, without knowing what you are doing, there's a lot of assuming going on, which isn't especially handy for you. Can you post some photos and offer a better description of what you're trying to do?

[bluecat]

hi thanks for your time
heres a pic i found on the net that best defines what we are doing

we also have quite a lot of room as there was plenty of rot in the floor and the stringers were also in bad shape
so you are saying once the transom ply has been glued and clamped into place,the the several inches of over lap around the perimeter provides the strength necessary to keep it in place and there is no need to worry about doing the whole transom in one coverage for strength as its really only "cosmetic"?
cheers chris

[PAR]

Yes, that's correct, you just need the tabbing for strength, but a lot can be said about sealing up the core so you don't get moisture in it again.

In the above picture I don't see tabbing (though it may well be there), but I do see a fillet, which in some spots looks like it should have a bigger radius. You need this radius so the tabbing will make the transition from a vertical to a horizontal surface. As you know it does pucker and bunch if the corner is too tight.

A light layer of cloth will seal it up if using epoxy. If using polyester or vinylester resin, you'll want to build up some mat thickness, as it's not nearly as waterproof as epoxy.

[bluecat]

thanks for your help,the tabbing question was my main concern i now have faith!
i can now mentally plan ahead

[bigdawg10132009]

sooooo....you epoxy the first ply to the outer skin....then the second to the first.....thicken the epoxy and make a radius of fillet and then tape the seams.........finally cover the face of the transom...