New project 1971 proline flatback. First decision engine bracket.

[Conrad4784]

Although it might be laminating resin, that doesn’t necessarily mean it doesn’t have wax. The boatyard polyester resin from FGCI is considered a laminating resin (up to 1/8”) but typically contains wax and will cure tack free (their literature call it a non spec resin that may or may not contain wax). However, it’s hard to read the bottle you have but from what I find online it looks to be made without wax.

Regarding the layup, your best adhesion especially when going with poly is going to be wet on wet so you have a chemical bond and mechanical bond. It’s hard to tell from your precious post but did you layup a layer flat on a table of melamine and then bring that to the boat to bond to transom corners? Most I’ve seen set the melamine against transom and layup till the outer skin is done. Then bond the core into a bed of thickened resin to eliminate any voids or hard spots while also filling to create fillets so it’s close to ready for layup of structural tabbing to inner hullside/bottom.

Just my thoughts..

I did lay a layer of 1708 on the board and sandwiched it to the hull with thickened poly.  There was a 1/4 bevel tapering in that I wanted to fill.  I was trying to do the entire thing wet on wet but got interrupted.  I guess I was misunderstanding the entire laminating resin concept, I thought the resin was made to stay tacky at the surface so the next layer would form a chemical bond with the layer below.  I guess I'm going to rough up the coat with 36 grit , mount my layers to a board up top, and try to finish it out wet on wet.  I just hope it all bonds well to the one I already laid.

[Ulysses485]

Conrad, is it safe to assume you are going to be adding additional full width layers of 1708 to the inside of the one you bonded from the inside of the transom? On second thought, I would personally not feel comfortable with the bonded layer adding much tensile strength to the transom. They should be laid up AND tied to the inner hullsides at the same time so the full length of glass is brought inside the transom sides for greater strength. I don’t know if that makes sense.

[Conrad4784]

Conrad, is it safe to assume you are going to be adding additional full width layers of 1708 to the inside of the one you bonded from the inside of the transom? On second thought, I would personally not feel comfortable with the bonded layer adding much tensile strength to the transom. They should be laid up AND tied to the inner hullsides at the same time so the full length of glass is brought inside the transom sides for greater strength. I don’t know if that makes sense.

I am adding three full layers tabbing in from the inside against the melamine(layer of glass now) then coosa and another three layers.  the exterior layer was added to make sure I had a flat surface with out voids due to a 1/4 bevel inwards around the entire transom.  it should still have good strength 6 more layers of glass and coring goin in. I tried to show it in the previous post pictures.

[Ulysses485]

You’ll have plenty of strength with three additional full layers to build the exterior skin. The only concern I would have would be stress cracking on the edge joint of where the first layer was bonded. There is a lot of stress on the transom from the outboard. Just my thoughts.

[Tampa Bay Mike]

Laminating resin will still harden but it's probably not fully cured. If you're not sure, give it a little wipe with some acetone and give it a few seconds to flash off and then touch it. If it's still tacky then you're good to go. If you do the same thing on something fully cured like the outside of the hull it will stay dry.