Flattening transom skin before installing core.

[steel686]

I had good luck with one wrap of packing tape on my hex bolts. Gave them a quarter turn the next morning and left if alone for two days. I think someone mentioned this but why not dry fit your core with strongbacks on the outside, drill out your thru-bolts, and then wrap the core material with poly. Lay up the extra 1708 and then pull it together with your core until your inner skin cures. Peel the core, glue it up and reclamp. I had a little bow in mine and now it is dead flat. I have a feeling some of it was always there because I had to fill a big gap where the cap wraps over the transom.

[captsuperfly]

All good ideas. thanks.

I dry fitted the 3/4 inch ply to the outside of the transom and secured it with 5 carriage bolts - three down the center and one through the old eye hardware holes in the upper corners. it pulled nice and flat.

I did wrap the threads and the head of the bolts with packing tape. I may wax it too.

[Bikecop1]

Pics??

[Capt Terry]

I may not have kept in the loop about how you are using carriage bolts. If you intend to remove them and it sounds like it because you are taping and waxing them, you are loosing the ability to rotate them to make removal easier. When I used the plywood on the brace my aft sheet for my Seacast pour I through bolted from the plywood thru to the fwd fiberglass with slightly smaller hex head bolts through the engine mount holes with flat washers and rubber washers to prevent seepage. Also waxed the hex bolts. But rotating the bolts as well as tapping on them aided removal.

[captsuperfly]

Originally Posted by Capt Terry

I may not have kept in the loop about how you are using carriage bolts. If you intend to remove them and it sounds like it because you are taping and waxing them, you are loosing the ability to rotate them to make removal easier. When I used the plywood on the brace my aft sheet for my Seacast pour I through bolted from the plywood thru to the fwd fiberglass with slightly smaller hex head bolts through the engine mount holes with flat washers and rubber washers to prevent seepage. Also waxed the hex bolts. But rotating the bolts as well as tapping on them aided removal.

To be clear, this is just my solution for the glass I'm adding to the skin. I'll thru-bolt again with 2X4 or angle iron braces when I install the core.

I used the carriage bolts because they have a larger lip but very low profile so they gripped the skin nicely but will make a smaller bubble when I glass over them.

My Once everything cures, I my plan is to grind the bit of glass off the heads of the bolts and hopefully I can twist them free and pop them out. If I can't, I have a plug cutter that can cut them out. Either way I'll need to repair the holes but they are small. I'll likely use the same holes to thru bolt through the core once I set that.

[Xcomunic8d]

Do you have a t bevel gauge?
Try to cut or sand the angle into the transom base should help keep the shape. And round the edges some.
PL premium adhesive was a lifesaver for me. I used a lot of that in various ways.

2x4’s with thread all as clamps
2x4’s braced against outside so you don’t lose the shape. Be murder to put the cap back on...

Plenty of clamps around the edges. I have tons as a wood worker. I suggest putting 1x4’s between them and clamping down to keep even pressure.

I tried to put no holes in my new work. But you will for bracket, anchor bolts etc.

Good luck. I have plenty pics I can share and many very knowledgeable guys here on all things seacraft. You are in the right place.

[steel686]

I did a 3 1/2” x 3 1/2” version of this and ran my hex bolts through. Think I had 1” ply around from some cabinet jobs.