Mold makiing technique for hull and deck repairs

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catalacmarc
1st mate
1st mate
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Joined: Tue Aug 16, 2016 12:58 am

Mold makiing technique for hull and deck repairs

Post by catalacmarc » Tue May 14, 2019 1:58 pm

Friends, I recently dinged the bow of my 36 and made a mold of the Pt. bow area of damage to help with the repair of the Stbd bow. Here is the technique that I used to create the mold. it requires an undamaged section with the same camber as that of the damaged area.

1st, use blue tape to mark off an area on the undamaged section the maximum size of the repair plus extra to overlap the repair, make it bigger as it can always be cut to size.

2nd, take a un-creased piece of wax paper several inches larger than the first taped area and tape it over the previously taped area. Take pains to gently tape it tight over the surface and tape along the edges with blue tape. Blue tape is important as you need to see this when you glass the mold.

3rd and this is Important! Take a piece of fiberglass cloth significantly larger than the wax paper and, using duct tape, hem the cloth by laying it halfway across the duct tape on each edge and folding it over, press hard. Do all edges. This keeps the cloth from sliding on the bias and allows you to stretch it tight on the section.

4th, tape the hemmed cloth over the area to that there is a relatively even space around the wax paper. I use a clear duct tape that does not damage the gelcoat but if you have paint, use a tape that is compatible. Again, take pains to be gentle so as not to damage the wax paper underneath and stretch the cloth as tight as you can.

5th, I used West epoxy to soak the cloth ONLY OVER THE AREA OF THE MOLD MARKED BY THE INNER MOST LINE OF BLUE TAPE! That should be well within the piece of wax paper. Give it several coats. And allow it to cure several days, removal too soon means that the epoxy is still soft enough to deform.

The resulting mold can be cut to a desired size. I plan on lining it with either wax paper or plastic wrap and using it to mold the gel coat on the stem. Any imperfections in the mold can be faired. I think that there rpobably are other nonstick solutions.

Marc

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