Week 227 - Cowling Part 5

Hours to date: 2158.5


The decision has been made - enough work has been done on the plug - I am now working towards making a mold from it.

Before making the parting supports I sanded the whole plug down with 320 grade sandpaper, used wet, then 600 grade - also used wet. Then gave the whole thing a good clean with warm water and a sponge.

After drying I put 2 coats of wax on and buffed them off - by hand, making sure not to take too much wax off.

Finally the plug was ready to accept the parting supports which are made from painted builders hardboard (known as Masonite in the USA) and hot glued into place. The hot glue from a standard hot glue gun easily peels off the waxed plug - so doesn't cause any damage to the lower half. The parting boards are only for the first half of the mold. When that is done they are removed leaving the mold which is now a perfect parting for the second half of the mold.

The small gaps between the hardboard and plug are then filled with filleting wax. This works best when it is warmed up. Scraping off any excess wax with a wooden stirring stick cut in half.


Now it is time to protect the plug and provide a release for the mold. The wax is a good base to protect the mold but I have also used 10 sprayed on coats of PVA which ends up making a thin skin which will allow (hopefully) for an easy release of the mold from the plug.

Hopefully this weekend I can actually start making the first half of the mold.

Filleting wax - for filling any gaps.

First parting board in place after sanding and waxing the plug.

Yellow stuff is filleting wax in the gaps.

Making up the parting boards for the sides. Using body filler to hold the bits of wood supports on.

Front and one side done.

Lots of supports underneath - parting boards held in place with hot glue where they touch the plug.

Other side done.

I screwed up the first attempt at PVA - getting used to my new spray gun. Anyway it is easily washed off with water and a sponge - start again!

Going much better this time - about 3 coats in here.

After 10 coats - last one is sprayed on thick and allowed to 'Orange Peel' then when it drys it shrinks and produces a smooth flat surface. This photo was taken just after spraying so it doesn't look smooth yet.