Week 229 - Cowling Part 6

Hours to date: 2164.75

Cracking on with the mold until I ran out of resin! Got some more on order but it may not get delivered for a few days. 

I'm using the time to work on my motorbike.

So far I've got the gelcoat on and one layer of light weight chopped strand mat, followed by 2 layers of thick chopped strand mat.

Another 3 thick layers and it will be done.

All I have to do then is add some plywood supporting braces - which will be glued in place using the chopped strand mat and resin - and the top mold will be done.

PVA release when dry - shrinks to form a smooth surface.

Gelcoat was clear so to make life easier when spotting mistakes a pigment was added - Tangerine of course!

Agent Orange. Brushed on thick gelcoat that forms the inner surface of the mold.

After 1 thin and 2 thick layers of chopped strand mat. Another 3 thick layers to go.

Not a Twister! My Benelli Tornado 900. New stubby carbon muffler fitted - going to be very loud.

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.

 

Week 226 - Cowling Part 4

Hours to date: 2141.0

Those of you who are observant will have figured out I am now up to about 85 hours on this cowl project. If you're getting bored with it imagine how I feel!

I had a very down day after spraying on the guide coat and sanding it down - there were low points EVERYWHERE.

My technique had been wrong all along - working in small areas rather than in big sweeping movements at 45 degree angles - as it should have been.

Watching the master Mike Arnold at work I soon learned what to do.

Ironically I have all his other videos on DVD except for the one which shows how to make a plug. If only I had watched it before I started this job it would have saved a lot of pain.

The video in question is here: https://youtu.be/qStFDcZs5Og

If you find that interesting then I highly recommend watching all his other videos - so much to learn from this guy who I rate as the 'God of Glass'.

Anyway back to the amateur - me. 

So what I had to do was cover the entire surface again with a layer of body filler. I've gone through another 4kg tin of filler!

Then sand that off using the big sweeping movements and repeat until all the low points are filled - that's where I'm at now. I've just sprayed yet another coat of primer and it's looking very good, it's not perfect, you could spend forever on this but it should be okay for a mold.  

I've just started making a bridge for the split line as the mold has to come off in two parts due to 'draw' - you cannot remove a mold from a negative angle. In this case the only way to split my mold is along the thickest part of the sides.

I don't think I'm going to get much done this week as I'm off to Barcelona for two days but will hopefully get back on it over next weekend.

Covering with a layer of filler due to my shit technique

Thinking about buying shares in a sandpaper manufacturer about now.

After much more sanding and filling and primer. But is it ready?

 

 Quick video of the cowl as a walkaround. I'm really happy with the shape.