I'm building a plane at the moment (sonic 500) it only a small plane and the kit has just a stub nose with the engine screwed to it. I have gone to the trouble to fibreglass the plane and finish I a nice paint finish but the thing look pretty ordinary without a cowl.

Has anyone got some tip on how to make a cowl, I was thinking about useing a plastic coke bottle end and fibreglassing it and then removing the plastic bottle, did know how to seperate the 2 at the end of the process but. Any ideas.......

Maybe use foam and form a cowl and then use glass and z-poxy finishing resin and when dry use some thing like petrol to eat the foam out an then I would be left with the shell.

any simple tips?

There are lots of ways you can do it. The foam I use on my full scale Long EZ would be ideal but you might not want to buy a huge chunk of it. It is high density foam and you could put that on the nose and sand a good shape, then glass it and take the foam out. If you just use white bead board foam, gas will eat the foam out like you said. Harder to get a good shape with it though. You could use a wood block on the front and sand your shape out of it. Glass it and remove the wood from it.

To remove anything from the inside, wax whatever you use as a plug well. I would use many coats. I use PVA mold release in my molds too, then wax with a good paste wax a few times. Make sure there are no holes. Glue will get in them and make it stick more. Once it is waxed really good, you can glass it with really light glass, maybe 4 layers of .5 oz cloth for a cowel. It will be thin, but you don't want too much up there. You could do heavier if you need nose weight. Remember to make the plug just a bit smaller than you want the part because you are glassing the outside of it. If you want it exact, make a mold from the plug.

Hope that helps some.

I use standard cheap styrofoam. Tack glue a chunk on the planes firewall and sand to shape. Paint on a very thined coat of water and elmers white glue. Fill in the dents with light weight spackling and sand again. Paint on another coat of water/white glue. Then glass over the plug using thined epoxy or finish reson. I suggest using a heavier glass cloth 2 to 6 oz at about 3 layers. You will end up sanding one layer off. Sanding goes pretty fast if you use an aluminum sanding bar with aluminum oxide stick on sand paper, about 80 grit, for the rough sanding. Make sure the overlap past the firewall onto the fuse sides isnt too long, you have to break if off at some point. When done, break off from the firewall. Pour a little gasoline onto the styrofoam and watch it dissolve. Scrape out the crap and clean it with soap and water. Sometimes its easier to do the finish cleaning on the inside when its dried out and use a dremil with a wire crown bit and wire wheel bit. And thats all there is to it. This is a male mould process that does the cloth on the outside. It gives a decent finish dependent on sanding. Takes about a weekend to make a cowl. I wrote an article for the clubs newsletter last year about this. Contact me PM if interest in a copy.

Edwin

I use the method FlyBoy described with a chunk of green florists foam. Just go to your local florist an buy one. It sands well and is easy to work with. It does make a mess though so do the sanding outdoors.

http://www.cstsales.com/articles_for_model_builders.htm

heres a site on making actual molds if you are interested.

Thanks for the tips.. the florist foam sound good. I have some polystyrene in the garage but it a course grade and doesn't sand to well.

I'll try it out

I was reading all of the replys here and thought that I would add my two cents worth

I take it one step further...... Many times my kit may have an abs cowl, if it does I use it as a mold and glass the inside after putting some furniture paste wax in it. It takes about an hour and I have a perfect cowl with very little if any sanding

Or sometimes I have glassed the outside of an abs cowl and made a perfect mold ... which I cut in half, attach wood strips to the edges, drill bolt holes, and then I can bolt it together perfectly lined up. I can pop out a new cowl in about an hour, over and over again!

If you had the need for a replacement cowl, post crash stuff, a mold like this could easily be made from you foam plug, before you pour the gas on it and erase all your efforts

I like your foam idea. I will use it to form my deadly Stuka's cowl and wheel pants. Thank you friend.

Kraus