rxAxilleas

hi all,
one question please. i am thinking to replicate my cowl for future damaging of the prototype due to my not very good flying skils. since i waited many months to arive i think it is a good idea to make a second one to use as a spare.
i read a few forums about cowlin making but they all use a custom built plug from foam or something instead for the prototype.
my worrie is:
since i will use the prototype cowl as a plug to make a female my concern is how to remove the wax release from its surfase prior priming and painting it.
do you think it will be a problem?
anyone knows a tutorial?
please help.
thanks very much

MasterAlex

Here's a great site for everything RC building related. Caffenman's site is a work of art. [link=http://www.airfieldmodels.com/information_source/how_to_articles_for_model_builders/construction/make_a_fiberglass_cowl/index.htm]Link[/link] to "How to make a fiberglass cowl". Good luck!!

-MA

rxAxilleas

thanks Alex!!

jrcaster

I think you will find this site usefull. This is a direct link to the tutorials. Check out the one about making fiberglass molds.

http://www.cstsales.com/tutorials.html

rxAxilleas

hi guys ,

i made a researh and i have a few questions .i would apreciate if you could help me.

i am new to this area and dont know many about the technicks and materials.
i have already the prototype . first i must make a mold. what materials do i need? is it posible to make a mold from polyester that it is cheaper?

i am planing to make mold from polyester and then proceed to cowl making from epoxy materials and cloth.

do i use pva and wax both to polyester and epoxy systems?the prototype cowl is waxed and sprayed with pva, right?

is it posible to use only pva without wax?
the wax is used for making perfect surfase or to help releasing from the mold?i am asking this because since the cowl will be primered and painted , it is not necesary to have a perfect surfase.

what exactly is the use of the gelcoat? it is used on the mold only?
it is necesary?
do i use gelcoat on the new cowl before i start to layout the cloths or it is used only for making the mold?
there are gelcoats for epoxy and for polyesters?


i would apreciate if you would sugest a complete system,
thanks for you help.
achilles

jrcaster

Go back to my last post and go through the tutorials on that site.

The wax is to fill in small imperfections on the original piece, and to start the release process. You don't want the resin to have anything to grab to. If the resin has a chance to grab to your cowl you might loose both the original cowl and your mold.

The Gell coat is basically a layer of resin that is allowed to gell before the glass is started to lay in. That is so you have a perfectly smooth surface to form or paint to.

http://www.cstsales.com

Go back to this site and reread all the tutorials. There are instructions for making molds, and also for forming parts from the molds. They even use a cowl as their subject so you should be able to follow right allong.

They also have the products for sale, and have kits available with everything you need to produce the molds and products from the molds.

Even though you are planning to prime and paint the cowl you still want it to be perfect. Paint will show any imperfections of the surface. If you have a perfect cowl, you won't have to use primer/filler, and be able to keep it light.

The more work you do to the mold, the less work you will have to do to the cowl.
The more perfect the cowl the less work you will have to do to prep for paint.