Liquid Foam

Approx. 25-30x Liquid Volume, however the expansion is temperature critical....

ref links....
http://www.uscomposites.com/faq_foam.html


http://www.uscomposites.com/foam.html

There are many different foams that could be used in this application. Which one are you using or contemplating using?

Better questions = better answers

Good Luck, Old Salt

I tried to make a light aircraft canard wing like that once. Failure followed. Much gnashing of teeth resulted.

It will be nearly impossible to prevent fiberglass from distorting unless you place it into a very solid mold.

I think the way you describe is the hard way. Better to glue the fiberglass door panels onto pre-formed sheets of medium or high density foam. Pick a compatable glue...or compatable resin.

Do not attempt this until you have made at least two test pours using sacrificial materials.

I promise you that you will fail if you try this without ever doing it before. With foam, you don't get a second chance.

Heed the previous posters. The pressures generated can be very high.

Thanks all for your assistance. Actually i am new to all this, but one of the links mentioned; www.uscomposites gave me a lot of needed answers in their FAQ, and now the 2 lbs urethane looks like a good choice. Also the video in one of the above links was awesome in simlplifying how that stuff works. As many may know, ther are alot of ways to make doors, but if one wants to develop a manufacturing process that is simple, better, cheaper and faster, to be able to compete, i thought using the foam process would contribute to the above strategy. Another related question is which method would be best to make the maximum number of the fiberglass doors?: manual layering by hand in gelcoated molds, vs silicon lined molds, vs other methods which i have no experience with what so ever, like resin infusion, or even vacum molding. Any thoughts on that?

If I were starting a business, or adding a line of "doors" to my existing business, I would make sure I was not making what anybody else is making.

When developing a new product, you can rarely win the "race to the bottom". Somebody somewhere will figure out how to make it cheaper than you. I agree that the price is the most important feature of any new product, BUT there are others. For instance, decorative door skins that look like wood, or stone, or carved marble. These can bring an artistic element to the product which can be changed as often as your competiton steals your old ideas. Often fiberglass laid up by hand and backed by foam will be cost effective, but a lot depends upon what you are making. Some foams are solid enough to stand on their own, but of course a few rough boards hidden under the foam to stiffen a door would make the product more saleable.

Foam is a versatile material which, to be fair, is wasted by just using it to fill voids in a flat door. They make flat foam sheet which can be sandwiched between two door skins for a superior and cheaper result. Foam will take the shape of a mould, and when you pop it out of the mould, it can be used as the "skin" of a door, or a decoration added to a door or a wall....a lot of crown mouldings nowadays are simply made from foam. Even baseboards are often not made from wood....foam is more stable, has no resin pockets or knots, and is easier to paint. It has replaced plaster for most decorative applications. Foam is becoming more common even for architectural applications.

The trick is to hire good artists to design your moulds. As the moulds wear out and your competiton steals your ideas, you can always get new and different shapes to stay out in front.

Q1. Ask the suppliers.

Q2. Very much so.

Q3. Yes, but it will greatly increase in viscosity before it stops expanding so it may stop flowing where you want it to but it still has to go somewhere.

Have you taken a look at the expanding polyurethane insulation spray foam used to fill cavity walls? It's what they call a slow rise formula, which helps to alleviate the problems caused by excessive pressure build up. There are loads of sites out there describe the process. Here's one to get you started:-

http://www.eps-systemsltd.com/

Hope this helps.