Sorry for asking in RC planes but I thought it was the logical choice of a place to ask this question.
My wife is working ona project involving the use of styrofoam. She is making an indoorwaterfall and will layer pieces of the stuff up.. The styrofoam will be coated with a waterproofing and painted so the glue does not have to be waterproof.
I know many of you make planes from either that or something similar.
She would like something that works fairly quickly.
I guess she could try some CA foam safe glue but that's a little pricey.
She tried her hot glue gun (40w) and it worked while heating up but was too hot once it got to temp.
I assume she could go to a lower temp glue gun and they are pretty cheap.
But I though with all the experimenting you all do that somebody has come across something that has reasonable cost and works pretty quick.
I have heard that Weldbond and Gorilla Glue works pretty good too but I was not sure about cure time.
Anyone have a cheap solution that isfairly quickbonding?

You have come to the right place. We typically use the foam safe CA (also called odorless CA). It is quick and effective, but not cheap. Polyurethane wood glue (e.g. gorilla glue) will work well but takes hours to set up. Epoxy works and you can buy whatever "speed" you want. 5 minute epoxy for example will start to set up in 5 minutes but maybe 15 minutes before it is pretty strong.

The polyurethane glues foam and expand, so it can leave a messy looking joint. It's dark brown in color so the glue seams are quite visible. But it sounds like the project will be covered up anyway so cosmetic issues don't really matter. You might try the polyurethane with a little water sprayer. When you spray a mist of water on the polyurethane glue it accelerates the cure. This may give a reasonable compromise between cost, strength and time to cure.

OK thanks.
I am thinking at this point that she may wind up going with either epoxy or CA foam safe. It won't be cheap but she just stacks chunks of rough shaped foam together to form a hill as such with a waterfall at the top. She likes to do this process quickly and keep moving with the project not unlike many of us.
Then she grouts the whole mess and waterproofs it with something or the other.

Lower temp glue works really well. 5 minute epoxy too. If you do get the Foam safe CA, but a spray container of CA accelerator. it will cause to CA to bond instantly.

Actually, if you can hold the pieces in place, Elmer's Glue, or any of the Carpenters' glues will work well. They usually have a good bond strength in about 2-3 hours. If you need the glue to set "right now", then use a foam-safe CA or 5-10 minute Epoxy. Use rubbing alcohol to clean up the epoxy.

OK,I had read somewhere here that you could make your own accelerator and it was sandable too.
But I am not sure she needs it to be that quick.
I am thinking that the medium would work for her well in that if she put something in place she could move it for a few seconds anyway.
Someday I may try a foam electric, everyone else I run into is trying them. Hey, repairs are pretty quick!

Best to use epoxy on that one due to the long term water situation

I am not sure it matters as the whole thing is waterproofed in the end process.

All it takes is a little pin hole

3M 77Spray - It's a spray contact cement. Cheap, very strong, water is no real problem and very quick. A single light dust spray on each piece, wait about one minute and put them together done.

Used to use the 77 Spray directly on foam wing cores to adhere paper board wing skins.

As always test on a small piece first.

John

Mighty putty is durable (i fixed my boatplane with it), just stick it where it can't be seen : )