Thread: Those who have useed foam..need help

Tweet

Ok I was looking at doing a duct tape body form and filling it with foam. However what worries me is my last expeience with using foam. I was making some pvc candles and filled them with foam (Graet Stuff). However the foam didnt adhere to the inside of the pvc so it would just slip when I tryed to drill into it. So I decided to just push it out of the tube and go without the foam filling. However only the ends where harded and expanded. The middle of the foam was all gooey/sticky and looked more liquid then expanded. Now I let this dry or cure for aleast 3-4 days.

Now my questions is what went wrong? Has anyone had this experience? And how can I ensure this doesnt happen when I start filling large cavities like a lower leg or upper leg. Is there a better brand to use? And how does the stuff work that fx supplies sell that is a 2 jug componet? Any help you all can give and advice would be appreciated. Thanks All, Steve

Your best bet if using Great Stuff type spray foam is to apply it in thin layers. Fill up your parts gradually allowing each application to expand and set, usually set enough within a few hours. If the spray foam is enclosed and has little air it will take longer to set. Using a 2 part spray foam is the ideal way to go, because the foam sets up instantly and you can fill up parts completely in one application. As far as the problem that you had with the foam slipping out of the pipe I would say that it would have been caused by a couple of things, the first being the pipe is non porous and the gloss on it makes for a slippers surface, lastly the foam was probably not filled thorouly to create max compression. This should not be a problem typically if these factors are not replicated.

I have found that very dry climates (like New Mexico) make Great Stuff take forever to dry!!! I have also used it in humid places and it dries in a snap! It seems that the more humidity you have, the faster it "Dries". (Weird, huh?)

Try applying layers and spraying a fine mist of water on it. (I think it says that on the can somewhere if I remember correctly.)

Make sure the surfaces you want the foam to stick to are clean and dry. If you didnt clean the PVC before use,that was part of the problem, theres all kinds of grime inside it...

Also, you should sand the inside of the pvc to rough it up. That will allow the great stuff to "grip" better.

i have had the same problem recently.

i believe that part of the solution is to dampen the surfaces as mentioned above.

i filled some balloons with foam and they took a couple of days left outside in the not so sunny british weather to dry.

another point of interest to add here is that i used some foam in some gloves to make some hands. (you have to cut the ends of the fingers off and spray the foam right into them). the fingers and wrist area dried ok, the palm area of the hand expanded and looked to be going ok until suddenly it just "drooped" like you mentioned above.

the palm area of the hand did dry eventually (about a week) and looks all veiny and haggered (so it was ok for me).

from this i am led to believe that the foam needs air to dry.

Yep use the water trick. I spent all winter perfecting my skulls (pictured). I was using half a can per skull and it was taking 2 to 3 days to dry. With the water trick I can get 4 to 5 skulls from one can and it takes max of 2 hours to dry completley. Pumped out abou 30 skulls over a week after figuring that out! You dont even need to wait for each layer to fill out, just add a layer, spray it, add a layer, spray it... rinse / repeat.

Interesting stuff Bubbels. I had planned on making several foam skulls out of great stuff for various things for the display this year. Most posts on here relating to making foam skulls with great stuff seem to end up with the recommendation to forgo the great stuff for a 2-part foam. But it appears your skulls look pretty good, I would be more than happy if my results looked even remotely close to yours.

How did you setup your mold? Is it a two piece plaster mold or did you use a latex glove type mold to spray the great stuff into? Might you be able to share a picture of your mold and detail how you made it just a bit? Thanks.

I dont have any pictures of my mold. But I did use a plaster of paris mold. Use a clay wall to split it in the middle. Upon pulling it apart it came off in pieces. I think the only way around that would be if you used wet clay that you dug out afterwards, but I used a ceramic skull. So you get out the super glue, piece it back together then drop another layer of plaster paris on the outside to strenghten it. The cracks are not noticeable in the finished product.

From there you just drop your two parts upside down inside a bucket. Mine fits real good inside an ice cream pale so I dont need any straps to hold it together. I use vaseline as a releasing agent.

Oh and probably the most important suggestion I can give. Wear an old t-shirt. Greatstuff does not come off! I wrecked a few t-shirts doing this and my wife isn't to happy about it!

Originally Posted by Bubbels

Oh and probably the most important suggestion I can give. Wear an old t-shirt. Greatstuff does not come off! I wrecked a few t-shirts doing this and my wife isn't to happy about it!

Ha! My wife is already yelling at me about getting a few t-shirts beyond dirty while recovering landscape timbers and breaking down pallets. I guess it is a common theme for all us haunters!

Okay, let me make sure I understand your process. You made a mold out of plaster of paris of the skull with a clay wall divider. Once the mold dried you took the two parts (front & back based on your molds) and coated the inside with vaseline. Then you assembled the two pieces and placed it upside down in a container (or could use straps to hold the two pieces of the mold together). You then sprayed a bit of water into the mold. Then sprayed a thin layer of great stuff. Then sprayed another layer of water and repeated till the mold was full?

How long did you wait between applying the layers? How humid is it where you are?

Thanks.