Great stuff instead of resin, plaster etc.?

[Panaflex]

Hi all, I'm starting my first mold making project ever. It will be a small decorative tile about 2.5 in. square. I'm wondering if I can use "Great stuff" foam instead of resin or plaster to cut down on weight.

I'll be making the mold itself out of latex rubber. Also wondering if I'd need a release agent for these materials. Anyone ever do this kind of thing?

Thanks for any replies.

 

[ob1al]

No, I don't think you can use any type of expanding foam to cast from a latex mold. It will stick like hell and swell in a dreadfully mishapen fashion (that's what she said).

You could laminate the surface of the mold with resin then backfill with expanding foam and trim off the excess, I guess. that would keep it lightweight.

 

[Panaflex]

Thanks Al, I appreciate the input.

 

[Zed]

Hi all, I'm starting my first mold making project ever. It will be a small decorative tile about 2.5 in. square. I'm wondering if I can use "Great stuff" foam instead of resin or plaster to cut down on weight.

I'll be making the mold itself out of latex rubber. Also wondering if I'd need a release agent for these materials. Anyone ever do this kind of thing?

Thanks for any replies.

Hi, I'm new to this forum, and you post was one of the first I read. I'm sort of in the same situation. I've been using resin, foam and even a thin overlay concrete mixture in some small projects. For me it's just trial and error, and a whole lot of sandpaper lol. What sparked my interest was your
latex rubber idea. My mother is a highly experienced lab tech for Goodyear Chemical plant in Houston. I know she can make synthetic latex rubber by adding two chemicals together, but my question is your also a lab tech, or you have found some kit that sells these two chemicals? I also know that raw latex is paper white in color, then carbon black is added to give it a smoother texture and black color.

I also work in the chemical industry and have the chemical formula to make styrafoam, and have almost unlimited access to styrene (the main chemical). The only problem is it's easier to buy the stuff at home depot. Anyhow, I wont babble on, have a nice day.

 

[modelnutz]

When casting foam...you should use a wax based release agent.
Smooth-on carries a few good ones.

Standard release agents have a de-foaming agent included in their chemistry.

As for using "Great Stuff"...ugg...that stuff is crap.
Go to Smooth-on and check out their rigid foams....great material to work with ! You have a choice of densities/weight... 5,10,15 etc.
You can get a sample kit for $30.00 or so....I'd say that Foam-it 10 would be a good choice for your project.
They also have coloring agents for the foam.

I also agree...the money spent on silicone is money well spent...you will not have any issues with the foam sticking.

 

[modelnutz]

I also work in the chemical industry and have the chemical formula to make styrafoam, and have almost unlimited access to styrene (the main chemical). The only problem is it's easier to buy the stuff at home depot. Anyhow, I wont babble on, have a nice day.[/QUOTE]

OH MAN ! I seriously want to talk with you about the formula !!!!
I have a Ton of projects that have been wanting for that material in a castable form !

Please...tell me more ! ( or, send me a PM and we'll chat . )

 

[PHArchivist]

Great Stuff is highly agressive in both its adhesion and expansion properties.

In its home world (of home improvement) its been know to blow out window frames (dislodging a previously attached window frame from the house).

 

[JPolacchi]

Bad idea using a latex glove mold and filling it with the expanding urethane foam from a can. You'd be better off making a silicone mold,then casting with a 2-part urethane foam system.Afterward you can brush a few coats of polyester resin over it or even lay some fiber glass fabric on top and more resin.The stuff in the can can have the ability to "not cure" 100%.It cures by evaporation as opposed to a 2-part chemical cure where you are guaranteed a full cure (unless you get the mix ratio wrong,its really old,or some other environmental calamity).I say stick with silicone,that just my opinion.

 

[dellharbin]

Hi, I'm new to this forum, and you post was one of the first I read. I'm sort of in the same situation. I've been using resin, foam and even a thin overlay concrete mixture in some small projects. For me it's just trial and error, and a whole lot of sandpaper lol. What sparked my interest was your
latex rubber idea. My mother is a highly experienced lab tech for Goodyear Chemical plant in Houston. I know she can make synthetic latex rubber by adding two chemicals together, but my question is your also a lab tech, or you have found some kit that sells these two chemicals? I also know that raw latex is paper white in color, then carbon black is added to give it a smoother texture and black color.

I also work in the chemical industry and have the chemical formula to make styrofoam, and have almost unlimited access to styrene (the main chemical). The only problem is it's easier to buy the stuff at home depot. Anyhow, I wont babble on, have a nice day.

I need to make a mold of some deteriorating column bases...I am thinking to block the sides with plywood screwed into hat remains, then spray in Great Stuff to make a mold of the rounded parts. Then, when it is cured, turn it over, close off the side with more plywood and pour in cement to make a replica casting. (originals were wood...so cement will last longer.) Any ideas on a release agent? Oil? Dish soap? Any input appreciated.

 

[rollerboi]

Great Stuff isn't a moldmaking material. At all.

You can try using 100% silicone from the hardware store if you can't afford (or won't) to get proper materials. It's in a red can. Search this forum for a link to a tutorial (or google it, the tutorial is quite good and found on a taxidermy forum).

 

[DethBecomesYou]

I need to make a mold of some deteriorating column bases...I am thinking to block the sides with plywood screwed into hat remains, then spray in Great Stuff to make a mold of the rounded parts. Then, when it is cured, turn it over, close off the side with more plywood and pour in cement to make a replica casting. (originals were wood...so cement will last longer.) Any ideas on a release agent? Oil? Dish soap? Any input appreciated.

I have had success with using pam cooking spray as a release agent for the Great Stuff expanding foam. You must spray(foam) in thin layers though. It hates thickness. Create layers if it needs to be thicker but wait for the previous layer to fully cure before adding another.