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I just wanted to give an update in regards to: http://www.halloweenforum.com/halloween-props/76298-skulls-can.html . As I have perfected the foam process! Thanks to Lurks In the Shadows I have a solution.

In order for your foam to to cure all the way through and quickly you need to add moisture to your process. My earlier skulls were turning out great, and what i had found was that this had to be due to the fact that we hadn't sealed the house for winter, so there was still alot of humidity in the air. Once the atmosphere became dry, my skulls were not coming out in one piece or big sticky holes would be present on the pull.

So in short, get a spray bottle of water. Spray the inside of your mold, spray a layer of foam, then spray the top of it with water. Rinse and repeat until complete. This process allows you to lay down a very small amount of foam and also decreases your wait time for a full cure from 48 hours to 2 hours!

I recently bought some 16 oz cans of great stuff from home depot for $3.98, it was on sale. I have in the last 2 days created 6 skulls with one can!
 

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HEY! Great to hear that it worked out for you!

If you're getting a good cure in just a couple of hours, you have the process down perfect.
Enjoy those cheap skulls! (and start looking for more things to cast in foam!)
 

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What did you use to make your original mold? I'm a cheap ##@!$!! and don't feel like shelling out big dollar to get alot o skulls. Any advice is appreciated!
 

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Mill Creek Haunted Hollow
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Yes, please! Tell us how you made the original mold.

Also, could you put up a pic or two of your new skulls?
 

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Discussion Starter #5
Here is all the information you will need except the water trick: http://www.halloweenforum.com/halloween-props/76298-skulls-can.html

In short for the mold, I used PP, I believe it is about $7 a bucket. It was two halves seperated by a wall of clay. Now be advised, that when I pulled the PP from the skull I ended up cracking the mold a couple times. What I did was super glue it back together, then added another layer of PP on top to strengthen it. Considering that foam isn't extremly detailed, the cracks in my mold never cam through on the foam.

Anyhow, its a cheap solution, and I think the real creativeness comes in when you paint them.


One other trick I have used is making a temporary clay sculpture. PP that, then just dig the clay out. I did this for a pair of hands and feet that I created from foam. It is a good trick if you don't mind destroying your creation at the end.

Up to 22 skulls now, my goal is 50! Definitley thinking of other ideas for my foam creations. Maybe I will look at building foam heads. Those mannequin heads you get at the beauty shop run about $4 each, if one could turn out 3 or 4 heads in a can, it could be a good way to go!
 

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Bubbels,
You're using a PoP mold? You're getting good results from one of the worst mold materials! Plaster is great for many things, but in my opinion, it makes for a poor mold. It is rather weak and breaks down rapidly. If you get 50 castings from a PoP mold you're lucky. Plasters one big advantage is it's cost.
I think you must be doing a pretty good job to get decent results. It looks to me that with a little more experiance you'll be wanting to step up to some other mold and casting materials!
You'll be impressed with what you can do with some of these other materials. The drawback is... yep, they get pricey. But, if your mold will make 10 times as many castings, the cost may be justified.

Anyway, I'm very glad to see you getting good, cheap castings!
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Hey Deadna,
The one-part polyurethane foam that Bubbels is using needs moisture to cure. It doesn't matter what the mold material is.
Now if you are asking if a little moisture will help the silicone for the mold cure faster, the answer is yes to that as well! A very small amount of water will cause silicone to cure faster. I don't often do that, as I would rather have the time to make sure my mold is good. It can cure very fast, and it does weaken it a little bit.
 

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This might cost a little more than the GREAT STUFF , but , is also more controllable and fills in the gaps nicely .

Urethane Foam , Expanding Marine Polyurethane Foam

I use this to fill in scratch build wood RC racing boat hulls , It not only adds strength , but floatablity in case the boat flips or whatever .
Anyway , my point is that it will not burst your boat hull apart and needless to say . it will act the same for your skull mold also .

( just a thought )
 

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Mill Creek Haunted Hollow
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You'll be impressed with what you can do with some of these other materials. The drawback is... yep, they get pricey. But, if your mold will make 10 times as many castings, the cost may be justified.
Lurks/Shadows, what can you tell me about other molding agents? I want to do something similar, where I am using a master mold and creating many copies. I haven;t decided on the material yet. Might be PoP, might be foam in a can, might even be quickrete. I don't minf spending $30-$40 if I get a good set of molds that will turn out.
 

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The use of a little water to adjust the cure of polyurethane has been around since it was first formulated. This is not exactly a secret or recent discovery, and certainly not "my idea".

Instead of continuing to hijack Bubbels thread, maybe I'll write up a molding and casting one of my own.
Sorry about the hijacking, B!
 

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Hey Deadna,
The one-part polyurethane foam that Bubbels is using needs moisture to cure. It doesn't matter what the mold material is.
Now if you are asking if a little moisture will help the silicone for the mold cure faster, the answer is yes to that as well! A very small amount of water will cause silicone to cure faster. I don't often do that, as I would rather have the time to make sure my mold is good. It can cure very fast, and it does weaken it a little bit.
Now that you answered me I guess I really don't know what I'm asking...LOL!
Here is what I have to work with and maybe someone can help..............

I have a 2 1/2" plastic skull candy container that opens around (top to bottom)into two halves. Years ago I tried different products(cement,greatstuff,plaster)to make finials for my cemetery fencing. The plaster was the only thing that worked and completely filled the mold but I need to make more and wanted something less fragile. The plaster has held up fine for 7-8 years but people tend to grab hold of the skulls while standing around talking and crack them.
What I want is to make more molds out of the silicone and then use the greatstuff to make a bunch at once.Since I only had ONE candy container I had to make one finial a day thru out the whole year!
Will the water cure the greatstuff in a small mold like I plan to use?
 

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Deadna,
Yep it'll work in a small mold to speed the cure. Make a good casting, then make a few more molds from it. Then you can do five or ten a day, even with a slow cure.

A few years ago, I did some finials with a hot melt glue mold, cheap molding material!
I changed my mind and now my fence has some skull finials as well as the trefoils. I bought plastic skulls though... I didn't cast them.
 

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Discussion Starter #15
A tutorial video of the same process has been on youtube for over a year now from Dr. Kreepy.

Covered in this thread: http://www.halloweenforum.com/halloween-props/76433-need-styrofoam-skeleton-heads.html?highlight=foam+skulls


I've made dozens of these.

Dr. Kreepy was where I got my inspiration for this. My process is fairly the same, but with a few different variations. I suppose it goes in line with the various FCG tutorials as there is one original inventor of the idea, just many different tutorials on it out there.

Dr. Kreepy's videos are great! I don't believe he talks about the water trick though, it would be great if he could update that. The videos is really the way to go, and the water trick truly is an essential part.
 

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Thanks Bubbels and everyone. This gives me hope of creating a skull wall without breaking my bank account or taking forever to create the "building blocks". I always thought a bottomless pit/hallway with skulls for walls and red lights shining around and though the skull eye sockets would have an intense creepy factor. But it would require ALOT of skulls.

Demon Dog
 

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Discussion Starter #17
Just an update. I have been using the water trick for my skulls for just about a week now. I have gone through 5 16 ounce cans and I have 27 skulls to show for it.

I have also noticed that skulls made this way, taking advantage of the full expansion of great stuff, that when they sit for a couple days, there is a small amount of shrinking. Its not a bad thing. Just for future reference, that making a mold out of a slightly larger than normal skull should give you the best result.
 

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Bubbels, if you have time, would you please quantify the foam shrinkage you had? This would probably be best described by measuring the distance between two features (the farther apart the better) on the foam part and then dividing that by the dimension across the same two features in the mold. If it's important for someone wanting a part as close as possible to full scale, they can then divide the desired dimension in the final part by this number to figure out how large to make each feature in the mold. I'm hoping the shrinkage is small enough that it won't matter for what I'm thinking about making.

Thanks again for the info on this method.

Demon Dog
 
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