Head Forming - Reticulated Foam versa Regular construction

[Ian Mac]

Hi I have searched the forums and can't find what I'm looking for, so I apolgies if this question is answered else where.
When I build a foam head out of sections Im not getting a smooth round form. Instead Im getting flat spots. Is this because Im using the wrong type of foam or is it poor cutting teqnique?
I'm using regular white and blue half inch foam.
Any help please,
Ian

 

[D'Snowth]

I think it may have more to do with your cutting, particularly, how the foam is patterned.

From my own experiences, I too always come up with flat spots when working on skulls for puppets. In the old days, the heads always come out flat and shapeless like this purple AM from the very early days of SST:

What I usually ended up doing was wedging the inside of the foam skulls (usually old, discarded pencils, or the tubs of old ink pens) to help round-out the skulls, but I eventually learned that the patterns have to have darts in the sides of the heads that help give the skulls more of a natural curvature and roundness to them, but even then I still come up with flat spots.

It's very trial and error, you have to play around with it a lot till you find what works best for you.

 

[Buck-Beaver]

D'Snowth is right, if you're not getting a smooth, round shape the problem is either your pattern, your cutting, your gluing technique or some combination of the three.

Using what's known as "the wedge method", if you cut 8 wedges with a ratio of 4:1 (four times longer than they are wide) and glue them together you should end up with a perfect - or almost perfect - sphere.

However, if you make any mistakes cutting out the wedges or if you cut with your blade at anything other than a 90 degree angle from the cutting surface you won't end up with a perfect sphere. It's also very important to apply a thin, even coat of glue (usually contact cement) and press the edges together after it has become tacky, but not before it has completely dried.

I have a basic wedge pattern you can download here. You can make other round shapes like eggs simply by varying the shape and number of wedges, but the basic principles are the same.

Likewise, if you use a two piece head patterns like the Project Puppet Patterns you need to have clean, straight, even edges.

 

[D'Snowth]

I've seen the two piece head pattern floating around for quite some time.

I used to construct my heads in a similar fashion, however, I found that making the entire head in two pieces like that limited the puppet's expression and performance, which is why I eventually began constructing skulls and jaws separately - similar to a pattern that's been used for a hundred years for stock puppets that Rick Lyon despises, only without that odd blocking in the back of the neck.

 

[Ian Mac]

Thank you Buck-Beavers and D'Snowth for your replies and valued information. I have downloaded Buck-Beavers wedge pattern but before I start playing around with the different shapes I'm going to invest in a flat bed hot wire foam cutter to ensure I get a good straight cut. The pattern for the skull halves is great it was just my initial rushing and poor craftsmanship that caused issues and the wedge from Buck-Beaver blows the door open for loads of new head shapes.
Cheers both

 

[Buck-Beaver]

You don't need a flatbed hot wire foam cutter. Unless you have other uses for it, imho that's a waste of money. I haven't tried cutting sheet foam with a hot wire foam cutter, but I suspect it might not work very well (those are primarily designed for cutting harder closed cell foams like Styrofoam). Just use razor blades or box cutter blades to cut sheet foam, which is the method that almost everyone uses.

If you were going to use something mechanical, you can cut the foam with a band saw. Personally I only use a band saw for foam thicker than 1" (which is difficult to cut with precession by hand). Bosch makes a handheld cutting tool especially for foam rubber that is primarily used in the upholstery industry, but honestly a $20 package of blades works just as well as a $150-300 gadget. You just need to practice your hand cutting technique if you're having difficulty.

 

[Ian Mac]

You don't need a flatbed hot wire foam cutter. Unless you have other uses for it, imho that's a waste of money. I haven't tried cutting sheet foam with a hot wire foam cutter, but I suspect it might not work very well (those are primarily designed for cutting harder closed cell foams like Styrofoam). Just use razor blades or box cutter blades to cut sheet foam, which is the method that almost everyone uses.

If you were going to use something mechanical, you can cut the foam with a band saw. Personally I only use a band saw for foam thicker than 1" (which is difficult to cut with precession by hand). Bosch makes a handheld cutting tool especially for foam rubber that is primarily used in the upholstery industry, but honestly a $20 package of blades works just as well as a $150-300 gadget. You just need to practice your hand cutting technique if you're having difficulty.

Cheers Buck-Beaver I'll look at the Box cutter you mention in the post

 

[Ian Mac]

Buck-beaver just spent a couple of hours with some scrap foam and blades from a Stanley knife (box cutter) wow those blades blunt very quick but the positive is they cut like butter when fresh. So plenty of fresh blades and patience I'm a lot happier with the cutting.
Cheers again

 

[Buck-Beaver]

Foam will dull any kind of blade, scissors or sharp edge very quickly, but if you put just a tiny bit of oil (3-in-1 oil is best in my experience, but even vegetable oil or olive oil will work if you don't have anything else) it will extend the life of the blades and save you a lot of money.

I usually put a drop or two of oil on a scrap piece of foam and then run the cutting edge of the blade through the oil once or twice, you should be able to see a thin coat of the oil glistening on the blade. You don't need or want a lot, just enough to lubricate the surface the sharpened edge that actually cuts the foam. Put the blade through the oil drop(s) to re-lubricate it every 2-4 cuts.

 

[Ian Mac]

Hi Buck that's a great tip to save blades thanks for sharing that