Extruded Polystyrene Blocks

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Gary Byrum

Overstable By Design
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Even though I'm a bit new to using this stuff for making nose cones, I am no stranger to the outcome of gluing it together. Many adhesives have a tendency to leave wafers of adhesive protruding from the foam after you turn it on a lathe and start sanding it down. This is my downside to using extruded polystyrene insulation boards from big box stores. Any thing bigger than 2" has to be glued and I would rather not have to go that route.

With that, I'd like to be able to find the same kind of extruded polystyrene but in block form. Much like you might find when ordering balsa blocks for turning. It would be ideal to find someone in the USA to order custom sizes from. 4" x 4" or 5" x 5" possibly 7" x 7", you get the picture. I'm not interested in making small nose cones out of this stuff, balsa is just fine for that. Just the bigger tubes. Let's dispense with any recommendations on adhesives if we can and stick to just the foam inquiry. Any help would be much appreciated.
 
Home Despot has flotation blocks 10x20x48" that (I think) are extruded styrene, not cheap ($110) but it'd be almost a lifetime supply for nose cones up to 10" dia. Marine supply places might have smaller blocks.

Best -- Terry
 
Go to one of the many EPS suppliers and get a quote for blocks of whatever size you want. https://univfoam.com/products/eps-sheets-blocks is one.

Check sculpting supply firms for ready made foam blocks in some standard sizes. https://shop.sculpt.com/foam/styrofoam/blocks/ is one.

kj
Universal has a 250.00 minimum. I'd hope to be able to buy in smaller quantities. The other place seemed a bit pricey. I did browse a lot of other sites until it got confusing with all the different grades of foam to choose from. I suppose another search is in order as I became overwhelmed with all the varieties.
Home Despot has flotation blocks 10x20x48" that (I think) are extruded styrene, not cheap ($110) but it'd be almost a lifetime supply for nose cones up to 10" dia. Marine supply places might have smaller blocks.

Best -- Terry
That's pretty pricey also. Seems to me, I should be able to find something like that Pink Panther brand in thicker pieces. Like I said, I have some searching to do yet. I appreciate you guys input on this though.
 
You could also just use a 1 part expanding foam to glue the blocks together .
I did that already. I wasn't satisfied with how that sands down. This is why I asked to dispense of the adhesive suggestions. I have tried things most people never thought of before along with a great many others.
 
Here's the rub. Most adhesives that will work with foam board dry harder than the foam is. Thus, when you sand it down, you get ridges where the adhesive is. That's why epoxy is frowned upon. I tried it too. I've used Great stuff and it glues exceptionally well, but you still get ridges. In the Hollywood and Halloween prop forums, people are using Glidden Gripper primer. Terrific stuff for gluing with thin layers of the primer. Takes many days to dry and still leaves a tough ridge. Comparatively, ridges on a nose cone are going to be quite visible than on some large stage prop. I've gone as far as gouging out the ridge and repacking it, but that has it's own set of issues. I get warped looking surfaces. I'll admit, I am new to using foam and I'm sure there are methods I haven't heard about. Turning a solid piece seems to be an answer I can live with as long as it doesn't break the bank and I can order a few chunks at a time. Storing large quantities is out of the question.
 
Re do link

www.fmi-eps.com

my Father has used them for custom foam trim and quions for stucco finishes. Blocks of the dimensions you want woud be easy for them, you could even get cylinders odf the proper diameter to start. They have a huge CNC hotwire setup, they compress and recycle their materials, its a low/zero waste process they use.
 
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I assume you checked Amazon? 6"x6" cube is the largest available but I saw listings for 24"x24" https://www.amazon.com/dp/B074KNC5HQ/?tag=skimlinks_replacement-20

I saw that ad earlier. Unfortunate they are only 6" long. Be real nice to find something 6" x 6" x 36"

If your after EPS try,
https://www.fmi-eps.com/site/c3b08c...ome?url=http://fmi-eps.com/Home_Page.php#2992


my Father has used them for custom foam trim and quions for stucco finishes. Blocks of the dimensions you want woud be easy for them, you could even get cylinders odf the proper diameter to start. They have a huge CNC hotwire setup, they compress and recycle their materials, its a low/zero waste process they use.

The link is bad. 404 page error.
 
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I love the line "If you think that a special shape is too small or complex to produce. No problem, our philosophy is 'no special shape is too small or complex to produce'"
 
Re do link

www.fmi-eps.com

my Father has used them for custom foam trim and quions for stucco finishes. Blocks of the dimensions you want woud be easy for them, you could even get cylinders odf the proper diameter to start. They have a huge CNC hotwire setup, they compress and recycle their materials, its a low/zero waste process they use.


Thanks guys. That's looks like a great lead. I'll call them after the holidays.
 
So after so much research, phone calls and such, I have discovered that NO one makes extruded polystyrene foam thicker than 2 inches. The idea that a 3" x 3" MIGHT possibly be an option somewhere in the vast foam industry, is a wasted pursuit because I wanted bigger than that. The only way to get custom blocks of any particular size, is to go with expanded poly and I have no use for that. Not for turning nose cones anyway. Dow Corning is pretty much the industry leader in polystyrene production and even having viewed their production video, it's clear that they only make it so thick. Maybe there's a production issue with thicker pieces or maybe it's just not a profitable option for them.
 
Hi,
I use epoxy and sand with abrasive paper fixed to a flat piece of wood with double sided tape and do not get noticeable ridges, gaps maybe, but the foam is covered with epoxy fibreglass. Are you using the foam as a male mould, is that why the ridges cause a problem?
 
So after so much research, phone calls and such, I have discovered that NO one makes extruded polystyrene foam thicker than 2 inches. The idea that a 3" x 3" MIGHT possibly be an option somewhere in the vast foam industry, is a wasted pursuit because I wanted bigger than that. The only way to get custom blocks of any particular size, is to go with expanded poly and I have no use for that. Not for turning nose cones anyway. Dow Corning is pretty much the industry leader in polystyrene production and even having viewed their production video, it's clear that they only make it so thick. Maybe there's a production issue with thicker pieces or maybe it's just not a profitable option for them.

Well that simply is not true . I work in the insulation field , and we buy 3x48x96 inch sheet weekly , and yes it is blue EPS.
 
Well that simply is not true . I work in the insulation field , and we buy 3x48x96 inch sheet weekly , and yes it is blue EPS.

I take it you mean 3" (inches) thick. Yes, I did say that....sorta. But regardless of it's width or length, I was told that 4" 5" or 6" thick just isn't available. I apologize if I didn't make that clear. See, I was hoping to find pieces large enough that I wouldn't have to glue in layers before I turn it on a lathe. Ideally, a 4"x4"x36", 5"x5"x36" and 6'x6'x36"blocks would be perfect. Haven't found anyone that can or will produce that. Even if it came in sheets that were 4, 5 & 6" thick would suffice.
 
Thanks guys. That's looks like a great lead. I'll call them after the holidays.

So after so much research, phone calls and such, I have discovered that NO one makes extruded polystyrene foam thicker than 2 inches.

What was wrong with the FMI EPS? Too porous, built up out if glued layers, too expensive, other?
 
What was wrong with the FMI EPS? Too porous, built up out if glued layers, too expensive, other?

EPS foam is that expanded poly foam. That's what FMI has. I need the XPS (extruded) poly foam like the stuff at big box hardware's. Only I want it much thicker than 3 inches. 4, 5 & 6" preferably.
 
EPS foam is that expanded poly foam. That's what FMI has. I need the XPS (extruded) poly foam like the stuff at big box hardware's. Only I want it much thicker than 3 inches. 4, 5 & 6" preferably.
Owens Corning Foamular series should be available in ~4in thickness. Menard's carries it.
 
Most of the 4" thick stuff will not be carried normally by a home improvement store (I have no experience with Menards and as such no idea what they carry), usually the they top out at 2", for the thicker stuff its necessary (again, generally) to contact a construction supplier or a concrete construction supplier. The thickest foams are used in concrete tilt-up wall construction as insulation for the walls (a layer of concrete on both sides), it will also be a higher density/stronger material. I have literally delivered truck loads of the 4" foam to construction sites.
 
Most of the 4" thick stuff will not be carried normally by a home improvement store (I have no experience with Menards and as such no idea what they carry), usually the they top out at 2", for the thicker stuff its necessary (again, generally) to contact a construction supplier or a concrete construction supplier. The thickest foams are used in concrete tilt-up wall construction as insulation for the walls (a layer of concrete on both sides), it will also be a higher density/stronger material. I have literally delivered truck loads of the 4" foam to construction sites.

And you just made a really big light come on. I hadn't thought about my landlord owning a construction company. I'll bet he knows a thing or ten. Prolly get me a discount as well. Thanks guys!!!
 
I also have fought the battle with glued-up foam boards. I usually have a hard core (1" dowel) running through the layers. I try to keep the glue on the dowel and the inner couple inches of the foam, avoiding the outside. This tends to leave small gaps on the outside, but they're easier to fill or cover with glass afterwards than to get the hard glue layer sanded evenly.

Another (untried!) approach which will probably be cheaper than trying to buy "big" blocks of foam is to make your own. Get a 6" concrete forming tube from Menards, line it with parchment paper, and fill ti with 2-part urethane foam. Then, peel and toss the cardboard. You could even cut centering rings and mount the central wooden dowel before you pour the foam. I think I'll try it on my next nose cone.
 
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