Foam

[Chris Smith]

There are several choices when it comes to foam. I prefer to use Dow blue board. This is an extruded form of polystyrene. This means that the entire board is made of one continuous piece of foam. This foam of very durable and will last many years. Blue board comes in several forms and it is important to get the right one. The best is "square edge" and not the "score board". Square edge foam is a solid sheet of foam. The score board has scores top and bottom to make it easy to break. The scores are at a standard stud layout and intended for insulation in walls. The scores make it easy for contractors to break and install.

The other type of foam is EPS or expanded polystyrene which is thousands of small pellets that are expanded into a form. The EPS foam is not nearly as strong as extruded and will break down easily. Roots of aggressive plants will actually grow into the foam. I have one of these sheets in my system and it is now dedicated to mint as the roots are growing throughout the foam.

[Vlad Jovanovic]

Holy shit! 18K just for the stupid mold?!? Try calling or writing Beaver plastics and/or see with Jon Parr (since he uses/has a bunch of them) about what he knows...

As far as testing...hmm...IDK. Since you're in Texas, you might try checking with Arnold Schecter, MD, MPH, professor of environmental and occupational health at the University of Texas School of Public Health in Dallas. 

He has recently tested for HBCD flame retardant in a bunch of common food items (36 items, 15 of which came back with detectable amounts present). Industry of course doesn't think that that is a problem, he and some other scientists feel that it may, and gov't...well...gov't is probably still trying to figure out how to spell "hexabromocyclododecane" and wondering why they can't find any in the toothe-paste isle...That would be my best suggestion at the moment...

http://www.webmd.com/food-recipes/news/20120530/flame-retardant-fou...

[Joe Bifano]

I just got off the phone with my manufacturer and another guy who does custom cutting and they both said the same thing about the law that was passed and every foam has to have the fire retardant in it even the blue board. They can't get it any other way they said.

I used polystyrene 2-1/2 pound and it is really heavy duty. I am 170 lbs and can rest most of my weight on it to reach and it hardly goes under the water. I have to really push to get it to go under.

But on the special type of things to be made, what exactly are you looking for to have made. They were telling me for cutting polystyrene with there hot wire machines they would have a lead in cut of 1/16" to make a hole.

What kind of a mold are you all looking at making?

Also if there were a food industry foam manufacturer would they use fire retardant?

[Vlad Jovanovic]

When was this law passed in the US, if you or they happen to know?

Again, a real easy and painless thing to do is to check with Beaver Plastics Canada, since they make a whole range of different products for both insulation as well as horticulture...comes with pre-made holes for lettuce and everything, don't see why the Canadians would make them use any flame retardant for a product that is designed, engineered, and intended for horiculture..? Cheaper than the blueboard as well, or so I hear...

[Dave Love]

Joe Bifano said:

I just got off the phone with my manufacturer and another guy who does custom cutting and they both said the same thing about the law that was passed and every foam has to have the fire retardant in it even the blue board. They can't get it any other way they said.

I used polystyrene 2-1/2 pound and it is really heavy duty. I am 170 lbs and can rest most of my weight on it to reach and it hardly goes under the water. I have to really push to get it to go under.

But on the special type of things to be made, what exactly are you looking for to have made. They were telling me for cutting polystyrene with there hot wire machines they would have a lead in cut of 1/16" to make a hole.

What kind of a mold are you all looking at making?

Also if there were a food industry foam manufacturer would they use fire retardant?

HI JOE, 

You are correct, foam used as containers by the food and pharmaceutical industries does not contain flame retardants.  I actually toured a Mid-Atlantic polystyrene plant a couple of weeks ago that makes coolers (i.e. "styrafoam" coolers, but that a brand-name).  (http://www.lifoam.com/)  

There are other options for foam besides rigid foam insulation.  They don't typically make 4'x8' sheets, without a special order, but they do make other products like 2'x3' coolers that are about the right thickness for rafts.  I'm trying them out and will report back in a week or two.