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Old Feb 25, 2012, 06:24 PM
Guz
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Question
High Density Urethane - cheap source?

Anyone know of a cheap source for sheets of High Density Urethane foam, 1" thick? It's commonly used for 3 dimensional sign making, btw.
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Old Feb 26, 2012, 12:49 PM
Father of Fr3aK, DLG Pilot
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Probably the cheapest way is to make your own sheets. I've only found it through places like freeman supply etc... and it's quite expensive. Its available as two part liquid.
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Old Feb 26, 2012, 01:41 PM
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I remember that Joe Manor was selling some excess Last-A-Foam sheets. Maybe he still has some?


I have a feeling that making your own might not be as easy as it sounds as for as getting a homogeneous final product.
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Old Feb 26, 2012, 01:54 PM
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It's not hard at all. Build simple forms, mix well and pour, control curing temp and humidity.

The stuff used for signmaking is a lower grade foam that usually isn't homogeneous anyhow. The density will vary (sometimes quite) a bit by location in the sheet's thickness... usually more dense at the outside and slightly less dense in the core. If you are looking for something like Renshape that is very controlled in density and thermally stable to machine, you're probably right that it's not practical to make yourself.
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Old Feb 26, 2012, 03:18 PM
Guz
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I'm not making molds, btw.

What I am trying to make is some floating marks.


(the wood was just thin ply sealed so I could put an eye hook on from the bottom)

I originally made them out of craft store Styrofoam and they looked AWESOME, but the damn ducks chewed them up. So now I'm on the look out for some other material that will not absorb water, I can paint them, will sit on water 24x7x365, and ducks, kids can't destroy. I really need 1" thick, as it was the best viability from a distance.

In searching local plastic, foam suppliers I was given a sample of HDU which looked and felt perfect. Being a closed cell foam, it won't absorb water, paint-able, durable, etc.., but damn expensive.

But I am open to ALL suggestions!!! I only need a minimum of 2'x4'x1" sheet, but 4'x4'x1" would be preferred so I could make extras.
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Old Feb 26, 2012, 03:55 PM
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We made some similar markers for a ski tournament several years ago using a traffic cone as a mold and an expanding urethane core. Lots of options...

You may be able to find 100PSI XPS (Dow or OC) locally too, which hotwires and is almost as dense / durable as the HDU. You can paint it if you start with light coats so the solvent flashes off before damaging the foam. Once it's basically covered, coats can get heavier.
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Old Feb 26, 2012, 05:54 PM
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Another option is a syntactic foam. You mix casting resin with a lot of micro spheres. You can mix it to the consistency of of cookie dough or something pourable. This would be very durable and still float. You can make sheets and cut them or make simple forms and pour or pack the stuff in. This is how many manufacturers make durable floatation. This is also how many tooling boards are made.
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Old Feb 26, 2012, 10:19 PM
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Why don't you just put a layer of glass over the styrofoam? 6 oz ought to do it.
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Old Feb 26, 2012, 10:50 PM
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Quote:
Originally Posted by BillO View Post
Why don't you just put a layer of glass over the styrofoam? 6 oz ought to do it.
BillO! I thought you had died. Good to know you are still about.
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Old Feb 27, 2012, 01:14 AM
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Thanks Adam, I check in every now and again. I hope to have a Zmax update soon.
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Old Feb 27, 2012, 09:47 AM
Guz
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Tempe, AZ
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Quote:
Originally Posted by tom43004 View Post
You may be able to find 100PSI XPS (Dow or OC) locally too, which hotwires and is almost as dense / durable as the HDU. You can paint it if you start with light coats so the solvent flashes off before damaging the foam. Once it's basically covered, coats can get heavier.
Doh! I forgot I have some of that around the shop (blue Dow). I will make one mark and put it out to see how it fairs. I was hoping to find something in white, but if it holds up, it might be worth it.
Quote:
Originally Posted by BillO View Post
Why don't you just put a layer of glass over the styrofoam? 6 oz ought to do it.
Trying to avoid that... Just being lazy
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Old Feb 28, 2012, 01:33 PM
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United States, VA, Falls Church
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Why not make them out of EPP?

Quote:
Originally Posted by Guz View Post
I'm not making molds, btw.

What I am trying to make is some floating marks.

I originally made them out of craft store Styrofoam and they looked AWESOME, but the damn ducks chewed them up. So now I'm on the look out for some other material that will not absorb water, I can paint them, will sit on water 24x7x365, and ducks, kids can't destroy. I really need 1" thick, as it was the best viability from a distance.

In searching local plastic, foam suppliers I was given a sample of HDU which looked and felt perfect. Being a closed cell foam, it won't absorb water, paint-able, durable, etc.., but damn expensive.

But I am open to ALL suggestions!!! I only need a minimum of 2'x4'x1" sheet, but 4'x4'x1" would be preferred so I could make extras.
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