Take the 2-minute tour ×
Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. It's 100% free, no registration required.

I found this recipe for EPS concrete, and am thinking of using it to make a fire bowl (a decorative concrete bowl like the one described here, which holds a chafing dish gel fuel pack.) I would like to avoid generating toxic fumes, however, so I would like to know whether burning a gel fuel pack in a bowl made of EPS concrete would be safe. The main reason I want to use EPS concrete instead of the regular heavy stuff is weight.

enter image description here

share|improve this question
    
If you're burning the sterno in the can, then you could probably get away with any material. If you're dumping the sterno into the depression, then you might have issues. –  Chris Cudmore Sep 16 '13 at 19:43
    
i'd definitely burn the sterno in the can. –  kewpiedoll99 Sep 17 '13 at 20:14

2 Answers 2

up vote 3 down vote accepted

EPS concrete is basically concrete with EPS beads and a few other things in it like latex paint.

The fact is, polystyrene melts at about 200 degrees F. The flash point of DIETHYLENE GLYCOL (which is at least a component of many such cans contain, along with other components) is 255 degrees. So it seems likely that a Sterno flame can easily melt, if not burn the EPS in your bowl. This is surely not a good idea! If it melts, it will surely be giving off some fumes at that point too.

I won't bother to look at when latex paint burns, but do you want it exposed to a flame source?

I'd suggest this is a poor idea.

If you really want to make a matrix that will be lighter in weight than pure concrete, there are surely some better things you can add to a concrete mix that will lighten it, while still not being a fire risk. A quick internet search just found hollow glass beads for sale at a low price in various places. And skip the latex paint in the mix too.

Edit:

I originally looked on ebay, under "hollow glass beads". What I found does look too expensive, usually hand made. Depending on how many you need, maybe buy some cheap costume jewelry necklaces, but you would need a few to make a big bowl. I would also check craft stores like Michaels, and I was told just the other day that there are stores that specialize in beaded crafts. So then I looked for hollow steel or aluminum balls. Wagner sells a package (25 count) of 1/2 inch steel balls, though I did not see a price.

Then I started thinking more out of the box (ok, out of the bowl.) As a woodturner, I could make a bowl completely out of foam (or balsa wood, which is also pretty cheap and light), by glueing up a block, then turning it into a bowl on a lathe. One could create this as a form, then covering the bowl form inside and out with a thin shell of pure concrete. That shell would absolutely be adequate insulation to prevent any problems. If you are not a wood turner, then I'd find a wood turning group. There are MANY of them around the country, probably one in any significant metropolitan area. Go to one of their meetings, then ask around for some help. I'd bet that at least a few people would happily turn a balsa wood bowl for you if you provided the wood. At worst, some pizza might work to grease the wheels.

share|improve this answer
    
this was pretty helpful (and confirmed my suspicions). i had actually been thinking of adding something hollow to the mix and had thought of glass spheres, but i am stymied trying to find them for sale at a low price anywhere. the best i found was this at 3M (shop3m.com/3m-glass-bubbles.html) but their smallest price is $50 for a gallon and i think they are too small anyway. or i can buy "hand crafted, hand blown" art spheres, but nothing in between. if you have any links for me i'd greatly appreciate it. –  kewpiedoll99 Sep 15 '13 at 18:18
1  
After thought, I'd go with the idea I added to my answer, which is to make a balsa wood or foam bowl form with a lathe, then apply a concrete coating to the outside. This would be quite light in weight. If you simply can't dig up a wood turner, these materials are easily soft enough to shape with hand tools into a rough bowl shape. Perfection is not needed, since it will be covered over. –  user558 Sep 15 '13 at 19:06
1  
You haven't provided an analysis of EPS concrete, just an offhand, opinion based answer. Do you have any facts or corporate data sheets proving what you are saying? By extension, you'd pan using water for firefighting, since its constituent parts can be explosively ignited. You have to rate the assembly as a whole. –  HerrBag Sep 15 '13 at 19:58
    
This link DOES state that diethylene gycol is used in many such cans, along with other components. zenstoves.net/Sterno.htm –  user558 Sep 15 '13 at 22:17
1  
All this is irrelevant, because the flame of the fuel is not in contact with the concrete, it burns UPWARDS. See the photo #6, there is an air gap around the fuel canister. The alcohol based cans (which I specified in my answer) burn much cooler, around 175F. –  HerrBag Sep 16 '13 at 12:40

If you stick to a metal enclosed gelled alcohol fuel, like Sterno, you should be fine. The hottest Sterno is less than 200F (Sterno typical temperatures).

Sterno food warming tins do NOT contain Diethelene glycol, as evidenced by the Sterno MSDS. The only OSHA regulated materials are ethanol and methanol (3% to keep it from being drinkable)

Edit EPS concrete or EPScrete is used in many applications, primarily in Europe. Of note is the Lightweight Concrete Company's Construction Characteristics page, Which notes EPS concrete as:

Fireproof, with a rating of 4 hours for a 6.8″ wall*

share|improve this answer
    
Sorry, but polystyrene melts at about that temperature. It will surely be giving off gases if subjected to heat below that point. –  user558 Sep 14 '13 at 17:53
2  
Sorry back atcha, but the heat output is UP. The case gets nowhere near the flame temp. The EPS beads are embedded in a matrix of cement and sand, insulating the whole. You may be interested to know EPS concrete or Styrocrete is used for building and and a 1/4 " coating over EPS foam gives a ASTM E 108 Class A rating for fire retardancy. –  HerrBag Sep 15 '13 at 17:52
    
I KNOW that it is used in building. However, your answer did not address this at all. Your statement gave a temperature for Sterno (which is anyway not apparently accurate from what I could find) and then stated that there should be no problem. The fact is, there WILL be beads on the surface of such an aggregate. Those beads will be affected if the Sterno spills. –  user558 Sep 15 '13 at 18:09
    
Safe Heat, with a wick, is NOT the same as a alcohol based fuel, and is NOT recommended (for backpackers) due to its toxic burn characteristics, which your own source states. –  HerrBag Sep 16 '13 at 13:00

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.