Retail Availability of XPS Foam Board

Discussion in 'Lost foam casting' started by Al2O3, May 30, 2023.

  1. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Just thought I'd see what other lost foam casters are seeing for availability of XPS stock in your area.

    First, just to define what we’re looking for, you want unfaced, Extruded PolyStyrene between 1 and 1.5lb/ft3 density. I’ve been using the Owens Corning product because it was plentiful and available in the preferred density in 1”, 1.5”, and 2” thick boards.

    I live in central USA on Iowa Illinois border. My choices for big box stores are Home Depot, Menards, and Lowes.

    You’ll typically see a few brands. For me it shakes out like this:
    • Owens Corning – Foamular, the pink stuff, Menards and Home Depot
    • Dow – Styrafoam – The blue now grey stuff, Lowes
    • Kingspan – The Green stuff, Lowes
    It’s hard to tell the density of these products because they are primarily marketed by R factor and Compressive strength. You have to really dig to get all the physical properties for the various manufacturers, having done so, I can tell you the best proxy for density is compressive strength. R factor is not a good proxy.

    For the Owens Corning brand, they’re tradename is Foamular and their product line is branded by compressive strength like Foamular xxx. Foamular 150 and 250 are what you most usually see in retail stores and occasionally 100. 150 & 250 stand for 15psi & 25 psig compressive strength respectively. That corresponds to 1.3lb/ft3 & 1.5lbs/ft3 respectively. I’ve found this density to be the best compromise of density (pattern evaporation rate), strength, and workability. Occasionally I’ll use 250, but far prefer 150. So if you are looking at other brands, compare by compressive strength, preferably 15psi. Color is meaningless other than marketing.

    There are EPS products available too but they don’t machine and finish as well at these densities.

    Prepandemic, everything was economical and plentiful. Now not so much. Prices are up 50-100%, inventory sucks, website inventory and by-store information is never accurate. -Seems to be a sign of the times. My closest retailer is Home Depot. I was going there for some other items so I checked the website foam board stock. It said my store had 25 sheets of 2” thick Foamular 150. I was out, so I took my truck. When I get there they have plenty of 250 but only 4 sheets of 150 and two of the four were so damaged, I couldn’t even understand why they were for sale. -I bought the other two sheets. Prices are crazy too. Those two sheets of 150 were $40 each but the 250 was $60. 1” and 1.5” thick boards were the same price at $30……Huh? All of these sheets are scored which kind of sucks because I have to cut around that and it reduces yield.

    Also, I got excited a year or so ago because the Menards website showed 3” & 4” thick Foamular 150 was available. I tried to buy a few sheets. They said it was special order. I said no problem, I can wait. After a couple weeks I call back and they said oh yah, it’s only available if I buy a truckload. I said, they cant add afew sheets to the next truckload of other sheet?....Nope.

    Has anyone ever seen 3” or 4” Foamular at a retail store? Have you discovered any other sources for thick stock?

    Best,
    Kelly
     
  2. Smoking Shoe

    Smoking Shoe Silver

    Try some of the commercial roofing contractors.
    Boat dock billet is generally large cell - worthless for lost foam, great for airplane wings - but I've seen the small cell used as well.

    Shortage may be related to all things insulation rather than just foam board. My brother is getting the same kind of response for R19 glass of any congratulation.
     
  3. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    No luck yet. Only EPS replies from them so far, if they will reply. But I kick at it when the opportunity presents itself.

    The large DOW floatation billets are actually XPS, and very nice, but far too dense. :(

    There are XPS planks used under concrete and underground too, but they are also too dense.

    Best,
    Kelly
     
  4. Tops

    Tops Silver Banner Member

    Kelly, have you ever tried 1.5PCF EPS? I could send you a piece if you like., it's about 2x as dense at big box store EPS.
     
  5. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Yes. That's about the same density as Foamular 250 XPS. It's a little higher density than I would prefer but if it has fairly fine/small bead size, it machines ok and can be sanded to improve finish so if you have access to it, it's viable. There are people/places that will make EPS billets of almost any size and density you want but I haven't found one near me and shipping such is a killer. A few years ago I bought a small billet online in that density and was about 1 ft3. I still have a chunk of it and have also collected some similar pieces from appliance packaging, but the latter isn't big enough for most of my patterns.

    Best,
    Kelly

    Owens Corning XPS.jpg
     
    Tops likes this.
  6. Tops

    Tops Silver Banner Member

    Here is the datasheet for what I have, it would be the '150' column. I used to buy direct from the old PolyFoam (now Plastifab) factory in Lester Prarie, MN.
    Piece on the trailer is 25" x 48" x 144" . I still have a couple surfboard's worth left.


    foam_control_eps.jpg
    eps_foam_rockers.jpg
     
  7. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Thanks for posting that Tops. I'd take you up on your offer but I suspect there isn't a whole lot of variation in how well a given density machines and finishes. I'd like to find a local source as opposed to a 5 or 10hr round trip drive or apying $500 to ship a $1000 billet of EPS. Your post prompted another web surfing session. They all end the same way.......20 open search windows, those of interest are never near me or they wouldn't answer the phone to sell a single billet.

    For EPS, the number of offerers is kind of mind numbing, but still none near me, else I probably would settle for the right density.

    I can tell you what hasn't worked:

    • Flotation billets are available from multiple sources in XPS and EPS but way too dense......usually 6-8lbs/ft3. That makes them durable and still very buoyant but useless for LF.
    • Concrete underlayment is a typical usage but that is almost always too dense as well, but more like 2-3lbs/ft3, so not unthinkable, but not something I'd be willing to invest time in.
    • Roofing underlayment is the most promising source because it will be the lowest density XPS in thick planks. I went as far as calling the Owens Corning and DOW corporate sales reps and they said that is the typical customer for the low density (1.3-1.5lb) planks, but they only sell in 24pc pallets plus shipping. I asked if they could give me any names of a customer withing 150 miles of me thinking I could buy a sheet or drops from them but answer was no, although one did say the shipped to a Menards in Georgia.

    Last I checked at the local retail outlet, a pallet of 24 pcs of 8'x 4ft' x4" XPS was $3300. That's about $140/plank. It was unclear if there would be shipping on top of that but I'd say likely. Even if someone was willing to ship a sheet, without elaborate packaging, the chances it would arrive undamaged are slim, which is likely the 24 sheet minimum......a 8'x 4' pallet stacked 8' tall.

    I've called many local commercial roofing business locally. -No Joy. I've even stopped by build sites and asked around. Nope. I have several acquaintences that a General Contractors for large commercial builds. I may eventually get an intro to a source through them.

    Right now, the cutting envelop of my present CNC router limits me to 2" thickness and my work around is assembling pre-cut layers from 2" XPS but when my new CNC build is complete I'll be longing for thicker material.

    I actually started this thread because I was on the verge of a rant about retail stores, high prices, no selection, no inventory, damaged inventory, and no knowledge......and that's not limited to foam insulation board, but I figured after all the above, now I cant even reliably get 2" XPS in the preferred density? .....There. Mini-rant!

    Best,
    Kelly
     
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  8. BattyZ

    BattyZ Silver Banner Member

    To pile on top of this. About a year ago I was talking to Kelly about a roofing company that does XPS, up to ten inches, only 2 friggin towns over. Years prior I had gone there, before I was doing LF, to get some strips out the door. Cash and carry. So I got Kelly and I all excited....business had been bought out, rules changed, and your job was on the line for even giving away cutoffs.

    With this all said it could have also been way too dense as well but still frustrating.
     
  9. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    I had some success locating thicker XPS. A friend of mine that is a general contractor connected me with a Commercial Roofing contractor who has a satellite facility here in town........1.5 miles from me. They are planks of 96"L x 16"W x 4" thick Owens Corning Foamular 250 XPS NGX. Through weighing and measuring I determined its density was 1.6lb/ft3. I also took the opportunity toti weigh 6 different samples of Foamular 150 I hade in my shop and discovered it's density 1.5 lb/ft3, higher than the 1.3 lb/ft3 published data. So I did a quick comparison of how this machined compared to a couple EPS Samples. See this post:

    Comparing Machinability of XPS & EPS Foam | The Home Foundry

    It appears I will be able to get this when and as needed within a few days or weeks without minimum buys, which is great. The cost is comparable or slightly more than retail costs per board or cubic foot. Since the retail stuff is all scoreboard, I never get wider than 16" stock anyway. If I could get 8'x4' sheets of 4" or thicker that was not scored, it would probaly be cheaper pattern stock than retail sourced sheets due to higher yield from not having to cut around the scoring lines, but it can be difficult to resize wide plank to thickness with hot wire so retail sourced stock will still have it's place.

    Best,
    Kelly
     

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