So, I contacted Poly-Props Ltd if they would be willing to send me a test batch of their foam so i could do some testing, and they were super nice and send me a whole bunch of different foams. They have a wide array of craft foams, so I decided to test them all for density, shape, heatforming, sealing and painting. Here is the conclusion of the test:
I had 3 different foam types, in 1 to 3 Thicknesses:
Lets start out with the regular Craft foam: It is their cheapest product. For regular armor building its good enough. The 5 and 10 mm foam bends really well with heat, and keep the shape very nicely. The 2mm barely keeps its shape, because it is just too thin and soft, but i wouldnt suggest using the 2 mm foam for any form pieces anyway, just for details. The foam sands really well, and if you go over it with a heatgun after sanding, you cant really tell the difference to the normal surface of the foam. It glues well with hot glue and basicly bonds itself together.
The major difference between the Poly-Props foam to the foam I am currently using (puzzle floor mats aka EVA foam) is that it does not shrink with heat at all. This is fantastic if you want to lasercut things out of it, but horrible, if you wanna use the detailing technique of cutting in lines and then heating it to open up the lines. It goes as far as that the cuts just "melt" together again, and only leaving slight little imprints. Also to be said is (this counts for all foams) that you shouldn't press too hard on the heated foam, as it will leave finger imprints, but you can get those out by reheating the foam slightly after it has cooled.
Now to the CF 65: Its slightly denser than the regular Craft foam, and therefor holds its shape slightly better after heat forming, but the difference is marginal. As you can see in the pictures, this is most noticable on the 2mm foam; the Craft Foam goes almost back to flat, while the CF65 stays in a good round shape. Sanding is pretty much the same as the regular Craft Foam, and it gives a nice surface after heatsealing. It also does not shrink after being heaterd, therefor making it great for lasercutting, but not for heat detailing.
Finally the CF 100: Hardest of the foams, still flexible, but way more durable. It holds its shape way better than the other 2, and thats even though I only had a 5 mm piece to test. I would go as far as to say that you could easily make any armor pieces out of 5mm foam of the cf 100 at the same quality and sturdiness as any other foam at 10mm. Sanding is pretty much the same, it seems like a slightly nicer surface, because of the denser foam, but overall after sealing, you wouldnt see a difference.
Now for the other huge difference between the cf100 and the other two: it does shrink under heat, not as much as the EVA foam I use regularly, but enough to use it for detailing. For lasercutting, you would probably get a slight tapered edge with this foam.
I have sealed all three foam identically. I used 3 coats of pva glue and then painted the coated part as well as painting the uncoated part to show the difference. 3 Coats of glue were easily enough to seal the foam. The CF100 would have probably been fine with just 1 coat, but I did three to be safe. The foam definitely need to be sealed as you can see from the pictures, the unsealed painted parts looked very dull and not shiny at all. If you have any more questions about these foam types, feel free to message me on my page [HERE], and I will tell you what i know ;)
Left: CF100, Middle: regular CF, Right: CF 65
All test pieces in one picture to compare the shape and detailing options.
CF 100, was my favorite foam of this test of the set. It is a bit more expensive than the other two but definitely worth checking out.
Regular Craft Foam, might be replacing the foam I use for general crafting soon :)
The foam also comes in White. Here i used regular white Craft Foam, cut it, then tried to weld it back together using just a heat gun and it worked better than expected.
Since we established the baseline for the Poly-Props Ltd foam a couple of weeks ago, it was time to hit it with something more fancy, mostly lasors! Here is an in depth review of how the Foam held up against the laser cutter. Disclaimer: Ive also tried laser cutting regular floor mat foam (aka EVA foam), and while its ok to engrave, its almost impossible to cut due to heat shrinkage. This foam holds up way better, to the point that you lose almost no material in heat. I will explain everything more closely against each photo.
Click on each image below to enlarge them.
Ive tried both 5 mm and 10 mm of the regular Craft Foam, and the first thing that stood out is how little is lost with cutting it on the laser. As you can see in this picture theres only a very small gap (barely half a millimeter) where the foam was cut, which is basicly neglectable on foam props. This test was carried out with the 10 mm Craft Foam. You can also see the first engraving attempts, but the power wasnt set high enough so it was very flat (this obviously depends on what kind of engraving you need).
Cutting multiple boxes out of the 5 mm foam, including one that goes over both the regular spraypaint and the 3 layers of pva glue coating, no problem for either the lazer or the foam.
At this point I figured out we need different settings engraving coated foam to uncoated foam. As you can see here, with this setting, only the paint got taken off the pva glue, while the untreated foam was allready nicely engraved
After a bit of tinkering, we got the perfect setting for the coated foam too, which gives it a really nice effect of glossy paint on matte foam. This is my favorite result.
We also tried engraving over rounded edges, since sometimes you dont want a square edge on a foam piece. On the first try, the power settings were too high so it engraved too deep, but even with the 1 cm rounded edge, the lazer didnt go out of focus too much and engraved all of the curve
After we figured out the right settings for foam engraving, I once again tried to engrave over a rounded edge, and then continue on for a bit so you could see how the foam would look like with a bigger surface engraving and rounded edge.
Overall I can say that I will definitely use this method for future projects, as it has infinite possibilities, thanks to the better quality of the Poly-Props Ltd foam.