3 test materials:
#1 EVA foam mat from Lowes
https://www.lowes.com/pd/Gray-Anti-Fatigue-Mat-Common-4-ft-x-4-ft-Actual-49-21-in-x-49-21-in/3111467
1.56m^2 of material for $17.98=$11.53/m^2
#2 EVA “45 degree” foam from Amazon (shipped from china)
1.8m^2 of material for $62= $34.44/m^2
#3 EVA 100kg/m^3 foam from Redmoon Cosplay (shipped from Canada)
2m^2 of material for $84.40 USD= $42.20/m^2
Cut sample squares 30mm square
Actual sizes: 1) 30.00x30x12.29mm 2) 29.70x29.66x29.8x10.50mm 3) 30.10x30.10x10.25 mm
Weight: 1) 1.14g 2) .82g 3) .98g
Calculated density: 1) 103.0kg/m^3 2) 88.7 kg/m^3 3) 105.5 kg/m^3
I think #1 is has a “skewed” density due to the heat seal that is applied to the bottom of the floor mats effectively reducing the thickness. (main section of foam is likely in the 80-90 range while the bottom texture sealed area is 120+)
Test cut using 5mm focal height, 150 speed, full power, single pass
Results:
Left to right:
- dimensionally square, consistent thickness, corners have visible shrinkage in mid depth
- dimensionally square, significant char, shrink, burn on back
- dimensionally square, consistent thickness, no charring, corners have minimal shrinkage in mid depth
Functional thin cross section part check 5mm focal height, 150 speed, full power, single pass:
1)Thinning/twist/warp at upper surface. Bottom surface retains closer to original cut patter shape. Visually distracting heat seal texture.
2) Thinning on upper surface (at bottom of circle)and some melting on back.
3) Base of circle didn’t thin. No melting in back. Some areas didn’t fully cut through.
I will further refine the number of passes and final power settings as I begin to cut the project.
Overall I’m satisfied with the #3 results, but the most expensive of the 3 options.