Years ago in response to my first phone call to Marko, I got a quick return phone call from Coby Peterson within several hours.
After sending the proprietary file requested during that phone call, it took 3 emails, 2 phone calls, 28 days and a certified letter to finally get a response — A defensive “No-Bid.”
Ten business days is not unreasonable for a “No-Bid.”
Exactly.
The only way for foams with “open” passages between gas-filled balls to release air/gas is to rupture/cut the gas-filled balls. The gas will then exit immediately through the open passages between the balls.
Only other way for air/gas to vent is for the air/gas in the “open” passages (or damaged balls) to expand and exit the blank in an environment where ambient temperature is increasing above the blank’s core temperature (exiting gas/air causing bubbles or pinholes in uncured resin).
Allowing blanks to equalize core temperature, to a stable ambient workshop temperature first, prevents this.
Right, this is true. However, it is my - albeit limited - understanding that the foam that comes out of a block has more variation as you get further from the edge of the mold. Much the same way PU does, thus blanks cut from large foam blocks can have more difference as they are taken from different block sections. Perhaps this is negligible, but it would make sense to me that foam density would be subject to change through a large block. What are your thoughts here?
Quality and uniformity of density is dependent on the manufacturer. One of the advantages of EPS blanks immediately following the Clark Foam debacle was the uniformity of EPS slab density relative Clark PU density.
“Expanded Polystyrene is made from solid beads of polystyrene that contain an expansion gas, today most commonly pentane, that is dissolved into the bead at the time of manufacture.
When these solid polystyrene beads are exposed to heat in the form of steam, the pentane in them expands causing the solid bead to expand to about 40 times its original size, these are known as pre-puff or expanded beads. To you and me they are known as beanbag filling.
These expanded polystyrene beads can be further processed by being loaded into moulds and steamed again to create blocks of various sizes, shapes and densities. These can be cut into sheets or blocks of varying thicknesses.”
(BTW happy to provide a link to my credentials off forum)
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From my experience variation are from block to block more than in same block.
Pentan can give headache when shaping eps work in high air flow with right mask.
Construction grade foam. Meant for insulation, not surfboards. Does not lend itself to hand shaping by almost anyone. Although some shapers with “grit barrels, a sanding block and spackle can make it look pretty good. Looks like fake molded foam though if the block is slab cut with CNC Hotwire, outline cut, milled once and a cool stencil. If the shape is CNC’ed chunks of dock foam can look pretty good.
Absolutely ! And was doing so ten years before you burned your bridges in So. Cal. First blanks I sold up here were Clarks.
Eps blocks i buy are make localy for contruction and others industrial use. For many years i don’t have any more quality problems. Only seal with epoxy spackle, stop construction spackle for long time, may be it help, with enough fiber over too.