I am beginning my adventure into ski/snowboard construction and am curious what the minimum pressure (PSI) a press should be able to sustain?
I've heard about people using discharge hose that only holds 35 psi, and others who go with 150 psi. Is there a difference in the outcome of the ski or board with smaller pressure range such as 35 psi?
Esscher
what is minimum operating pressure of press?
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esscher,
I have been making light and thin skis lately and have noticed some differences in how they turn out at different psi. I've made thicker maple/poplar skis (12-14 mm down to 3mm cores) at 60-70 psi with no real problems. When I use pine cores with poplar sidewalls the amount of psi has come into play. At both 40 and 60 psi the cores warped a bit where I had routed out for where the edges protrude from the base. On the pair I did at 60 psi the tips and tails came out a bit convex. On the pair I did at 40 psi the sidewalls stood proud and the pine section compressed more. I am finding that when parts don't fit perfectly, are not attached properly or are different densities, the level of psi can bring these problems to the fore.
In general the higher the pressure the more little imperfections can be seen but higher pressures allow for the expulsion of excess epoxy. Vacuum systems use only the atmospheric pressure which is around 15 psi depending on where you live. I think you might have to go a bit higher than this in order to get your hose to spread out and fully press your materials into the mold. I bet 30 psi would work pretty well.
Even if you plan never to go above 50 psi it would be good to build a press that could withstand twice that amount of psi (just to be safe and to have a long lived press).
I have been making light and thin skis lately and have noticed some differences in how they turn out at different psi. I've made thicker maple/poplar skis (12-14 mm down to 3mm cores) at 60-70 psi with no real problems. When I use pine cores with poplar sidewalls the amount of psi has come into play. At both 40 and 60 psi the cores warped a bit where I had routed out for where the edges protrude from the base. On the pair I did at 60 psi the tips and tails came out a bit convex. On the pair I did at 40 psi the sidewalls stood proud and the pine section compressed more. I am finding that when parts don't fit perfectly, are not attached properly or are different densities, the level of psi can bring these problems to the fore.
In general the higher the pressure the more little imperfections can be seen but higher pressures allow for the expulsion of excess epoxy. Vacuum systems use only the atmospheric pressure which is around 15 psi depending on where you live. I think you might have to go a bit higher than this in order to get your hose to spread out and fully press your materials into the mold. I bet 30 psi would work pretty well.
Even if you plan never to go above 50 psi it would be good to build a press that could withstand twice that amount of psi (just to be safe and to have a long lived press).