Ski Builders Forum

Thanks Chris(mp) for showing me(us) the Ghetto box!
I think we are on the same path here, but when I saw yours I decided to change the name of mine. From "grill" to "heat".. The "heat" produced in my box is for the moment only close to 70°C. For the moment I'm using a fan and element from an old drying cabinet for clothes. It comes with both thermostat and timer. It dosen't really show in the pictures, but on the top of the box, there is an inlet and outlet for the air to circulate. This is ok, but I'm aiming for 90°C.
I will experiment with a foil I got from richuk. It will reach 180°C according to the specs. I haven't figured out how to control it for the moment....




ATH
(yeah, yeah, I know I can reach a little higher with some proper isolation, but right now I'm "research mode")

More details after the weekend

nice!
post-heat treating some resins, at just 60-70oC for half a day, may dramatically increase their hardness

I believe that with insulation you could get temp way up inside
cover the box with bed blankets or something, and run a test for an h
i think you ll be surprised

Nice work!

Isolation in progress....

I just found out that max on the thermometer is +70°C. JIT :-)

what is the weight on top of the box for?

a.badner wrote:what is the weight on top of the box for?

Do you really want me to tell you?..

This was just in the POC phase when I needed something to hold the top channel down and minimizing the air-flow-heat loss.

ah, makes sense.

im just used to seeing olympic weights on a bar.

btw, how are the plastic parts in the heater holding up?

There aren't really any plastic parts in the press construction. All the plastics are in the skis And the heat is for them. And I'm aiming for "just" 80°C which shoudn't melt any plastic I use. I will change the rubber sheet on the press to silicone which don't dry out that easy compare to rubber. But none of them will burn or melt.

sounds like you have a plan.

how does the wife feel about the build?

i can't really tell if your heater has any plastic parts from your photos, but often times the fan itself is just plastic. and that's the part that sits right next to the heating element which can get really hot if there's no fresh air flow coming from outside.
i guess you're good as long as those ribs provide enough air to keep the fan cool.

the problem with this construction is, that it needs a lot more power to warm up the fresh air it constantly draws. plus the maximum temperature you can reach depends a lot on the ambient temperature.

heat blankets are still the best way to heat a pneumatic press since it's a lot easier to warm up a sheet of aluminum pressed against the heater than warming up the air surrounding your press.

for OAC's press it works since he only needs to heat a pretty small room and is inside a heated workshop. but i don't see this being a good option for you badner, since your press is a lot bigger and outside.

chrismp wrote: the problem with this construction is, that it needs a lot more power to warm up the fresh air it constantly draws. plus the maximum temperature you can reach depends a lot on the ambient temperature.

My intention is that the air should circulate within the box and use as little as possible air from the outside. You can't really tell from the picture, but there are two holes in the top. One for the fan to take the air from the box and then deliver it to the other hole. So the air flow should be over the mold with the laminate...round and around...

I hit 76°C yesterday! I think I have some improvements today...going for 80...

There!


Now, cutting out material for the next ski and press it in 80°C!!

(I can reach higher, but the rubber don't like it.....I hacked the thermostat.. )

Result !!!

btw, what kind of heater is that? how much power does it need?

Its a fan(Tangentiallüfter) with a heater element in front of it:

The heater element(Heizvorsatz) is marked 2000W and has a thermal fuse at +120°C.
I moved the thermostat a little bit to the side to simulate 80°C
Residue work:
I need to work a little more on the isolation. Replace the thermostat and timer(it doesn't work).