2 questions about press modifications

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sleepycp
Posts: 22
Joined: Wed Oct 11, 2006 3:39 pm

2 questions about press modifications

Post by sleepycp »

First off, thanks to all who maintain this site and post here regularly because I have used much of your knowledge to complete and ski my first pair of garage builts last week. I was so stoked. When I am not traveling all over I will post pics and a TR of the whole process up to now.

But I learned I want to improve my press, specifically to add heat and improve my top mold. I have an adjustable bottom mold, which will handle lengths from 191 to 165 cm, and I am curious how you handle getting heat evenly to the tip and tail area of the layup while accommodating different lengths. I haven't really noticed that anyone talked about having to use different lengths of aluminum sheet for different length skis, or specially heating the tip and tail areas. I also want to know if you lay up directly on the aluminum sheet. I laid up on a piece of melamine coated Masonite covered with packing tape and sprayed with silicone. I used the same for the pressing sheet on the top of the skis, and wrapped the whole deal in painters plastic. That worked great.


The other thing is I was thinking of rebuilding my top mold as an exact mirror of my bottom mold, adjustability and all, rather than just as a space filler. Can I press the two molds together, with the layup in between, and the fire hose between the top mold and the press frame? I went with the top mold on top of the hose and some Masonite sheets to even out the pressure on top of the layup. That worked pretty good, but not quite perfect.

I look forward to any advice, and to more excellent homebrew fun. And to next Winter!
Idris
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Location: Chamonix, France
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Post by Idris »

sleepycp - The Press at PM gear used aluminum plate to protect the heat pad over and adjustable mold. We then had a further top and bottom aluminum plate which was covered in mold release (wax) to lay up on/ cover the layup.

Our top mold was more a space filler while the bottom mold was exact. the fire hose made up all the discrepencies in the toop mold.
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sleepycp
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Post by sleepycp »

Idris -
So the heater sits under a piece of aluminum on the bottom mold, which is of a fixed length and doesn't follow the tip and tail curvature, I gather. The skis are then pressed on another sheet of aluminum, on top of that, and THAT sheet follows all the curves of the mold. You rely upon conduction to get the heat to all the areas being pressed. Yes?
Idris
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Location: Chamonix, France
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Post by Idris »

sleepycp wrote:Idris -
So the heater sits under a piece of aluminum on the bottom mold, which is of a fixed length and doesn't follow the tip and tail curvature, I gather. The skis are then pressed on another sheet of aluminum, on top of that, and THAT sheet follows all the curves of the mold. You rely upon conduction to get the heat to all the areas being pressed. Yes?
You are right about having 2 sheets of aluminum, one to press on and one to guard/shield the heat pad. But both of ours ran the full lenght over both tip and tail curvatures. Our heat pads were actually longer and wider than our skis!
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sleepycp
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Post by sleepycp »

Where did you measure the temperature? On the bottom sheet covering the heaating pads or somewhere else?
Idris
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Post by Idris »

The top and bottom heat pads are controlled independently. The Temperature probe wire (thermocouple?) was between the heat pad and it's protective aluminum sheet - Giving heat pd temp not ski temp. But as near to the ski whist being protected
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jhstroup
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Post by jhstroup »

How thick were the aluminum sheets you were using?
Idris
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Post by Idris »

jhstroup wrote:How thick were the aluminum sheets you were using?
Not sure, they varied....up to 4 times as thik sometimes...depends on the mold or the platten...Thicker toakes longer to heat, but the eventuall temp is the same.
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