Top Mold question
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Top Mold question
I know the top mold doesn't need to be exactly fitted because the bladder will compensate for it. How much difference can there be though? If I make a press I'll make an adjustable one and I'd rather not make a different top mold for every different size of ski.
Would a top mold made for say a 170 ski still work for a 165 or 175?
Would a top mold made for say a 170 ski still work for a 165 or 175?
Go skiing
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- Posts: 3
- Joined: Fri Jun 09, 2006 7:53 pm
- Location: Bellingham, Washington
you could use two firehoses, but you shouldnt need to. i have yet to build my own skis, but i have talked to a guy that builds snowboards. he uses 2 fire hoses lade next to eachother. the only firehose i've seen is 5 inches when its fully inflated (the hose is a circle). the firehose lays 8-9 inches when flat. this snowboad friend of mine says he leaves enough room between the molds so that the firehose has about 1.5-2 inches of clearence before he inflates it. if you want to build a pair of skis at the same time, then 2 firehoses is the way to go i think. 1 firehose should be good enough if your pressing one ski at a time unless your making some sort of reverse sidecut mega-fat ski.
Re: Top Mold question
Should be fine. The negative isn't critical.AndrewT wrote:I know the top mold doesn't need to be exactly fitted because the bladder will compensate for it. How much difference can there be though? If I make a press I'll make an adjustable one and I'd rather not make a different top mold for every different size of ski.
Would a top mold made for say a 170 ski still work for a 165 or 175?
Yeah thats a good point. My ski was completely coverd with hose so my negative didnt matter too much. I did a rush job on it and the one ski I have done so far came out fineteam08 wrote:This is only true if you are only using a hose that covers the entire ski (and you are POSITIVE that it is covering the whole ski). If you have a distribution layer (ie cat track) the negative is extremely critical for even pressure.Should be fine. The negative isn't critical.
Hi Andrew,
I'll chime in here. Yes, if you have about 2 inches of space between your top and bottom molds, an inflated 5 inch fire hose bladder has a surface contact area of about 6 1/2 to 7 inches. I also throw in two 8 inch wide layers of 1/8 inch masonite (smooth sides down) between the ski lay-up and the bladder. I used to use an HDPE pressing layer, but it didn't hold up to the heat very well... warped pretty badly. The masonite works well for me. The masonite also helps to insulate the fire hose from the heat of a heated press. My fire hose is only rated to 122F or 50C. A bladder pressure of 50 PSI is a lot of pressure (KA-BOOM), so, I think it's worth while to pay attention to those fire hose temperature limits. Hose-man, what's your take on it?
G-man
I'll chime in here. Yes, if you have about 2 inches of space between your top and bottom molds, an inflated 5 inch fire hose bladder has a surface contact area of about 6 1/2 to 7 inches. I also throw in two 8 inch wide layers of 1/8 inch masonite (smooth sides down) between the ski lay-up and the bladder. I used to use an HDPE pressing layer, but it didn't hold up to the heat very well... warped pretty badly. The masonite works well for me. The masonite also helps to insulate the fire hose from the heat of a heated press. My fire hose is only rated to 122F or 50C. A bladder pressure of 50 PSI is a lot of pressure (KA-BOOM), so, I think it's worth while to pay attention to those fire hose temperature limits. Hose-man, what's your take on it?
G-man