Another First Pair

[Three31]

Like Bill (First Pair) I just recently finished a first pair. After months of gathering supplies, building a press, making cores, messing up the first set of cores I made and getting everything prep'd I finally was ready. About a week and a half ago I told myself I was going to finish getting things together and lay them up. When all was ready and it was finally time to mix the epoxy I looked at everything . . . It didnt seem real. I asked myself, okay, what did I forget? what am I going to mess up? After a few minutes of hesitating looking around checking everything and a praying I wnet for it. All of the time spent preparing, designing, preparing, getting frustrated to the point of never wanting to try building sksi ever again and preparing materials some more payed off when the firts ski came out of the press the way it was supposed to.

See Pics











Some problems I had where:

The aluminum over the heat blanket was too thin and deformed/expanded when heated, and pulled up when pulling the ski out of the mold.

DONT USE PLASTIC FOOD RAP IN A HEATED PRESS, it melts.

the edges are delaming in the tail. Im not sure if it is from not enough pressure at that point, not enough epoxy, epoxy being old, or not mixed well enough.

[Mongo]

Excellent looking first pair!!! Your setup looks really nice and the press looks killer.

Couple of questions for you with regard to your setup and skis:

-What are the dimensions?
-What is the ski composition (Composites, topsheet, graphics, core, etc.)?
-What kind of method did you use for bending your edges and profiling your core?
-Did you use a top pressing sheet between the topsheet and firehose? From the picture it kind of looks like my first pair where the firehose stiching imprinted on the topsheet.
-What were the pressing conditions (temp, pressure, ambient temp, etc.)?
-Do your edges stop short of the end of the ski in the up-tail curvature or go completely to the end?
-What are you plotting for your next pair?

As for the edge delam in the tail, I am assuming the short height end of your mold is the tail. From the picture the hose seems to be a bit more expanded at the tail curvature than the tip. I built my tail sections with the same height as my tip, with a different radius, and I have not had any delam issues. With your existing mold, I think shimming the tail section with additional top mold material to pinch the hose down more would probably solve the problem.

Again, really good looking skis and hopefully you will get to ride them soon. --Geoff

[plywood]

the edges are delaming in the tail. Im not sure if it is from not enough pressure at that point, not enough epoxy, epoxy being old, or not mixed well enough.

it if was old epoxy: your whole skis would delam. so i don`t think this is the reason
not enough pressure: normally this isn`t an issue. but if it is connected with 3...
not enought epoxy: then there are signs of using not enough epoxy. you could see it before trimming the flash. if you didn`t use enough epoxy, there would be some "dry" flash and supposedly no puddles of epoxy in the area of the tail.

so i really think you could find out which of your possible reasons occured.

but i`m bringing up an other one: did you clean the edges properly?


can you give us some more dimensions of the skis? i like the shape and they look well crafted. so congrats on your first pair and welcome to the illustrious circle of the magical skibuilders! i`d say your first attempt was fully successful and worth every hour of work you put in

[Three31]

After I posted I thought about how I didnt clean the edges . . . so that is most likely the reason for the delam. There was most definetly enough epoxy because it came out the sides. Next pair I will clean the edges better. The skis are 110 under foot, 188 with a 35 m radius. because of the small turn up in the tail they have more running legth than a 190 Gotama. I pressed them at 180 deg and 70 - 75 psi for 60 min. the cores are bamboo. Used a vacume router table to profile. the bases are 2000 grade black, got all the materials from snowboardmaterials.com. 1 layer of fiber glass on top and bottom core profile is 12.5 mm underfoot to 2.5 mm (parabolic flex patern as opposet to a linear change). The core runs to the end of the tip and tail. The topsheet is clear over black fabric (actually pin stripe but they didnt show) underneath and a green piece of fabric in the tail.

[plywood]

cleaning the edges is very important. i once sanded the edges, but then just wiped away the dust and didn`t clean them with alcohol - the didn`t delaminate, but the bond to the base was very weak under the edges. when hitting rocks with this skis its very likely to rip out a part of the base material in the area directly under the edges...

bamboo cores, sweet! fully bamboo? vertically laminated? how flexy are they? i suppose relatively stiff?