I hope to be doing my first layup sunday AM with my son. I have concerns that I planed the core too thin. The core is all poplar, 3/4" strips and planed down to 2mm. I am using tip and tail spacers. The core seems very soft. So my question is this. Would it be advisable to double up on the glass (triaxial) on the top or the bottom? I have the belief that this first ski is a trial and will be okay with the learning curve, However I would like to have one that works and is strong. Any insight to this would be great!
Okay another question. The sidewalls have been sanded and I plan on flame treating them to enhance the bond. Should the sidewall be cleaned then treated or treated then cleaned? Thanks for the help.
rockaukum
Multiple glass layers??
Moderators: Head Monkey, kelvin, bigKam, skidesmond, chrismp
Hey.
Whats your current lay up?
I recently did a 1m test just to see the difference between carbon and glass. the glass test i used 3 layers ontop of the core and found that the extra layers did not make it that much stiffer. So adding a extra layer of glass should be ok in your case. if you would like 'pop' i found having it under the core is best.
Whats your current lay up?
I recently did a 1m test just to see the difference between carbon and glass. the glass test i used 3 layers ontop of the core and found that the extra layers did not make it that much stiffer. So adding a extra layer of glass should be ok in your case. if you would like 'pop' i found having it under the core is best.
SCHÜSS 2011
At PM Gear we varied the stifness of the skis by adding more glass.
Are you using a heated or room temp press? If it's a heated press, them more glass one one side changes your camber. At room temp dosen't seem to mess thing up the same way, just changes the stiffness.
In a heated press, more glass on top = less camber, More glass on bottom = more camber. The glass contracts more than the wood when cooling hence the affect.
Sidewalls need cleaning then treating, or you remove the treatment?...or at least that the way I did it.....haven't heard of any delams of sidewalls yet from Pat
You could try the layup without the extra glass, and no topsheet/graphics. See how the ski hand flexes. If you need it stiffer add glass when pressing with the topsheet/grahpics. I belive Davide has added extra stiffness to some of his skis this way.
Are you using a heated or room temp press? If it's a heated press, them more glass one one side changes your camber. At room temp dosen't seem to mess thing up the same way, just changes the stiffness.
In a heated press, more glass on top = less camber, More glass on bottom = more camber. The glass contracts more than the wood when cooling hence the affect.
Sidewalls need cleaning then treating, or you remove the treatment?...or at least that the way I did it.....haven't heard of any delams of sidewalls yet from Pat
You could try the layup without the extra glass, and no topsheet/graphics. See how the ski hand flexes. If you need it stiffer add glass when pressing with the topsheet/grahpics. I belive Davide has added extra stiffness to some of his skis this way.
Thanks for the replys. I am just about to head out to the shop for the lay-up. It is 37* and raining. I will be using a pellet stove to heat a small room in the shop for my heat source. Should be a comfortable 80 -90* in the room (Ihope!). I will probably clean then treat however my confusion is the Durasurf material has been treated and we clean prior to layup? and this does not affect the treatment?
The layup will be with a top sheet and no graphics in order to see the effects inside the ski.
Wish me luck!
rockaukum
The layup will be with a top sheet and no graphics in order to see the effects inside the ski.
Wish me luck!
rockaukum
Hi rockaukum,
I tried to reply to your post earlier, but our power went when I was about half way through my reply... too much SNOW I guess!!
So, your first ski is probably curing by now. I hope the lay-up went smootlhy.
Regarding core thickness... 2mm is just about right for the tip and tail thickness. any more than that and it becomes difficult to get the core to conform to the mold without the wood cracking or breaking. I've done with 3mm thickness before, but, I'm pretty sure that I heard the wood breaking as I pressurized the bladder... couldn't really tell after the ski was pressed, though. I think that the cores always feel really soft in their raw state. Even a core with a 12.5 mm waist thickness is pretty flimsy. But, once it's laid up with conventional weight composites, it becomes pretty stiff. How wide is your core? Wide skis should be a little soft anyway... wide skis for flotation in soft snow, and a soft flex to allow the ski to flex into a nice deep, surfy arc. If you do decide to add some additional composite to increase stiffness, I recommend that you keep a log of all of your baseline parameters and what you change in particular lay-ups. I thought I'd be able to remember various changes, only to realize later that I wasn't exactly sure what I'd done differently on this or that ski.
I did a lot of surface treatment dyne level testing on UHMW samples to test whether the surface tension was affected by chemical degreasing. All of the testing I did indicated that the surface treatment/tension is not effected by degreasing with alcohol, acetone, or MEK. This conclusion is also supported by all of the dozens of on-line info sources that I have studied. The general recommendation of the bond experts is to flame treat, degrease, abrade, and degrease again. Regarding soot and carbon deposits on the UHMW after flame treating, there really shouldn't be any if flame treatment is properly carried out.
Looking forward to news regarding the success of your first pressing.
G-man
I tried to reply to your post earlier, but our power went when I was about half way through my reply... too much SNOW I guess!!
So, your first ski is probably curing by now. I hope the lay-up went smootlhy.
Regarding core thickness... 2mm is just about right for the tip and tail thickness. any more than that and it becomes difficult to get the core to conform to the mold without the wood cracking or breaking. I've done with 3mm thickness before, but, I'm pretty sure that I heard the wood breaking as I pressurized the bladder... couldn't really tell after the ski was pressed, though. I think that the cores always feel really soft in their raw state. Even a core with a 12.5 mm waist thickness is pretty flimsy. But, once it's laid up with conventional weight composites, it becomes pretty stiff. How wide is your core? Wide skis should be a little soft anyway... wide skis for flotation in soft snow, and a soft flex to allow the ski to flex into a nice deep, surfy arc. If you do decide to add some additional composite to increase stiffness, I recommend that you keep a log of all of your baseline parameters and what you change in particular lay-ups. I thought I'd be able to remember various changes, only to realize later that I wasn't exactly sure what I'd done differently on this or that ski.
I did a lot of surface treatment dyne level testing on UHMW samples to test whether the surface tension was affected by chemical degreasing. All of the testing I did indicated that the surface treatment/tension is not effected by degreasing with alcohol, acetone, or MEK. This conclusion is also supported by all of the dozens of on-line info sources that I have studied. The general recommendation of the bond experts is to flame treat, degrease, abrade, and degrease again. Regarding soot and carbon deposits on the UHMW after flame treating, there really shouldn't be any if flame treatment is properly carried out.
Looking forward to news regarding the success of your first pressing.
G-man
Well here is the story. The core is 12mm in the center and down to 2mm at the ends. I was very concerned that the core was too soft and as the layup went along I planned on two layers of glass on top of the core. However, I decided for some unknown reason to only use one above and one below the core. In all the excitement I forgot to use the vds and hope that my diligent cleaning and complete wet out of the edge material will hold up. WE pressed at 20+ psi for about one half an hour then bumped to 30 psi then to 40psi. We wheeled the press into the "oven". In the oven we were using a pellet stove to heat the room. The temp started at 65*F. We hung a canvas tarp over the doorway and turned up the heat. Prior to leaving to my other sons basketball game we checked the temp and it was at 80+*F. Things were looking good. We got home from the game (they won by one point!) and checked the set up. The leftover expoxie was hard and the temp was up to 98*F! I left the press under pressure and will do so until the morning. I turned down the stove to keep the room warm until then. In the morning I will release the pressure and leave the skis in the mold until after school pick-up.
What an exciting time it was. I had my son (14) doing the mixing of epoxie and handling of the materials prior to placement. His sonwborad is next! I'm keeping my fingers crossed and will be thinking about the outcome all day while turning up fresh ones on the hill!
rockaukum
What an exciting time it was. I had my son (14) doing the mixing of epoxie and handling of the materials prior to placement. His sonwborad is next! I'm keeping my fingers crossed and will be thinking about the outcome all day while turning up fresh ones on the hill!
rockaukum