Ski Builders Forum

I am having a few isues with the bases warping a bit like a banana after/ as the edges have been glued on. Prior to glueing the edges the bases are dead straight. Any tips

keep the temperature stable.

have you tried rough-cutting the base material and letting it sit over night before doing a final cut? i've even went as far as stretching the material back into 'shape'.

the other thing you can try is symmetrically attaching the edges, meaning, attach both edges at the same time: start at one end and gluing both sides and working your way along the length of the base. this way there's essentially the same force, but opposite direction, applied to both sides of the base to minimize warping.

what you mean by a bananna? you mean nose and tail lift a little?

almost ANY temp change will alter your edge tacking job.

best bet is to stay in a room where temp doesnt change much, and do the edging just before your layup.

if it has to wait, tack the rails, work the nose adn tail and prebend them and stuff but hold off on tacking down the nose/tail curves till you're close to layup

doing tucked in edges is way easier too

knightsofnii wrote:what you mean by a bananna? you mean nose and tail lift a little?

http://www.skibuilders.com/gallery/kanana.shtml
http://www.skibuilders.com/phpBB2/viewtopic.php?t=87

I had the same problem on one of my sets (sun dogs). I tried letting the p-tex relax and then rough cutting the bases etc. All that stuff helped but as knightsofnii said tacking the edges on right before layup is really the only good solution (at least the only good one I have come up with)

If your edges are prebent and already have all the tip and/or tail curve they need then tacking them on only takes a few minutes. Don't be afraid of pulling them off and trying again. I've had to do it more than once to get my bases exactly the same.

I also have tried the router vs. razer blade technique. Using a router is superior but I didn't have any problem with a knife. Good Luck

I don't get it. I have done 4 bases through some pretty drastic temperature ranges, and had absolutely no warping. All I did was cut the base oversize (usually with scissors) and let it sit for a few days, and then I cut to final size (with a router) and attached edges. I think one base sat for a month or so in 90 degree heat with edges attached and no warping.

IMHO, if the bases are becoming warped after the edges are attached, you have residual stresses in the edges from not bending them correctly. In other words, you bend the edge close to the base, then force it over and hold it there with glue and clamps. When this relaxes over time, the "memory" in the metal pulls/warps the base.

If the edges are bent correctly, without internal stresses, then as soon as they are attached they should stabilize any movement of the base.

bending them correctly for curve, and for tip/tail upcurve, will also prevent tip/tail delams. you should definitely prebend the base, or the edges will want to pull off the board/ski and be flat

Thanks for all the advice, it has been helpful. My problem is that I have allready cut all my bases (6 pairs) and have glued on the edges - some of them have warped while gluing the edges on (some have warped from 1 to 3mm in the centre, when comparing it to the base template) - Not wanting to start over, if i used theses warped bases will it effect the final outcome of the ski's performance? if so how and to what degree?

If your bases are warped the skis will be too. You don't want skis that can't arc left.

I don't think you will have to start all over again and it will definatly be worth your time try fixing the problem. I am guessing that, like the last guy said, the edges are pulling your base out of symmetry. Popping the edges off will only take a second. The trick to getting the edges back on quickly is a lot of clamps. If you don't have a shop full of spare spring clamps you can make cheap ones with PVC pipe.

There are better instructions than I can write at this link.
http://www.clcboats.com/shoptips/stitch ... lamps.html

The more clams you have the faster it goes.

with reply to knightsofnii - bending them correctly for curve, and for tip/tail upcurve, will also prevent tip/tail delams. you should definitely prebend the base, or the edges will want to pull off the board/ski and be flat.

Where can i find on the website or can some one help me with how we prebend the bases to suit the lay up mould.

thanks Noel and Zara