Powdercow, Titebond II should be just fine. I have used both Titebond II and Titebond original for making cores, and either one works really well. I think someone above mentioned it, but I really can't tell much difference between the two.
Really though, if your ski is well constructed with tip spacers, the only way for water to get to the core is if the ski has some major delamination signalling much greater problems in your ski build.
Lamination + tipspacers + rivets
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i too use titebond II in cores and dont see the need to use up my resin. if the core ever splits, it never splits at the seams, the grain of even rock maple seems to be weaker than the wood glue. also, i have to agree on the earlier mention of Resin Research. I recently switched to this from a Shopman resin because we needed the clarity and UV protection since our longboards used fiberglass as the topsheet. None of these longboards have shown any yellowing and the resin is far harder, stiffer, and wets out easier than the previous resin. Big step forward for us...and at a better price per gallon. Dynel and other poly weaves is an interesting idea for tip spacers...how many layers do you use? and of what weight fabric (i have only seen 5oz in dynel)?
Y’all are probably right about the titebond being fine. It would take a lot to soak the core enough to cause a delam, and if you did there would be some other serious issues with the ski, but I still like to use epoxy. I works well for me.
The poly and the dynel are both 5 oz plan weave. I’m thinking it will take 6 layers of the poly for 2 MM and I know I get 1/8” buildup with 8 layers of dynel in a wet lay-up, so it should be a bit thinner in the vacuum press . I plan to use poly next to the wood core between the glass but it will be an inch short of the tip. Then leaf some dynel into that a ½”-1’ with added dynel in the last inch. It will make the tip all dynel. Should be very tough. I’ll cut all of the parts to size from fabric that is bias cut (it frays less). Stack it all together and loosely sew it together with fiber glass roving. Wet it out and place it between the 22 oz tri axial glass. All wet out at the same time it will be one piece when done. I’ll have to use a bit more for the thicker tails. I may use fewer layers of poly and alternate one or two 22 oz. tri-axe layers as well since the poly is not very stiff on its own. I’m going to have to try a couple of variations to see what will work best. I’m a bit concerned about weight on this setup as well , but it is only the last few cm of the ski…
Hafte
The poly and the dynel are both 5 oz plan weave. I’m thinking it will take 6 layers of the poly for 2 MM and I know I get 1/8” buildup with 8 layers of dynel in a wet lay-up, so it should be a bit thinner in the vacuum press . I plan to use poly next to the wood core between the glass but it will be an inch short of the tip. Then leaf some dynel into that a ½”-1’ with added dynel in the last inch. It will make the tip all dynel. Should be very tough. I’ll cut all of the parts to size from fabric that is bias cut (it frays less). Stack it all together and loosely sew it together with fiber glass roving. Wet it out and place it between the 22 oz tri axial glass. All wet out at the same time it will be one piece when done. I’ll have to use a bit more for the thicker tails. I may use fewer layers of poly and alternate one or two 22 oz. tri-axe layers as well since the poly is not very stiff on its own. I’m going to have to try a couple of variations to see what will work best. I’m a bit concerned about weight on this setup as well , but it is only the last few cm of the ski…
Hafte
i like that...you actually stitch with glass strands? impressive. i would think that if you pre-molded the poly tips on the ski mold with a silicone topcap (silicone caulking mixed with glycerine will mold nicely) it would make the final layup easier, and less likely to shift. you could even mold the dynel between two layers of peel ply to improve later adhesion. i wouldnt think that the dynel molded piece would be that heavy...it should only end up 30 to 40 percent resin. UHMW isnt exactly lightweight either. i might just try this method if my vacuum bag cant bend the wood tips (they are 2mm thick, but 1/3 of the strips are rock maple). for now i dont see the need to use a tip spacer, i imagine that a good swatch of 4X4 carbon will provide all the impact protection i need.
HA HA not really. Its just needle and thread basically. I use a sock darning needle (its dull) and loose warp or fill strand from a piece of scrap glass or poly. Pretty low tech. It doesn’t need to be fancy.
I thought about making a mold, but that’s one more tool to make. And I figured the chemical bond would be stronger. Shifting in the press is part of the reason for stitching the layers together. I’m hoping with the tip parts between two layer of glass and most of the air worked out the poly and dynel will not shift too easily. I figured that forcing the wood into the tip with a vacuum would present problems. I’m going to bend the edges around part of the tip and also try to get them pre bent into the form in an effort to make the lay up easier, and create less problems with alignment.
Hafte
I thought about making a mold, but that’s one more tool to make. And I figured the chemical bond would be stronger. Shifting in the press is part of the reason for stitching the layers together. I’m hoping with the tip parts between two layer of glass and most of the air worked out the poly and dynel will not shift too easily. I figured that forcing the wood into the tip with a vacuum would present problems. I’m going to bend the edges around part of the tip and also try to get them pre bent into the form in an effort to make the lay up easier, and create less problems with alignment.
Hafte