Pre-treating paulownia or balsa core

[vinman]

I'm pretty stoked on how well this set came out with the new core material. I'm not really sure that I even needed to pre-seal such a small amount of paulownia. For the next set I'm going with no seal to see what it does.

It won't be a direct comparison because it is going in a much bigger ski, 188 cm 140/112/125 swallow tail. The expectation for lightness in this ski is not as great since it is pretty big, only to cut a bit of weight so it isn't sooooo heavy due to its size. But based on this last set I'd say I can get this ski into the 4.5-4.75 lbs range.

[pmg]

I will be in for some Balsa lightweight touring skis within the next 3 weeks. I shared exactly the same idea. After poeple here did pre-seal, I will go for it, too and publish my findings. I have a very thin epoxy though, and the idea with the wood glue seems sensible, too.

Did someone ever try sealing balsa/paulownia using wood glue?

[mammuth]

Balsa oder Bcomp Core?

[pmg]

Hi,

BComp bcore 200.

Its starting to snow outside just now

[vinman]

After layup maybe 10 pair with paulownia stingers, I don’t really feel that pre-treatment is necessary.

If the paulownia soaks up some resin, I don’t the ink that would be bad since it is so soft. The resin will toughen the paulownia.

If you are doing a full paulownia core with only a hardwood
Mounting zone, then you might want to add something like a Kevlar layer or innnegra layer to increase the impact resistance.

My cores use only 2 stringers of paulownia in the range of 10-15mm wide depending on how ouch weight I’m looking to cut. With stringers like this a free ride ski in the range of 180cm with a waist of around 105mm the weight would be between 4 lbs and 4 lbs 6 oz range per ski.

[Lerio]

We have done some test on the subject using vertically laminated balsa, the sealed laminate was actualy heavier than the not sealed one and a little bit more prone to delamination.

[pmg]

Thanks for all the feedback, will go without pre-treating.

Another question came up: How much extra resin did you put on the fabric to get a sufficient bond with the balsa? I calculated that a layer of fabric (one below core, one above) will take up 85g of resin. I would add 25g = 110g per layer to have some extra resin to go into the balsa.
What do you think about this calculation? Too much, too little?

Thanks & regards
Philipp