biax

[tunnels]

Originally Posted by Landlubber

"Still wories me even with wax free resin the fact you can hammer a wedge in and split the layers."....you are laminating........whats with this wax free bit, surely you were not using waxed resin during lamination......tell me I have read this wrong.

Hammering a wedge is pretty scientific NOT !! Even using epoxy it will come apart !!!! A little harder to get apart but will still shear.Peel resistance its called
Waxed resin should only be used on the final layer to have a non sticky feel when finished . Throughout the laminate build use non waxed for better bond between layers and less than 24 hours between layers . So when you start keep going till its finished !!. Biaxle has no csm between the layers so is the weak point of the structure ,csm helps with the shear strength !!.
Use woven with Vinylester resin is you best and possibly cheapest choice !!! or simply bight the bullet and use epoxy and your Biaxle !!

[tunnels]

I posted a new artical about making boats lighter this could be interesting for you to read also .
Laying a couple of layers of glass and letting it go hard uses lots a resin in a over all lay up !! there a couple of ways to reduce the amount of resin used , One is to drop your catalyst ratio a little and lay more layers of glass. and at the end lay Peel ply over the top and roll it down to compress the glass layers and bring the resin up throught the peel ply and when its hard tear the peel ply off and the surplus resin with it . in combination these two things make a really good job and noticably make the job better and neater . Peel ply is a way of saving not only resin but time cleaning and sanding and all those kinds a things specially at the end of the job . Time taken laying and rolling neatly gives a finish the is ready for painting or what ever at the end of the job !!
Saves resin weight and saves sanding and cleaning time !!!

[keith66]

Interesting info, the stitched biax we get here uses a strong terylene or polyester thread quite closely sewn so i presume it is less likely to delaminate.
I built an 18ft simulated clinker rowing skiff last year using 50/50 CSM & Biax & saved 20 kgs of resin on what is a small boat, a fairly large percentage weight saving! She was laid up with polyester resin by the way. After some hard use she is standing up well.
Also recently did a repair on a Westerly Konsort class yacht where they had reinforced the bilge keel area with heavy floors, bonded in with a high proportion of Biax, she had had a good bounce on the beach & the floors had all delamininated along the biax layer line.
A lot of builders round here use it extensively to save weight, after reading this i would be more circumspect!

[Steve W]

Keith, im guessing that the floors on that westerly were tabbed in with polyester resin with the Biax which is going to delam at the secondary bond line regardles of what laminate is used, secondary bonding is always better done with epoxy or vinylester but rarely is on production boats. I have seen exactly the same thing where floors and bulkheads broke free on a J35 we repaired which hadnt even hit bottom but was T boned on the race course.
Steve.

[nevilleh]

Sorry for the time getting back to you all, Im 10 miles offshore Iraq with poor internet!

We used to use Cray Valley Encore 30 which was a low styrene resin for a few years. This is the most common boat building resin over here. And was the one on the drawing.

On realising that it was not wax free & the potential delamination problems we changed to a wax free which is actually very uncommon here. I dont know why, probably ignorance between the smaller boat builders & distributors.

We have never had any delamination issues but quite a few others have especially with frames coming off etc, and I presume that this maybe why.

We are exceptionally careful doing grind backs etc for secondary bondings which is a real headache for the dust.

With reference to going epoxy or vinylester, the money just isnt there to do it, the vessels are workboats 10 - 12 metres long in a highly competitive market.

Thanks for your help guys. Neville




"Still wories me even with wax free resin the fact you can hammer a wedge in and split the layers."....you are laminating........whats with this wax free bit, surely you were not using waxed resin during lamination......tell me I have read this wrong