Boat Building Forum

Find advice on all aspects of building your own kayak, canoe or any lightweight boats

Re: Lets settle it
By:Rob Cochrane
Date: 10/20/1998, 7:09 am
In Response To: Lets settle it (Jon K.)

> I have an idea to help settle this long arguement.

> There is an Instron testing machine (static loads to 30,000 lbs) at work
> that I can use. We have several three-point beam bending fixtures and a
> whole R&D lab to make sure the tests are done right. If someone will
> make the coupons, I will test them.

> There are other tests that may be performed with the machine. ASTM
> tension, compression, climbing drum peel, etc., but the three-point is
> probably the most suitable. I am open to any suggestions on tests to be
> performed and the matrix of coupons to test.

> Anyone interested?

Hi All and Sundry

This subject has now grown haid and a beard and a whole whak of other things.

The tests have all been done at many Varsities and material testing stations world wide. In South Africa alone the CSIR, Wits and Stellenbosh have all done extensive testing.

I when working for a R&D operation did extensive testing with wood core and glass carbon kevlar and a mix of them to distruction in 3 point peel sheer etc. etc.

In 99% of tests the failue is of the surface long before the wood fails. When flex is a significant factor then one finds that the core fails before the surface. Now with a Kayak flex is a factor and the thinner you make your total matrix the more likely is the core to fail. My recomendation: use 6mm .25" core material and high quality 6 oz cloth and you are safe. It will handle the occasional rock.

But if someone wants to play on the rocks then build a kevlar/ Carbon nomex or aluminium core kayak.

OR a tupperware boat.


Messages In This Thread

Lets settle it
Jon K. -- 10/20/1998, 1:06 am
Re: Lets settle it
Nick Schade -- 10/21/1998, 2:26 pm
Re: Lets settle it
Rob Cochrane -- 10/20/1998, 7:09 am