Evening all,
Just wondered if any of you had come across this stuff before?
http://www.easycomposites.co.uk/Products/Kevlar-Aramid-Others/Black-Diolen-200g-1200mm.aspx
Thought it may have the potential to provide a relatively inexpensive laminate reinforcement to model yacht hulls/decks etc.
Although the spec says that it’s not as strong as kevlar it may have benefits in carbonfibre layups or standard glass cloth.
Any thoughts?
Regards,
Row
It’s a polyester fibre, and is very elastic. It won’t really do much to stiffen a hull as the resin medium will fracture before the fibres reach a point where they will do anything aside from hold the broken pieces together. Then again, the fibres in a thin, single-skinned laminate such as found in model yachts don’t do much, regardless. On the bright side it should drape beautifully and that twill weave is a beauty!
Twill weave is not appropriate for hand layup as this weave soaks up a lot of resin. Twill weaves should be vacuum bagged or press molded (as in a keel mold). Plain weave cloths are better for hand layup of hulls.
Model yachts do not see the abrasion or impact of full size boats. Carbon or Kevlar fabrics are pretty cheap in our applications as we don’t use much, not so in Kayaks or Canoes with a lot of area to cover. The strength of these materials in the typical thin shells of model yachts make polyester based cloth in racing yachts undesirable. For most boats a meter long and under the cheaper alternative to the exotic fibers is structural fiberglass.
Thanks for the replies and advice. Some time last year I came across a website that outlined the build methods used by the top commercial Marblehead molders and I recall that one of the hulls was a carbon / kevlar laminate. Having seen the diolen recently appear on one of my suppliers sites, I wondered if it would have an application in our builds. I guess not, although for a cosmetic look-alike carbon skin it may have merit.
I’m intrigued by the comment that twill weave isn’t really suitable for hand layup. I was under the impression that, as a rule of thumb, whatever the overall mass of the fabric was (for woven fabrics) gave the weight of resin to be used, therefore giving a 50:50 ratio of resin to cloth. Obviously vacuum bagging allows a higher ratio of cloth to be achieved in the final laminate, but in my relative inexperience I’ve found that it makes little or no difference whether I use a plain weave or twill, the overall weights come out the same, the only major difference being that the twills drape so much better, especially when the hull shapes include very apparent transitions from convex to concave shapes.
Regards,
Row
Not forget that this material is also rather heavy to be used for models
ClaudioD
When you spend hundreds of hours on your boat why go cheap on material? Get the real stuff.
KP
Just to point out - I would consider the biggest variation in the resin content of the fibre is down to the skill and ability of the person performing the layup, not the weave of the fabric!
My assumption was that the individual doing the layup was competent in creating a competitive weight hull, so the comparison of fabric weaves relative to the method of layup info omitted the variable mentioned above. The level of difficulty of various layup systems is another subject entirely.
In single-skin construction at the model scale especially, the qualities of the reinforcement fabric (weave or content) are virtually insignicant. I use rice paper, personally.
I’m intrigued! Got any pictures etc?
Regards,
Row
Then all things bein equal there should be no difference between twill and plain weave…
We have purchased a roll of Diolen for the purpose of chafe protection for our products.
I want to share the results so people can make an informed decision.
It handles nicely, and has a similar, but not identical 2/2 Twill finish to Carbon.
Cuts well with normal shears too.
My initial test revealed a material that required a immense amount of resin to ‘wet out’ correctly.
For a hand layup, with peel-ply required 283g of resin for 156g/0.7m2 of cloth!
That is a huge amount.
Vacuum consolidation did nothing to improve matters, if the resin content was reduced, the next issue was porosity and a poor surface finish.
Also the when the cured ply’s were flexed the resin would separate from the fibre, producing an unsightly crazing, and resulting in loss of structural integrity.
My feeling is that Diolen is unsuitable for the construction of hulls and decks.
Our next plan is to infuse with this material, and have some impregnated to use as Pre-Preg to see if a high quality result can be achieved.
Cheers, Jim