JEM Watercraft

Hi,

I received my plan for the Townsend two days ago, thank you very much.

I saw you posted a link about rubber wood plywood, thx, i did the same on Boatdesign forum without much answers...Anyway, i do not have much choice so I'll do with it.

My fiberglass dealer is not giving me the specs of fiberglass tape by weight like 6 ounce per square yard...Cloth tape is available up to 120gr and that is not enough, and have to buy it per 30 m rolls...

Here is a website link and the guys are quite helpful and do speak enough English:
http://www.askn.co.th/web/index.php?opt ... 20&lang=en

Based on other tape and stitch and glue boat designer specs, 0.5mm woven roving fiberglass tape is used.

Is it possible to replace a layer of 0.5mm woven roving fiberglass tape for :

-2 layers of 0.2mm of Cloth E glass tape Unidirectional (Plain Weave, loomstate)
or
-1 layer of 1.6mm of Cloth E glass tape Unidirectional ( Plain Weave, loomstate)
or
-3 layers of 0.18mm woven roving tape

You kindly gave me a formula as do not reduce the thickness of Fg more than 1/5 from specs.

Shall I mix those products?
Unidirectional (lengthwise) may lack tensile strength on seems (or width) but could be ok on the bottom.
Many layers of thin woven roving seems ok to me but is there cons?

If somebody could sort out something of this I would greatly appreciate it.

See you

Thank you

I wouldn't use Woven Roving. It's to be used to build bulk more than strength.

6-ounce e-glass is .0093" thick. .0093" converts to .23 millimeters. 5-ounce is .0076" and coverts to about .2mm thickness. .2mm should get the job done. Problem is the unidirectional aspect.

They don't have .2mm plain weave e-glass that is not unidiractional? Where in the world are you? Is there perhaps another source?

Hi,

I think, I ll give a try to 0.18mm/2" tape woven roving.
The picture that i have shows quite tight weaved textile. And at 0.18mm it would probably get wet enough with epoxy resin.
I would like to double it or triple it.
Where do you think i may/shall double it or triple it (in, out, sides, bottom), please?

Peace

If you're going to double or triple, on the seams on bows stems are the best places.

Hi,

-Brittle epoxy
I received 1/3 to 1/4 ratio epoxy sold in bottles without any brand or informations.
1/3 sets in three hours and 1/4 sets in four hours.

I did a test yesterday with a 1/3 ratio+ sawdust and i find the result very hard and quite brittle (i can break an half inch wide epoxy drop bending it strongly with my thumbs and forefingers).
-From your experiences, would a a 1/4 ratio make the epoxy more "gummy"?
-Is "gummy" better than hard?


Fiberglass cloth
I have only found and bought 200gr fiberglass cloth 0.75*20 meters (and pieces of 0.75*1 meter)
I'm thinking about fiberglassing the whole outside hull (found only 5mm plywood).
-Would it better to apply it lengthwise from the middle then apply the sides (is there any illustrated example that you know of, please) ?

-Or would it be easier to apply the fabric width-wise overlapping the pieces starting from the bow?

-Or maybe stronger applying it diagonally with overlapping (is there any illustrated example that you know of , please)?

-or just the seams (with my hard brittle epoxy)?

I hope not being too annoying


Thank you,
Have a good day