need help with glass and resin info/HELP!

[Woodonglass]

Re: need help with glass and resin info/HELP!

Epoxy does not have styrene to break down the CSM fibers and thus will not create the chemical bond that it should. 1700 Biaxial cloth is normally used with epoxy and not 1708. CSM is not usually required when using epoxy. However there are CSM materials that can be used with epoxy but do not yield as strong of a bond as using a lightweight 6 oz cloth. For me, using CSM with epoxy is a waste of expensive Epoxy resin.

 

[oops!]

Re: need help with glass and resin info/HELP!

totally agreed on the above.....

and a standard 17 oz cross stitch is advised with epoxy.....the 1708 with out as much binder can be used with epoxy with very good results.

but we are getting off track here.....

the reason we all suggest 1708 on a polyester resin based project is because it is a fantastic product, both for the low weight high strength aspect, but also for the closer weave better bond aspect of the material.

 

[ncnjeremy]

Re: need help with glass and resin info/HELP!

I used the biax on my transom and alternated layers of chopped strand and woven on the stringers. Like oops said above the woven gives strength in the 90 degrees. The woven is just layers of glass "woven" together. The Chopped Strand is just chopped glass all kinda stuck together. Matted.. The woven will come apart very easy. Just the way its made. Around the edges it is not stitched at all so of coarse there is nothing holding it together. Just your hands being gentle with it. With those two fabrics together make a great bond. A little cheaper then the Biax. It was for me anyways.

But like mentioned above the Biax instead of being just woven together it has another layer crossing the 90 degree to make it stronger in more directions. Also it has a stitching on it to hold it all together, cause it also has a layer of chopped strand on the back of it. Really good stuff but pricey. I would suggest to use the biax anywhere you need strength in several directions (like the transom) I chose to use it on mine and I also used it on the knees attaching the transom to the stringers.

 

[ncnjeremy]

Re: need help with glass and resin info/HELP!

Im not sure how necessary it way, but when building my transom I laid a layer of biax on the inner skin then laid the 1st 3/4 inch plywood. After I laid another layer of biax with another 3/4 inch plywood during curing I clamped it all together. Then a layer of csm attaching the transom/knees/stringers. Then a final layer of biax over the knees and transom. Now I believe that it will last a while!