xynole installation questions

[BDysart]

I'm re-decking my Chris 42 with marine ply and Xynole, with expoxy resin.
A couple of qestions. What's the best way of joining the fabric so the joints don't show and still retain strength. Secondly, There are areas I would like to come out smooth (as opposed the canvas-like finish of the xynole). These would be where I want to bed hardware, such as toe rails, cleats and a hatch. Does anybody know the best way to do this. I was thinking perhaps of ending the Xynole at the edge of the smooth area and using mat on the smooth area. Any other ideas?
Thanks for any help.

[paladin]

Drape the xynole fabric over the hull after the hull is finished to your satisfaction....stretch it smooth and tight, secure with masking tape. Roll epoxy on with a nap roller (do not use polyester resin, do not use a cheap roller, the epoxy will dissolve it). If you are intending a single layer of Xynole, you may need 3 coats of resin. M.A.S. resin works well as it's lower in viscosity than other resins. Start fron the center and work toward the edges, wetting out the fabric but not so much resin to make it pool. Recoat while still tacky. Finish with fillers as desired...paint.

[RodB]

Secondly, There are areas I would like to come out smooth (as opposed the canvas-like finish of the xynole). These would be where I want to bed hardware, such as toe rails, cleats and a hatch. Does anybody know the best way to do this. I was thinking perhaps of ending the Xynole at the edge of the smooth area and using mat on the smooth area. Any other ideas?


On getting a smooth area to bed hardware... you can let the textured xynole fabric cure till just dry to touch... and tape off a section that you want to be smooth...and apply a couple of coats of epoxy with a roller cut in half...and tip with a foam 3' BRUSH. This will give you are hard line where the additional epoxy is applied, but the additional coats will fill the weave and become very smooth if you apply enough epoxy coats. If taped off smartly...it could look pretty cool

RodB.

[BDysart]

"On getting a smooth area to bed hardware... you can let the textured xynole fabric cure till just dry to touch... and tape off a section that you want to be smooth...and apply a couple of coats of epoxy with a roller cut in half...and tip with a foam 3' BRUSH. This will give you are hard line where the additional epoxy is applied, but the additional coats will fill the weave and become very smooth if you apply enough epoxy coats. If taped off smartly...it could look pretty cool"


Have you tried this method? I'm wondering about the line at the tape edge. It might be kind of messy there?

Also, I need to figure out how to make the joints in the fabric. As it is 60 inches wide, I will need to have some joints. I know with matt I would overlay the two pieces and then sand down the joint but I'm wondering, with the extra thickness of the xynole, plus the desired canvas-look, whether that would work.

[Tom Lathrop]

"
Also, I need to figure out how to make the joints in the fabric. As it is 60 inches wide, I will need to have some joints. I know with matt I would overlay the two pieces and then sand down the joint but I'm wondering, with the extra thickness of the xynole, plus the desired canvas-look, whether that would work.

Sanding an overlaid joint in Xynole is an exercise in futility. The stuff does not like to be sanded. That is one of its best qualities since it creates outstanding abrasion resistance. One method of joining Xynole is the same as fiberglass. Overlay the joint by an inch or so and wait until it gets just a little rubbery, but don't wait too long. Cut through both layers with a razor knife and peel away both overlapped sections, one at a time. Then work the two cut edges to meet each other. It's a little tricky but can result in a very tight and almost invisible edge.

[mcdenny]

What Tom said about the joint.

I'd suspect that tape on the "canvas look" surface would leak resin. How about just using bedding compound under the parts to be screwed down on the xynole? Easiest solution plus that's how it would have been done with real canvas.

[RodB]

Have you tried this method? I'm wondering about the line at the tape edge. It might be kind of messy there?

No...I have not tried it...but I sure would try it on an experimental basis first. You are right, taping the textured surface might not allow a smooth line where the tape is... but if you press the tape down really firmly... It should be ok.

Why not just leave everything textured...except for the outline of the hardware to be installed... It would be easier and not show lines of demarkation from textured to smooth... I think it would look better.

Just apply enough epoxy to the outline of the hardware to get a smooth surface before bedding and installing the hardware...

RodB

[BDysart]

Thanks all for the input.
I think I will use the overlap method for the joints. Seems to me the timing must be critical. Start too soon and it would be extremely messy making the cuts through the fabric; wait too long and risk not getting a proper bond back to the plywood when done.
Seems to me filling the weave with a bedding compound or filler might be the simplest way to re-bed the hardware.

[Philip Maynard]

But if you cut across both layers you have no fabric strength across the joint. I have not found a way to both keep strength and looks if you want the weave to show. The only way I can think of would be to hide the overlap in a smooth section - maybe you can lay out the joints between non-skid sections.

[Roaminaway]

Remember the purpose of the xynole. It is to provide an abraision resistant waterproof surface that expands and contracts with the wood substrate. A double-cut butt seam does not compromise those properties.

The tensile strength of the xynole is effectively less than that of glass cloth, due the stretch. It is because of the elasticity that xynole is chosen. If tensile strength is the goal, either a glass cloth should be chosen, or a multi-layer lamination of xynole should be used.

Because the xynole expands and contracts with the substrate, the butt seam is not put under stress.