: Hi All,
: My thanks to everyone who commented on my prevous epoxy problem.
: Now that Ive decided to remove the poorly laid glass from the
: boat, Ive been exploring suppliers for the replacement glass
: cloth. Ive stumbled across a wee problem.
: I know Im trying to find 4 oz (115g)deck and 6oz hull, fiberglass
: cloth, but I now see there are several types. What is the best
: for covering the boat, woven roving, plain weave. What is the
: most commonly used cloth ? and whats the difference?

: Sorry if it seems like a stupid question but having made a mess
: first time round Id like to get it right now :-)

: Paul

Good day Paul,

Woven Roving is usually a thick mat and usually offered in very heavy weights like 20 ounce. It is used mostly for thick layups. It's loosely woven of thick threads. I use woven roving by pulling the strands apart into bundles of loose thread when I need to fill a gap, support a fin or skeg, or other times I need to strengthen a bond. Other than that it's more for building "big boats." It takes tons of resin to fill. Usually you lay up woven roving for structure in glass layups and then finish with a finer outer layer if you are doing an all-glass boat.

S Glass was developed originally by Corning for military applications and is stronger than E glass. It is a biaxial weave, tighter and stronger. Also the thread compound itself is different and overall you will find a 20% to 30% greater strength with the same weight S glass versus E glass. (S being stronger)

You will find E Glass a little more forgiving as far as being able to flex into corners and over curvatures, but the difference in my opinion doesn't outweigh the advantage of S Glass in strength.

All that said, my recommendation is to go with the Raka 3.25 ounce and double-layer it, doing two glassings. The 3.25 ounce, by their claim and verified by me weighing surfboards that I build with it, once wet out is not much different from just the epoxy alone. The glass is thin enough and the weave tight enough that it does not absorb much resin. Two layers of this stuff will be as strong as 9 ounce cloth, but as light as a layer of 6 ounce.

A thing to remember is that the weight is the weight of the cloth itself. The cloth when fully saturated could weigh more or less depending on the tightness of the weave, and the. type of fibers in the cloth. I remember buying some cloth locally and the guy at the chandlery didn't know the weight of the cloth they sold. He said, "What's the big difference, six ounce, nine ounce... three ounces- big deal." I explained to him that it's not the weight of the cloth, but rather the resin it absorbs that makes it so heavy. A 6 ounce cloth will generally absorb a lot less than a 9 ounce. The difference will be pounds, not ounces, over a whole boat. Also a tighter weave will take less resin to wet out than a loose weave. There are always exceptions to the rules, but it's a rule of thumb

I highly recommend Raka.com for your glass. I once ordered 30 yards from them of 3.25 ounce. They somehow sent me 20 ounce by mistake. I called and told them and they said "just keep that, and we will send you another roll of what you ordered." I insisted that they at least let me pay shipping, as they were giving me free of charge about $400 worth of cloth! Customer for life. I will never ever order from anyone else due to the service, selection, and knowledge of the product. They are in the US but they do ship international. It may be better for you to find something local due to shipping costs. I think you mentioned you are in the UK.

Raka also has a very cost-effective resin that gets excellent feedback and did very well in One Ocean Kayaks' long-term test. I actually have not tried it because I live on an island and the only thing we can get on island is West System. I don't want to be half-way through a project (and I do a lot of glassing projects, so I use a lot of glass) and have to order more and wait for delivery. Also it always seems when I start one project I always have some West System left over so I end up going with West System. I absolutley love the West 207 clear and highly recommend it. It's just more expensive. No issues at all with quality. I have abused it, exposed it to UV, and basically tortured it and it holds up amazingly well.

Best of luck!

Malcolm