Here's a question (Paul?): I found an internet source for 6.4 oz. fiberglass cloth, specified as "woven roving Grade E". My understanding is that roving cloth is very heavy: 18 or 24 oz. The picture of this cloth looks very much like the flat weave 6 oz. cloth I used on my Weekender. What is this product, and is it suitable for glassing the boat? The price is right!
Dave
Woven roving is a very course fabric. It's made from relatively thick fibers, which are bundled into strands, then woven like cloth. Unlike roving, 'glass cloth is made from quite fine fibers, which its twisted into strands then woven into an "open weave" (basket weave) fabric.
The terms roving and cloth are becoming interchangeable and aren't especially accurate any more. Both are usually open weave fabrics, though roving usually has heavier yarns, making up the strands, which makes it harder to wet out. Some manufactures intentionally mis-lable these products to be different, if confusing to customers.
E-'glass is the most common form of fabric available and one of the lower grades too. This is what you see for sale in West Marine and other typical locations. S-'glass is much stronger. 6 ounce (usually 5.6) E-'glass runs about 12 to 20 cents per inch on a 50" roll. Bateau.com sells 6 ounce cloth on a 50" roll $6.50 a yard (18 cents per inch). Fiberglass Supply sells S-2 cloth 6 ounce off a 30" roll for 24 cents an inch.
Whee did you find this roving and can they tell you what "sizing" is used on the fabric? Some sizing (fabric finish to make it wet out better) isn't epoxy compatible.
Thanks for the input, Paul. The photo I saw suggested the cloth is typical 6 oz. like you might buy at Bateau or West Marine. The seller seemed fairly ignorant about fiberglass in general and referred to me as the "expert" when I questioned him! He did pop a sample in the mail yesterday and I should have it to check out Monday or Tuesday. The price is right: 60" X 50 yds. for $75 plus shipping! Seems too good to be true! But I suppose If they got a bunch of the stuff at a bankruptcy liquidation or estate sale they may be willing to let it go for cheap just to be rid of it. These people are not in the fiberglass business, I don't think.
DaveÂ
Sometimes bad lots of 'glass get out on the market and are resold to unsuspecting builders. I see this type of thing often on Ebay. If the seller doesn't have a clue, this should be a big red flag, as a person without a clue doesn't have to answer questions. Maybe you got lucky, but look closely at the sample, maybe doing a test wet out on some scrap ply to see if the sizing is compatible.
It's a shame that the term roving is being used for cloth, as I really dislike roving for any use. (I know: we called for it in the Vacationer plans, but I would not use it now. Either just sheathe in cloth, and double-up is you think a bit of abrasion resistance is needed, or use bi-ax). Since Paul is right on the button about the use of Bi-ax as a structural fabric in the other current thread discussing fiberglass, I'd suggest people read those comments also.
Xynole is probably a better choice for what our boats need: weather-resitance and minor impact protection. Minor impacts, not adding tons of structure. We're looking for ding-resistance at the dock, keeping an errant floating branch from scraping and gougingâthat sort of thing.
Paul's suggestion about a test lay-up is a good one. I had a bad bit of cloth once and it teaches one about not wanting to do that again.
Mike