What's the difference?

[capt-dave]

Can somebody tell me the difference between Fiberglass woven roving and fiberglass cloth tape. I am currently working on the interior seams of my Tideway 14. Drawing #04 says to use 2 layers of 100mm (3.94 inches) wide woven roving tape. I’m having troubles finding woven roving in 4” tape here in Texas. I have found woven roving in rolls usually starting at 12” wide running up to 60” wide but nothing in 4” tape. I did however find plenty of Fiberglass cloth tape (7.5oz) in rolls of 4” wide. I guess I’m having troubles understanding the difference. Can this Fiberglass cloth tape be used as a substitution for the woven roving tape? What is the difference?

Thanks for the help!
-Capt Dave-
Galveston Bay, Texas

[Bob Cleek]

The difference in the weaves affects the absorption and distribution of resin and thereby the structural properties of the finished product.

http://www.indiamart.com/impexinsulation/pcat-gifs/products-small/Image2.jpg

Roving.

http://product-image.tradeindia.com/00242256/b/Fibreglass-Cloth.jpg

Cloth.

http://www.smartmarine.co.nz/images/large/fibreglass%20mat.jpg

Mat.

Tape is just a narrow bolt of fibreglass material, usually with finished selvage on both edges. You can take bolt width material and cut it into strips and, voila!, you got yourself tape. (Although it will tend to fray at the edges unless you handle it carefully.)

[Bill Huson]

could the boat be a UK/AU design? Since the tape width was in mm. If so, maybe the term "roving" is designer local term, such as "kicking strap" on a UK design cat I'm building. Kicking strap = boom vang.

Anyhow, on a 14' boat I wouldn't sweat the details of tapeology. 4" 7.5 ounce tape is good to go. As Mr Cleek mentioned, if you have glass cloth scraps left over, just cut them into 4" strips and slap `em on the seams. If aforementioned seams have curvey parts, cut the srtips at a bias (45 deg) to the weave and they'll travel around the bendy parts better.

[capt-dave]

Thank for the input. “YES”; the design is by Paul Fisher of the Selway-Fisher Design Group and they are in England. I thought that it might be a translation problem. There is never a shortage of things to learn when you’re building a boat. I’m already hard at it this morning moving forward with the 7.5 oz – 4” fiberglass cloth tape that I purchased from the local hardware store.

By the way, you can sneak a peek of my project at:
www.BuildingReunion.com (http://www.buildingreunion.com/)

-Capt Dave-
Galveston Bay, Texas

[JimConlin]

For a boat that size, two layers of 4" tape is probably OK. Stagger them by 1/2" or so.
I've never seen narrow woven roving tape. Unless it had a stitched edge, it would be miserable stuff to handle.

[ccx2]

Good question and answers, now, which is stronger, roving or cloth?

[Todd Bradshaw]

Roving is stronger because most of it is much heavier than fiberglass cloth. The most common weight for roving in the US is 24 oz. That's what you see on the inside of most fiberglass boats. If something like that is what the designer actually had in mind, you would probably need three or four layers of most typical fiberglass tapes to get similar tear strength and stiffness. Here is a 5" wide, 18 oz. roving tape.

http://www.fiberglasssite.com/servlet/the-87/WOVEN-ROVING-TAPE-STRIPS/Detail

Roving is pretty stiff, since the yarn bundles woven to make it are pretty big (like 3/16"wide). Trying to get it to lay down into a corner (or over one) such as you might find on a chine seam is probably going to be a real bear. You're not going to be sure that it's going to stay down tight to the wood until the resin starts to harden. For a high-strength seam from a heavy-duty, but more conformable fabric, you might want to switch to a stitched biaxial tape with a mat backing. It would be a lot easier to work with.

http://www.jamestowndistributors.com/userportal/show_product.do?pid=1470&familyName=Fiberglass+Biaxial+Cloth+Tape+-+4+inches+Wide