4 & 6 oz. fiberglass cloth

[Doug Canada]

Other than 2 oz. what are the differences between the 4 & 6 oz. fiberglass cloth?

Which is one is the tighter weave?
Which one takes more epoxy?
I assume that the 6 oz. cloth is denser and thus stronger?

Any websites out there concerning this?

Thanks,
Doug

[Steve Miller]

6 oz per yard vs 4 oz per yard. The 6 ounce is a bit thicker and heavier. It will take more epoxy to wet out and fill. I am not sure 6 oz cloth is any denser or tighter weave but the threads are bigger if that makes sense. Sort of like denim vs t-shirt material maybe.

It will also require care to really get it wet out properly if you are going to bright finish the area (varnish). I used 6 oz to do the deck on the kayak I built for my daughter since I wanted the boat to be kid bang and dent resistant. Took a lot of goo to wet out but turned out fine. No glass visible. 4 oz would have been fine in hind site.

[ 02-19-2005, 03:07 PM: Message edited by: Steve Miller ]

[ssor]

I recently bought some 4.3 oz fiberglass on ebay. The weave is about the same appearance as oxford shirt cloth. 6 oz cloth looks like burlap by comparison. In test panels the 4.3 oz needed less epoxy to completely wet it and fill the weave. Two plies on each side of a 4"x10" Corecell panel yielded test pieces that were very nearly the same in bending strength and deflection. The 6 oz. material will require much more filler to yield a smooth surface.

[George Roberts]

Doug Canada ---

3 layers of 4oz glass will perform the same and require the same amount of epoxy as 2 layers of 6oz glass.

[JimD]

Doug, why do you ask, pray tell? Inquiring minds want to know :D

[Doug Canada]

JimD,
I've used 6 oz several times now.
But for my up coming solo (Osprey) cedarstrip canoe I want to make it under 40 lbs.
Thinking of ways to shave weight, with as little structural strength loss as possible.

Doug

[ssor]

It really depends on the weave. I have seen satin weave cloth that weighed 36 oz/ yard and just as fine and smooth as wedding gown fabric and I have 24 oz woven roving that is about 6x6 weave and very stiff. shop around for the cloth that will best serve your needs. They even make glass cloth for model airplanes, it is as smooth as a silk neck tie.

[ 02-19-2005, 07:12 PM: Message edited by: ssor ]

[JimD]

Originally posted by Doug Canada:
JimD,
I've used 6 oz several times now.
But for my up coming solo (Osprey) cedarstrip canoe I want to make it under 40 lbs.
Thinking of ways to shave weight, with as little structural strength loss as possible.

DougPossibly someone will come along and say if the designer calls for 6 oz then by golly you'd better stick with 6 oz or risk loss of boat and life, but I am now also considering a stripper kayak I will likely settle for 4 ounce no matter what the plans call for.

[ssor]

If you keep her off the rocks then four ounce should keep the water out but if you treat her carelessly then six ounce will break-up just as well.

[Doug Canada]

I'm planning on placing a football shape piece of 4 oz. fiberglass on the outside bottom of the hull, for the pleasure of meeting a few rocks. As well as a reinforcement strip on the outside stems. I am also thinking of reinforcing the inside, somehow, with overlapping of the cloth.

None of my cedarstrips see many rocks. I have a bit of a reputation concerning that matter.

Doug