Yes we do......

Uhmmmmm- there's a bunch of ways to figure it. You can predict on weight of cloth vs weight of resin and figure a 30/70 cloth/resin by weight ratio for hand lamination plus what slops over and is wasted.You could go from other uses, what have ya.

But the easy way might be this. You'll be finishing up with a panel 8" x 10" x however thick - lets say 1/4". Call it 25 cm x 25 cm x 0.6cm, if you're gonna go to real units. Okay: calculator time. If I can remember where I put it.

You wind up with 375 cubic centimeters, or 375 ml for the volume of the whole shebang. Figure you'll squeegee off some in the process of laminating plus you'll have some waste, but the cloth itself will have some volume too, so around 375 ml of resin should be a pretty good guess, including waste.

Now, back to the orriginal question:

*HOW MUCH / how many litres of resin do i need for 65 metres of 6 and 4oz cloth*

Okay, if you're gonna be doing it up as X number of fin panels of a given width, length and thickness, well, figure the volume and pretty much equate the volume of the finished panel to the volume of resin.

If you're not..... okay, a quick and dirty weight/weight thing. Figure 70% resin to 30% cloth, by weight. 50/50 is ideal, but hand lamination plus waste, 70/30 ain't bad. Mixing 4 oz and 6 oz cloth evenly, average it to 5. Cloth weight is by the square yard, so we'll call it a square meter times ~0.8 ( 36"/ 39.37", squared )

Awright, weight of 65 meters of 1 meter wide 5 oz cloth goes to ( very roughly ) 5/4 ( or 1/0.8) times 5 times 65 or 25/4 oz times 65 or pretty near 400 ounces. 400 / X = 30/70 . A little algebra: 400 * 70/30 = X and then it spits out 933.3333 ( goes on forever) ounces of resin by weight. 58 1/3 lbs of resin. Specific gravity of polyester resin is around 1.1 kg/liter or 1 liter/1.1 kg, or good enough to go on. I love real units. Cubic inches per gallon is a pain, I'm here to tell ya.

Conversion time. 58 1/3 is about equal to 26.51 kg. Not done yet, multiply by the specific gravity (1 liter/1.1 kg )and ya get 24.1 liters, near enough.

Cloth narrower or wider than 1 meter? Okay, use that instead of 1 meter in the equation. Length/36" * width/36" * cloth weight per square yard, do the math tricks I did above and there you are.

Sammy's answer of ~30 quarts is pretty good, by the way. A quart is on the order of 0.9 liters, so calling it 27 liters or so is maybe a number I'd go with, especially if you were for some reason laying it all up in one shot. Better to have too much and not neeed it than too little.

Hope that's of help... and Sammy, its getting to be time for a few beers....

doc...

Note- edited later as something occurred to me: if you're laminating that 65 meters of cloth onto foam or something porous, go with the 1.25 quarts/~1.2 liters per 2 square yards number or even some more, as the resin needed will necessarily go up 'cos of the amount needed to get into the foam or wood or whatever.

doc...