# a question for 'Doc' and other technically minded people here ...

...hi Doc ! [I hope you still come here , or i guess i'll be waiting a LONG time for a response ?!]

q :

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

[a metre = 39"]

sorry , i can't remember how many litres in a "quart" [or is it vice versa ??]

i ask this question , because i'm trying to work out quantities / bulk versus a fin panel done "here and there" ....

as a rough guide ,

to make  an  8 x 10" fin panel , doing six laminations [ with a MAXIMUM  of 6 layers of 4 and 6oz cloth at a time] , i use between 300 to 420 mls [less than half a litre ] per large panel

because my panels vary in size [depending on offcuts sizes] , it does my head in trying to work it out .... i'm a "simple ben" ,  at times !!

anyways Doc [? and others ? ] .....  many thanks in advance for your help !

cheers !

ben

Hi Ben -

Rough figures....

A square meter is pretty close to a square yard which is what cloth weight is based upon.  I.E. 6 ounces per square yard.  Often the actual weight of the cloth is a bit less.

A liter is pretty close to a quart.

Resin (water) weighs around 8.5 lbs/gallon.

I'm not sure by your post if your cloth amount is 65 meters of 6 oz, 65 meteres of 4 ounce or a blend of each.  Assuming a blend, estimate on the high side to allow for waste and the difference between meters and yards.  65 X 6 = 390 ounces divided by 16 (16 ounces per pound) = 24.5 lbs divided by 8.5 (lbs per gallon)  equals roughly 3 gallons for a 1:1 ratio.

A resin to cloth ratio might be used to more accurately calculate the total amount of resin needed.  Since you are likely not getting a 1:1 ration in your laminated panels and since resin often is discounted when you buy a 5 gallon bucket, maybe go for 5 gallons?   You might have some left over but it will still be cheaper than buying 4 individual gallons plus quarts or liters.

Just lay up your panels and cut them later.  Shelf life of resin is about one year.  Use left over resin for fin plug installs and ding repairs.

Hope that helps.

Here ya go Chip

1 liter = 1.0567 qts

1 meter =  1.0936 yds.

65 meters = 71.084 yards

A typical shortboard, roughly 6 ft in length, takes about 1.25 qts per side to laminate with 6 oz cloth. That’s equal to approximately 1.33 sq yds. (2’x6’)

Ballpark estimate… I’d figure 1.25 qts for every 2 sq yds of 6oz, and 1 qt per 2 sq yds of 4oz.

Doc might be more precise with this stuff. I’ll try to contact him. We keep in touch.

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...

great stuff thank you very much guys

yep ,

doc , GREAT to see you here and here from you !!

my panels [from offcuts at the moment wound up being 6x8" [x5]

8x10" [x3]

5x7" [x8]

4x6" [x3]

…that’s SO FAR…

I still have about an equal amount of cloth left …

yes i think buying in bulk WILL be the way to go , as i figure it WILL be a few weeks work ahead

thanks again for your help ,

it’s not often i ask a “technical” question ,

and it’s great to know that people here with experience [ as opposed to worthless opinions !] so willingly answer

cheers

``````ben
``````

p.s. - i miss our skype conversations , ‘Doc’… they were fun , we could amuse each other for ages with our accents and banter eh ? hahahhh…