We use the fluid ounce (16 oz/pint) for volume, e.g. beer.
http://en.wikipedia.org/wiki/Fluid_ounce
We also use ounces (16 oz/lb) for mass/weight as in 6-oz (per square yard) fiberglass cloth.
I work in the chemical industry over here in the U.S. The plant I work in does everything by wieght and we only use grams and Kilograms. But my job is High Tech and my personal workshop is Low Tech.
As a professional, I work with metrics but most of my clients use ounces, pounds and gallons.
Outside the office I use ounces, pounds and gallons.
Stingray, you are highly observant in pointing out my school boy error…I’ve clearly spent too much time in an enclosed room with resin fumes…I did post 500ml…when I actually meant 500gm…I ALWAYS measure epoxy by weight with digital scales to ensure the correct mix…I have seen the effects of another guy’s attempt who got the mix wrong and ended up with an embarassingly soft epoxy eps board…THANKYOU FOR POINTING OUT MY ERROR…and apologies to anyone who previously read my post as it could have led to confusion and a very bad job. Cheers
Rich
www.thirdshade.com
The effects of a slightly off mix are not always observable.
to little hardener: soft epoxy
to much hardener: brittle epoxy, faster yellowing
But is gradual, it is not succes or fail.
It is in your own interest to mix as accurately as possible, but your board won’t fail if the mix is slightly off.
If you use 2:1 by weight instead of 100:45, your board won’t fail. But since there always is an error in your mixing, a little “to much hardener” than 2:1 is more “to much hardener” than when you use 100:45.
With epoxy, you should mix as closely as you can. With polyester only the curing time is affected by the amount of catalyst, not the mechanical properties (this is a simplification of the facts, but it is how you should interpret it).
If your board doesn’t break, that’s great! But if it breaks, you will never know if it is because of bad mixing or if the wave was just to powerfull.
At work 50 grams is a really big deal....Mixing up ml with grams is a really big deal. But I'm not at work right now..... and it's not a big deal. I'm just trained to look out for stuff like that.
Greg Loehr is the guy that makes Resin Research. He's a surfer. Greg went through 20 years of crap before his Resin became what it is today....The number one Epoxy Resin used to build surfboards....RR...Surfers are designed into the formula....You can do a "not so good mix" and it will still work. I don't know what the tolerance is....but...mixing by volume has never been a problem in my Lab......If your epoxy resin "yellows"...you are not using the latest RR formula.
We drove around for days with a 9'3" on the roof of the truck.................still looking good........
I totally agree with you.
I’m not saying that you shouldn’t mix by volume. I’m sure it works great, certainly if you mix large amounts.
The point I’m trying to make is: Don’t mix by weight using the 2:1 ratio. That’s just doing it wrong.
I recieved my first RR epoxy this week, I’m very curious for the results. Before I’ve used vosschemie epoxy for surfboards but it yellows quite quick, I’ll keep using it for plug installs since doesn’t cure very exothermal.
Other epoxies I used are high performace epoxies, but thats another category. These guys need to be stored in the freezer and postcuring is a must, if I would have mixed these epoxies by volume, I think the professors would have killed me.
dont get me wrong,,,
I am not knocking anyone when I say,,,,,, what the F is with all this fussing over mixing RR epoxy????
it says on the lable "2 to 1 by volume" nothing else...
why is there even a discussion about it?
this stuff is so forgiving that I can fricken eyeball it in an unmarked paper cup and still it cures just fine.
you guys better stay out of the kitchen or your sure to fuck up dinner.
ahhh! I feel better now,,,, thanks guys
I'm with ken I have mixed RR just by eye and it came out great, no big deal.
Why is it that this place can make something as easy as mixing 2 to 1, so difficult.
It's like the Wave Jet surfboard? How can you make something as easy as surfing and complicate it with all this other crap.
Just mix 2 to 1...that it,................. just 2 to 1. No more, no less........2 to 1. No scales, no Phifster valves, no ball bearings, no 40 wt motor oil.
I like the surform in the picture......gives it street cred.
it's not rocket science
