So I'm getting ready to glue up a tri-lam, I use to use urac185 and mix it 2:1. But now I have the unibond 800 and i have scene all kinds of recommendations for mixing. I'm hoping some one who has used it a lot has a simple mix ratio that is tried and proven.
Thanks

I mix 1 grain of hardener to 12 grains of resin by weight.

is that the same ratio you used with Urac, Roy?

Yes

I do like Roy. Use a,grain scale.
I save tuna fish cans to mix in.
I use the original ratio which was 100 to 13
You can vary this a little like Roy it changes the set time slightly is all.

I usually mix about 600 grains of liquid to 78 grains of powder.
For a reflex,deflex  BBO in a youth size bow.

I always went 7 to 1 (by weight) with Urac. Still do, actually as I still am using Urac. provides more than adequate open working time, fills gaps very well, too.

why you mixing it so lean?

I might try it thicker to see if fills in the voids a little better.
I always mixed the 13 to 1 because that is what urac said on the instructions.

That's how I mixed it too Mac, 13 to 1. Unibond can me mixed three ways, each one gives a little different open air drying time. The 12 to 1 is the middle of the road time, but it only takes me 15 minutes to apply the glue and clamp up the bow.

I don't measure anything, just add hardener until I have what I think is the right consistency.

I used to measure everything on a powder scale to the grain. I haven't had any failures with my haphazard mixing method.

There you go certainly proof that the ratio is not critical to success.

I always measured Urac by volume, about 2:1 but its been a while and I don't remember exactly. Never used Unibond.

I mix Unibond 10 to 1 by weight.  After reading all the different responses, there seems to be a lot of leeway in the ratio.  I'd check the instructions on the can, but I'm all out at the moment.  I used Smooth On for my last wood bow glue up.

You know how to read a scale, Greg? I'm impressed..  

fyi, everyone. from the label on my last can of Urac resin; "The average amount of hardener to use is 13 parts to 100 parts of liquid resin by weight" 13 to 100 is the same as 1 to 7.692 (I always went 1 to 7 for a little better gap filling ability). 1 to 12 is very thin on hardener, but maybe it doesn't matter much. from my Unibond instructions sheet:

"Mixing
Unibond 800 blends easily and can be mixed by hand or mechanically.
Always mix the hardener into the resin, and stir until mixture is
smooth. The curing action of Unibond 800 can be increased or
decreased by resin to hardener ratio. A faster set is usually used at a
lower temperature to shorten clamp times and a lower set is used to
provide adequate open assembly time at higher temperatures. DO
NOT EXCEED THESE RATIOS OR PROPER BONDING
CANNOT BE ASSURED.
When possible, it is recommended that Unibond 800 be measured
by weight rather than volume for maximum accuracy.

Mixing Ratios by weight:

fast set - 7 resin to 1 hardener
slow set - 12 resin to 1 hardener"

Jamie, after reading that, I did mix urac 13 to 100. Got confused for a while

that happens to old people sometimes.    

Ah excuse me... Never thought I would see the day I added your name to the thumping list. LMFAO    

well I learned a expensive lesson today, mixed up my unbond, glued up my bow clamped it and stood back quite proud of myself, then later in the day I was getting ready to glue up some wood for a riser when I realized my scale was on grams not grain. So when I glued my bow up I actually had a 12:1 ratio but it was in grams. I thought it looked like a lot of glue. And i'm not gonna lie, I made one heck of a mess. I hope it holds up. Hard lesson learned.

as long as you got it clamped up properly, it should be fine aside from the mess.

aw shucks, when the door is open that wide, I just can't help my self, Roy. who can?    :D

LOL