Mix Proportions for 2-Part Urea Formaldehyde Glue

Ten-to-one mix ratios are easy to figure with decimals, while 7-to-1 ratios are easy to mix using eighths of an ounce. February 7, 2009

I am new to vacuum pressing and Unibond 800 two part glue. I was recommended to use a 10:1 mix ratio. I have a scale and not sure how to mix it. If I have 3.5 lb of resin how much hardener powder do I add and is it that critical? How do I do the math to figure out how much hardener to add?

Forum Responses
(Adhesive Forum)
From contributor J:
10:1 is an easy one to do in your head, which is as good a reason as any to use that ratio. The instructions suggest a range of anywhere from 7:1 (fast) to 12:1 (slow). There are 16 oz. in a pound. You've got 3.5 pounds of resin, which is 56 ozs. Move the decimal one digit to the left, and you've got 5.6 ozs, which is the amount of catalyst you're looking for. 3.5 pounds of resin, by the way, is a whole lot of glue. It seems unlikely that you'd want to catalyze it all at once.

From contributor T:
We use the 800 a lot and the simplest method to use is the 7:1 ratio and a small cheap digital scale. Tare the container and work in ounces. 1/8oz. catalyst to 7/8oz. of powder. Its hard to screw this up. Works like a charm in our shop.

From contributor J:
You could also use PPR. Same properties but you can save some money and get a longer shelf life.