Mixing glue and consolidants

[DPS Ammonite]

I would like to dilute a 50% solution of Paraloid B 72 glue to 20% (for a label varnish) and 10% (consolidant). How much solvent, acetone, do I add to create a 20% solution? What is the general formula for quantity x of solvent needed to add to y percent solution to create z percent solution? I realize that if I add 1 part of acetone to 1 part of a 50% solution that I get a 25% solution. 
 

Thanks.
 

 

https://museumservicescorporation.com/products/paraloid-b-72-glue

 

 

Edited Thursday at 08:44 PM by DPS Ammonite

[hadrosauridae]

The dilution is pretty straight forward, but your example is flawed.  If you have a 50% solution (1 part A and 1 part B ) and then add an additional part of A  you get a 33% solution of B, not a 25%.

 

The math is a lot easier if you use a metric scale to make your solutions.  If you have 100 grams of 50% solution, you have 50 grams of plastic. 

You want  X final solution.   

C1 x V1 = C2 x V2 where C1 is starting solution %, V1 is starting volume of solution  C2 is final solution % and V2 is final volume.

 

50 x 100 = 20 x V2

5000 = 20V2

5000/20 = 20V2/20

250 = V2

 

So you add another 150 grams of acetone to take the total to 250 grams.  Then you have a 20% solution.

Edited Thursday at 10:03 PM by hadrosauridae
checking my math

[DPS Ammonite]

15 minutes ago, hadrosauridae said:

The dilution is pretty straight forward, but your example is flawed.  If you have a 50% solution (1 part A and 1 part B ) and then add an additional part of A  you get a 33% solution of B, not a 25%.

If I have 1 liter of a 50% solution and add 1 liter of pure solvent then I should have 2 liters of 25% solution. In your explanation above, if you consider a 50% solution as being 2 units (a plus b) then I want to add 2 units of solvent which should yield a 25% solution.

 

I want to know how many liters of acetone I need to add to a 1 liter of 50% solution to get a 20% solution. The answer should be between 1 and 3 liters.

Edited Thursday at 09:51 PM by DPS Ammonite

[hadrosauridae]

7 minutes ago, DPS Ammonite said:

If I have 1 liter of a 50% solution and add 1 liter of pure solvent then I should have 2 liters of 25% solution.

 

Yes, THAT is correct.  When you say "part" that is referring to a set amount.  IF you say add 1 part A to 3 parts B, thats 25%.  If you say a 50% solution and ADD A PART, you already have a solution that is 1 part A and 1 Part B.  Adding another part of something doesnt mean adding the total volume of the first solution.

 

Anyway, I already edited my original reply with the solution you need.

[DPS Ammonite]

1 minute ago, hadrosauridae said:

 

Yes, THAT is correct.  When you say "part" that is referring to a set amount.  IF you say add 1 part A to 3 parts B, thats 25%.  If you say a 50% solution and ADD A PART, you already have a solution that is 1 part A and 1 Part B.  Adding another part of something doesnt mean adding the total volume of the first solution.

 

Anyway, I already edited my original reply with the solution you need.

Thanks.

So in summary, if I add 1.5 liters of acetone to 1 liter of a 50% solution I will get 2.5 litres of a 20% solution. Correct?

[hadrosauridae]

2 minutes ago, DPS Ammonite said:

Thanks.

So in summary, if I add 1.5 liters of acetone to 1 liter of a 50% solution I will get 2.5 litres of a 20% solution. Correct?

 

You got it!

[hadrosauridae]

You can also work the math the other way and find how much of your starting solution to make up 100ml of a final solution.

[DPS Ammonite]

Just now, hadrosauridae said:

 

You got it!

By the way, I probably will be mixing enough 20% solution to fit into a nail polish bottle.

 

The object of this exercise it to get three different dilutions of 50% Parallid  B 72 solution to use for consolidation, gluing a label on and coating underneath and on top of paper and/or ink label. 

[hadrosauridae]

8 minutes ago, DPS Ammonite said:

By the way, I probably will be mixing enough 20% solution to fit into a nail polish bottle.

 

The object of this exercise it to get three different dilutions of 50% Parallid  B 72 solution to use for consolidation, gluing a label on and coating underneath and on top of paper and/or ink label. 

 

Yep, use the formula above and solve for V1 where V2 is the amount to "fill" your nail polish bottle.  The only problem here is that those are TINY bottles.  IT might be easier to get a few nalgene chemical storage bottles, and make you solutions into those.  Then as you use up a nail polish bottle, you can refill it from the nalgene bottle.

[DPS Ammonite]

Has anyone made Paraloid B 72 glue? If so, is it relatively easy to mix a 50% resin solution in acetone? For the price of a one ounce bottle of glue I can buy lots of resin pellets.

 

Will a 50% Paraloid B 72 solution glue dispense in a nail polish bottle with a brush or do you need a squeeze tube or bottle?

How long is does a tube of glue stay useable?

 

@Ptychodus04

 

 

[Ptychodus04]

The exact percentages aren’t really that important. I mix roughly by ratios but approximate viscosity is just as useful. Remember, the moment you open a container of solution, the amount of acetone in it decreases.

 

The higher ratio of Paraloid to solvent you have, the longer it takes to dissolve and set. I’ve mixed up Paraloid for glue so thick that it doesn’t pour and you have to use a tool to apply it. It works well for pieces that aren’t too heavy. The trick with it is a process called “creating tack”. Apply the Paraloid glue to one side of the joint, then press the pieces together, pull them slightly apart and press back together. Repeat this a few times and the glue becomes very sticky. This process helps keep the pieces in place as the glue dries.