Call me stupid, but how do you read these paint mixing cups?
 

Got these mixing cups from my paint supplier. They are 1 qt models with several different graduated mixing scales on the sides.
2:1:1:1
3:1:1
4:1:1
6:1:1
8:1:1

I need to measure out a mixture of 4:2:1
How do I use one of these scales for my needs w/o having to use 1 can to measure out 4 parts, empty, 2 parts, empty, 1 part empty, all into another can?

I know it's RIGHT IN FRONT of me, but it hasn't punched me in the nose yet!
:rolleyes: :confused:

.

wrong scales for 4:2:1.

What you can do, though, is use any of the columns in a particular ratio and fill with partA to 4, then with partB to 6, then partC to 7. Mix. This gives you 4:2:1.

Savvy?

If you want a 4:1:1 mixture, you'd fill the level to 4 on each of the 3 scales. The two columns to the right of the first one are exactly 1/4 of the first one.

For example: You fill the cup to the level 7 with paint. You now would fill the second column with reducer to the 7 level. Now add the catalyst to the 7 level in the right column.

It gets messed up because you want a 4:2:1. Lets rearrange the rato though. If it's 4:1:2 it'll be a little easier to measure out. Now from our above example, we'll start with 7 parts of paint again. Now add the catalyst to the 7 level. Exactly the same as above. Now for the thinner we need two parts. Fill it to the 7 level. That's one part. Now fill it to the 8 level. That's your second part. Get it?

no no.

if you use cords method, you are fine when you fill the final ingredient to the 7 level, but to get the final ratio to 2, you can't go on and fill to the 8 - that would be wrong - you can fill up above the 7 the same distance as there was from the column two 7 to the column three 7 again. Look at it as if you were using the 1's. You can see that to go to the 2 is too much. If you use the 12's you can see that to go from the 12 to the 13 is not enough. You gotta use the same relative addition if you use the three columns...

You know, at 1st I thought Cord was right using the #4, But I see your point using the '12' as an example. Going from 12 in row 2, to the 12 in row 3 equals 17/32". But going on up to '13' is only 9/32". I know there is an allowance for the flare of the cup, but not 1/4".

But then I don't know if your method is correct either. The numbers in all the 1st rows are an even 3/16" increment. They are not graduated by volume. Also no allowance for the cups flare, nor the amount unaccounted for from 'empty' to '0'. (which there is no zero) But from empty to 1 is alot more than from 1 to 2. That amount has to be accounted somehow. Everything has to be in relation to the same number of each row within each ratio.

Stupid cup. :hothead:

I see that you are right. My example is one of the few that actually seems to work. You're right, the top and bottom are off.

But I don't think your first example is right either. If you were using the same column for all the numbers, then you are not compensating for the taper of the cup. That's why the other numbers space out as they go up. The taper increases the capacity of the cup. You method would be correct with a straight cylinder. If you were using all 3 columns, then the ratio would be really wacked.

I gotta tell you US1, I've never used a cup like that. I've always measured the components and then dumped them into the cup and then mixed them in the cup before straining into the gun.

Maybe I'll just get 7 cups.
Use the same number on all.

4 cups filled with paint to that number
2 cups filled with thinner to that number
and 1 cup filled with hardener to that number.

:D :D

No, you have the right cup, but the wrong paint system!

:D :D :D

And here I sit wondering how many professional painters are getting a kick out of some guys trying to figure out how to use a damn $0.25 cup!