Hi guys,

Any tips for simply calculating volume required for custom mix ratios? I know about using the mixing cups, but say for example I need a mix of 10:4:1, which is definitely not on a mixing cup.

How do you guys go about it simply?

Say I want to mix 500ml of paint total. Having a brain fart

Usually the TDS has both weights and volumes, certainly the case for the paints I use. From that I can easily calculate the weight for any given volume and just measure it out on the scales.

If your measuring cup doesn't have what you want then it may have something else that you can convert. Same goes for measuring sticks.

The other way is to pour a given volume (say 100ml) into a cup with those graduations and then weigh it. Not quite as accurate but works ok for primers, clears and 2K solids. Nowhere near accurate enough for colour matching or colours with metallics and pearls.

10-4-1 15 parts. 500/15= 33.33 10 x 33.33=333 4 x 33.33=133.3 1 x 33.33= 33.33

I just measure in ounces. Mixing cups have ounces.
Like 10oz 4oz 1oz

or increments of ounces, like half of that would be.
5oz 2oz .5oz.

^^^^^^^^^^Yeah, that's what I do as well, ounces..... dividing it down to get whatever smaller batch I need....

^^^^ there are several different sizes of cups, your looking at 500ml. = 17 oz actually 16.907 oz. so use the cup that suits this.
Jay D.

Today I used a new primer. I looked up the weights and volumes and then mixed batches of 280ml which required 300g primer, 48g activator and 45g thinner. That's a 4:1:1 mix. Weighing it out is much more accurate.

What was the primer? Valspar HS35 actually. Goes on nice but absolutely stinks. I'll find out tomorrow how easy it sands.

JCCLARK wrote:I just measure in ounces. Mixing cups have ounces.
Like 10oz 4oz 1oz

or increments of ounces, like half of that would be.
5oz 2oz .5oz.

This is how I do it as well. Thinking of a 10-4-1 ratio as 10 parts, 4 parts, 1 part.

NFT5 wrote:.......which required 300g primer, 48g activator and 45g thinner. That's a 4:1:1 mix. Weighing it out is much more accurate.........

Not to be labeled a critical math instructor, but wouldn't that actually be
a 6:1:1 mix? I'd call it a typo...

This discussion brought back memories of watching my Dad mix paint.
He used the calibrated eyeball method, whereby he would dip the paint
stir stick into the mix, pull it up and watch how the paint dripped and
flowed off the stick. If it appeared too thick, he would add reducer. If too
thin, add more paint. He painted professionally for several years and was
very good. This was back in the old days when you would punch a hole
in your mask for your cigarette.

NightTrain wrote:Not to be labeled a critical math instructor, but wouldn't that actually be
a 6:1:1 mix? I'd call it a typo...

Nope. Not a typo. It was my whole point. The primer is much heavier than thinners or activator so 4 parts by volume weighed 100g while one part activator was 48g and one part thinners 45g. You could not get that degree of accuracy measuring by volume in a cup or using a stick.

That said, I do have a full paint system and paint formulae are always weighed out, for which I have 2 sets of scales, with the smaller set accurate to 0.01g while the bigger ones are only good to 0.05g. So, if I'm mixing a small quantity, say less than 500ml, I'll use the smaller scales. The Cromax system that I have uses concentrated tinters so getting weights as near to perfect as I can results in more accurate colours.

Because I'm used to weighing out paint I use the same method for primers and clears. It's easy once you get used to it and, as I said, means I can achieve exactly reproducible mixes.