Mixing ratios

[CroppyBoy1798]

Forgive me if this sounds rediculous but I've always had an issue with maths and numbers and stuff so it's probably a relatively simple problem.

I'm using a product that requires a mix ratio of 9:1 by weight. But I've obviously gone wrong somewhere as I've run out of acid catalyst while I still have some of the high build in the tin!

I just can't get my head around it and can't find an online calculator.

So for instance if I pour out 330ml of the high build clear and the ratio is 9:1 by weight how much catalyst do I pour in? Is there a simple formula or quick method for working it out as I'd be using different amounts depending on the job.

Thanks

 

[rob1693]

If your using 330ml then you should use 36.6 ml of catalyst 330ml ÷ 9 = 36.6666666667 i think I'm not exactly Einstein when it comes to maths

 

[Jake]

It's easiest to do it all by weight, and the fact there's a total of 10 parts makes the calculations of how much of each easy enough to work out.

If you start with volume you'll just need to weigh it anyway - it's not water!

 

[Spectric]

Just think of 9 weight units of one to 1 weight unit of the other, so 9 grams & 1 gram, 90 grams & 10 grams etc etc. It helped owning many two stroke motorcycles where you had to mix oil into the fuel at a set ratio, 16 or 25 to 1.

 

[Adam W.]

If your using 330ml then you should use 36.6 ml of catalyst 330ml ÷ 9 = 36.6666666667 i think I'm not exactly Einstein when it comes to maths

Is right
330/9 = 36.6 or 37 for ease
330 parts of A to 37 parts of B

 

[profchris]

Is right
330/9 = 36.6 or 37 for ease
330 parts of A to 37 parts of B

But this probably wont work if the two have different densities - as an easy example, 330ml of salt wont weigh the same as 330ml of water.

So you need to mix by weight - that's probably why you ran out.

 

[Adam W.]

I doubt there's much difference over 330ml.

 

[bushwhaker]

Edit: Use the following formula X: Y ⇢ X = X ÷ (X + Y) ×0.33 (example)

 

[Adam W.]

He's mixing semi solids in small quantities, there's no point in trying to make it complicated.

Anyway you spelt пример wrong.

 

[Sideways]

9 parts resin to 1 part catalyst by weight.
Just stick to easy multiples of 9 when you pour out the resin.
The resin is (I'm guessing) denser than the catalyst so you can't mix 9:1 by volume. You have to weigh it (at least the first time).
Put a disposable plastic cup on a kitchen scale, zero the scale, pour in 90 grams resin, add 10 grams of catalyst to make it up to 100grams. Stir and the jobs done.
Any of these work :
90 + 10 = 100 grams
180 + 20 = 200 grams
270 + 30 = 300 grams
360 + 40 = 400 grams
450 + 50 = 500 grams

If you only mix 100 or 200 g of finish, you're measuring pretty small amounts of catalyst. I'd get a scale that goes up in 1 gram steps rather than one that jumps up 5g at a time. Scales are super cheap on ebay.

 

[CroppyBoy1798]

Thanks so much for the help, makes sense now. Sorry, I put my measurements in ml's, I meant to say grams as it's mixed by weight on a scales.

 

[Adam W.]

That's funny.

Glad you got it sorted in the end, as it's been keeping me awake wondering if you allowed for the weight of the container, density or what.

How were you working it out originally ?

And it's still

330/9 = 36.6 or 37 for ease
330 parts of A to 37 parts of B

 

[Jacob]

If your maths is that bad I'd make it 10:1 instead, it won't make any difference. So to 330gm you add 33gm

 

[Hornbeam]

So for instance if I pour out 330ml of the high build clear and the ratio is 9:1 by weight how much catalyst do I pour in? Is there a simple formula or quick method for working it out as I'd be using different amounts depending on the job.

You are trying to work in both by weight and by volume at the same time and while for some products they can be similar it isnt always so.
The best thing to do is use a small electronic set of kitchen scales. 9g clear to 1 g catalyst. So for 330g clear you need 330/9 =37g catalyst

Just as an aside I was mixing aerolite yesterday 2:1 by weight but 3:1 by volume so you need to stay in the right units weight or volume
Ian

 

[Misterdog]

Is it Morrells lacquer ?, if so it's 9:1 by volume.

I use a clear measuring cup to pour in 450ml of lacquer but then use a glass lab measure for the catalyst.

The measuring/mixing cups are not accurate enough for the 50ml.

https://www.amazon.co.uk/Fast-Mover...t=&hvlocphy=9046357&hvtargid=pla-847541296958

I have the mix ratio's written on the wall for smaller amounts.