wet mixing for glaze tests

[Seth A]

I've been testing small 100g batches of various glazes and variations, and the way I've been doing it is... tedious.  I've been dry mixing 100g at a time, and I've been trying to find a more efficient way but haven't come up with much from books or internet.  I've had an idea I wanted to try, but thought I would run it by this fine crowd to see if it makes sense, or if someone has a better suggestion.

I figure if I'm doing a line blend or something where I'm just making tweaks to the same base over a series of tests, I should be able to use specific gravity and volume as a substitute for dry material weight.  That is, if 100ml of water is 100g (adjusted for my water and altitude of course), and I mix at a specific gravity of 145, then in 222ml I should have reasonably close to 100g of dry material.  I can then mix in the variable material like I would normally.

So, does this seem like a reasonable approach?  Any better suggestions?

Thanks!

[Callie Beller Diesel]

This will definitely get you in the right ballpark. You may find you have to fine tune things and do a more accurate measure on things you want to explore more, but if you’re doing line blends for colour, it works great. 

[JohnnyK]

The question I would have is How do you tweak a formula when you are adding minute amounts to get a specific SG?

[Seth A]

Thanks Callie

JohnnyK, I guess I wouldn't be adding minute amounts to get a specific SG.  I might mix up a  1000g batch of a base, add water / mix until I hit my target SG, which I do any time I'm mixing a glaze. I would then divide up the base glaze by volume.   If I've divided it up so there are 100g of dry base in each portion, then adding additional colorants or whatever makes for simple math.  I suppose if I really wanted to be on it I would readjust SG after adding colorants, but I'm not sure how finicky its worth being at that point.  Maybe I'll try both ways and see if it makes a difference.

Anyway, that's the theory.  Going to give it a try this weekend and see how it goes.

[Min]

@Seth A, try running a coaxial colour blend. In the one below I used one base glaze plus 7 colourants to get 28 glaze colourant combinations. I knew I needed 100 grams of base plus 90 of water to get the specific gravity I wanted so I mixed up the batch with this sg by doing 1000 base plus 900 water. If you use a vet syringe it makes measuring out really fast. The top row of the diagram can be any length across, add more cups to the base row if you like and increase the volume of base glaze you mix up. 

You then use the syringe to pull out wet glaze from the base row (1-7 cups) and add it to cups 8-28 as shown in the last diagram, choosing the colourants you want to test. This is for a 50:50 blend, I use 10 cc's of each base so cups 8-28 each have 20 cc's total. It's a tiny amount but enough to pour over a test tile.

(The tiles with 2 stacked tiles are ones I double poured in the base row to get different thickness of glaze on the tiles)

Last diagram shows how to combine the base glazes. This is where the syringe makes it really fast. I use throw a way paper dixie cups for cups 8-28 and larger plastic ones for the base row. I find I can reuse the paper cups a few times before they self destruct.

[Seth A]

@Min that's awesome!  I've heard about this but it hadn't really clicked until I saw your last diagram.  Great tip about the syringe.  I think I have a couple lying around that should do the trick.

Thanks! Its going to be a busy weekend

[Min]

It's really easy to  mess this up, I turn off the music, don't answer the phone etc when doing one of these blends. I write on the top inside part of the cups so you can see which number you are on (I find it easier to see than writing on the outside of the cups) and get the test tiles all numbered before you start mixing. I take a  pail of water and a few paintbrushes and use those to mix up the blends then rinse the brushes off in the water and wipe them off on a towel so I'm not diluting the glaze too much with the extra water on the brush. Make sure you make enough of your base glaze to pull off how ever many cc's you need. 20 cc's of glaze really is a tiny amount, doubling it for the first time you do one of these might be a good idea.

[Bill Kielb]

Sometimes when lazy I will just mix up. An even number of  base grams let’s say  1000. Add water till I have my SPG, (likely 138 ish for dipping)  equally distribute in 10 samples and treat them as 100 grams each for my line blend.
 

The most scientific I get is to measure in advance the volume of mixed base glaze in a graduated cylinder and divide evenly to represents 100 gram dry samples and dispense with handy large syringe  so each dose is almost spot on for all cups from the get go no shuffling and checking weight of each, no tracking how much water just  wet samples with 100 grams of  equivalent dry material in them. Super easy to do ten or twenty samples this way without thinking too much and making a mistake.

From there whatever blend I am trying for is usually easy without a bunch of brainpower.

[Min]

2 hours ago, Bill Kielb said:

is usually easy without a bunch of brainpower

Some of us don't mind using a bit of brainpower  

[Bill Kielb]

4 hours ago, Min said:

It's really easy to  mess this up, I turn off the music, don't answer the phone etc when doing one of these blends.

Some of us don't mind using a bit of brainpower  

I do leave my radio on (bone conducting wireless headphones) and answer the phone and occasional question though.  With that, it’s too easy for me to mess up so my brain is likely at its limit.

[Seth A]

Got into the studio yesterday and tried a mini blend.  Just 4 colorants to try to keep it simple for my first time.   I mixed my base to my target SG, did some math to figure out how many CCs per 100g of dry, and off I went.  The syringe works great, and the whole thing was super fun and relatively painless.  I can see how its very easy to mess up though, especially with a larger blend.  I'm not totally sure I didn't mess something up... we'll see.  I'll fire them today and we'll see how it turned out tomorrow.

Thanks for all the tips!

[Bill Kielb]

49 minutes ago, Seth A said:

Got into the studio yesterday and tried a mini blend.  Just 4 colorants to try to keep it simple for my first time.   I mixed my base to my target SG, did some math to figure out how many CCs per 100g of dry, and off I went.  The syringe works great, and the whole thing was super fun and relatively painless.  I can see how its very easy to mess up though, especially with a larger blend.  I'm not totally sure I didn't mess something up... we'll see.  I'll fire them today and we'll see how it turned out tomorrow.

Thanks for all the tips!

When I am super lazy for really small trials I will go out of my way to mix 400 grams dry, hydrate and simply pour into 4 Dixie cups equal amounts which usually means pouring and weighing each and pouring a bit between cups till they are all the same level while weighing to make sure they are filled exactly the same amount. Usually can get them within a gram or better by eye so now if I am interrupted I am sure each represents 100 grams dry mixed.

Pretty easy to mix colorants in (or anything else) with a plunge blender and I can dial my shade of colorant in within a test or two. I find measuring the small amounts of colorant needed to be a Potential source for error as measuring very small amounts of colorant accurately is tough  and getting them mixed completely in is as well.. I tend to weigh them on a tiny plastic spoon and simply dump and stir in neatly so I am sure I put the  entire measured amount in.  Wipe the spoon clean and on to the next tiny sample.

Nothing like mixing 8000 grams of something that is too dark because your test was off just a smidge. Haven't had a big oops in a long time now.

[Seth A]

30 minutes ago, Bill Kielb said:

Pretty easy to mix colorants in (or anything else) with a plunge blender and I can dial my shade of colorant in within a test or two. I find measuring the small amounts of colorant needed to be a Potential source for error as measuring very small amounts of colorant accurately is tough  and getting them mixed completely in is as well

I have a digital scale that's accurate (allegedly) within 100th of a gram, and sample cups that fit my immersion blender.  Even still getting getting things just right can be a challenge.   I still don't have a feel for how small errors at this scale play out in larger batches, but I've been trying to be within a 10th of a gram on things.   I imagine if I find something I like from this kind of test, I can do something similar with varying amounts of the same colorants to try to dial it in, and scale it up slowly.

I like the idea of measuring things out on a plastic spoon.  I'll have to give that a try.

[Min]

One way to do a quick test if you just want to try one colourant is to weigh out 10 grams of it then use a metal rib and press it into a square shape. Divide it in half then divide one of those halves into half again and then once more. Take your 100 of base glaze and put in the 0.625 amount, mix it up, dip a tile then add the next 0.625 amount and repeat. One weighing of colourant for 5 tests. Skip the 5 gram amount for colourants that don't require a large amount of. Got this trick from Robin Hopper years ago, saves a bit of time and although not super accurate it gets you in the ballpark. Split up the square of colourant into any number of divisions.