Additive A is a Lignosulphate, mainly used to produce plasticizers for the concrete, cement, and brick industry. I experimented with Additive A/ Type 2 in my porcelain for several months… I was able to acquire a 40 lb minimum at one point; however in the U.S., you may have to purchase hundreds or even thousands of lbs at a time from Borregaard LignoTech.
I was attempting to use Additive A -Type II to enhance my clay’s green strength, but found only marginal strength increases until the ware dried completely.
On that note, if you add more than just 1-2% and let it go to bone dry, it will dull even the best steel trimming blades within minutes. There is also a thin, but even harder, transpiration produced outer crust that is nearly impossible to cut through (imagine trimming dense plastic or wood).
As I said above, it is used as a plasticizer. But there are certainly better options when aiming for increased plasticity in clay (V-gum, CMC, MgSO4, Ball Clay…), so if this is the goal, Additive A wouldn’t be my first recommendation. It’s also important to note that lignosulphates are used as a deflocculant, which under normal conditions is the last thing you’d want to add to a throwing body.
The plasticity that it yielded was an odd one. It felt more like throwing a slime infused low-fire Redart body (sorry, best description I can give). It was neither naturally plastic or “rubbery”, but had a feel all it’s own.
I have heard of pottery studios and classrooms using small amounts (around 0.5%) of lignosulphate products to keep greenware from chipping –especially in terms of a public or commercial environment where pieces are handled often. However, the trade off can be difficult to get used to.
Right away, the resulting Additive A clay I mixed up smelled like dog food –and shortly thereafter, like dog “dood“!
I found the clay to work best after about 1-2 weeks of aging, but the smell permeated my skin and lingered on my hands for hours… sometimes even days. After pugging and aging for just a little over a month, the resulting clay had developed a non-plastic “black rot core” that was difficult to wedge back into a throwable condition.
Additive A will destroy the water absorption benefits of plaster, wood/Masonite, or bisqued tile throwing bats. In terms of casting slips, it will have the same result on plaster molds. A container with a 1/4 pound of liquefied Additive A once spilled onto my concrete studio floor… the resulting sticky mess took about an hour to clean up, & the stain is still visible (hey, I was gonna seal the floor anyway…).
I was also able to acquire some small samples of Lignotech’s Goulac and Ultrazine NA products. Although I experimented less with these, my limited experience with them did not make me want to continue.
“What Every Pottery Should Know” By Jeff Zamek