Some raku newbie questions

[ATauer]

I will soon be firing up my first raku kiln, and I have gotten quite obsessed with the art form and have been consuming every book I can find on it, no matter how old (just finally learned today what the actual real Raku kilns were/are like in Japan in one of the oldest books, all the other books didn’t bother to cover that only ways to make kilns for the Western version that are more contemporary. 

So I have two questions as I start off, planning on spending a whole day each week doing raku partly because I know it will be good for me to ruin and lot of pots and learn not to get attached to my work and I think it will help me with my perfectionism since I have only a real fraction of control with this method.

The first question is, what is the current consensus on copper mattes? Depending on a book’s age, or articles I have found etc. whether or not copper matte’s are doomed to have their colors fade within a fairly short amount of time seems to go back and forth, and frankly I find it a bit confusing to come across so much information about them losing colors in a few years and needed to warn customers about it while seeing so much copper matte for sale these days. While I recognize that perfecting the techniques for getting good copper mattes takes quite some time and is not easy, I’m not attracted to raku only for the simple easy beginner glazes, and I figure it couldn’t hurt anything to start right away working on getting good copper mattes just using small pinch pots so I’m not wasting a lot of nice pots and clay. But I don’t want to pursue the technique and its variations if it is pretty certain that the colors will disappear. I have a few really good glazes I love that are multi-colored and I could probably be quite happy with in place of copper mattes if they are essentially a waste of time. 

My other question is about naked raku, which I find fascinating and gorgeous, have read the recent Naked Raku book several times now, and am having a hard time picking whose version to go with. I realize I most likely need a two step naked raku system because while I won’t be producing work at all like the Jacobsons, I do really like the idea of using colored slip and colored terra sig that is burnished under the slip and glaze and then being able to scrape designs on my work, whether it is colored or black and white. However, it seems everyone these days has stopped using recipes for the slip for two step naked raku and for a variety of reasons I really do not want to buy Laguna’s clays or any commercial raku clay that I have to slake down and sieve out all the grog, leaving me with more grog over time than I really have use for. I’m wondering if anyone still uses some of the other recipes for the Jacobson’s slip that I have found in some of the older books, or have adapted any of the one step slips to work for use with sacrificial glaze? Especially as in the Naked Raku book they had a recipe that someone had developed for one step slip that worked at around cone 06, much higher temperature than normal, because that artist wanted to be able to use the naked raku slip on the same pots that she also fired some of her glazes, which all matured around cone 06. I also typically fire most of my ware to cone 06 or close to it, and to be able to use glazes on some of my naked raku pots as well as fire naked raku pots with glazed pots would be really nice, I have a pretty big raku kiln and do not want to be firing each naked raku pot alone, and waste fuel and heat. I’ve wondered why the Jacobsons in particular moved away from their slip made of dry ingredients and went with the same commercial clay they use to throw their pots- it seems to be that even if put on bisqueware the same clay would end up being harder to remove, versus something that is designed to more strongly not fit wonderfully but long enough to get the pot fired and reduced. And is the temp they pull their pots at because the slip matures or does their glaze mature too much by then and you don’t want it getting to the point it won’t come on, which seems like then just use a glaze that matures later. I’ve wondered about trying their original slip but sort of mashing it up a little with some of the one step slips, like adding more alumina hydrate to it in order to keep the slip from sticking too much. 

Obviously I have how I want to do naked raku, which is use dry materials to make the slip and be able to fire it to cone 06 for several reasons, and I’m wondering if anyone has managed to figure out how to do that, or has good suggestions on things to try to perhaps get there, or if I am pretty much stuck pulling the pots much earlier and therefore not being able to use my glazes on the those same pots together, and if there is any alternative to buying Laguna’s Amador, since I have sworn never to buy Laguna clay every in my life again. 

Thanks!

[PeterH]

7 hours ago, ATauer said:

and if there is any alternative to buying Laguna’s Amador

https://ceramicartsnetwork.org/daily/article/A-Colorful-Variation-on-the-Naked-Raku-Firing-Technique
After the bisque, we apply the resist slip and glaze combination that gives naked raku its special look (Figure 3). For the resist slip, we brush on a thin layer of our Amador throwing clay. It holds on to the pot very well throughout the process and comes off with ease after reduction. We have experimented with making the resist slip from lots of different stoneware clays with excellent results. Be sure that the pot does not feel too “cool” to the touch before glazing.

... my emphasis, maybe Amador has no unique/special properties (except already being used by the Jacobsons).

[neilestrick]

11 hours ago, ATauer said:

Depending on a book’s age, or articles I have found etc. whether or not copper matte’s are doomed to have their colors fade within a fairly short amount of time seems to go back and forth, and frankly I find it a bit confusing to come across so much information about them losing colors in a few years and needed to warn customers about it while seeing so much copper matte for sale these days.

Depends on the glaze. I've seen some that last years and years, others that fade quickly. Same goes for the glossy copper glazes.

[Callie Beller Diesel]

I think you’re overthinking it. Especially if you’re doing this as an exercise to be less precious about your work.

First, raku is a very immediate way of working, with simple materials that are engineered only to a point. American raku pots don’t meet food safety standards, so you don’t have to be limited by tight chemistry constraints. You work sculpturally, so it’s not a big concern anyways. There are lots of cold processes that can seal a piece so it doesn’t discolour over time. When you see people talk about using floor wax on the end result, it’s not just for shine. Even in HS, we would spray our raku pots with clear varnish to keep them from reoxidizing. (Yes I did raku in high school. It was the 90’s.)

What I’ve observed over the years is that as a given artist continues to work with technique, they do it to suit some sort of need they have as an individual. It either satisfies them emotionally somehow, or it provides a specific benefit to the end result. If someone starts with a laborious process and later simplifies it, usually they either got tired of doing the extra steps, they found it didn’t provide enough benefit in the end product, or they found something that worked better. It’s right there in the quote Peter mentioned: lots of other things will work too.

If you don’t want to use the Amador, I’d look at the properties that it has that could be germane. Looking at the catalog entry on the website, Amador is a cone 10 clay that is “difficult to crack in firing. Durable and affordable.” So if you’re using it at con 06, it’s going to be refractory as heck, and won’t start to fuse to the pot. It’s a stoneware, which means it will probably have ingredients that give it good green strength that will allow you to handle it a bit roughly. I’m going to guess from my VERY occasional access to some US clays that it maybe isn’t prone to readsorbtion when you dip or pour the waster glaze on it. If you can find a clay body that fits those criteria, that would be a place to start playing. Bonus if the manufacturer sells it in dry bags if you want to use a bunch of it.

[ATauer]

2 hours ago, Callie Beller Diesel said:

I think you’re overthinking it. Especially if you’re doing this as an exercise to be less precious about your work.

First, raku is a very immediate way of working, with simple materials that are engineered only to a point. American raku pots don’t meet food safety standards, so you don’t have to be limited by tight chemistry constraints. You work sculpturally, so it’s not a big concern anyways. There are lots of cold processes that can seal a piece so it doesn’t discolour over time. When you see people talk about using floor wax on the end result, it’s not just for shine. Even in HS, we would spray our raku pots with clear varnish to keep them from reoxidizing. (Yes I did raku in high school. It was the 90’s.)

What I’ve observed over the years is that as a given artist continues to work with technique, they do it to suit some sort of need they have as an individual. It either satisfies them emotionally somehow, or it provides a specific benefit to the end result. If someone starts with a laborious process and later simplifies it, usually they either got tired of doing the extra steps, they found it didn’t provide enough benefit in the end product, or they found something that worked better. It’s right there in the quote Peter mentioned: lots of other things will work too.

If you don’t want to use the Amador, I’d look at the properties that it has that could be germane. Looking at the catalog entry on the website, Amador is a cone 10 clay that is “difficult to crack in firing. Durable and affordable.” So if you’re using it at con 06, it’s going to be refractory as heck, and won’t start to fuse to the pot. It’s a stoneware, which means it will probably have ingredients that give it good green strength that will allow you to handle it a bit roughly. I’m going to guess from my VERY occasional access to some US clays that it maybe isn’t prone to readsorbtion when you dip or pour the waster glaze on it. If you can find a clay body that fits those criteria, that would be a place to start playing. Bonus if the manufacturer sells it in dry bags if you want to use a bunch of it.

I seal my pots with Trewax floor wax paste, have for a long time, starting with pitfiring, based on the recommendations from a huge number of raku and pit/alternative firing nerds - one of those Instagram posts where a well known raku artist in his captions mentioned he used it after doing the firing shown in his video, and a ton of other raku/alternative firing mid-late career artists whose work I know jumped in to say that was the best by far and from my own research because it is mostly Carnauba wax which is the hardest natural wax on earth plus it has some petroleum derived microcrystalline wax in it as well which I can’t be a hypocrite about using because I use it all the damn time for the lost wax process for glass casting, I believe the two types of waxes provide the best kind of protection, although no wax that I know of has been discovered to block the effects of UV rays…I believe a harder wax like this will be more likely to protect the rather fragile items in general and I like the type of gloss it gives and that it lasts a very long time, and I hope from it being a harder floor wax that it will protect better against things you would associate floors needing protection from, mainly in my case scratches and marks, fingerprint marks, smears of grease from being handled by dirty hands, dirt and dust…etc. But floor waxes don’t protect against UV degradation unfortunately! The only thing on the market that actually does protect against a lot of things ceramic objects need protection from and won’t turn yellow or amber from UV is aliphatic polyurethane, I have done a ridiculous amount of research about this in order to find anything at all I could use as cold glaze on my large scale sculptures when I’m hiding their seams and trying to match the shine level of the glaze on the rest of the sculpture, as I refused to use what most people used and just accepted that you would go to all that trouble, hours and hours of work, to hide a seam, only to have it turn yellow or amber in a few years and make it obvious, plus in my opinion pretty much ruin the sculpture. It is unfortunately often difficult to find as even Home Depot doesn’t carry any aliphatic polyurethanes, and the gallons are almost $200- which for my work you need gloss, satin, and matte versions to mix them so you get just the right match to your glaze, although I did recently find Lowe’s selling quarts sizes which I didn’t know they made for about $40. I bring this up because if it was cheaper and I wasn’t so happy with Trewax, I might use it on my raku and alternative fired work, FYI it is great for anything you want to leave outside especially year round, most cities have rules that it is the only thing that can be used to protect public murals, other than UV protection it protects against chemical attacks, physical wear and tear, is waterproof and I could go on with its benefits. So for outdoor raku work, and for me also any outdoor sculptures I make, but also would be great for the outside of planters etc. I bring it up & say so much about it because it is making me wonder if it wouldn’t help specifically with copper mattes and the copper lusters that lose their colors largely because of UV light. Maybe this is the best thing to use on those?

To jump to the naked raku, I asked because from what I have gathered the Jacobsons (and Asselborough who also uses some commercial clays for his slip, mixed with a few dry ingredients) did years and years of testing lots of slips, and say that Amador is the best they have found. Although yes, in one of the articles they did say they found a number of other good clays as well, but that is rare that anything like that is included with their descriptions of how to do their technique. So it seems like going back to their very first recipe and using it wouldn’t be the best idea. I think maybe I didn’t quite get the reason why I don’t want to use Amador, other than my Laguna hate- I *really don’t want to use a commercial clay and have to slake and sieve it*. As I make my own porcelain paperclay from dry ingredients and a recipe I developed, and I am working on a white stoneware recipe that I hope will also work as a raku clay in addition to me using my porcelain for raku/pit (I don’t know why I even feel like I should have a second clay for it, but partly it is with the idea if I want something with more tooth, or something more like a B clay, I could also just mix my white stoneware and porcelain 50:50 or 60:40 or whatever and get those properties. And I do need for right now something with just a little tooth to use on the wheel). I make up my own slips, terra sigs, my glazes, I even make my own underglazes…while right now there are two stonewares that I purchase pugged and use in small enough quantities that I’m content to buy them pugged (and they are a speckled light brown and a black stoneware, which would be a pain in the ass to develop recipes for especially when I don’t use them enough to merit it). It would be so much easier and better for my back and disabilities and convenience to make a slip for this out of dry materials instead of a pre-made clay. 

I wish Laguna provided more information on their clays to help guess what is in them. I could probably try my white stoneware once I have the recipe perfected (which it is a long way away from that happening) and again I think there is always the option of adding more alumina to the slip if it isn’t working perfectly- that seems to be what several people did with several of their versions of their one step slip, especially if it was sticking too much. I don’t really want to wait until I have my white stoneware recipe ready to start trying naked raku, but maybe I have to. Or maybe while I’m waiting I just use their original dry materials recipe, it certainly produced a lot of great work for many years even if they did feel like they needed to find something better. It doesn’t solve my issue with really wanting to be able to fire it up to cone06 or at least pretty close to it…I mean that is when the glaze they use matures, it has a pretty wide range actually but 06 or 05 is probably where it is its glossiest and you shouldn’t go beyond that. So I’ve inferred that if you go up that high it is hard to get the slip and glaze off. To change that, I would need to have access to my Naked Raku book (I’m in the hospital for…ever it seems, so I don’t have it at hand) to look at what the person who altered the Rigg’s one step slip so it would fire up to cone 06, and see if I can tell what were the important things that allowed that change…I’m going to guess in order to  fire it higher without it becoming too attached to the pot the main thing would probably be once again alumina, to make it more refractory. Then I would have to work on the glaze part, so it too doesn’t mature so much that it is too hard to come off. Most everyone loves and uses their original glaze, but maybe I just need to find a clear crackle glaze that fires up a lot higher, or alter the original to make it more refractory…so, reduce the gerstley borate by probably a good amount, and add in some clay? Still have to make sure it crazes and produces nice crackles at that too. 

If anyone knows of a good raku clear crackle recipe that matures more around cone 04-c2 (or somewhere in there) but still actually melts enough for naked raku by cone 06, please let me know! Ha! Probably a tall order. I have seen a ton of various clear crackle glazes, many of them very similar to each other, but while they might have slightly different maturation temps, most of them are within a pretty narrow area ultimately of c010 maybe at the lowest and not too much above 06-04 at the other end. It would be a lot easier to simply use a clear glaze for regular oxidation firing but am I going to be able to get nice crackles and could I change it so it produces them without lowering its cone down to where I don’t want it to be? It is frustrating as hell being in the hospital right now because I can’t go through my books to see if I can find anything helpful, and I also can’t DO anything damnit! I can’t just try their original slip and see if I like it just fine and don’t really need to alter it, to just try firing the slip and glaze up to cone 06 or a little below and just see what happens! I mean the glaze we know has a huge range, the slip it is a lot less known, but maybe it already works perfectly fine at cone 06, or only needs very minor modifications to make it work. Although I suppose if that were the truth others would have done it and talked and written about it by now and I certainly haven’t heard anything about it. It seems to me though that it shouldn’t be that difficult to adjust to, as they usually pull around 1700 deg now right? And 1800 or about 1860 is not that much hotte

[ATauer]

5 hours ago, neilestrick said:

Depends on the glaze. I've seen some that last years and years, others that fade quickly. Same goes for the glossy copper glazes.

You don’t happen to have access to some of the recipes for the ones that last years and years, do you? That is definitely not something they tend to disclose when publishing them. And for copper mattes that really makes me wonder, since the recipes are all quite similar, I mean it is usually 80 or 90% copper and the rest flux. With occasional RIO or cobalt added. Sometimes the ratios are a little bit different than that, but not too often. So what is there to add or change to make them last for years? Lithium? Frit?

[neilestrick]

14 minutes ago, ATauer said:

You don’t happen to have access to some of the recipes for the ones that last years and years, do you?

Sorry, I don't have any recipes. I don't do  Raku, I've just known people over the years who do, and some of their glazes held up and others didn't. Sealing the work after firing may have an effect, too. Someone will probably chime in here about that.

[ATauer]

9 hours ago, PeterH said:

https://ceramicartsnetwork.org/daily/article/A-Colorful-Variation-on-the-Naked-Raku-Firing-Technique
After the bisque, we apply the resist slip and glaze combination that gives naked raku its special look (Figure 3). For the resist slip, we brush on a thin layer of our Amador throwing clay. It holds on to the pot very well throughout the process and comes off with ease after reduction. We have experimented with making the resist slip from lots of different stoneware clays with excellent results. Be sure that the pot does not feel too “cool” to the touch before glazing.

... my emphasis, maybe Amador has no unique/special properties (except already being used by the Jacobsons).

The most difficult thing is right now being stuck in the hospital unable to walk since June 3rd, I just can’t DO anything to test any thing out. I’m taking Ceramic Materials Workshop clay class right now, in the spring I did the lectures only so I could develop my porcelain recipe and they let me upgrade so starting July 1 I have been in their full class, with labs and discussions etc. And my labs are individually designed by Matt to help me develop my white stoneware, that I hope as one of the things it does it will work as a raku clay but also might even work as the slip for naked raku. But I can’t do my labs because I’m in the hospital and there is no one in my circle of family or friends who might be willing to do the simple labs for me, because they know nothing about clay or kilns. It seems like maybe quite a few of the not too many labs don’t actually require firing, but even those I can’t do. I can save them and try the labs after the course is ended, but then I won’t be able to ask questions and ask for advice and I will be totally on my own in terms of developing this white stoneware. Which is really tricky with trying to get the clays you want in it while keeping it white. I really don’t know what to do. It is incredibly frustrating that the upgrade allowing me to do the labs kicked in 3 days before I hurt myself and ended up endlessly in the hospital. Which really there is no point to having the upgrade now because I can’t do the labs which means I don’t have anything to present or ask or contribute during discussions. It is totally worthless to me, unfortunately. 

[ATauer]

3 hours ago, neilestrick said:

Sorry, I don't have any recipes. I don't do  Raku, I've just known people over the years who do, and some of their glazes held up and others didn't. Sealing the work after firing may have an effect, too. Someone will probably chime in here about that.

It is buried in another reply but I already seal my alternatively fired and raku ware with Trewax, which is one of the best and most popular floor paste waxes used with raku. I’m quite happy with it.