Enamel on Steel – some insights

I commonly get emails asking for hints on how to enamel on steel. I have a little bit of experience – enough to make me dangerous you might posit – so I thought I might dump what little I know here to save anyone interested the time it might take me to respond to an email inquiry.

To enamel on steel, you need some enamel, and some steel. Liquid enamel is what I have been taught to use, and I have found that when using liquid enamel the process of getting it to stick to any grade of steel reasonably universal, though obviously the better grades (stainless steel typically used as a finishing material in architectural applications as an example) are generally easier to enamel, and are perhaps more resilient. Like any metal choice the material is of course application specific, so say you plan to enamel only one side and show the works outdoors, I would suggest an exterior grade stainless. I have found that you can get enamel to work pretty well for both stainless and mild steels, so long as you do the right preparation.

enamels

In the past I have ordered my enamels from two different companies, Thompson Enamel who exports to Australia from the US, and WG Ball, who export from the UK. I would suggest sticking with Thompson as the UK company was slower = it took months to get my order. Both Thompson Enamel and WG Ball sell dry forms of ‘liquid enamel‘ that you can purchase and add water to yourself.

Why is it called liquid enamel when what you get is powder? Liquid enamels are often delivered as a very fine powder, which is incidentally much finer than regular jewellers enamel (which my enamel guru Elizabeth Turrell calls ‘sifted enamel’.) Jewellers enamel is a much coarser grit, as it will fit through a 60-80 mesh, whereas industrial or liquid enamel will fit through a much finer 200 grade mesh. (So putting regular enamel in solution will not achieve the same end.)

So as explained, when you receive your enamels, chances are you will have to add the water. (If you’re in the US/UK, you can order them in solution, which I have been advised is the best way to go. Obviously shipping weight is a bigger factor in ordering internationally, (as are freezing temperatures in winter, I recently learned via Ganoksin.) Thus you have to purchase the right enamel, which on the Thompson website goes under the name of both Liquid Enamel and Brushable Enamel, while on WG Ball they are called Wet Process enamels (for copper and steel.) Thompson also sell tonnes of other types, including things like enamel crayons which are fun to use over the top of a fired surface.

When adding water to the enamel I have found it best to treat it a bit like making a batter, stirring while adding a little water at a time, until you get it to the right consistency. I sometimes get impatient, and think I’ll just add a bit more liquid this round, and I inevitably end up with it too runny. What’s right? Well, it depends on what you’re doing, but pancake (perhaps crepe?) mix to (pouring) cream or even milky consistency is good. It’s good to give it some time for  it to rest before you start using it, and of course it settles between uses, so always be sure to stir it before using. And as ever, have some metal around for testing. Ganoksin has a great in-depth guide on how to mix, which includes data on good ratios of enamel to water.

metal

I have used sandblasted recycled tin cans, washers, pristine stainless panels and sundry other objects in my works and tests, so my advice is that if you can prepare a steel surface correctly, you can probably enamel on it. A sandblasted steel can (known as a tin can in Australia) of the ilk that you get your canned veg in (big tomato tins are great) is a great test material. There’s also an enamel product called Grip Coat that can help you with using low-grade steel, which you can lay down as a first layer and fire before adding your other layers, and which bonds beautifully to just about any metal and other enamels.

You do have to be careful with mild steel, in that using a wet enamel will start to rust your pieces in some situations. This can be a great thing to promote, but if you’re after a pristine surface it’s something you will have to keep track of. The small yellow streak to on the right hand section of the work above is a rust stain starting to develop from the fired stainless steel wires. Yup, even stainless can sometime turn on you, because of the temperatures involved. I happened to like the stain, so I then had to carefully cultivate it through other firings…

This mild-steel recycled object work (below) looks fairly brown, as the enamel is a transparent that began to rust on application. It worked well with the piece, so well that I had planned on texturing it, but I left it shiny instead. I’ve also been collecting rust from some pieces of mild steel for a while now too, to try as a pigment, so I’ll keep you updated on what happens. If you’re inclined, start collecting copper fire-scale, since it can give lovely green tones too.

If you want a good steel surface, you need to look for a low carbon steel. Once in the kiln, carbon of a lesser quality steel will form gas bubbles that come up through the enamel. Right here a quote from the master, Elizabeth Turrell, is in order:

“Mild steel that is higher in carbon sometimes results in gas bubbles and poor adhesion of the enamel to the steel, (any gas bubbles can be rubbed back, worked over etc) but it is easier and cheaper to buy in small quantities or beg it from metals shops.

However, the key is adhesion of the enamel to the surface after each firing and once the work is finished. (No popping off as you walk away!) Metal preparation / sand blasting is essential for reliable adhesion. Always make sure you wipe any residue of the sandblaster material off the metal before enamelling, other wise you will get pinholes on the fired surface. If you have no access to a sandblaster, an electric grinder [sander] will give you a surface that the enamel will adhere to.”

metal preparation

Like the lady said, sandblast it. Using a reasonably coarse grit (aluminium oxide, or garnet if it comes to that) sandblast the surfaces to be enamelled. Be sure to wipe off the residue once you pull it from the sandblast cabinet, because as per Elizabeth’s quote, this will stop proper bondage of the enamel to the metal surface.

If you don’t have a sandblaster, never fear, you can rough up the surface in other ways. Try detergent and leftover enamel (take precautions, you’re dealing with glass and you might need your fingerprints afterwards) or a coarse sandpaper. Or, purchase (or find) pre-enamelled panels to which you can add more enamel. Thompson sell a range of pre-enamelled sample squares, though there are plenty of places to get pre-enamelled objects to work with.  When I was in the studio in Bristol an artist was working on translating a bunch of drawings from some children (he was working on a commission for a primary school) onto a bunch of oven panels. Yup, old white oven walls, doors and the like. Properly cleaned these pre-enamelled panels are a great surface on which to add more enamel. No need for a ground coat and they take liquid and sifted enamels over the top of the base coat really well. So if you were planning to use recycled metal (a little hard to cut, I’ll grant you) you can work straight over something already enamelled with regular jewellers enamel. The cleanup before firing in this case is the hard part, especially on an old oven…

Whiteboards are enamelled, as are camping mugs and plates. And if you happen to have access to a decent cutter/guillotine, it is possible to put some masking tape down and slice through a pre-enamelled panel. I’ve seen it done, though once again, shards of glass are… well, shards of glass!

application

The trick with enamelling steel is a thin first layer. Very early on I learned that if I did too thick a layer with an object I was working on the layer of enamel would literally jump off the steel. (This can also happen when the metal preparation is not quite biting enough.) It pings the fired glass in small shards, which littered the surface of the bench I was at. Messy and a little bit dangerous (I’ll say it one more time, it is glass…) So, depending on the object (and some shapes or enamels are just more likely to ping so you have to put in extra effort with them), it is possible to put on a thin layer of enamel (I use clear, I have found heavily pigmented enamels, red, for instance, to not be a friend in these delicate first layer scenarios) over steel and have it stick, but the trick is thin. But not so thin so as to have the coverage be broken.

Remember that unlike copper, counter enamelling the panel/object is not so important. You can build up the front without having to build up the back. The strength of the steel is your friend. If I do a backing layer it’s generally for decorative purposes.

buying enamels

There are great local places for enamel too – Koodak in Melbourne has started stocking liquid enamels, so look local. Below I have listed what I have (as at July 2012). You do have to  remember, as with any enamel on metal, the clears will give you the base colour of the fired metal underneath. With steel, that is often very close to black, or a smokey grey if you’ve really layered up the enamel. So translucent colours might need a base layer of white under them, and very often this is also a suitable first layer as it’s relatively stable. Often times I don’t use any black, simply because a single layer of clear will give me a dark enough surface for my needs.

One of the first questions on perusing my list you’ll ask is “what is the difference between Low and  Medium firing enamels?” I didn’t know, so I bought both and tested. (Doing some reading probably would have been less time consuming. Thompson sells their Thompson Enamel Workbook for around ten bucks) The answer is the amount of expansion. The Low expands minimally, and it goes up from there. When they say on the website that layering different expansion levels ‘will produce crackle effects’ they are right! When that happens in your experimentation, you’ll know what they mean. I’m still not completely in control of what happens as I’m still learning, so all I can say is ‘keep experimenting’, but from memory, if you fire a transparent low expansion layer first then add a white low expansion layer you will get the white (the upper layer) cracking and peeling on firing. That is in my experience, anyway. I’ve found low then medium to work ok, but it’s been a while so I may have it confused. Sorry! I’m only an enthusiastic amateur!

Thompson
BC-1070 Medium fusing white
BC-969A Low fusing clear transparent
BC-303L Medium fusing clear transparent

533 White
772 Black
930 Chinese Red

WG ball
Light Blue 6117
Metallic Light Silver
Sheet Steel Groundcoat
Ivory
Sky Blue
Royal Blue
Dark Green
Yellow
Clear Flux
Metallic Dark Silver
Metallic Gold

I’m yet to try a lot of the WG Ball versions (busy year…) but the ones I have used have seemed a little more grainy. It is possibly my mixes haven’t been great, as at the time I didn’t want to put the whole bag in solution so I only used a small portion of the whole amount.

firing

ENAMEL: Make sure your enamel is thoroughly dry before putting it into the kiln. Sit it on or near the kiln if you want it to dry quickly.

KILN: Arrrgh! I cant answer this one! Firing depends on a lot of factors, your kiln, your material and the enamel. Some enamels say don’t fire over 800°C [1470°F] while some (W.G. Ball) say fire between 800-820°C [1470-1510°F]. Sometimes you need a minute, sometimes 2, sometimes less if your kiln responds well to the door being open, or more if it’s a little slower on the heat or it’s a big piece of steel.

Generally enamels are best fired between 750-800°C [1380-1470°F] but I have a note here from a workshop with Elizabeth that reads “don’t fire steel over 800°C – it warps” right after a note that says “Steel: in industry grip coat fired @ 840°C [1545°F], enamels @ 800°C.”

My advice? Test, sample, try out, evaluate, trial, check and study. And if you get a definitive answer, email me!

surface

As mentioned earlier, on the Thompson website you can also find pre-enamelled steel squares, which are great to practice on. They have a base coat so just about anything will stick to it. In the workshop I did with Elizabeth we were encouraged to use enamel as glue, and put all sorts of sands and even metal shavings into the wet enamel so it would fire solid. That’s where I got the idea of using my sandblast grit as a surface texture.

Like any other sand, fire scale or shaved metal that you want to use, glass beads go onto a layer of fired enamel, and then are fired to get them to stick. It’s up to you if you add layers over the top – such as clear – for binding, but I generally don’t. That way you can really feel the texture (though you have to be prepared to lose some if it’s a really fine sand). You can use a product like Klyr-Fire to help with adhesion until you fire the work, or lay down some marker or a stamp on which to sift your sand/grit/favourite-jewellers-enamel and then shake of the excess. Or you can use unfired wet process enamel to bond it – just add the grit once you’ve put down your layer of enamel, then wait for it to dry before firing.  Now, in the case of glass beads, the more you fire them, the less ‘beady’ they become so if you’re using larger glass beads it might be the very last thing you do if you really want them to stand out. Peter Daglish in the studio in Bristol was using big Murano glass roundels as eyes for his works. The finished result bulged off the panel which was kinda freaky!

using graphite

Graphite (in liquid or pencil form) needs to be applied onto a base of fired enamel. The layer of graphite then must be fired to get some of the graphite to stick. To finish, cover with a layer of clear enamel, and of course, re-fire. If you use pencil some of the graphite can rub off, so you may what to try to shake it or use a clean brush to coax it off (after firing) before you apply the clear, as the linework will smudge if there is remaining graphite on it. Sometimes it’s not as noticeable as others. An example is here,

If you are so inclined to draw with graphite pencil on your piece, you might want to get a drawing surface by mixing some clear enamel with porcelain slip and then firing a thin layer of the mix onto your piece. The ‘tooth’ of the slip helps you lay down a lot of graphite. Porcelain slip is available at any ceramics/pottery supplier. In Melbourne I can direct you to Northcote Pottery Supplies, but I don’t know who you would go to anyplace else, sorry! It’s pretty common, though usually sold in large quantities. I managed to get some from a friend, which, once rehydrated, even managed to survive the trip to the ‘States.

more

If you need more help there’s W.G. Ball‘s instructions on their site, and of course there are always books. I believe that Elizabeth had some input into The Art of Enameling by Linda Darty. This is available on your favourite online reseller, as well as at the Thompson website, where you can also get your copy of the Thompson Enamel Workbook of course!

*NEW*

for some tips on how Thompson enamels behave, check out this on the Schlaifer’s Enameling Supplies site

enamel brands: behaviour of unfired and fired enamels

I’ve recently been working with my WG Ball enamels in earnest, enamelling a series of neckpieces that I have also enamelled in a Thompson colour, a 930 Chinese Red. The WG Ball colour I will use for comparison is their 10104 Sky Blue. Both are liquid enamels that I bought in powdered form, and both applied over a Thompson Clear (low fusing) base. First up, I have found the WG ball enamels to be grainier than the Thompson ones when in solution, and the application to be tougher as they either don’t give good, even coverage (too little water) or when they are covered nicely they then ages to dry and have a tendency to run as they dry (too much water). I’m yet to find a good medium, though as I’m newer to them than the Thompson ones it might just be my water adding and mixing technique. I’ve also tried grinding them down more to help them mix and therefore have better application results, which worked but due to other issues (see below) seemed to be of minimal overall benefit.

The other issue is that thus far, the aforementioned Sky Blue, (as well as some of the other WG Ball enamels I have tried) don’t seem to take on a glossy surface when fired. Again, this is measured in comparison to the Thompson colours (and other colours from Elizabeth Turrell’s studio – I remember a German range there) that I have worked with.

Even to get a semi-gloss is tough. It could be that in my temperature control and timing I am missing the optimum fuse point repeatedly (but once again, I’m hitting the desired time/heat fine with other brands), so the best I can say is that it is very elusive. I’ve either managed to overcook them (they started to flake off the work) or have them look slightly under-fired, with the tell-tale lack of glossy final surface. In the end I have resorted to adding a final layer of clear.

To save time I decided to try mixing them in with some Thompson low-fusing clear. This turned out quite well, to the point that I have begun to mix some of my own colours, thus far just sticking with a single coloured enamel with a single clear.

This works especially well if you are after a more transparent finish, which is something that I happened to want at the time, but in the long run is not really a solution to the gloss-less problem. So far the combinations have played well together in mixing, (meaning they actually go onto the work better) and in finish, as they have fired easily to the desired surface finish.

In my work I have been trying to dilute the strength of the colours a bit too – I’m not into opaque colours at the moment (I like the black of the steel to make itself known and the variegation of the thicknesses of the enamel over a surface give what I find is a desirable smokey quality), but opaque colours are just about everything that I have. In my experiments I’ve been making a mixture of 2:1 (the ratio being premixed clear to premixed coloured enamel, or even more on the clear side of the equation for stronger pigments or to get lighter colouration) on some to ‘water’ them down a bit. That seems to have worked well.