Thursday, 11 August 2011
Glass frosting: etchant vs. tumbler
I've got a tag on this blog that says "etched glass/stone", though actually it has come to include not just beads, pendants, cabs and glass stones I've frosted using etching cream but also glass frosted in a tumbler. I've been thinking about doing a comparison between these to techniques for creating frosted/etched surfaces on -- primarily -- glass. I'd love to try sand blasting too (small scale, using Sand Etch), but right now I only have experience using the two other methods.
Before I begin discussing the pros and cons of the methods, I'd like to add that I'm still a beginner when it comes to using etching liquids as well as a tumbler. In fact, the tumbler is not even mine so it's my sis who's in charge of it, I just pitch in every now and then with my views and ideas. But so far, this is what I've learned:
Safety and usage
Etching liquid etches not only glass but also skin so you have to wear protective gloves and think about what kind of tools to use etc. It's also said that vapours can cloud mirrors and damage glass in storage. Add to that discussions on whether it really is a safe chemical or not. Besides, even if it claims to be non-toxic, it doesn't mean it's safe if used without care!
The tumbler on the other hand contains nothing caustic. You should of cause not inhale the abrasive powders (if using that rather than e.g. sand) and if tumbling crystal glass in particular, you should dispose of the dross wisely as it can contain lead. The waste can also clog the pipes so it shouldn't be poured down the drain.
The etchant shouldn't be stored or used cold as it forms crystals that has to be removed before etching my heating and stirring the liquid.
Etching cream can also get stuck in holes as well as nooks and crannies on the surface, which are hard to clean. When it dries, it could just as well be cement. That's how hard it can be to remove.
Personally, I find etching creams more messy than a tumbler, but if working with an etchant you just dip the beads into that would probably be easier.
As for the saftey of the younger members of the household, I'd say it's a bigger problem if a kid or pet walks into a room where you have etching cream/fluid on the table than a tumbler.
It takes perhaps 15-20 minutes according to the instructions for the etch cream/fluid to great a good finish while it takes hours to acheive a nice texture in a tumbler. However, especially if using cream rather than a dipping fluid, you have to apply the etchant to each piece individually and make sure it's covered. With a tumbler, you just chuck it all in and let the machine do the work. Likewise, you don't have to thoroughly clean the tumbled glass piece by piece as you have to with an etch cream (you must remove every trace of the chemicals). You have to check on it at intervals to stop the process at the right point, but that goes for both methods.
While i takes weeks to tumble raw stones into shiny, polished cabs and pendants, it is a matter of hours or at tops a couple of days to frost glass. In fact, if you just want to burnish the sharp edges instead of getting the matte finish, it can take as little as 30 minutes.
The barrels for the tumbler comes in different sizes and also the tumblers themselves are made for different volumes, so you can choose a bigger solution for tumbling larger quantities at once.
With an etchant, you can vary the depth of the etching by letting it work for a longer or shorter periods. Just like with the tumbler. However, with a tumbler you can choose between different abrasive and thus create everything from fine to coarse textures. There's room for experimentation.
With and etching cream you can use stencils, resist gels or stickers to create patterns or motif on the surface, which I doubt is possible with a tumbler where the water and mechanical abrasion would wear down the resists.
There's also one more important difference: the etchant with etch the entire (uncovered) surface while the tumbler usually leaves the recesses untouched. See the fifth picture in this post: notice the oily AB finish still there in the crevices while the raised areas are matte. Here, the alternative to the chemicals would be sand blasting, not a tumbler, if looking for an even matte finish.
The etchant I used (by EtchAll) works on "soft" glass, but not on Pyrex/borosilicate glass. According to Rings & Things it works most of the time on japanese seed beads, but the coatings seem to weaken the etchant, make it less effective. It also works on some stones, e.g. agates and onyxes, but not on all -- and you might not know which ones works until you test it yourself. Some stones with etch terribly unevenly, with both shiny and matte areas, which looks really bad.
For the tumbler, different abrasive have different efficiency: it shouldn't be too hard to be able and grind down most surfaces, hard or soft.
To be honest, I haven't really done any calculations. However, I will offer a few points to keep in mind.
First of all, the tumbler isn't cheap and the abrasives will need to be replaced as they're being used. On the other hand, a tumbler can be used for many more things than the etchant. You can work-harden and polish metal, tumble stones, ceramics, polymer clay etc and creating hematite like oxidized finishes on metal. The tumbler is supposed to use a moderate amount of electricity even if it's on for several hours for each batch.
The etchant can be reused many times, while the abrasives for the tumbler, mixed with glass residue, can't be used for a new batch. Buying etchant is cheaper than the starting cost for buying tumblers and abrasives, but I haven't calculated the cost per piece. You can often use plastic tools and protective gloves you already have at home.
Both methods have their pros and cons. Which one you prefer depends both on what you want to be able to acheive in terms of textures and finishes or what materials you want to work with. I use both etchants and tumblers and don't see myself abandoning one for the other. They do a similar job, yes, but in different ways with different results -- and I like them both!
Buying a tumbler isn't cheap and so it might be a decision that needs to be thought over more than buying a jar of etchant (a small jar isn't too expensive) just to test it. You probably shouldn't buy one unless you actually plan on using it more than once or twice. If possible, ask if you can borrow someone else's tumbler for a trial run or buy a used one if you aren't sure of whether you "need" a new tumbler of your own. If you work with metal, make beads or wants to get into lapidary, it might be more useful than if just etching a few glass pebbles once a month or perhaps even less as you can take advantage of the versatility of it then.
The third alternative: Sand blasting
Another alternative to potentially harmful chemicals is sand blasting. There are special set-ups for small items and home studios, such as a Sand Blast kit. I haven't tested it myself, but hope to be able to do it in the future. It could be an alternative to etch creams and a complement to a tumbler as it can achieve even matte finish on textured surfaces and you can use resists unlike in a tumbler.
Do you use tumblers or etchants -- or sand blasting for that matter -- to give glass and stone a nice texture or etch motifs? Please, feel free to share your experiences and add to the list of pros and cons.
Footnote: For our experiments, we have used EtchAll etching cream (but not Dip 'n' etch) and a Lortone tumbler with commercial abrasives.