PDA

View Full Version : Lutings - Ancient & Modern



thrival
02-02-2013, 11:18 PM
Some of my experiments have been held up for some time for lack of a material that I could identify that would stand up to strong acids, nitric, to be specific. It's such a dangerous acid that I surely don't want to make any mistakes. Henley's manual recommends cement & asbestos powder, the latter is pretty impossible to find these days. Recently I found CaCO2, linseed oil & rubber cement, but I'd prefer something that removes cleanly and leaves no residue. There's teflon foam that fills and seals nicely (but pricey) and doesn't regain it's original shape once compressed.

I'm wondering if anyone would be willing to share their favorite lute recipes (Useful for those who come after.)

Krisztian
02-02-2013, 11:57 PM
I'm wondering if anyone would be willing to share their favorite lute recipes (Useful for those who come after.)

Depending on the glassware, yes, there're many recipes that are worth exploring, red clay in particular mixed with raw eggs is quite good.

My suggestion would be - it's done blindly for I don't know what glassware you refer to - but I think such http://www.chemglass.com/product_view.asp?pnr=CG-137&item=CG-137-04&this=1#CG-137-04 would also provide peace of mind.

thrival
02-03-2013, 05:48 AM
Raw eggs and clay? Interesting, and a lot cheaper than labware.

I've created ceramic ware collars for joining wide-mouth jars (think: angel-food cake molds joined at their bottoms, with an outlet drain.) The idea is to have one appliance to do a variety of things, with commonly available glassware. The lute seals the gap between the jar mouth and collar. I could upload pics from my computer if that feature were available, but I'm only finding this board accepts files & links from urls.

Krisztian
02-04-2013, 07:08 PM
Raw eggs and clay?

Yes, I've read that combination in several old manuscripts. Common practice in those days.

I'm certain there're others on this Forum who would have suggestions.


I've created ceramic ware collars for joining wide-mouth jars (think: angel-food cake molds joined at their bottoms, with an outlet drain.) The idea is to have one appliance to do a variety of things, with commonly available glassware. The lute seals the gap between the jar mouth and collar. I could upload pics from my computer if that feature were available, but I'm only finding this board accepts files & links from urls.

Interesting.

If photo available, it would be my pleasure seeing it.

Krisztian
02-06-2013, 02:11 AM
I'm wondering if anyone would be willing to share their favorite lute recipes (Useful for those who come after.)

Zosimos believed to have used flour-paste.

thrival
02-06-2013, 02:54 PM
Here's the pic.

http://img27.imageshack.us/img27/589/im001161.jpg

Again, my special need is for a lute that stands up to nitric acid. If any of you have experience other than the
high-end laboratory glassware route, it would be very helpful toward making this art accessible to everyone.

thrival
02-15-2013, 05:21 AM
As for lutings, it seems I found some answers. There is a PTFE based oil & grease that can stand up to strong, boiling acids, is called Krytox made by Dupont. It is VERY pricey. The idea is to cut such an acid-resistant oil/grease with clay powder to form a non-drying, easily removable putty. Several other companies sell similar product, rebranded; Halogen comes to mind. Also there's a product called Chesterton 3500 Valvelon that comes in a roll, you pull off the amount needed and smush it in. Haven't priced it yet, if too expensive I may just go with PTFE plumbing paste, mixed with clay, per above.

thrival
02-16-2013, 02:18 PM
I found a PTFE plumbing paste, reasonably priced, called "Real-Tuff" made by Hercules company, that can stand up to acids. I will mix with clay and use as a sealant putty. Here's a diagram how to use the ceramic collar.

http://img18.imageshack.us/img18/7646/ceramiccollar.jpg (http://imageshack.us/photo/my-images/18/ceramiccollar.jpg/)

Krisztian
02-16-2013, 04:43 PM
I found a PTFE plumbing paste, reasonably priced. . .

Excellent, I'm happy. There's always a solution. I use PTFE also. Can't go wrong with it, much recommended for Soxhlet extractor.

theFool
02-16-2013, 04:57 PM
You could try "teflon paint" also (http://www2.dupont.com/Teflon/en_US/products/paint/surface_protector.html). It creates a teflon coating, resistant to acid.

Karl
03-12-2013, 01:46 AM
Hi Thrival

I am loving that ceramic collar! Well done. Those technical drawings get top marks as well. Is it slab built? My solution for making mason jars into labware was to drill a hole with a step bit through a regular mason jar lid and connect piping to it with compression fittings. Your ceramic collar would have the advantage in acid resistance though.

This is highly theoretical but a mixture of wax and rosin might do the trick - it would be thermally unstable but both are nitric acid resistant and have been used historically as a luting. If it ran and stopped working, perhaps mixed with a fine silica it would concretize sufficiently to do the job. Might just create a big gooey mess. Should come off with turpentine or naptha.

thrival
03-30-2013, 04:28 PM
Hi Karl;

Thanks for the kind words & suggestion. The collar was made using push-mold technique-- dog-dishes, plastic cup & saran wrap to get the basic shape. I lost quite a few in an oil-fired outdoor kiln/foundry, unable to control the heat. Since then have bought a used electric kiln and can get good finishes by repeat firings. I didn't expect I'd need to become a potter before becoming an alchemist, but it will save you money in the long run, if you have the time.

Well my desire was to have something that removes cleanly to reduce possibility of contaminating the work when dissassembling the parts. Having come up with my teflon-clay putty mix have since realized that damp stiff clay alone should work with nitric and other strong acid. As long as the experiment has some dampness inside the container, the lute shouldn't dry out. Also the danger of explosions with acids is really scary, can mess up your work area and yourself if in proximity. In worst case I would rather have a clay lute give and vent than have glassware go boom.

Karl
04-06-2013, 08:44 PM
Hey Thrival-

You inspired me to design my own version of this- this one fits a narrow mouthed mason jar and is assembled from slab built clay. Tried to minimize the wall thickness to 1/4" everywhere- the spout would be a 3/8" diameter glass tube. I am going to do a clay body shrinkage test to come up with a scale factor and give it a whirl.

http://i60.photobucket.com/albums/h19/karlcrosby/collar1_zps5611247f.jpg

thrival
04-08-2013, 12:51 AM
Karl:

Go for it! Personally I'd like to find a nontoxic, non-reactive material that can withstand heat and air-harden, or in a low-temp oven.