Sciencemadness Discussion Board

Quartz Tubing

IrC - 22-9-2005 at 14:48

I have some 3 foot lengths of 25mm OD quartz tubing. I want to cut a 14 inch length from one for building a tube furnace. What is the best method to make a perfect cut without danger of cracking the tubing? Also what method would be best to bend one into a U-tube and would danger of cracking on cooldown be an issue? Never worked with quartz tubing before and it took a long time to find the perfect size, do not wish to take any chances wrecking any of them if possible. I figure this tubing is the safest way to run hydrogen gas through my glow powders at 1,100 C.

Eclectic - 22-9-2005 at 15:09

Thin kerf diamond saw. Check lapidary suppliers. Alternately, a thin copper disk with diamond or SiC grit. Maybe even a dry cut diamond masonry blade from the hardware supply in a skillsaw. Do you mind sharing your glow powder recipes?

uber luminal - 22-9-2005 at 15:42

Quartz is some cool stuff. Its coef of thermal expansion is lower than most materials,(except, say Diamond or special engineered materials), and its resistance to thermal shock is also very high.

You can take a quartz tube straight up to 1500-1600C (rapidly) and quench it into water or oil and it wont crack.

I would use a diamond saw to cut it, but a good blade and saw cost more than you probably want to even consider. I would not recommend trying to score it, and break it because its in the form of a tube(you will always be going against some plain)

As for getting a bend in it, buy a preformed bend. hah. I can make nice bends in small tubes like 10-18 mm tubes, but the larger diameter you get, the thinner the walls are, and its harder to work with.

You will have to find a heating source, that reaches above 1700C and has a wide area of heating. what I do to get good bends in tubes is something like this...
1. Place the tube in a test tube holder vertically.
2. use a hand torch with O2+natgas or whatever, (and a #5 shade to protect eyes) to heat the area around where the bend or U will start. you must constantly go around all sides to get even heating. It will become a soft white through the goggles/face shield when the quartz is soft. I then gently pull (or just let gravity to do the work), and neck down a little and hold it there, then heat further down where from where you necked a little, and make a slight bend. then you need to let this cool, and start again a little further down... making small bends and letting the quartz ooze a little each time so not to make anything too thin.

if the tube is small enough, you can just heat the thing and bend it however you want, but it will likely collapse or kink.

IrC - 22-9-2005 at 16:22

Not at all Eclectic, I do not mind sharing my experiments, and thank you and uber luminal for the quartz manipulating ideas. I have to run right now so I can only go in to it a little bit at this time.

I can tell you I use the basic patents and experiment with mostly changing the co-activators from Dy2O3 to various lanthanide and actinides from hydroxides to oxides to carbonates. I have found my best results in starting with calcium metal in water and then aluminum dust to get to an aluminate. Usually say 99 percent molar strontium or calcium (one or the other) carbonates or oxides (or hydroxides) and 102 percent molar aluminum oxide, with about .05 percent molar Eu2O3 and around 0.1 percent molar La2O3 (or Co3). Ball mill the hell out of it all, sinter at 900 C for an hour. Ball mill again, then run at 900 C to 1,100 C for an hour with 3 percent H2 and 97 percent N2 at 0.1 liter/minute. The fun is in altering the basic patents in working to find better reds (especially) and other colors, with glow times of 24 hours from a 20 minute exposure to Uv at I have no idea what intensity the light is.

I am trying many variations on reducing the Eu from three to two, I do not like the H2 idea at all but I am experimenting with designing a tube furnace to make this safer. I also have 4 pounds of calcium hydride and I was hoping to figure out a way to use this as the reduction and the calcium all at once with no need to use a gas. Especially since purity is very important (the reason I use ceramic media in my ball mill and even this is not so good). So many elements act as quenching agents that this is a hard mad science subject to do. Iron for example wipes out all hope of a glow and I don't care how small the amount of it there is, any at all and you end up in failure. Found this out using steel balls in the mill and studying online as to what was happening. I don't think ceramic media is so good either but I am not sure what else to use. I even bought a pound of boiling stones and experimented with these as media for the ball mill.

Right now my main focus is all about playing with different ideas to find the impossibly bright and long lasting red. I hope. One of these days I was going to write up some of this but I am not far enough along yet and my DSL will not allow me to FTP images to the site anyway. It will appear to log in but refuses to list no matter what FTP method I use.

I once read about an explosion in a lab making their own aluminates from aluminum dust and calcium metal, I lost the page and never could find it again so I try to look for it every so often as I really would like to refresh my memory as to what they did so I do not do the same thing by accident. So far I minimize this possibility by making small amounts at a time and adding the 500 mesh Al in small amounts while hoping I do not end up on the dark side of the moon. I am mixing this in a beaker with distilled water and Al dust isn't so happy here. Magnetic stir forever, then dry it on low in the kiln, mill, sinter, and then go on with whatever recipe from there.

There are also experiments not using water to make aluminates but rather sintering the compounds in the kiln after ball milling well, and then going on from there. Also adding the activator and co-activater before or after this step. Lots of room to play in this area. Like I mentioned my best results were wet methods starting with pure calcuim and aluminum metals, but also the most dangerous I imagine.

For the most part if you have no metals on the chart around iron (or it's neighbors) and can whip the Eu reduction problem it is harder to NOT make a glow powder than to make one. What is interesting is these very glow killing elements are the very ones that end you up with high temperature superconducting ceramics, explain that one to me. I have done a lot of study and experiments (minus the 3 weeks of kiln rebuilding - that ITC 100 works miracles!), and for whatever reason in this weird mad science ceramic area I keep running into the fact that superconductivity and glow are exactly opposite. At least I think so, it seems the elements used act this way.

When I have some time I will list what patents I know of so you can read them.

[Edited on 23-9-2005 by IrC]

Quibbler - 23-9-2005 at 04:09

It is difficult to add anything to the excellent replies above, but I must emphasise the eye protection. Ordinary didymium glass blowing goggles do not work, I had spots before my eyes for weeks after finding this out. Also quartz contaminates easily. I was using the tube for pyrolysis experiments using electrically heated nichrome wire directly wound on the tube, after a short time it causes the quartz to become brittle.

uber luminal - 23-9-2005 at 09:13

Good points Quibbler. Quartz will glow a soft red/orange (very cool looking) and then start to get yellow/white around edges and soon the its a high intensity white. This semi-white light WILL damage vision without any filters.

and for contamination, yes, added impurities will diffuse and cause stress in the structure. (making it more brittle) You can guess diffusion will happen if the radii of the atoms are about the same as the Si, about the same electroneg, about the same valence (although higher valance is perfered). The structure shouldnt matter much because you are only looking at partial diffusion contamination.

I thought I would add 2 other things...

Quartz isnt the answer to everything. There are some metals that will react with the Si in the tetrahral. This on its own creates vacancies and charge problems (more brittle from added stress).

Quartz may have an awsome thermal expansion, but anything that is inside it, may not. If a material touching the quartz expands a great deal, this can spall the surface of the quartz on cooling. Spalls don't act like cracks, but they do physically weaken the walls.

Oxy-Natgas is a good option. I think oxy-propane would work too. I have heard... from an expert quartz/glass blower that Acetylene can contaminate the structure, from one of the inner envelopes of the flame. (I have used it anyway, to fuse quartz, but I would not bet my reputation on the strength of those fused sections.

Cyrus - 23-9-2005 at 10:07

I'm interested in your method of producing calcium aluminate, because it's used as a refractory binder in many commercial products.


IrC - 23-9-2005 at 13:01

It is painfully slow the way I do it and only for small amounts. To keep H2 from building up I use a beaker that will be 70 percent full with whatever amount of distilled water I am using, just so the H2 flows off the top into a vent fan to the outside right behind the beaker. In this I was just trying not to have a volume of H2 buildup, but rather as fast as it is produced it is gone. Anyway, I figure out how much calcium metal and aluminum dust I am going to use for the glow formula at the time. Then I drop the calcium metal in one pellot at a time and let it fiz around until gone. This I put in a somewhat larger beaker with a coated magnetic stir bar. Start stirring, and slowly over time add Al dust (more H2) in small amounts at a time letting it all react before adding any more. Then I warm it while stirring a few hours. You will have a suspension of sorts but no raw metal left of any kind. This I dry slowly below 300 F in the kiln until dry.

If any aluminum remains I either recalculate the entire batch to get away with adding more calcium metal, or let settle and do not use portion with Al (but this messes up molar amounts overall and I am trying to carefully formulate rather than make bulk amounts of glow powders, so it is important to me to have no unreacted Al left). Remove, ball mill, then back in the kiln at 1,000 C for an hour.

I am sure there are better ways but so far nothing has exploded in my face and when I add lanthanides and reduce in kiln for an hour to make a glow powder, I find good results in my experiments (yellow for example if I use Eu2O3 and Dy2O3).

I also have calcium and aluminum hydroxides and I have tried various and sundry methods just using raw chemicals but for whatever reason I cannot explain the glow powders made starting with nothing but the pure metals are much better. For your purposes my method of starting with calcium metal does not make sense as I am sure you need quantities greater than what I play with. I have one thought about why starting with metals works better and this pertains to my belief that the processed chemicals such as calcium hydroxide (from anywhere I have found it anyway) may have trace impurities related to iron in the plumbing in whatever factory made it leaching into the final product. All I can say is this is my best guess, but even a small number of atoms of iron in a glow powder will end in a ceramic that only glows at ground zero on national nuke day.

IrC - 1-10-2005 at 16:07

I found a metal backed diamond wheel made by dremel that comes with an arbor for 15 bucks. It smoothly cuts the quartz tubing like going through paper, no cracks - perfection.

Quince - 8-10-2005 at 04:45

I have some of those wheels. I tried to cut sapphire wafer and it fucking sucks, wore the diamond powder off the wheel in no time. Dremel attachments are the biggest scam after religion and alternative medicine.

[Edited on 8-10-2005 by Quince]

vulture - 8-10-2005 at 07:51

Well, hardness of quartz is around 7, where sapphire is 9, so no wonder even diamond blades wear fast.

IrC - 8-10-2005 at 08:53

Originally posted by Quince
I have some of those wheels. I tried to cut sapphire wafer and it fucking sucks, wore the diamond powder off the wheel in no time. Dremel attachments are the biggest scam after religion and alternative medicine.

[Edited on 8-10-2005 by Quince]

Boy have you got that right! I paid 15 bucks for one at home depot. Later I found a place that I can mail order five wheels also for 15 dollars! Not a dremel part but exactly the same thing. Everything dremel is robbery!

Maya - 14-11-2006 at 03:57

I have some 3 foot X 25mm open ended quartz tubes that I would like to make closed ended on the one side, what is the technique people use to to this?

I am looking to use in my furnace which has one opening only , for use with an inert atmosphere or vacuum up to 1100 -1200c


Fleaker - 14-11-2006 at 15:52

You will need a very hot torch that will get to about 1750*C, oxyhydrogen or oxypropane will get the job done easily. Look through cobalt glass or a welder's mask; if you look directly at the quartz as it melts, you will blind yourself. I would heat the end of the tube while spinning it until it melts. While still spinning and applying heat, I'd suck in at the cool end and pull the molten quartz, effectively shutting it.

Maya - 15-11-2006 at 03:38

Okay, so you don't use a graphite flat / spherical tool for shaping the quartz like you do with glass? just let it flow when the temp reaches a high enough temp.

OxygenPropane premix 3a torch enough to seal the end on a 19mm ID 24mm OD quartz tube, I guess i'll find out.

use a big tip like 0.2mm on the torch instead of a narrow 0.05mm tip I assume....

[Edited on 15-11-2006 by Maya]