Sciencemadness Discussion Board

DIY glassware

Quince - 14-8-2005 at 23:26

Any glassblowers here? Would it be possible to DIY a Gregar extractor?

BTW, where can I buy for a good price glass fiber extraction thimbles?

bio2 - 15-8-2005 at 00:48

Make it from plastic! Depending on what you will do with it polypropylene is good for many boiling solvents and Teflon stands up to damn near anything.

Argonne is sure a bunch of hype IMHO. What is so "revolutionary" about a couple 3 way valves and a dip tube. Hell, I had a continuos 22 Liter extractor hooked to a drum of solvent that did this using FEP 7/8 tubing and compression fittings for vegetable oil extractions many moons ago.

There is a HDPE cutting board I bought at the restaurant supply a while ago that has a US patent on it. Which goes to show that just about anything can be patented.

I bet there are a lot of chemists that have similar apparatus that they have pieced together. It took these 2 guys 8 months to build this thing, give me a break.

http://www.techtransfer.anl.gov/techtour/gregar.html

zoomer - 15-8-2005 at 15:27

Maybe this isn't the best place to admit it :), but for most simple activities I use disposable "tupperware"-type food containers. They are cheap, flexible and easily modifiable, don't break when dropped, heat well in the microwave, have airtight lids for long storage (such as crystal growing), and if something goes wrong, they have guilt-free disposal. Since I work a lot with kids, the durability and lids are especially important. Obviously many reactions must be done in glass, and if in doubt I always use glass. But by using the food containers where logical I have dramatically reduced my apparatus expenses. FWIW.

z

bio2 - 16-8-2005 at 03:06

My neighbor saves me these graduated 500ml
PP square containers that infant electrolyte comes in. The closures are so good that the bottle will explode before it leaks.

He drinks a couple everyday so I use them for lots of things like beakers with the tops cut off. These bottles are just as good as $7 Nalgene ones I've bought.

Did you ever wonder why Nalgene says "immediate damage may occur" with toluene in polypropylene then there PP sep funnel ditty says compatible with virtually anything that will be used in a separatory funnel.

I love my PP sep funnel but not as much as the 2L FEP one. Sometimes I will just toss it on the table after washing and smile!

Quince - 16-8-2005 at 04:25

Quote:
My neighbor...infant electrolyte....He drinks a couple everyday

Why does your neighbor drink infant electrolyte?! :o
Quote:
I love my PP sep funnel but not as much as the 2L FEP one. Sometimes I will just toss it on the table after washing and smile!

Well, I already have a glass one, but I guess you're right, can't toss that across the table.

BTW, do you guys think an art glass blower could make me a Gregar extractor if I provide a sketch (without mentioning it's patented, of course)? I don't think there are any scientific glassblowers around Vancouver, and I don't have the tools (or money to cover failures) to try myself. How much should I find reasonable to pay for such a job? I thought of buying a Soxhlet, but then I figure this would be better. But I couldn't even think of paying the $400 to buy from the licensed manufacturer.

There's glassblowing services at my university, but I'm not in the chemistry department, so I think they'll be very suspicious if I ask them.

[Edited on 16-8-2005 by Quince]

zoomer - 16-8-2005 at 11:03

Glass-blowing requires a good deal of skill, and consequently it is typically not cheap. A pro who builds a one-of-a-kind (for him) is likely to be at least as expensive as purchasing the labware. A student may offer you a significant discount, but caveat emptor.

If you do find an inexpensive source for custom glassware, let us know.

Quince - 17-8-2005 at 13:58

Well, the chemistry department guy never replied. He must have simply reported me to the cops or something. :)

However, a scientific glassblower in the neighboring town replied: "Dear Sir,
We can manufacture the glassware as per your drawing. What dimensions?"
When I emailed them this image:
http://chemistry.anl.gov/preview/GregarWeb/GregarAll.JPG

Now, I want to see if they'll quote me less than the retail price ($430 US at chemglass.com).

So, I want to ask you guys, do I really need the secondary condenser, or should I skip that to get a smaller quote? Also, instead of using the special thimble, wouldn't it be better to be able to use regular Soxhlet glass fibre thimbles? It seems the walls here have to be non-pervious, so one should ba able to get this by putting a Soxhlet thimble in a glass cylinder.

Gregar extractor

Primathon - 17-8-2005 at 14:56

I have been working with pyrex for almost six years now, and that project should be doable by anyone with a decent amount of skill.

If you don't have any scientific glassblowing contacts, check out your local head shops (you're in freakin' Vancouver. They're everywhere), and inquire as to where they get their quality glass. Some of it may be outsourced, but again, you're in BC, so there is a lot of local action going on. Hell, half of my glassblowing videos are from shops in that area. They should be able to provide you with a quote.

Also, look around online to find glass supply shops, as it would be worth your while to source the ground glass joints and the T-connections ahead of time (this will make the project significantly less expensive than if the blower has to find these things). This will also give you a good excuse to go with the extra condenser, as you can just fit a ground glass joint on the side. Hook a condenser up if you need it, stopper the joint if you don't. This also gives the benifit of making sure that this apparatus will be perfectly compatible with all of your existing glassware, as you get to choose the connections.

As for the thimble, I think that would depend a lot on what exactly it is you would be extracting. You'll have to do the research there...

And as to zoomer's comment on the expenses involved, I think he overestimated it a bit (but I suppose I could be wrong). Using clear tubing (I suppose you could get it worked with color... but why?), the total cost of glass tubing involved there (excluding T-connections and GG joints) is well under twenty dollars. Any decent glass studio will have most of the required diameters on hand.

Hope this helps. Let me know how it turns out.

Quince - 17-8-2005 at 15:12

Hey, maybe we should do an interest check for a group order, if someone can locate a cheap glassblower. Buying in quantity is bound to get a pretty good price.

zoomer - 17-8-2005 at 17:29

Agreed that the materials are cheap, I imagined that the labor costs would be very high. But that was in reference to an earlier comment about an artist doing the work. I'm now very curious to see what Quince's quote comes to.

Z

Mr. Wizard - 17-8-2005 at 19:30

Primathon, do you use propane to heat your pyrex? All the books I've seen mention natural gas, but I don't have access to any,not in usable amounts anyway;) I've had problems with the pyrex getting a black shiny tinge to it while using propane and air, which I guess is carbon being deposited. I guess the question is: what fuel and oxidizers do you use.

Quince - 17-8-2005 at 21:25

If you're getting carbon deposits, you're probably not using enough air, or holding the piece too close to the centre of the flame where the gas hasn't completely burned yet. I've used a plumbing-intended propane torch on pyrex tubing and never had any such problem.

I still haven't gotten a quote, but I'm guessing I won't like it, since their non-custom products are pricy (I'm talking about a local scientific glassblowing place). I'll probably try an artist later on.

[Edited on 18-8-2005 by Quince]

12AX7 - 17-8-2005 at 21:41

I just finished melting some lead and lead chloride in a nearly-trashed pyrex flask... worked fine. Did I mention I used a small foundry burner? :D

No soot to worry about if the mixture is right, it should be a greenish-blue to blue to purple flame with NO yellow in sight (although there may be some thin orange on incandescent things in the flame, I don't know why).

Tim

Pyrex information

Primathon - 17-8-2005 at 21:51

I use a combination propane/oxygen torch, which is what almost every pyrex lampworker uses as well. It's easy, cheap, available, and powerful. At the correct ratio, you can get the temperature of propane/oxygen up pretty damn high. I've heard it quoted at a theoretical max of 4579°F (2526°C).

I think my torch gets pretty close to that, seeing as how at full blast it sounds very much like a turbine engine, shoots a blue/bright white flame a good foot and a half, and can burn (not melt, mind you) any number of metals, including (but not limited to :D) Silver, Gold, Platinum, Aluminum, and Iron. Also works very well for instantly incinerating moths and various other flying bugs that are attracted to UV light...

Oh, and if you grill with charcoal, it's an easy way to get your coals white-hot in about 3 minutes :). What? Quit looking at me like that...

As for how hot your torch needs to be:

Physical properties of Pyrex
Working point = 1,252°C
Softening point = 821°C
Annealing point = 565°C
Strain point = 510°C

Links:
Pyrex Borosilicate Glass Information
I rant for a little bit about pyrex here as well.
A link I got from LabTop way back in the day - Scientific Glassblowing

Quince - 17-8-2005 at 22:28

I also need to seal off a quartz glass bulb. The problem is that the softening point is about 1700*C. Can't do this with a regular propane torch. :(

Quince - 19-8-2005 at 16:30

Got a quote from one sci.glassblower. Canadian $400 = US $330. That's only US $100 cheaper than the retail price I found on the Web (chemglass.com). I was hoping to spend no more than Canadian $300. I'm going to try another local sci.glassblower, and then artists.

BTW, are the 3-way valves supposed to be Teflon or glass?

[Edited on 20-8-2005 by Quince]

Primathon - 20-8-2005 at 07:20

I think you may end up having better luck trying with an artist, especially if you have your extra pieces (GG Joints, T-connections) available ahead of time. Then all they have to do is work a bit of clear tubing, which shouldn't take more than maybe 2 hours. I think you'll get a much better deal, seeing as how the majority of their work is done with intricately crafted cane, colors, inside-out, fuming, marbles, etc. Clear glass is a piece of cake in comparison.

As for the 3-way valves, they can be either (AFIAK). Just make sure you remove the stopcocks before you ask the blower to work on them :D.

And for your quartz bulb, take that with you when you go along to get a quote (hell, ask if you can watch for some of the actual work; it's pretty impressive), and see if they can seal it off for you. Propane/oxygen will take a while, but I think it will get hot enough to do what you're looking for.

Good luck.

Fleaker - 20-8-2005 at 14:37

Propane/oxygen should handle quartz fine. Hm, I might look into that, it seems like a good idea getting custom glassware made. Since most artistic glassblowers in my area aren't making that much revenue, they should be willing to do a little fabrication for decent prices. Do you think they would have enough precision to make say, 24/40 connections (I have a broken fractionating column, needs a connector.)?

Quince - 20-8-2005 at 20:57

Oops, I mean I need to seal the bulb with it containing metal samples in vacuum for high heat treatment. The blower can't do that.

[Edited on 21-8-2005 by Quince]

neutrino - 20-8-2005 at 21:36

Quartz wouldn’t be easy to work with. I have done basic operations with Vycor (which softens ~200*C below quartz), and even an oxy-acetylene torch barely got the job done. It took a good minute of holding the piece in the flame just to soften the tubing (~1cm diameter) to a workable degree. I’m not sure if quartz could be worked at all.

You might want to look around for the type of oxy-hydrogen torch used by jewelers to weld Pt.

Fleaker - 20-8-2005 at 22:41

Oxy-acetylene gets hotter than oxy- hydrogen. A lot of heat is lost due to radiation at those white hot temperatures. With a large enough tip however, it is possible to work it.

Quince - 22-8-2005 at 12:34

Got a new quote: $298 CAD = $245 USD. This includeds main body with side arm and plug and 4-mm bore stopcocks, funnel/solvent guide, thimble with coarse frit, and top with cold finger condenser. I don't think I'll get a better price. The guy said he was aware of this design, but didn't mention anything about patent royalties etc.

Now, the guy did ask me what company I work for, so I just said I'm a student at UBC (true), but I didn't say it wasn't for school work...

If anyone wants to get a quote from this blower on custom work, send me a PM and I'll give his contact info.

neutrino - 22-8-2005 at 18:50

I always thought that hydrogen was superior to acetylene. Thanks for enlightening me.

The problem must have been in the tip. The flame was only about 1cm in diameter.

Quince - 15-9-2005 at 10:41

Just got the Gregar extractor today. Now, for extracting HNO3 with methylene chloride, as per the patent, which configuration would I use? I assume it's this one:
http://chemistry.anl.gov/preview/GregarWeb/ExtractLL2.jpg

FrankRizzo - 16-9-2005 at 19:57

Quince,

Would you mind posting a picture of your new toy?

Quince - 16-9-2005 at 22:18

Unfortunately, I use a film camera. My only digital camera is the crappy one on my phone, so the attached image is the best I can do.

gregar.jpg - 41kB

Quince - 22-9-2005 at 20:26

Anyone try making their own extraction thimbles? The only ones I found are cellulose and quite expensive.

I tried to fold coffee filters in the right shape, but it doesn't work very good.

I was thinking just using mineral wool as used in insulation, and first washing it in the solvent I plan to use in extraction. Any comments, ideas?

[Edited on 23-9-2005 by Quince]

Rosco Bodine - 23-9-2005 at 07:15

An idea which I never tried but should work is to use the same principle as the
" sand filter " used on swimming pools
and spas for water filtration . You could make a little sandbag from fiberglass cloth or other cloth , and twist tie it closed , just large enough to be a snug fit against the walls of the extractor . This would allow dissolved material to pass through . Even a loose layer of mixed grit sizes of sand and gravel might work okay as a filter . You should have very little contamination from any solubles using quartz sands , especially if the sands were prewashed with muriatic acid and rinsed with water followed by a rinse with whatever solvent will be used for the extraction .

12AX7 - 23-9-2005 at 12:48

And/or diatomaceous earth. ;)

Tim

Quince - 24-9-2005 at 17:16

Here's a slighlty better picture showing extraction of ASA with acetone. I just packed a bit of cleaned fiberglass wool at the bottom and it seems to work fine. The only problem is I got it a bit too big, as the minimum amount of solvent is about a cup.

Yep, the stands are DIY...that's copper pipe you see there :D

I did something stupid -- greased up the joints with glycerine, so now most of it is in the extract...

The hardest part will be getting the ASA out of the flask.

[Edited on 25-9-2005 by Quince]

gregar.jpg - 40kB

Beatnik - 26-9-2005 at 05:02

Quince. Its beutifull! and here i was working with a crude pvc concept :)

Quince - 26-9-2005 at 05:07

Took about one hour to do the extraction, with about 3:2 by volume aspirin and acetone. Worked better once I thought to also insulate the lower half of the extractor body. LOL, I initially had set the valves wrong...

Quince - 6-10-2005 at 20:02

OK, broke the thimble already...knocked over a cognac bottle and it fell on the thimble...