Sciencemadness Discussion Board - Glassblowing

Glassblowing

DFliyerz - 19-4-2015 at 19:13

I've seen a little bit of interesting discussion on glassblowing to make your own RBFs and other things, and was wondering what sort of things are needed to get started?

Zombie - 19-4-2015 at 19:29

Do a youtube search on Lab Glass Blowing. There are dozens of very cool videos. There is quite a lot of it you can do at home or in a glass blowers co-op. This vid shows a basic set up, and demonstration.

https://www.youtube.com/watch?v=CGngoVau4ME

Dr.Bob - 19-4-2015 at 19:32

The main challenge is the gas and oxygen to run a real glass torch, plus the torch, those all add up to a good bit, unfortunately, otherwise I would have one. I sent some stuff to the guy said that he would repair stuff, but I have not gotten anything back yet.

DFliyerz - 20-4-2015 at 06:39

Could a propane/MAPP gas torch work for very small-scale glasswork?

gdflp - 20-4-2015 at 06:46

Very small-scale. It takes a lot of practice to make sure that the heat of the flame is focused on just the right part of the glass, but even then you won't be able to do anything very large. Sealing the necks of ampoules is the only "glassblowing" I do frequently and a propane torch is hot enough if it's focused on the right spot, but anything much larger than that or similarly sized glass tubing will need a real oxygen-fuel torch. I find MAPP gas, or at least the torch I have, is not preferable for any sort of glassblowing because the flame is much less focused in one spot whereas a propane torch has a very sharp, well defined flame.

Zombie - 20-4-2015 at 07:07

Quote: Originally posted by gdflp

I find MAPP gas, or at least the torch I have, is not preferable for any sort of glassblowing because the flame is much less focused in one spot whereas a propane torch has a very sharp, well defined flame.

That IS a result of your torch. and not the gas.

Mapp gas is simply hotter than propane, and in reality much easier to use for small scale glass work. The work is faster, and you use less gas, saving money in the long run.

Magpie - 20-4-2015 at 08:37

Quote: Originally posted by Zombie

That IS a result of your torch. and not the gas.

I agree. A Bernz-O-matic torch will give a fine point with MAPP.
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I looked hard at Bernz-0-matic's oxy-propane torch sold by Home Depot for ~$60. But the customer comments were only about 50% favorable. Comments ranged from "...never should have been put on the market..." to "...did the job, what you would expect...." The major problem centered around the fine control of the oxygen. It does not use the typical regulator but instead has a multi-turn needle valve.

The Bernz torch w/MAPP will melt borosilicate, barely. It would probably do a good job with lime-soda glass. But who uses that anymore - maybe for some test tubes.

[Edited on 20-4-2015 by Magpie]

[Edited on 20-4-2015 by Magpie]

Kitsune1 - 21-4-2015 at 06:43

I have managed to do a few things with a simple alcohol lamp, a few days ago I converted a shattered borosilicate burette into an air cooled condenser column (it works great, used it today with MeOH) all without using my torch, It just takes a very long time with heating, you need to be careful and sometimes your joints might pick up small amounts of carbon. I often just use an alcohol lamp to make small pieces of apparatus from tubes, pipettes, ampoules and even the small glass ampoules that you can find inside a long thin glowstick (it actually works really well for making Tetraphosphorus as long as you are careful when you make the apparatus and also for ampouling very small quantities of compounds in either solid, liquid or gaseous states).

DFliyerz - 22-4-2015 at 08:01

Quote: Originally posted by Kitsune1

I have managed to do a few things with a simple alcohol lamp, a few days ago I converted a shattered borosilicate burette into an air cooled condenser column (it works great, used it today with MeOH) all without using my torch, It just takes a very long time with heating, you need to be careful and sometimes your joints might pick up small amounts of carbon. I often just use an alcohol lamp to make small pieces of apparatus from tubes, pipettes, ampoules and even the small glass ampoules that you can find inside a long thin glowstick (it actually works really well for making Tetraphosphorus as long as you are careful when you make the apparatus and also for ampouling very small quantities of compounds in either solid, liquid or gaseous states).

Sounds like fun, actually!

Magpie - 22-4-2015 at 22:10

Using a Bernz0matic torch on MAPP I have made some very rugged looking annular sparge tubes. The fusing is solid with no visible seam. But these eventually fail in testing as the inner 6mm tube snaps off right at the base of the weld. I suspect that the failures may be due to inadequate annealing, a subject about which I am just learning.

Any suggestions or guidance on annealing would be appreciated.

Jylliana - 24-4-2015 at 01:53

I haven't read the full thing, but it may be interesting for people here to read

A Handbook of Laboratory Glass-Blowing by Bernard D. Bolas
Download free and legal, afaik.

violet sin - 24-4-2015 at 02:33

I have done glass blowing in the past. but it was art and pipes for a glass blower that serviced shops in the area. he barely paid me, but I did learn a lot. what you guys are describing with the map gas torch and all,... no where near as easy as a real torch set up.... which wasn't easy at all.

for one, there was really great control, and 2 separate torches built into one device. it had a head roughly 1.5" square for heating a large area, and a small head directly above it that was the fine flame. you could run both at the same time and adjust individually to heat and work larger areas or thicker glass. while adjusting O2 and propane for oxidizing/reducing flame or running a lot of O2 for a cool flame for delicate work. the oxygen came out cold if you turned it up on high. up to 3" borosilicate tube on a regular basis. we used a huge standalone oxygen take about 5' tall and 2' across with propane tanks you might find on an RV or large BBQ. ( we also lived/worked in a prop 215 friendly county ) I didn't jump on the medical band wagon but we( mendocino county) were some of the first to use medical legally, and it was a legitimate business. so please don't bust my chops about that. all above board.

we ALWAYS wore the rosy color eye protection to block out IR, and shield you from shattering glass. we worked on a standard oak desk with two layers of concrete board atop it. on this was an assortment of graphite tipped tools. there was a large graphite plate to set stuff down on while using your hands for other things. we had the blow tube routed around the flames in PCV with rubber hose to the mouth and back of the work piece with a cork. for blowing out a sphere after gathering some tube into a larger lump at one end. there were tweezers for pulling off extra borosillicate when you gathered too much, ya we used the good stuff. metal shears for trimming, cutting and making petals in hot glass tubing ends for decorative pieces. there were 2 graphite blocks. one with half spheres of different sizes cut into it, and one with horisontal half cylinders for necking down or trueing. all the extra's and still it was no easy task to make repeatably good work. besides the clear glass we used colored stock for the designs and dichroic glass for glitter like effects. "millies" were rods of glass with a design already built in. like a peace sign, skull, flower or smiley face. the rod was the same down the entire lenght if cut into thin wafers. you would make a hot spot on the glass and stick it on there, after cooling a bit, you would snap off the rod leaving a thin layer of the design stuck to the piece. we had an electric kiln to anneal the pieces. which still shattered occasionally, for no reason = not easy.

I got to fume the pieces with gold and silver, made some colored 3" butterfly decorations on the end of a rod to be placed in a flower pot, several small jars with colored designs, many many crappy pipes that were just fumed, quite a few that were full colored, some that were fumed and colored... but he stopped paying the employee that was teaching me and had been working for him for a few years... so I quit. she did nothing wrong. he was just into his hobbies way too much to support employees... all in all it was really fun and I wish I had a set up to play with again. surely wouldn't be making art or pipes any more.

the blower was talented, made a bubbler that was almost 3 foot long with a dragons head receptacle for the "tobacco". and all kinds of designs, warts, and a scale pattern scheme. in the middle there was a clear section about 10" long that he put a dragons head with long waving tongue INSIDE. when you drew through the thing, the smoke would percolate throught the body and come out the dragons mouth *visibly* swirling through the clear part as if the dragon was blowing fire. it then went to the mouth piece and out. he did the inside out version of things where the design was done on an opened up tube( flared like a funnel) and just about any other trick you see in a high times magazine. he promised but never came through with some beakers etc. before I knew where to find any. this was about 10 years ago.

simple glassware on a makeshift torch, not out of the question, but repeatability, quality and durability,... I doubt that. the annealing was really important. one of the pipes was dropped off the front of a bluff overlooking the ocean. sloping quite steeply, 75' if it was an inch, banging off rocks and all, barely a chip... now that is bullet proof. think he is living in the bay areas here in cali now for some time, 7 yrs, still blowing glass. if it weren't for the start up costs, I would love to do that again. the torch alone was 450$ back then though. who knows you may find one for cheap some where used.

[Edited on 24-4-2015 by violet sin]

polariscope

Magpie - 13-5-2015 at 10:00

I have assembled a new sparge tube using Simax borosilicate as in previous tries. Again I used MAPP gas and a Bernz-0-Matic torch. Not being an oxy-torch the heat provided is marginal. But the weld looks good and I carefully annealed the assembly. At this time I am assembling a polariscope so that I can check for residual stress. If this device proves out I will post the results.

Texium - 13-5-2015 at 14:31

Yeah... annealing. That's something I definitely need to work on. The simple work that I've done with shaping small tubes in a Bunsen flame didn't really require much work as far as annealing goes, but when I tried attaching a piece of tubing to a hole I drilled into a broken test tube (all for practice) using a MAPP torch, I was able to fuse the pieces well, but it was far too hot, and shattered after cooling. Would quickly switching from MAPP to propane for a while before slowly removing it from the heat be sufficient to allow it to cool slowly enough, or would I need to use an oven?

Magpie - 13-5-2015 at 15:15

I think you could help the glass cool slowly by just wafting the torch over the worked area for a few minutes with a decreasing frequency.

Possibly a better method would be to place the work under a fiberglass blanket, or better yet submerge the work under 2-3" of vermiculite until cool. This last method is something I read on a glass blowing site.

aga - 13-5-2015 at 15:51

Erm, hasn't glass technology been around for a while ?

Heat and Brains are required.

The early glass-blowers had no access to gas torches yet managed incredible structures ( e.g. a tube ).

Gas torches make it whole lot easier, granted, yet you can still do this at home.

Here's a Challenge : make something useful (for chemistry) from a bottle/bottles you found in the garbage.

Long Steel pipe, Barbecue, Charcoal, Hairdryer : give it a go !

(hint: use a long steel tube (fence post) so your hairdryer doesn't melt)

One suggestion would be a gas-wash bottle.

vmelkon - 14-5-2015 at 07:01

Quote: Originally posted by Kitsune1

That's unlikely.
Borosiliate glass softening point is in the 800 C range. I had a lot of difficulty in melting shut a test tube with a propane torch. Borosilicate glass requires a oxy-gas torch to reach large volumes of heat.

Of course, you can melt fine copper wire in a methanol flame as I often did when I was a teen.

Magpie - 15-5-2015 at 19:31

I finished making a polariscope today. This is to be used for examination of glass work for residual stress. I followed the instructions found at the link below except that (1) I used 86mm linear polarizing filters vs his 72mm filters, and (2) I used 48 LEDs vs his 44 LEDs for the light source.

http://www.rhunt.f9.co.uk/Glass_Blowing/Polariscope/Polarisc...

The picture below shows my completed polariscope:

completed polariscope

The next picture was taken with the two polarizing lenses aligned to maximum light. The LEDs are quite visible through the Lucite (60% transmittance) diffuser. The cone of of light is only 12° for these LEDs which makes them quite distinct.

polariscope with light planes aligned.jpg - 63kB

polarizing lenses aligned

The next picture shows the polariscope with the polarizing lenses crossed for maximum darkness. The photo is poor. In my view it is totally dark. The flecks of dust are bits of construction debris (cuttings) that I haven't completely removed yet.

Attachment: phpyCobug (92kB)
This file has been downloaded 546 times
polarizing lenses at 90°

The last picture shows an annealed sparge tube. I could see no stress pattern. You can clearly see the extended inner tube and where the tubes are fused. The orange color on the end is where I had placed a short piece of 8AWG copper wire to prevent closure of the inner tube. After the fusing the wire was removed by dissolution with nitric acid.

annealed sparge tube

I also looked at a sparge tube that had not been annealed. It showed considerable stress lines. I will try to post some better pictures later.

[Edited on 16-5-2015 by Magpie]

j_sum1 - 15-5-2015 at 20:29

Magpie. I am continually impressed by the gidgets and gadgets you construct. Nice work.

Magpie - 16-5-2015 at 10:22

Thank you j_. I only build gadgets that are needed to support my chemistry hobby, or solve some other problem. I don't build them as a hobby per se. But they are usually fun and always educational. Sometimes the structural aspects can be tedious and expensive. The polariscope is a good example. Try to find (locally) spring clips to support the glass plate that supports the upper polaroid lense, for example. Cost on the internet: pennies, shipping cost: $8. I ended up making the 4 spring clips from two bicycle handle bar clips by cutting them in half and drilling mounting holes. Spring steel is extremely hard.

Dirt cheap polaroid lenses from China made the polariscope feasible.

Magpie - 16-5-2015 at 19:22

Here's some more pictures taken of the polariscope in use. I tried to clean all the surfaces with glass cleaner, wiping with bilbous paper which is used to clean glass slides. Obviously it didn't do any good.

The first picture is the end of a stirring rod showing the stress in the end. I'm presuming this is residual stress resulting from the manufacturing process. This is a used rod. I should have checked a new rod.

stirring rod stress

The next picture is that of an unstressed 5 mm borosilicate glass tube.

unstressed glass tube

The last picture is of that same tube experiencing bending moment stress (using my hands).

5mm glass tube under bending moment.jpg - 73kB

bending stress in tube

SimpleChemist-238 - 18-5-2015 at 16:15

I was making spirals with a propane torch today, lots of fun.

Dr.Bob - 18-5-2015 at 19:33

I want to say that I sent some items to theglassguy, and after a little while, I got most back, most repaired, with one or two items were not fixable, one got fixed them broke, and one got broke in repairing it, and he remade it. The repairs look reasonable, some I cannot really tell that they were even repaired.

So I just wanted to post that. I would try to get a real email address and keep in closer contact, it took a while and I was not sure what was happening until done. But since it was all broken then, it was not much of a risk to try out. Not sure what his schedule is like, but I just wanted to give him cudos for helping me.

j_sum1 - 18-5-2015 at 20:59

I presume this is your reference DrBob http://www.sciencemadness.org/talk/viewthread.php?tid=37974
I think I might have taken advantage of that offer if I had been in a different location.

Nice to get some results back. I wondered how that had all worked out.

Dr.Bob - 19-5-2015 at 06:25

Yes, thanks for posting, I was in a hurry and did not have to look up the old thread, but that is it. I just wanted to acknowledge his good work. Its been a bit crazy since my travel, still trying to get my act together, and answer a few emails and u2us.

Bob

theglassguy - 23-5-2015 at 20:50

Thanks for the kudos, Dr. Bob. I'm glad the repairs worked out for you. I'm done with school now and have relocated back to the west coast for the time being. My schedule is much more open now should anyone else want repairs or something made. I will also be making a few example products in the next couple of weeks and posting them for sale as examples of my work. I would also like to say that I am very open to the idea of trading equipment for glass work.