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Teralab Guestbook

This is the place where readers can post their thoughts and comments about the site. The message form can also be useed to ask questions. This guestbook was opened on the 1st of March 2004.


Andrea Baldoni (Italy)
13 August 2012
I'm very happy to see that there is still someone in the world who is "living the science", in special way in our old Europe where everything seems it's "drying"... I'm reading the very interesting book "Uncle Tungsten" that depicts a completely different world 60-70 years ago and I remember the old men who still repaired valve radios in the '80, but now... science is pseudoscience and technology is the new cell phone. Your site is very interesting, like just no many other (one is for instance). I also think you may find interesting the book, "Building Scientific Apparatus" ISBN 9780521878586. Go ahead! Me too I'm trying to make a nice lab and sooner or later I hope I will succeed.

Subject: Glass to metal seals

Tony Bustamante (Los Angeles,C USA)
17 June 2012
Hello Robert. The way you document your efforts are excellent! As said by another in your guestbook , I spent hours experiencing your site. I truly welcomed it. I have been searching sites for months now looking for more info on glass to metal sealing. Your info provide me Inspiration to go it myself on a project I have been working on. I'd sure like to see how you do the glass/wire pinch, and the tools you use to do that. Thanks for taking the time to build this site. Tonyb


Jackson Compton (United States)
19 March 2012
Thank you for your contribution to all of us whom visit your site Robert. Your enlightenment to those who visit here is not without appreciation. THANK YOU! Respectfully, Jackson Compton

Cloud chamber

Peter March (UK)
3 January 2012
Hi I am Pete and a Radio Amateur call M0FMT. I did Open University Science in 1972? and we did some Quantum Physics which included particle visulization with bubble and cloud chambers and your site reminded me of this. Needless to say I never followed this surge of scientific interest up. Thanks for such an interesting site. Cheers Pete HNY.


Gordon C Kirkwood (United States)
2nd November 2011
Thanks for posting such detailed records of your experiments and interests. We have a lot in common! I am interested in glassblowing of scientific glassware and physics too, and found your site as I searched for high voltage resistors and glassblowing. I'm attempting to make a series of glass liquid resistors for high voltage duty in a marx generator and was looking for a precedent. No dice in that specific regard here, but much other inspiration.


Puhazhenthi (India)
11th September 2011
Interesting and inspiring.


Mike Jackson (Canada)
6th August 2011
Thanks so much for putting this site together. I was looking to see how practical it would be to make glass structures for various vacuum devices like heat pipes, and found your site inspiring. Keep up the good work!


Glen Hutson (Australia)
20 December 2010
Hi Robert, Just stumbled on your site while looking for cloud chamber inspiration. Nice work, I intend to write you a considered email about your site and experiments but for now want to thank you for sharing with us. just wonderful to see someone with a brain and some curiosity .. the net is so full of dull science 'entertainment'. Cheers. Glen


Arthur (Mexico)
4th September 2010
I really want to thank you for the info, here in my country is dificult to get conductive ito glass, Im gonna try this option that sounds great thanks from mexico.

Conductive glass

Lisa (Germany)
28th May 2010
Hi, Great site. All the sort of things I would like to do if I had the time! I wonder whether you have tried making Aluminised Zinc Oxide (AZO) conductive glass? I guess it would be more difficult than tin oxide conductive glass. Keep up the great work! Lisa.

TV/vaccuum physics etc.

Malcolm Burrell (UK)
28th May 2010
Dear Robert, I really enjoyed your website. It describes and illustrates your experiments quite beautifully. I encountered it accidentally while looking at methods of joining glass. My own interest relates vintage (405-Lines) TV, of course. Your Video Monitor using an oscilloscope tube is very interesting in that it reminds me of the receivers built by enthusiasts using ex-Government components. I might one day even try it myself. I do recollect fitting a 12" radar tube to a TV with quite spectacular results (orange & black picture with a long persistence). And in one workshop I did modulate the tube cathode of our little Telequipment oscilloscope to produce a picture which intrigued my colleague at the time. Your Virtual Museum is also interesting. I once also mistook a Barretter for a lamp. Some GEC TV receivers in the early 1950s used the device to assist in stabilising the series heater chain although most engineers simply replaced them with high wattage wire-wound resistors. Your hologram experiments are interesting. I'm reminded of the 'father' of Holography, Prof. Dennis Gabor. He, in fact, also proposed a 'Flat CRT for Colour TV' during the mid-1950s. I spent many years as a TV engineer but, like most, tended to take the replacement parts market for granted. Of course, when dealing with a set 50 years beyond its 'sell by' date, it isn't possible to pop along the road to buy a new line output transformer so devising methods of reconstruction is necessary. I've collected several vintage TVs which I'm slowly renovating. One of the major problems is the fact that some of the cathode ray tubes have faults such as low emission or partially short-circuit heaters. 'Rejuvenation' techniques can sometimes temporarily restore operation but the only permanent cure is to rebuild the device. Of course, I realise the hazards of implosion but have been thinking seriously about the possibility of trying to replace defective heater/cathode assemblies in some tubes. Again, the numerous back street tube rebuilders vanished once the TV rental market collapsed so the expertise seems to have been lost. I think just one or two remain - in the USA and France! This suggests that rebuilding a given monochrome tube would cost 300 or more. Of course a good vacuum pump is essential but first I've been considering the problems of safely opening tubes without damaging the fluoreseen material and concluded that the 'hot wire' method is probably the best. The second problem I'm considering is that of dismantling the electron gun, obtaining the correct 29mm, 35mm,or 38mm glass tubing then joining it to the remnants of the neck. The third is to There are other factors such as obtaining Barium to coat cathodes or the construction of new heater (filaments). Fitting new components would demand spot welding with some precision while evacuation should be accomplished with the device placed in an oven - all areas where I have no expertise! But I'm still thinking! I'd be pleased to hear any comments you might have...? Best wishes and good luck, Malcolm


Garry Anderson (USA)
4 May 2010
I am the head engineer for CIT and have access to dumet for the last 30 years. For some small quantities of dumet .015 to .040 I may be able to help someone on special projects.


Geert (Netherlands)
30 April 2010
Great site! Amazing experiments! I just bumped into it searching for some Dumet info. I have worked for Philips Lighting for 32 year, doing all the stuff you are doing at home (great job btw). Now I'm self employed as hot glass handling consultant ( I haven't read all of your site yet, but certainly will once I am back home (currently on a job in China for a couple of weeks). Best regards, Geert

Scientific Glassblowing

John Rultedge (USA)
18 August 2009
This site was the only reliable source I found on the net that could answer some questions I have for a glass project I'm involved with at work. Definitely will come back to this site again for updates.

Making your own lamps

Mark Lawton (UK)
14 May 2009
Hi there, I like your site in general, but especially about making your own low voltage filament lamps. I also like the museum of old lamps and thermionic valves too. My Name is Mark, and I am an electronics engineer working in Aldridge, Walsall at We repair drives and controls there for industrial use. I read your history, and I have always made projects and tinkered about with things too. My parents had a "G8" too, and I kept on repairing it a lot! I used to visit "Thackers" in Cheslyn Hay to pick up old radio bits, I am a radio amateur, and a hobbyist, as well as working in electronics. One big project I did was to convert my Skoda Favorit to run on LPG. It was a success, and I sold the car with it fitted some years later. I like your filament lamps because they are nostalgic to look at, and the light is nice from them. I don't like the CF lamps we use today, and I have been looking for some 240V squirrel cage bulbs for my floor lamp in the lounge, as well as for my ceiling fan lamps as well. I'm not sure how they stand vibration in a fan lamp, but they sure do look pretty. I am looking for some way to start an online business, so I am always searching the net looking for "bespoke" items, hence how I fell upon your website. I would love to work for myself doing something, it does not have to be electronic either. I did a search on "glass blowing lamps" and I found you from this search on Google. Thanks for a great site.

Glass to Metal Seal

Kamal Baid (India)
19 December 2008
Hi, I carefully read the amazing work done by you. I also noticed that you acknowledge JLC Electromet as a Dumet supplier. Yes I developed production of dumet wire from basic stage by reading and understanding the fundamentals of glass to metal seals and properties of materials. I am a mechanical engineer who has developed many many technologies, materials and very special purpose machines including dumetplant for mass commercial production. Any body in world and in any country if want to do any scientific work with Dumet of any kind,(Bare,Borated,Oxidised or Nickel plated) I offer him free Dumet for his Scientific work, Ex factory , Jaipur, India.
Any body want to share knowledge on Glass Sealing and material can contact me at
Once again I congratulate to you for doing wonderfull work by hand and assure you of all of my Technical Support for the enhencement of this knowledge for the betterment of all living being.
Kamal Baid

Electron Optics and Tesla Coil

Galang Hakim (Indonesia)
8 December 2008
Hi Mr. hunt
its good to know that there are a great people that always share their experimental to the world and thanks to you I can go on with my own research again
its a nice, great, and its fun to see this site after a long... long... tiredness searching. by the way i would like to ask question how about we combine tesla coil and electron gun you had made, so we can transfer energi wirelessly Via electron modulate with specific frequency by tesla coil. it seems fun but sounds crazy isnt it???
last words.... thanks for all of your experiments and keep the good job all the time Cheer Hakim Galang

Reply from Teralab:
I think you may have invented the magnetron.

Vacuum System -- Nice

Tom K (USA)
23 September 2008
Dear Mr. Hunt, I found your website while searching for information on power supplies for a metal evaporator. I didn't expect to find a hobbyist doing these kinds of experiments, but I'm glad I did. So much fun, and an inspiration to me, as I've been wondering if I could put an evaporator together to show to my daughter's Kindergarten-1st grade (ages 5-7) class. Your work is an existence proof that it can be done. Well done! Have you tried pumping down your vacuum system with a glass of water inside the chamber? Maybe not so good for the system, but it is fun to see water boil at room temperature!

Reply from Teralab:
Yes I have tried it. When you see it it's hard to believe it's at room temperature. It is bad for the pumps but one can get away with it for a while with the gas ballast fully open on the rotary pump. Better still use somebody else's pump.

Re Your Site

Tim (New Zealand)
2 March 2008
Hi, normally I flick through various internet sites and look (at the 1 in 100 that don't seem to be trying to sell you something) for a few mins..Ive been on yours for hours..I love the kinds of things you're into myself...I pulled things to bits when I was very young and have electrocuted,burnt and poisoned myself many times...Now that im older I am a bit more careful and of course a lot wiser from my mistakes and experiments...I was wrapt to see the tesla coil and I read everything you have on the glass bulb type stuff...Im gonna give that a go..Its hard to buy glass tube in this country as they think you're making drugs !!!In fact I think I have read everything in your site and some of the link sites as well. I think you did a great job with this site...Thanks for sharing it all...Cheers Tim

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