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The best site ever!

Xarru (Estonia)
23 November 2007
These are the best physical experiments I have ever heard about, especially those glass blowing things... Yea, anyways, all I'm saying: keep going!


Andreas Franzen (Germany)
26 October 2007
To my knowledge the first US patent on Dumet is USP 1083070 by Eldred. Instead of Dumet it is also possible to use easy to get thin walled copper tubes, like in USP 1093997 by Kraus. Another possibility that works well even with water pipe stuff from the hardware store is the knife edge technique as described in USP 1294466 by Houskeeper. Most important seams to be the borating procedure to get the bright red CU(I) shine. In "Reimann, A.L.: Coppered-Tungsten Seals through Hard Glass, Journal of Scientific Instruments, Vol. 23, June 1946, pp. 121-124" a method is described to clean the copper by immersion into chromic acid, wash it with tap water, dip it into a saturated solution of borax and pass it horizontally slowly through the oxidizing zone of a gas flame.

Reply from Teralab:
On further investigation, it appears that Dumet was introduced by Fink and Eldred. I have updated the page.

General comment

Ely Silk (USA)
14 August 2007
I thank you for a very interesting Web site. The demonstrations are really nice and well photographed.


Geoff Vane (Netherlands)
12 August 2007
Good to see that there still are mad scientists! Keep up the good work. Just don't read any Mary Shelley books... :) I am currently thinking of making an improved nixie, with a separate neon tube per nixie, to avoid cathode poisoning. I could be asking you some questions in future.

Congratulations... and thank you!

Hugo Gavarini (Argentina)
19 April 2007
Robert Hunt, Your site is a very informative and clear one. Despite the fact that science is a bit difficult matter to approach, you have made it easy to understand! We are trying to be glass artists, so we use to search research and develop ancient techniques. Thank you very much for your generosity. Graciela and Hugo.


Hannah (England)
8 February 2007
Well done, an inspiring site! Great for a-level students to link ideas with mathematics, thankyou. Hannah x

3rp1-a PAL video display

Mark Carter (Australia)
3 January 2007
Hey there, Thanks for putting in the work on the 3rp1-a display for PAL video. I have begun to gather the parts to build one for my self to display a digital TV signal and use it as an alarm/tv for my Nixie clock project. I'll send you some photos once I'm done. Keep up the great work, Mark


Keith Gerard (Scotland)
22 November 2006
Dear Robert, I just wanted to congratulate you on your website. As a seven or eight year old, I used to beg my Father to bring home old TV's for me to pull apart (My Father, a self taught Radio and TV man), you know, the Bakelite Bush which sell for a fortune now. Reading your biography and browsing your website has reminded me that in this modern world, where technology is so much taken for granted, there are those people like yourself, whose enthusiasm for all things technological is infectious. It is my hope that you expand on your website so that your enthusiasm inspires the young to look a little closer at all that surrounds them, as well as the technology of a bygone age! Best Regards, Keith.

Gambrell Brothers

Tim Rich (Wales)
4 November 2006
Nice to see the Coil Resistance 200 Ohms Mk1 made by the Gambrell Brothers - my Great Grandfather's firm! They also made the first modern radios with mains power and no batteries, and many other things.

Your Dedication for Raw Minds

Peter Vaz (Goa, India)
19 July 2006
Excellent site with interesting experiments and using this site as a tool I began my first experiments on glass.This site will help millions around the world like me in quest of the noble stuff like Glass. Everything is discussed in length but I would like the author to describe more in breadth about the methods of cooling the glass (unlike ceramic wool)rather than going for the annealing ovens.

Your Site

Jim Tyson (Canada)
25 June 2006
Excellent. I'm envious. The electron gun especially is a beautiful piece of work. What made me write however, was the chuckle that I got picturing your spouse patiently waiting for her dinner while you x-rayed the crab.

General Comments

Bert Koehler (USA)
8 June 2006
I agree with all that your site is excellent. You're an inspiration and encouragement to experimenters, and I'm positive you make Dr. Who quite jealous. I hope you keep working on interesting things and posting reports. My thanks.

X-ray of Baby House Martin

Nelson (USA)
5 May 2006
Only thing I can think of about the solid objects that were in the bird is that they could be rocks and sand. Birds have been known to swallow rocks and sand to help grind up food in their stomachs. Its possible that the mother may have given the sand and rocks to the baby bird when the mother regurgitated food to feed it. Just my idea, no facts or animals were harmed in this process....

X-Ray Gallery

Stephan (Germany)
4 May 2006
Hi, regarding the white objects on the x-ray of the dead baby bird: like dinosaurs, birds swallow small stones and keep them in their stomach to aid in digestion, the stones work like millstones.

Whole Site

George Schmermund (USA)
20 March 2006

Scientific Glass Blowing

Ramon Morales (Texas)
11 March 2006

I learn a little off hand glass blowing from Mr David Hammer. He used to work for PPG so did I. I am not sure if this has being covered by previous articles in this site but here I go: Use dydimium glasses when doing glass blowing, It removes the glare from the sodium spectral lines and you will be able to see your job. Other types of glasses or goggles provide only marginal results.

You can buy two pairs of polaroid sunglasses and wear one of them, while using the other polarized glass with a lamp behind to provide polarized light. insert the annealed or newly made piece between the two, and you will be able to see stress lines etc. That will indicate if further annealing is necessary.

Home Experimenting

Ramon S. Morales (Texas)
8 March 2006
I love your site. We have the the same curiosity to find out by ourself, instead of just accepting what we read. By recreating an experiment, other scientists have notice details that perhaps were overlook. Remember the expert opinion of the Physics professor who declare that "No machine heavier than air would fly"? Thank you and all who share their own experiments and ideas to the site.

Vacuum Metalizing & Glass Glow

Sabou Constantin (Romania)
Thanks for your existing Robert Hunt! This site is a large quantity pure practical information. This thinks is not present in any University from presennt only theoretical form. Congratiulation! You are hot. You are a amazing man. Thanks!

Reply from Teralab:
I've gone all red.

Very Good Site

Joseph Heeren (Belgium)
6 February 2006
Congratulations with your very interesting experiments and the clear way you explained them in the Teralab site. These are very inspiring subjects, I am amazed how one individual can reproduce such important experiments in an artisanal manner. I am 57 years old and build some things myself, but as medical doctor I had not much time for myself, now that I think of retiring I am glad that websites like yours offers a lot of ideas to people who are interested in science in some way like the pioneers did. Keep up the good work, this should be an example for mankind for spending its time in peaceful activities.

Glass Seal

salemlampworks (USA)
16 January 2006
Hello. You might want to try JLC Electromet it produces dumet seals. Regards. Gary.

Dumet Seals Source

Jerome Callahan (USA)
27 September 2005
Thanks for all the helpful info. I just came across a source for dumet seals

Wheatstone Bridge

Pete Andrews (United Kingdom)
2 September 2005
Hi. Just found your virtual museum whilst searching for wartime electronic equipment. I believe the 1940 Wheatstone bridge is a "Coil, resistance, 200-ohms" used by the Royal Engineers to test the integrity of electric demolition firing circuits and to check that dynamo exploders were generating sufficient power. It was one of three components included in a demolitions testing kit, the "Box, testing and jointing". I have another item from the same kit which is the "Detector Q & I Mk.1", a form of galvanometer. The third component was a battery (cell) contained in a wooden box. Different tests could be performed by hooking up the 3 components in various combinations. There is a description of the device and a couple of diagrams in the war office 1942 booklet "Military Engineering: Demolitions". Cheers. Pete Andrews

Reply from Teralab:
Thank you for this information. This makes the box even more interesting. So it is a Wheatstone bridge, but with other functions designed specifically for testing demolition circuits. I have updated the page.

Nice Scientific Site

Nalle (Finland)
31 August 2005
Very nice scientific site! I liked the glass works and spot welding article.

Avo Minor

Jonny Gresswell (England)
28 August 2005
I have been searching for information on the Avo Minor for a while and this is the first site with anything on it. I have recently acquired one in excellent condition and in its original box. It was given to me and I was just interested in finding out a bit about it. Thanks.


Doug Coulter (USA)
21 August 2005
We seem to have somewhat similar pasts, interesting. I enjoyed your site, especially as I am now putting together a high vacuum system here. I run a little computer business, mostly embedded programming, but have added a pretty complete machine shop (I will be making most of the vacuum gear in it) and electroplating/anodizing lines. I'd pass on my website, but it's about to move anyway. If you get in touch, I'll keep you posted.

All Those CRTs...

Chris McMahon (Canada)
19 August 2005
This is one of the coolest sites there is. I was especially amazed that you made your own X-ray and gamma photography. I was wondering where you get all those CRTs. you have so many, you even sacrificed one for your electron gun (almost as cool as your own private X-ray machine).

Nice Site

Brian Symons (Australia)
15 August 2005

This is a fabulous site. Well laid out, thoughtfully presented & most of all it is practical.

I really enjoyed the info on glass blowing. I've had an interest in electrostatics for a long time & a little glass work would be handy.

Liked the mini spot welder. I might make one too. One warning I saw recently was NOT to use plastic insulated wire in rewinding these. Apparently people wanting high currents have been using auto battery cable etc & the short circuit currents if the insulation fails are horrendous - easy to cause a fire if not detected early enough.

One last question. Have you considered electroplating the wire section that will be in the glass. Instead of a "bath" for electroplating, you can use a small "swab plating" unit - where only the "swab" contains the chemical. A conductive wire electrode wrapped in a tiny bit of cotton wool and covered with cloth would be all you need. You may even be able to find hollow shaft Qtips or cotton buds (some cheap ones use a hollow plastic shaft) and slide the wire up the centre. I don't know if just copper sulphate solution would do - do a little web surfing.

Thanks for the site, Brian.

Reply from Teralab:
Thanks for the warning about shorted turns. I used shrink sleeve which can stand a fairly high temperature. Also the transformer is only pulsed on when doing a weld. I don't leave it energized. I did once try copper plating Ni/Fe wire using copper sulphate in sulfuric acid. The finish was lumpy and I could not make a good seal with it. I might have another go at some point. I know the type of cotton buds you are referring to. In fact I have got some with hollow shafts. That is an interesting idea.

Mystery Object

Nigel Walker (UK)
14 July 2005
Your mystery object might be a thermostat. I have a Weller soldering iron, which works using the ferromagnetic principle : if you heat a magnet to a certain temperature, determined when the magnet is made, it suddenly loses its magnetism. When it cools off, the magnetism returns! Your object might have been mounted in some other assembly. Does that sound feasible?

Reply from Teralab:
It's an interesting idea. Ferromagnetic materials have a Curie point, above which they become paramagnetic. I suppose it is conceivable that during this transition, an EMF would be induced in the coil by the changing field. The polarity of the pulse would depend upon whether the temperature was rising or falling through the Curie point. I still think it was for sensing a moving ferrous material in a high temperature environment. It would have worked like a magnetic tape head, with the magnet providing the bias.

Great Web site

Ely Silk (USA)
8 July 2005
I really enjoyed my visit to your web site. Thank you for posting your fine work for us to look at and learn from!

Glass Blowing

Dan Eggar (USA)
3 July 2005
I am a beginner glass blower my self but I found a couple items to be very handy; a spark plug boot and a piece of surgical tubing. Slide the tubing in to the spark plug boot and insert your glass in to the boot. The boot can handle a lot of heat and will hold a variety of different sizes. The tubing is flexible, allowing you to be able to blow on the glass with out having to put it close to your face, plus you can better see the area you are working on.


Peter (UK)
18 June 2005
Totally mad (but fun!!!). Keep up the good work

Great Site!

Allen Pollock (Maine, USA)
25 March 2005
Thanks for sharing your wonder in discovery. I appreciate the interest you have and working in same area. Have fun. Keep enjoying it.


Gert Benadé (South Africa)
5 March 2005
I discovered your site by accident and found it extremely informative and interesting. Having been fascinated by scientific concepts from a very young age myself, but had nowhere to turn for help or guidance, it has always been a struggle. Thanks to people like you, 'rookies' like myself can now build on what we know from knowledge and experience we gain from guys like you! Great Site - Keep Up The Good Work!

A Totally Great Site

Joe Malek (USA)
09 February 2005

In high school my father bought me a copy of the Amateur Scientist's blue book filled with neat experiments. But the cloud chambers and atom smasher were my favorites. I converted and old refrigerator pump into a vacuum pump and built a discharge tube. Never got any further.

Now I am 55 years old and last night I fired up a rebuilt high vacuum system's mechanical pump and lit off a discharge tube with 13kV. It felt great. Your web site was a great inspiration. I plan on trying some of your discharge lamp building and then go on to build a particle accelerator. I am also working on a thermoelectrically cooled cloud chamber (in place of dry ice).

Here is an experiment with practical application. How about a cold cathode ionization gauge built like a hot cathode tube with grid and plate. But build it inline, a cathode block machined from metal separated from a grid block by a glass cylinder which in turn is separated from the plate by another glass cylinder. The plate block is also the exhaust port. The grid would have a piece of brass screening across the hole in the center. I was thinking of using 'O' rings in groves in the blocks that are the same diameter as the glass tubes and holding it all together with nylon compression screws from the plate to the cathode.

So all I can say is 'WOW', wonderful site. Keep up the good work.

Glass and Vacuum !

Abel Santoro (Argentina)
26 January 2005
Very interesting place! To work with glass and vacuum is exciting! I am working in homemade electron tubes. Best regards and good luck!

Great web site

Tim Dolan (USA)
18 January 2005
Hi, This is in the fine tradition of the Amateur Scientist Column that appeared for years in Scientific American. The collected articles can be purchased on CD. Try Regards, Tim Dolan...

Glass to Metal Seals

Larry Weber (USA)
31 December 2004
Have you considered prefiring the Ni48/Fe52 alloy in wet hydrogen to form a nice oxide layer that will easily stick to the glass? All the old tube books I have run across recommend it. I was wondering if this would reduce the bubbling that you experienced. Of course I hate to think of running hydrogen into a 900 C furnace but perhaps a forming gas made of a hydrogen/nitrogen mixture would be safe and would work just as well. I really enjoyed your site!!! Thanks for sharing your adventures with us.

Thank you

Jeff Andrews (Hawaii)
27 December 2004
Aloha, Very refreshing to read, clarity, professional standards. I have enjoyed the style and have learned fast. My area of learning, since 1993 is hyper composite design and manufacture of tubular structure, tapered parts (fishing rod blanks shhssh!). About powering a m.w. transformer, I have performed surgery on two identical Xfmers and remove one primary and lessened 90% of the wraps on the remaining primary coil. Have made spacers of metal and hi temp plastic. So I have 1 prim @20 wraps and 2 full secondaries @3000wraps each. The goal is to design an AC and Dc output Hi Voltage Pwr Supply, I have been scouring the web for how to do this. I would be very happy to proceed with professional direction. PS the nearest neighbor is 120 yrds away LOL Jeff.

Excellent Website

Rahim (South Africa)
16 December 2004
I really enjoyed the glass blowing info, I fell like doing it immediately. What an excellent website, I ended up going from page to page until I finished all the pages and then looked for more. Great, I wish you were in South Africa.

I wish you were my science teacher..

Ronnie Willett (USA)
9 December 2004
I love your site, mainly the part about glass blowing. I'm 15 and think it's the coolest thing. You have really sparked my mind with all the information. Everything is layed out beautifully with pictures and data. Thankyou for spending your time on this web-page. You don't know how much it teaches people. - Your next Einstein, RonE Willett.

Great things happening in the home works

John Lundy (Australia)
3 December 2004
Thank you for the wonderful webpages together with the fine photography. You forgive all the crazy things on the internet when you come across pages such as I have seen here. I have been highly interested in high vacuum and have been experimenting and finally making high power photographic flash tubes in my home workshop using scrounged equipment where possible. My background is television repairs, ham radio, photographic flash equipment repairs and manufacture for the last 30 years. I am a member of a local model and experimental engineering club (MSMEE). One of my best references has been the late Fred Rosebury's Electron Tube Handbook.

Vacuum Evaporation

Mike Burden (UK)
10 August 2004
Glad to see a Nanotech Microprep coater still working, I started Nanotech in 1970 and ran it until 1985. Great site!

Had a good time reading ALL

Jose Vicente (Brazil)
08 August 2004
I like to work with electronics since 1948 and still loving experiments enjoyed all I saw in your very good page. I have all kind of tools and surplus to play with, even a high vacuum pump. Would like to build a diffusion pump some day. Please keep up the good work, I will be your reader from now on. Thanks, Jose.


Dr M Rezaur Rahim (Bangladesh)
28 July 2004
Nice Site. The video amplifier scripts are very informative and detailed.


Mark Atherton (NZ by way of USA from UK)
28 July 2004
Your site is what I miss about living in the UK - original ingenuity on a shoestring. I should have snagged some vacuum pumps when I moved from the US. Regards and well done. - Mark.

Great Site

12 July 2004
Great site, I really enjoyed it.

Making Light Bulbs

Alice (USA)
03 July 2004
Since I'm old enough to have survived seeing 5 teenagers into adulthood, I can honestly admit that I have no memory of why I to clicked into this website (Need to prove Memory Loss is a parent's self defense mechanism against ending up going completely insane!) It has been sooooo long since anything scientific has sparked any interest in me. I had no earthly idea that one can actually MAKE light bulbs! Your step by step, picture by picture, account of the processes is amazingly easy to understand as well as profoundly interesting. It's been close to 3 hours since I started this unintended educational experience, but I feel as invigorated as if I'd just bought my first new car!


Paul (UK)
16 June 2004
What an ace site. Got the link from New Scientist. Really like the domestic X-ray photos, a real cool idea and I think the way you explain the experiments is cool to. Hope you add more stuff in the future, I will be sure to return. :-)

Thank You

Joe Sousa
03 April 2004
Thank you very much for doing such a great job of sharing your experiments with the world. Sites like yours fulfill the promise of the internet. I have not decided if I should be more impressed the quality of your presentation, or the actual material... My only modest effort in this direction was to upload a 1960's Philbrick catalog to Use my IINVNT id in the photo sharing - browse a member section. The 16 pages of scans show the first commercial tube opamps and also some of the first transistor opamps. I thought you might be interested because of the tube connection. Best regards, Joe Sousa.

Your Web Pages

Godfrey C Leggett
03 April 2004
A friend sent me your web address in an email. I went to your page on building a CRT. Wow, you built a real humvee version, certainly not a volkswagon. I then proceeded to find my way back to your home page and read every one of your pages. Fascinating, I applaud your dogged pursuit of your various projects. While reading your history, I felt that I was reading my own. Very entertaining stuff.

Glass Blowing

Tom Kinsky
29 March 2004
Hi, I just wanted to say that I enjoyed reading your very detailed and informative tips on glassblowing. The photos were very helpful, too. I am an elementary school science specialist and for a few years now have been capping off our fifth grade (11 year old) unit on matter by having the students spend two periods cutting, heating and bending glass tubing. I think it is borosilicate glass, and usually 6mm or slightly larger, and thick walled I believe. Anyway, the students get a 30 cm piece to do with as they will, and usually manage at least two or three bends in the 'straw', although sometimes as many as seven or eight. They seem to like the experience, especially as they get to work with alcohol burners. They have often asked about blowing into the tubes, but I never really knew how to go about it. Now, though, at least I can attempt a few on my own as demonstration pieces! Again, thanks for the site, it was fun to visit!

Nice site!

Fabio (Italy)
19 March 2004
The glass blowing section is wonderful and can be really useful for my experiments! :-) I suggest mercury vapours instead of neon for gas discharge experiments, you need only a small quicksilver droplet inside the tube before pumping. Ciao! Fabio.

Nice Site

Michael Betz
17 March 2004
Hey, a really nice site, I like it! Especially the glass blowing workshop. I didn't think that something like that could be so interesting! Cheers. Michi.

Very Nice Webpage

Anders Mikkelsen (Norway)
17 March 2004
It's a very nice webpage you have. I especially like the glass blowing page. I have always loved electronics in glass, like vacuum tubes and lightbulbs and neon signs (must be real neon tubes, not the modern kind with mercury/argon inside and a fluorescent coating, the glass must be transparent) and stuff like that. Your glass blowing page has inspired me, so now I'm buying glass tubes. Hmm, now I'll just have to get a vacuum pump. As I said, your page is very nice, keep up the good work.

Useful Site !

Steve Taylor
17 March 2004
At last ! Some decent pictures of a small spot welder - we are trying to spot molybdenum elements for one of our instruments and checking on-line resources for some notes. Great site. I'll be back..... Steve

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