Bottlehead Forum

General Category => Technical topics => Topic started by: Doc B. on July 15, 2025, 05:38:55 AM

Title: Basing Cement
Post by: Doc B. on July 15, 2025, 05:38:55 AM
Was just looking at a 1930s chart of the materials used to glue the metal base to an old fashioned incandescent light bulb. The recipe included -
alcohol
marble dust
pine resin
shellac
chalk
bakelite
glyptol
malachite green
Makes one wonder if a similar brew was used to attach the bakelite bases of vacuum tubes of that era.
Title: Re: Basing Cement
Post by: Thermioniclife on July 15, 2025, 05:57:47 AM
I would think so because I have seen separated tubes and burnt out light bulbs that separated from the base when removing, stuff looks similar.
Title: Re: Basing Cement
Post by: Doc B. on July 15, 2025, 06:51:52 AM
So you're saying that, if I dedicate the next 6 years to experimenting with various combinations of these ingredients to get it to work right, I just might come up with a product to sell to the three people who post here per year asking what to glue a loose tube base back on with.

Speaking of old tech I just found out that our neighbor across the parking lot had a 5000 sq. ft. facility that ground and polished aspherical lenses for the likes of Edmund Scientific. The main machines are rather archaic analog control pantographs that used precision machined metal patterns. He's retiring and selling off the machinery if anyone is interested in gigantic pantograph mills. Probably a good thing I don't have the space as he has some pretty cool machinery. I saw a pretty big and beautiful 1880s vintage gear driven lathe that sold very quickly.
Title: Re: Basing Cement
Post by: Thermioniclife on July 15, 2025, 09:12:27 AM
Jeese Dan I did not suggest that they were the same compound. I really don't understand your somewhat contentious opening statement to my reply? Frankly It is no concern of mine what you do with the next 6 years of your life. I merely stated that the stuff looks similar. Am I misunderstanding you?
Title: Re: Basing Cement
Post by: Doc B. on July 15, 2025, 09:19:41 AM
Yes, apparently. It was meant entirely as a poke at my own delusions. I was chuckling to myself that I found some insane new rabbit hole to go down. Apologies that it came across wrong.
Title: Re: Basing Cement
Post by: Thermioniclife on July 15, 2025, 02:57:07 PM
Roger that Dan. No offense taken.
Title: Re: Basing Cement
Post by: 2wo on July 15, 2025, 04:23:11 PM
Weren't you the same  guy who was refinishing old racing leathers?😁