Videokarma.org

Go Back   Videokarma.org TV - Video - Vintage Television & Radio Forums > Early Television Foundation CRT Rebuilding Project

We appreciate your help

in keeping this site going.
Reply
 
Thread Tools Display Modes
  #61  
Old 10-15-2014, 06:21 PM
Steve McVoy's Avatar
Steve McVoy Steve McVoy is offline
VideoKarma Member
 
Join Date: Oct 2002
Location: Columbus, Ohio
Posts: 1,128
More progress on the oven, though it still isn't finished. I bought some high temperature caulk (good to 750 deg C.) and sealed all the joints between the steel and frame on the inside of the oven. The caulk hardens like clay.

I was able to get the oven to 700 deg F, which is about what we need. However, when the oven had cooled down a good deal of the caulk had separated from the metal and fallen onto the floor of the oven. This is because of warping of the steel that occurs when it reaches a high temperature. I have the steel attached to the frame with bolts spaced 12-18 inches apart. By putting additional bolts along each edge of the steel I think I can contain the warping and that the caulk will stay in place.
Reply With Quote
  #62  
Old 10-15-2014, 08:10 PM
tvcollector's Avatar
tvcollector tvcollector is offline
VideoKarma Member
 
Join Date: Sep 2010
Location: So. Florida
Posts: 1,528
I'm very glad to hear all the progress reports.. It seems like everything is falling into place.. A few years ago many were worried if it will ever happen, and now we are most certain it will..
__________________
Looking for an all tube or hybrid color TV set from the late 1960s, early 1970s that's in a steal cabinet..
Reply With Quote
  #63  
Old 10-16-2014, 01:41 AM
ppppenguin's Avatar
ppppenguin ppppenguin is offline
VideoKarma Member
 
Join Date: Oct 2009
Location: London, UK
Posts: 230
Quote:
Originally Posted by Steve McVoy View Post
More progress on the oven, though it still isn't finished. I bought some high temperature caulk (good to 750 deg C.) ..........

I was able to get the oven to 700 deg F, .........
I worry about the mixed units. Didn't a space mission once fail because one part of the team was working in metric units while another was in feet and inches..
__________________
Jeffrey Borinsky www.borinsky.co.uk
Reply With Quote
  #64  
Old 10-16-2014, 08:53 AM
NoPegs's Avatar
NoPegs NoPegs is offline
The glass is -3dB.
 
Join Date: Mar 2014
Location: Amish Country PA.
Posts: 376
Quote:
Originally Posted by ppppenguin View Post
I worry about the mixed units. Didn't a space mission once fail because one part of the team was working in metric units while another was in feet and inches..
Quite a few space missions have ended in failure for this type of reason. To my knowledge the Hubble is the only one to have overcome it. Everything else crashed and burned.
Reply With Quote
  #65  
Old 10-16-2014, 09:10 AM
drussell drussell is offline
VideoKarma Member
 
Join Date: Feb 2013
Location: Calgary, AB
Posts: 68
Quote:
Originally Posted by Steve McVoy View Post
However, when the oven had cooled down a good deal of the caulk had separated from the metal and fallen onto the floor of the oven. This is because of warping of the steel that occurs when it reaches a high temperature. I have the steel attached to the frame with bolts spaced 12-18 inches apart. By putting additional bolts along each edge of the steel I think I can contain the warping and that the caulk will stay in place.
Can't you also disassemble the frame-steel interface and put caulk in the actual joint before squishing it together to help seal the joints all the way through?
Reply With Quote
Audiokarma
  #66  
Old 10-16-2014, 09:13 AM
drussell drussell is offline
VideoKarma Member
 
Join Date: Feb 2013
Location: Calgary, AB
Posts: 68
Quote:
Originally Posted by NoPegs View Post
Quite a few space missions have ended in failure for this type of reason. To my knowledge the Hubble is the only one to have overcome it. Everything else crashed and burned.
Yeah, it's a bit of a problem when you don't notice your problem until it crashes...

For Hubble, I'm assuming you're meaning the lens sag issue because they forgot to account for gravity bending the lens while it was sitting on Earth pre-launch?
Reply With Quote
  #67  
Old 10-16-2014, 01:01 PM
dtvmcdonald's Avatar
dtvmcdonald dtvmcdonald is offline
VideoKarma Member
 
Join Date: Nov 2012
Posts: 783
Quote:
Originally Posted by drussell View Post
Yeah, it's a bit of a problem when you don't notice your problem until it crashes...

For Hubble, I'm assuming you're meaning the lens sag issue because they forgot to account for gravity bending the lens while it was sitting on Earth pre-launch?
That was not the Hubble problem.

The Hubble problem was idiotic stupid pigheaded project leaders.

There were two different test devices used to measure it.
One, the simpler one, correctly said that it was exactly as it was:
very very wrong. The more complicated, expensive one, was simply
wrong. No one ever checked either test device. No one did a trivial
by-eye test that would have verified which was right, for
two reasons:

1) that doing so required a human to climb a scaffold and that was
deemed both too dangerous and too expensive (building the scaffold,
the by-eye test apparatus was free ... several workers personally owned one, as do I).

2) the idiots said that the by-eye test was not sensitive enough
to detect any possible error. That was, however, assuming that their
already-decided idea that the complicated tester was right was indeed correct: they knew that the by-eye test would be sensitive enough to tell
which tester was correct.
Reply With Quote
  #68  
Old 10-17-2014, 05:43 AM
Steve McVoy's Avatar
Steve McVoy Steve McVoy is offline
VideoKarma Member
 
Join Date: Oct 2002
Location: Columbus, Ohio
Posts: 1,128
drussell, yes I can put caulk between the steel sheets and the frame. However, the stuff cures like clay and probably wouldn't provide much of a seal.
Reply With Quote
  #69  
Old 10-17-2014, 06:50 AM
Username1's Avatar
Username1 Username1 is offline
Not sure how I got here.
 
Join Date: Dec 2009
Location: Orange County NY
Posts: 3,464
Maybe you need to forget the calking and go to overlaping strips of sheet steel like
corner molding not tied to the larger sheets so they can all expand and contract
without warping. Maybe tied to the frame, and rasting on the larger sheets inside
the oven, possibly made of several layers covering the area fully, but not a single
piece end to end so expansion will not cause it to warp.

.
__________________
Yes you can call me "Squirrel boy"

Last edited by Username1; 10-17-2014 at 06:53 AM.
Reply With Quote
  #70  
Old 10-17-2014, 08:52 AM
NoPegs's Avatar
NoPegs NoPegs is offline
The glass is -3dB.
 
Join Date: Mar 2014
Location: Amish Country PA.
Posts: 376
Quote:
Originally Posted by Steve McVoy View Post
drussell, yes I can put caulk between the steel sheets and the frame. However, the stuff cures like clay and probably wouldn't provide much of a seal.
Any members with some TIG skills? Pre-heat the oven and weld the corners up, then let things cool down and see if anything shears off. Since it is just mild steel I don't think it would present much of a challenge even to an "only-occasionally" TIG operator. Stainless would raise the bar a little, but still doable by a non-pro operator.

Your other option is to widen the gaps somehow, and "caulk" them with stove gasket. Caulk here is used in the original nautical term of shoving greased rope in between the decking boards with a mallet and tamping tool, not the modern stuff that comes out of a tube.
Reply With Quote
Audiokarma
  #71  
Old 10-18-2014, 05:44 AM
Steve McVoy's Avatar
Steve McVoy Steve McVoy is offline
VideoKarma Member
 
Join Date: Oct 2002
Location: Columbus, Ohio
Posts: 1,128
Success with the oven. By using lots of bolts to attach the steel to the frame I was able to seal it well enough to get up to 700 deg F in about 2 hours. To improve this, I'll get some stove gasket material and put it between the steel and the frame.

The next issue is the controller. It doesn't work, and I think I may have damaged it by applying 120 vac to the wrong terminals. I might have to buy another one.
Reply With Quote
  #72  
Old 10-18-2014, 03:31 PM
Steve McVoy's Avatar
Steve McVoy Steve McVoy is offline
VideoKarma Member
 
Join Date: Oct 2002
Location: Columbus, Ohio
Posts: 1,128
I'm going to try this:

http://www.amazon.com/Nomex-High-gas.../dp/B00CI7A69I
Reply With Quote
  #73  
Old 10-23-2014, 06:32 AM
Steve McVoy's Avatar
Steve McVoy Steve McVoy is offline
VideoKarma Member
 
Join Date: Oct 2002
Location: Columbus, Ohio
Posts: 1,128
Check out the latest progress report:

www.earlytelevision.org/crt_project.html
Reply With Quote
  #74  
Old 10-23-2014, 02:48 PM
dadsoldstuff dadsoldstuff is offline
VideoKarma Member
 
Join Date: Oct 2014
Posts: 2
1948 dumont WOW

Hi,
im just looking to find some info from some people who know what there talking about, I have what I believe to be a 1948 Dumont large screen tv, radio,and phonograph all in one mahogany entertainment center. The TV comes up in middle( very cool ) the unit is large approx. 5ft wide 4ft tall. from what info I do have is this was a high end unit back then.
If anyone can point me in the right direction or any help please contact me 516-707-3686

thank you
Rob
also have other small units ( help ) hate to see history go to waste
Attached Images
File Type: jpg dumont.jpg (69.5 KB, 17 views)
File Type: jpg dumont2.jpg (66.8 KB, 15 views)
File Type: jpg dumont3.jpg (62.5 KB, 14 views)

Last edited by dadsoldstuff; 10-23-2014 at 02:53 PM.
Reply With Quote
  #75  
Old 10-23-2014, 02:53 PM
dadsoldstuff dadsoldstuff is offline
VideoKarma Member
 
Join Date: Oct 2014
Posts: 2
thanks again
Reply With Quote
Audiokarma
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 05:29 AM.



Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
ęCopyright 2012 VideoKarma.org, All rights reserved.