thebes Posted November 8, 2009 Share Posted November 8, 2009 I think I saw someone (Marvel?) answer this question awhile back but I can't find it doing a search. In other words what do you use to re-glue a loose tube base. It's a common problem, especialy on some of the old radio tubes. Quote Link to comment Share on other sites More sharing options...
Cut-Throat Posted November 8, 2009 Share Posted November 8, 2009 I use 5 minute epoxy. It is composed of two parts - Mix 50/50 I use a toothpick and put a dab of epoxy on it and then press the epoxy in between the base and the glass all around the tube. I then follow up with a 'wet wipe' and press the remaining expoxy into the grove and wipe the base and glass clean of any remaining epoxy. This will hold forever! Quote Link to comment Share on other sites More sharing options...
HarryO Posted November 8, 2009 Share Posted November 8, 2009 I use clear drying speaker surround glue. It's not too hard that it may break the glass IF/WHEN you move or change a tube. I've been doing it a couple of years and it's holding up good. NO issues with it. I'll send you some if you need it. Harry Quote Link to comment Share on other sites More sharing options...
Marvel Posted November 8, 2009 Share Posted November 8, 2009 I think I saw someone (Marvel?) Not me...I would think that most epoxies would break down with the heat. Maybe some jbweld... [:|] Quote Link to comment Share on other sites More sharing options...
Oblio Posted November 8, 2009 Share Posted November 8, 2009 I think there is a Hi-Temp RTV available. I know we use it on our TWTs and HVPS that get pretty hot, not sure if it is available on the consumer market. Quote Link to comment Share on other sites More sharing options...
Cut-Throat Posted November 8, 2009 Share Posted November 8, 2009 I think I saw someone (Marvel?) Not me...I would think that most epoxies would break down with the heat. Maybe some jbweld... Not enough heat on Tubes in an Amp to break down 5 minute epoxy. I have been using it for years on my tubes. Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted November 8, 2009 Share Posted November 8, 2009 Cut Throat, you need to change your screen name here to "Golden Horn".[] Quote Link to comment Share on other sites More sharing options...
Cut-Throat Posted November 8, 2009 Share Posted November 8, 2009 Cut Throat, you need to change your screen name here to "Golden Horn". I went to a Fishing Lodge in Alaska Once called "Golden Horn" [] - I just got my Altec Horns painted, and here are some Pictures, in case you missed them. Quote Link to comment Share on other sites More sharing options...
Invidiosulus Posted November 9, 2009 Share Posted November 9, 2009 I think I saw someone (Marvel?) Not me...I would think that most epoxies would break down with the heat. Maybe some jbweld... That's Josh Brown Weld for those that don't know. Quote Link to comment Share on other sites More sharing options...
Mallette Posted November 9, 2009 Share Posted November 9, 2009 I think I saw someone (Marvel?) Not me...I would think that most epoxies would break down with the heat. Maybe some jbweld... Ah, the reason I checked in. JB Weld has been used to mend cracked engine blocks successfully. It can handle tube heat just fine. I've never known how far from Texas it's available, but only real welding is a better bond for heat and pressure than JB Weld. Dave Quote Link to comment Share on other sites More sharing options...
thebes Posted November 9, 2009 Author Share Posted November 9, 2009 Very cool and thanks for the responses. I've noticed a couple of tubes I've been testing that have loose bottoms will read great when twisted slightly, but bum out when just sitting there. I'm thinking since the JB weld is quick setting it'll do the trick, but the surround glue could probably be injected for a cleaner look. Does anybody know what they originally used in gluing up tubes? Whatever it is, it's amazing how well it has held up over the decades. Quote Link to comment Share on other sites More sharing options...
Cut-Throat Posted November 9, 2009 Share Posted November 9, 2009 I'm thinking since the JB weld is quick setting it'll do the trick, but the surround glue could probably be injected for a cleaner look. JB Weld epoxy (Yes it's an epoxy) sets up in about 30 minutes and 5 minute epoxy sets up in about 5 minutes - But what do I know, I've only glued hundreds of tube bases. Your choice..... Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted November 9, 2009 Share Posted November 9, 2009 Yeah, what Golden Horn said. Quote Link to comment Share on other sites More sharing options...
Marvel Posted November 9, 2009 Share Posted November 9, 2009 But what do I know, I didn't mean my comment to be critical. I just know that some epoxies don't handle heat very well. I.m glad it's working for you.I would love to hear your system if I ever get to Minnesota. I should be up that way next summer. Love to hear your Moondogs, too, since I think they are pretty awesome amps. Bruce Quote Link to comment Share on other sites More sharing options...
Mallette Posted November 9, 2009 Share Posted November 9, 2009 Original JB Weld takes a while to set to solid. I'd agree it "sets" in 30 minutes, but that is not a bond, It takes several hours and at least 24 hours cure to get a solid bond from it. At that point, I believe it would hold a vacuum under a couple of hundred degrees if required. JB makes a "new" quick set that gets pretty warm and bonds pretty well in about 5 minutes, but I don't know about its characteristics compared to the original. I stick with the original except for things that really need quick set and where extremes aren't an issue. A vacuum tube base is downright cold compared to an engine block, so I suspect the advice of 5 minute epoxy is just fine...especially since it comes from someone whose been doing it for years. Sheesh, I've been using the stuff (JB) for at least 30 years, and have a number of repairs still doing fine at about that length of time. I'd spread it on bread if I needed something to really "stick to my ribs." Dave Quote Link to comment Share on other sites More sharing options...
fini Posted November 10, 2009 Share Posted November 10, 2009 Very cool and thanks for the responses. I've noticed a couple of twins I've been testing that have loose bottoms will read great when twisted slightly, but bum out when just sitting there. I'm thinking since the JB weld is quick setting it'll do the trick, but the surround glue could probably be injected for a cleaner look. Does anybody know what they originally used in gluing up tubes? Whatever it is, it's amazing how well it has held up over the decades. Marty, I corrected your typo. Quote Link to comment Share on other sites More sharing options...
Cut-Throat Posted November 10, 2009 Share Posted November 10, 2009 I would love to hear your system if I ever get to Minnesota. I should be up that way next summer. Love to hear your Moondogs, too, since I think they are pretty awesome amps. Bruce Well, you are certainly invited! - Just send me a PM before and I'll SET somthing up. I have Welborne StarChief 45 amps (My favorite), 2A3 Moondogs and 300B Laurels. Quote Link to comment Share on other sites More sharing options...
Invidiosulus Posted November 10, 2009 Share Posted November 10, 2009 Original JB Weld takes a while to set to solid. I'd agree it "sets" in 30 minutes, but that is not a bond, It takes several hours and at least 24 hours cure to get a solid bond from it. At that point, I believe it would hold a vacuum under a couple of hundred degrees if required. JB makes a "new" quick set that gets pretty warm and bonds pretty well in about 5 minutes, but I don't know about its characteristics compared to the original. I stick with the original except for things that really need quick set and where extremes aren't an issue. A vacuum tube base is downright cold compared to an engine block, so I suspect the advice of 5 minute epoxy is just fine...especially since it comes from someone whose been doing it for years. Sheesh, I've been using the stuff (JB) for at least 30 years, and have a number of repairs still doing fine at about that length of time. I'd spread it on bread if I needed something to really "stick to my ribs." Dave I agree, It's quality stuff. I used Josh Brown Weld on my old station wagon. When I turbocharged it I had to add a fitting for the oil return line. I took some Josh Brown Weld and used it to hold a piece of small pipe in a hole I drilled in the oil pan. It held just fine and never leaked. I think I ended up replacing it when I changed the size of my oil drain line and I used a proper bulkhead AN fitting. Peace, Josh Quote Link to comment Share on other sites More sharing options...
Cut-Throat Posted November 11, 2009 Share Posted November 11, 2009 Another thing I thought I would mention as far as heat on the Tube. - Tonight I was listening to my 45 Amps and I grabbed a hold of the tube bases and had no trouble holding my fingers on the tube base where the epoxy would be applied. I am guessing that the Temp was around 120 degrees F. This was after the amps were powered up for about 5 hours. Most of the heat on a Tube is on the very top of the Glass Envelope. This is extremely hot to the touch. But where you would epoxy the Base to the glass it is very warm, but not near hot enough to destroy any epoxy. Try this and it will alleviate all your fears on this matter. Quote Link to comment Share on other sites More sharing options...
Marvel Posted November 11, 2009 Share Posted November 11, 2009 Tonight I was listening to my 45 Amps and I grabbed a hold of the tube bases and had no trouble holding my fingers on the tube base where the epoxy would be applied. Really... how hot can a 45 get? I bet some 6550s would be smokin'. [] Quote Link to comment Share on other sites More sharing options...
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