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Can I heat up Bakelite tube on RV-6?

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#1 Patrick.carter

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Posted 07 August 2014 - 08:53 PM

   I know you are the people to ask so here goes.  I'm rebuilding this RV-6 that I bought this summer, and I thought about painting it myself after reading so many of the other restoration.  I teach in an amazing high school that is associated with a Career Center that is identified by the National Research Center for Career and Technical Education as one of the top five secondary career centers in the United States and we have an auto body and collision program.  In talking with the instructor today about painting the scope body he wanted to know if the tube could take 140 degrees F temp.  At first I thought, "No, it's a type of plastic-Bakelite, but  then I began to wonder- "Bakelite is some pretty tough stuff, they made billiard and pool balls out of it, and 140F doesn't seem that hot."

   I told him that I knew some people to ask, so what say you?

 



#2 Mr Magoo

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Posted 07 August 2014 - 10:04 PM

The tubes are not Bakelite. They are a resin impregnated cardboard tube. I don't know how much heat they would take. When I painted my RV-8 tube I built a paint booth in my garage with a rig that rotated the tube as I painted. I used epoxy appliance paint and when it was drying I put an oil filled radiator heater in there with it for a while. I think it got up to around 95 degrees in there. 



#3 Chuck Hards

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Posted 08 August 2014 - 02:13 PM

The tube should be able to take 140F, it gets that hot inside car interiors in summertime in the southwest.   Just keep an eye on it and don't leave it in there overnight. 



#4 Gil V

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Posted 08 August 2014 - 10:30 PM

The tube was NOT cardboard. I resent that Celestron advertising lie. And that is what it was - a lie.

Phenolic-resin laminate.

140 degrees will be no issue at all.

#5 Jon Isaacs

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Posted 08 August 2014 - 11:17 PM

The tube was NOT cardboard. I resent that Celestron advertising lie. And that is what it was - a lie.

Phenolic-resin laminate.

140 degrees will be no issue at all.

 

The Phenolic is the adhesive, what was the actual base material used in the laminate, often it is paper. 

 

Jon


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#6 bremms

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Posted 08 August 2014 - 11:20 PM

Phenolic impregnated cardboard. about 8x stronger by weight. It is a composite, like early carbon fiber. But it will take 140 degrees without problems. It is a great tube material, the Blacklite tubes from Protostar are Bakelite but are not as tiff as the old criterion tubes.



#7 Lew Chilton

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Posted 09 August 2014 - 12:06 AM

Try heating it with an oxy-acetylene torch and see what happens. :)



#8 Datapanic

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Posted 09 August 2014 - 12:41 AM

Do it the old fashioned COLD way - nothing more than bondo and spotting putty, lots of sanding and paint.  Do Not Heat It up!


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#9 Patrick.carter

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Posted 09 August 2014 - 08:17 AM

Thanks to all of you, I knew you knew more than me.  I read somewhere (Company Seven?) that the criterion tubes were made of Bakelite, a phenolic resin makes more sense.  I think the scope maybe pre 1963 as it doesn't have a serial number only MR-V6 on both the scope and mount.

 

Now to pick a color!



#10 Mr Magoo

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Posted 09 August 2014 - 02:09 PM

The tube was NOT cardboard. I resent that Celestron advertising lie. And that is what it was - a lie.

Phenolic-resin laminate.

140 degrees will be no issue at all.

Okay, cardboard may be the wrong term, call it what you want but it is resin impregnated paper. I know nothing of the Celestron's advertising. All I know is what I had to work with when fixing a damaged tube. 



#11 Mr Magoo

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Posted 09 August 2014 - 02:18 PM

Patrick here is a link to the thread about my RV-8. http://www.cloudynig...-coming-my-way/ There are several pictures in there of my paint booth set up and what I did to paint my OTA. Good luck. 


Edited by Mr Magoo, 09 August 2014 - 02:20 PM.


#12 Gil V

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Posted 09 August 2014 - 03:29 PM

The very good paint job added a lot to those tubes. It took a pretty good impact to damage them. The edges chipped from time to time.

It was a lot of fun to drill those tubes. We put this metal housing over one end, it had bushings and we'd drill all the holes by hand. Took less than a minute. Then you'd put the fixture on the next tube in line and keep drilling. The tubes were all laying down on a set of three or four tables. We'd drill twenty tubes (give or take) in a set.

We had a veritable mountain of damaged tubes in a corner of the shop. I think it's visible in one of my article's photos.

#13 dgreyson

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Posted 15 August 2014 - 07:39 AM

I don't think Bakelite has been used much in anything since the 50's. It's first generation technology.  I think its used for knobs on pots and pans now is about it.  Its often sawdust mixed with resin and has to be compressed at high heat to set up.  Too brittle and the thin smooth surface is just a crust over the grainy exterior.  Epoxy resin and thermo plastics have supplanted it mostly.



#14 bremms

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Posted 15 August 2014 - 11:18 AM

Phenolics are still used for quite a few things. They have good dimensional stability and don't adsorb much moisture. They are used for fixtures, insulators and many other things. We still use it a bit for fixtures and other things. It has mostly been supplanted by other composites, but it still has uses. I have some phenolic plate that used linen and one that uses sheet paper for added strength. It still has many industrial uses.



#15 Chuck Hards

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Posted 15 August 2014 - 12:15 PM

Marc, some years ago I came across some large dimensional blocks of phenolic with linen reinforcement.  Pretty strong stuff, actually.



#16 terraclarke

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Posted 15 August 2014 - 02:00 PM

We made Bakelite in chemistry lab when I was either in high school or college? Used Phenol (carbolic acid), formaldehyde, acetic acid, hydrochloride acid, and I think sodium hydroxide? It seems to me that it was an exothermic reaction (generated its own heat) and the Bakelite precipitated out as a sort of milky gray-white gummy gel that gradually hardened. It was really nasty smelling and I remember that the phenol caused these weird yellow acid burns when you got any of it on your hands. I can't begin to tell you how noxiously nasty it smelled. But it was fun. I think making that and thermite were my two favorite chemistry experiments. :)


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#17 dgreyson

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Posted 15 August 2014 - 09:58 PM

We made Bakelite in chemistry lab when I was either in high school or college? Used Phenol (carbolic acid), formaldehyde, acetic acid, hydrochloride acid, and I think sodium hydroxide? It seems to me that it was an exothermic reaction (generated its own heat) and the Bakelite precipitated out as a sort of milky gray-white gummy gel that gradually hardened. It was really nasty smelling and I remember that the phenol caused these weird yellow acid burns when you got any of it on your hands. I can't begin to tell you how noxiously nasty it smelled. But it was fun. I think making that and thermite were my two favorite chemistry experiments. :)

  

When I made it,  it was a spongy purple crystalline mass full of bubbles that slowly turned hard as it cooled.  Looked at it, said "wow neat", and tossed it out.  

    I work with it a lot in Antique radios and Telephones.  Thermite has fond memories for me as well. Todays tame Micro-Chemistry is just not as much fun as the old experiments were I think.


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