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Restoring a '59 Cave 10" f/7.1

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#26 Guy Earle

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Posted 22 November 2018 - 08:42 AM

I never could get any of my Parks tube to come out clean. All had yellowed with age.

My first instinct was to smell the tube to see if was a smoker's house, but nada. I figured it was general yellowing and had already resigned myself to painting, but I will certainly try the cleaner/polish first. I saw both auto/marine are mentioned, and I do have Turtle Wax compound and wax that I use on my bathroom sinks. But not for the first time I'll ask a question than take a stab and do the wrong thing--which brand do you all recommend?

 

Guy



#27 Guy Earle

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Posted 22 November 2018 - 08:46 AM

This is my '59 with original paint. The mount I really only cleaned and touched up. The tube I used a marine fiberglass wax on - several times.

Do you have a particular brand? My tube has yellowed quite a bit, so I'm hoping waxing it works. It's hard to get the photos to accurately show how splotchy the yellow really is all down the tube.

 

Guy

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Edited by Guy Earle, 22 November 2018 - 08:47 AM.


#28 Guy Earle

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Posted 22 November 2018 - 08:48 AM

All I see are brass setting circles.  Just sayin'....  drool.gif

I can't wait to polish these up. Would you all recommend that I take the whole scope apart to polish the pieces individually? I figured that's how I'll be doing this.

 

But you can also see how the early white on black looks. Besides using brute force to take the pieces apart, isn't there some trick besides WD-40 to loosen them?

 

Guy

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Edited by Guy Earle, 22 November 2018 - 08:50 AM.

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#29 Guy Earle

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Posted 22 November 2018 - 08:52 AM

Brown Zolatone

I really like the look on yours. It preserves the theme of the original paint with the speckle. It looks much more refined than these early versions IMO.

 

Guy



#30 CHASLX200

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Posted 22 November 2018 - 08:53 AM

Waxing won't take away the yellow or sanding.  Just best to live it or deal with painting it and that can be a mess also.



#31 Geo31

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Posted 22 November 2018 - 09:10 AM

My first instinct was to smell the tube to see if was a smoker's house, but nada. I figured it was general yellowing and had already resigned myself to painting, but I will certainly try the cleaner/polish first. I saw both auto/marine are mentioned, and I do have Turtle Wax compound and wax that I use on my bathroom sinks. But not for the first time I'll ask a question than take a stab and do the wrong thing--which brand do you all recommend?

 

Guy

Gary, I'd recommend Meguiar's M205 for compounding and M105 for fine polishing.  These are both highly popular with the automotive detailing crowd.  They are used for "paint correction" which is a fancy way of saying "removing imperfections from the paint."  They should both also be readily available at any decent chain automotive store.  BTW, I used them on the bathroom sinks in my wife's old house we've got up for sale (using my random orbit polisher) and the result was amazing.

 

I use similar items from another brand on my cars as well as my scopes.  I polished out the fresh paint on my RVC-6N restomod scope (as well as a paint sealer - MUCH better than wax).  I also used it to polish the aluminum tube rings for the same scope.  I'd had a lot of trouble getting anything to clean up those tube rings, but the compound and polish made quick, easy work of it.  These products can be used with a random orbit polisher or by hand.  They are vastly superior to the old Turtle Wax products.

 

Well shoot.  I was going to post links to the Meguiar's products at Autozone, but they don't list them on their website.  I've seen both products there before.  I found one of them at Advance Auto, but only in the 32 oz size.  You can get both in the 8 oz size from here:

 

https://www.detailed...5-P388/8-oz-S3/

 

https://www.detailed...5-P389/8-oz-S3/


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#32 Geo31

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Posted 22 November 2018 - 09:23 AM

I can't wait to polish these up. Would you all recommend that I take the whole scope apart to polish the pieces individually? I figured that's how I'll be doing this.

 

But you can also see how the early white on black looks. Besides using brute force to take the pieces apart, isn't there some trick besides WD-40 to loosen them?

 

Guy

If you need a penetrating oil, the best is Kroil.  It's available in liquid as well as aerosol (Aerokroil).  You can get it direct from Kano Labs:

 

http://www.kanolabs.com/

 

For polishing the brass, I'd recommend NevR Dull.  I KNOW this is available from your local chain auto parts store  (as well as other places).  If you need a little more cut, the M105 would work, but I'd use a light an abrasive as possible first (NevR Dull is a padding polish that does contain a light abrasive).  When I polished the brass tubes on my RV-6 focuser, I actually used a silver polish I had on hand already.  I got into more detail on my Celesterion RVC-6N thread, but here are the before and after pics:

 

Here is the focuser before (note that the ugliness went all the way down the brass):

 

TwuBEuY.jpg

 

Here is the brass after using the silver polish:

 

TUnYmWK.jpg


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#33 sgorton99

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Posted 22 November 2018 - 09:58 AM

Do you have a particular brand? My tube has yellowed quite a bit, so I'm hoping waxing it works. It's hard to get the photos to accurately show how splotchy the yellow really is all down the tube.

 

Guy

We moved recently and I'm not sure if I still have it or where it is right now. It was made for fiberglass boats, and it did take away some of the yellowing. Be prepared to do several coats and use numerous clean rags.

 

Attached is a before pic...

 

Steve

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Edited by sgorton99, 22 November 2018 - 10:00 AM.

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#34 CHASLX200

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Posted 22 November 2018 - 10:37 AM

Just remember that Parks tubes were never real white to start with. They are a off white and not like Unitron White.


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#35 KentTolley

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Posted 03 December 2018 - 12:02 PM

I used a 3M product to clean my 10" Cave tube.  I removed the focuser, finder rings, outer ring of the rotating rings.  I left the spider in place and also tbe inner ring of the rotating tube rings.  3M has another product for more damaged fiberglass.  Google 3M fiberglass RESTORER for really badly weathered fiberglass.  My 1965 10" scope's tube is actually very light gray.  My 8" from 1963 is a yellowed white.   Here's what I used on 10" scope tube which was in exceptional condition and just dirty.  

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Edited by KentTolley, 03 December 2018 - 12:11 PM.

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#36 KentTolley

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Posted 03 December 2018 - 12:04 PM

Pottery elephant is not essential.  Here's the tube after the 3m Cleaner and wax.

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Edited by KentTolley, 03 December 2018 - 12:05 PM.

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#37 KentTolley

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Posted 03 December 2018 - 12:36 PM

Both 3M products I mentioned promise to "restore color."



#38 tcmzodiac

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Posted 03 December 2018 - 03:40 PM

Gorgeous!


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#39 CHASLX200

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Posted 03 December 2018 - 07:08 PM

I could never get my tubes to shine but mine were in very bad shape with no gloss left of the gel coat.  I had to paint mine.



#40 Guy Earle

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Posted 08 December 2018 - 07:13 PM

Sorry I have not posted lately, everyone. Between Thanksgiving, Xmas prep, work, and family, there has been no time to work on the scope (also count going out with he club observing Thursday and Friday night--going to rain here later tonight in Florida). I decided on not leaving the original speckle paint because I really just didn't like the pattern and how it has faded, so I got a Rustoleum "soft iron" which I think has some light speckling in it at least (like the Zolatone mentioned here). I've used the hammered metal look in the past, which is quite tough, but I wanted something much smoother. I tested on the legs with some fine metal sandpaper and a quick spray. And at any point please feel free to give tips in case I miss something. I'm used to working with wood, so my metal knowledge is quite limited.

 

I'm inspecting all the connections, and the motor cover will need to be drilled and retapped because 2 out of the 3 screws are broken off. Also, 2 of the 3 screws that hold the mount to the pier are rusted shut. I got the spray for loosing rusted screws, so I'll try that on them and the really large altitude bolt. 

 

I've attached photos of the motor. I'm thinking of just replacing the power cable and see if it works. They look good, I think. What would be beneficial to do to the gears? Anything? 

 

Cheers,

 

Guy

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Edited by Guy Earle, 08 December 2018 - 07:27 PM.

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#41 Guy Earle

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Posted 08 December 2018 - 07:21 PM

Here are some more pics. For the rotating ring (forgive me, I've always been a dob man and have marginal experience with EQ's--don't even ask how to help on SCT's lol), is the ring held onto the tube by those tiny little screws? I'm assuming the rusted nuts tighten for stiffness in turning. It only barely turns, and sounds like you're opening a rusted door on an abandoned ocean liner. I'm going to take them off to restore the tube, but I'd rather ask than make mistakes from trial and error on such an old tube.

 

Lastly, the bloody secondary does not want to come out. I've used Novak and Protstar over the years, so I'm guessing there's just an inner ring holding it in place, but I thought it weird that the tension screws are so close to the edge, and pulling on does not budget the backplate at all (I put the screws back in to give some leverage). I am loathe to wedge something in there to pry them apart and damage the mirror or dent the housing. Did anyone else run into this?

 

Thanks for any and all input. The pictures you guys have been posting are beautiful.

 

Guy

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#42 Guy Earle

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Posted 08 December 2018 - 07:24 PM

Pottery elephant is not essential.  Here's the tube after the 3m Cleaner and wax.

That truly is beautiful! I've got a buffer, but it's kind of abusive. I've always worked with sonotube/paint/poly, so fiberglass is new to me.

 

Thanks,

 

Guy


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#43 sgorton99

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Posted 08 December 2018 - 09:04 PM

 

Lastly, the bloody secondary does not want to come out. I've used Novak and Protstar over the years, so I'm guessing there's just an inner ring holding it in place, but I thought it weird that the tension screws are so close to the edge, and pulling on does not budget the backplate at all (I put the screws back in to give some leverage). I am loathe to wedge something in there to pry them apart and damage the mirror or dent the housing. Did anyone else run into this?

 

I'm trying to remember from when I had mine, doesn't it just push through the whole piece and come out the back? Message PiSigma (Jon), he will know.

 

Steve



#44 apfever

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Posted 08 December 2018 - 09:05 PM

There is a difference between fiberglass and gelcoat. Try to determine which you have. My 58 Cave 10" is fiberglass.  The outside has a semi transparent look and the mesh can be seen as well as having the smooth surface texture of fiberglass (shiny kind of 'smooth' yet shows the imprint of the underlying mesh).  A gelcoat will typically have a seam from end to end, and likely have crazing or crack marks emanating from stress points like holes.

 

Yeah, a new power cord looks like a good idea, no loss of nostalgia on that one.

 

The paint looks like a good match for the base color of the Zolatone.  A bit hard to tell for sure from the photos.  You might consider trying for a good match to the Zolatone base since the speckle could be added later for an original look. Use protected areas for color determination such as the pier pipe where the legs attached. Other areas may be quite faded and changed. This will get you closer to original.



#45 Geo31

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Posted 09 December 2018 - 08:35 AM

Gel coat is just a coating over the resin used with the fiberglass.  It typically makes the finish smoother and less porous.  It’s sprayed into a mold before the resin and mat is laid down.  I think it can be sprayed over the resin when no mold is used, but I’m not certain of that.  Chuck should be able to explain better if he sees this.


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#46 KentTolley

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Posted 09 December 2018 - 08:54 AM

Yes to your question.  The inner ring is attached to the tube with the 6-32 screws.  If you remove the inner ring note the upper and lower ring and the position of the holes in ring and tube.  The ring will only line up with the holes one way because these scopes were hand-made and the holes are not equally distant from each other.   If you replace those 6-32 screws do them one at a time and it will be easy.   I replaced these with brass screws.  Remove the rusted 3/8-24 jam nuts and the 3/8-24 socket set screws and the acorn nuts and the 3 bars holding the two rings together.  Then you can remove the outer ring to clean the inner track.  MacMaster Carr will have new hardware for you.  Under each socket set screw is a teflon plug which bears against the inner ring.  You can adjust the set screws until the tube rotates easily.  Then lock them down by tightening the jam nut.  Recommend you don't remove the inner ring.   You can clean and even paint the tube with it in place. 

 

you have the rare old-style legs.


Edited by KentTolley, 09 December 2018 - 09:07 AM.

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#47 KentTolley

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Posted 09 December 2018 - 09:19 AM

Consider Rustoleum self-etching primer before you paint with your chosen finish coat.  Cave usually did not primer and his paint peels off.  

 

Think hard before you remove the large "altitude bolt" if the polar axis angle matches you latitude.   If the angle is correct no need to remove it.   You can paint with it in place.

 

Secondary holder is a "backplate"  as you call it and a shroud.  There should be 3 small screws at 120 degrees at the base of the shroud which screw into the backplate.  Your pic shows one of the screw holes.  Remove screws and then pull the backplate away from the shroud.  It may be stuck from age but it should yield.


Edited by KentTolley, 09 December 2018 - 09:33 AM.


#48 PiSigma

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Posted 09 December 2018 - 09:58 AM

Kent has it on the secondary. The plate that is held in with the 3 small set screws is fairly thick so it is probably stuck a bit. Pull on the adjusting screws and it should come out. Just be careful the secondary mirror doesn't come out when the plate comes loose. It probably won't but just be careful. You should find the housing packed with cotton. This is what holds the secondary mirror up against the flange on the other end of the housing. Here are the pieces from my '58 Cave after bead blasting prior to paint.

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Edited by PiSigma, 09 December 2018 - 09:59 AM.

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#49 Mr Magoo

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Posted 09 December 2018 - 12:43 PM

Gel coat is just a coating over the resin used with the fiberglass.  It typically makes the finish smoother and less porous.  It’s sprayed into a mold before the resin and mat is laid down.  I think it can be sprayed over the resin when no mold is used, but I’m not certain of that.  Chuck should be able to explain better if he sees this.

Apfever's post confused me on this. Looked it up and that is what I found that the gel coat is applied to the fiberglass. So it either has a gel coat or something else. What is the other finish? I saw a how it is made show where they build a fiberglass boat and the gel coat was sprayed in the mold first. 



#50 Guy Earle

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Posted 09 December 2018 - 03:32 PM

Kent has it on the secondary. The plate that is held in with the 3 small set screws is fairly thick so it is probably stuck a bit. Pull on the adjusting screws and it should come out. Just be careful the secondary mirror doesn't come out when the plate comes loose. It probably won't but just be careful. You should find the housing packed with cotton. This is what holds the secondary mirror up against the flange on the other end of the housing. Here are the pieces from my '58 Cave after bead blasting prior to paint.

Thank you, Jon and Kent. Yes, I had taken the small 120 degree screws out but it's not budging a bit. I'll work more on it now that I know what the inner ring looks like and how far it goes into the shroud. 




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