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Post by vincent on Mar 6, 2017 15:49:47 GMT -5
First a little history on how I obtained this 'scope. For years, no...decades, I've always wanted a Cave Astrola. Through on-going internet searchs, ran across this one about 2 years ago. Called the owner in Albuquerque, told him I'd be there in 2 days, cash in hand, don't sell it. Took me 29 hours to drive from the foothills of the Blue Ridge Mtns. of NC to NM! That's how bad I wanted it. I took some pics of it in his garage, fully assembled, but I can't find them, otherwise I'd post them. Dis-assembled the scope, primary and secondary wrapped up and in the back seat, everything else tied down in the back of the truck. Then raced a winter storm all the way back home. Here's some pics of it when I got it home:    |
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Post by vincent on Mar 6, 2017 16:18:27 GMT -5
The primary edge markings: 10 f-6 M-793905 5-9-79 60 1/8 FL cave optical co On the back is a sticker from Spectrum Coatings, with a Campbell-Swayze signature. Optical Masters have redone this mirror! The red ring is an alignment/colimanation marking, that doesn't interfere with the image. Fully dis-assembled the scope, coated the ferrous metal parts with oil, then it sat for 2 years, while life interfered. |
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Post by vincent on Mar 6, 2017 16:51:29 GMT -5
Recently started working on the legs, pier, axis and gear casings, cradle, and rotating rings. Some of them had an yellow or grey undercoating, that I suspected was lead based. So I chemically stripped, instead of a mechanical stripping or penning. There was several coats of different paints on all the parts. Especially the OTA tube. The OTA tube is a 'Sonotube'. Have looked for a fiberglass, or Al tube to replace it, even dedicated phenolic tubes (http://www.fpi-protostar.com/index.htm). Nothing seems to fit within the rings, or has the proper length. So I'll keep it 'original'. |
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Post by vincent on Mar 6, 2017 17:04:44 GMT -5
Stripping and repainting parts with a gloss black.....Seems the pics I got are too large to attach! Oh well.
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Post by vincent on Mar 9, 2017 8:47:55 GMT -5
My next concern....The slow motion motor wasn't attached, and the mounting bracket and gearing was gone.
Anybody got a close-up photo of how it's installed. Maybe some design specs?
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Post by vincent on Mar 13, 2017 17:29:14 GMT -5
Been cleaning and redoing the gearing in the polar drive.
The brass bushings at either ends of the worm gearing assembly are cracked and one has a piece broken off it. That comes from the off-set hold-down screws used.
I can braze a small brass washer on the top of the bushing to reinforce, tap another screw across the bushing, and set a brass keeper across the ends.
But that's a hellova lot of work!
Anybody got a source for the bushings? It would be a lot easier to replace than repair! And would last longer.
This puts a hold on the gearing and electrical for now, so I'm moving on to the OTA.
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Post by vincent on Mar 13, 2017 18:34:49 GMT -5
So here I start on the OTA. Oh joy!
The original tube is a Sonotube. Something Cave did towards the end to save money, yet it worked!
I've spent some time studying OTA materials, and what's available. And here's what I found:
Aluminum is heavy, and once flocked or painted losses it's conduction. It's surface, inside and outside, must be perfectly clean before painting, so that corrosion blossoms don't occur.
Fiberglass is pretty, but it's conduction is nil and should be forced ventilated. Also, they have become way over-priced! I've notice this ever since Parks went out of business.
Carbon fiber is almost perfect, but the PRICE! I do what to save something for my retirement.
So what are we left with....cardboard. A 12"OD 12' long Sonotube is about $45. That would make 2 OTA, a spare if I messed up. Under the loads, it won't warp or sag.
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Post by prjctmercury on Mar 14, 2017 19:49:53 GMT -5
I just picked up a late 70's Cave 12.5. I think it is a Sonotube bacause it looks like the Gelcoat is covering a cardboard/paper type of tubing. When I look inside the tube, i see spirals going down it. Dont know if it is a sonotube with gelcoat covering or a ssonotube with fiberglass then gelcoat.
It is a heavy bastard though but I am luck because the gelcoat is in near new condition
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Post by vincent on Mar 23, 2017 14:20:12 GMT -5
I just picked up a late 70's Cave 12.5. I think it is a Sonotube bacause it looks like the Gelcoat is covering a cardboard/paper type of tubing. When I look inside the tube, i see spirals going down it. Dont know if it is a sonotube with gelcoat covering or a ssonotube with fiberglass then gelcoat. It is a heavy bastard though but I am luck because the gelcoat is in near new condition Mine is definitely an un-coated sonotube. In a few of the above pics, you can see paint missing and the markings on the tube, not to mention the spiral is obvious. I've had to back off the tube for now. I've been on Cloudy Nights forums and found I painted the pier and head unit wrong! Found it shouldn't be a solid gloss black, but a satin black and satin grey. A few gave Replicolor codes for the grey, but the price was out of my reach. so I went around to ALL the hardware stores in my area looking for anything close. Thing is, apparently Cave used many different shades of grey, especially towards the end. Settled on Rust-oleum ultra-cover satin granite grey. Not as dark as I wanted, but it is looking good. Here's what it looked like with the gloss black all over, with the old tube to give scale. Please ignore the mess on the work bench, it was late at night!   |
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Post by vincent on Mar 26, 2017 1:05:42 GMT -5
After joining the 'Cloudy Nights' site, I found I was painting the scope wrong. It should be a satin black, and a satin grey. So, I've stepped back from everything else to repaint the mount. Completely dis-assembled it, and went looking for a proper dark grey, for it's era. Spent a few evening roughing out the previous paint, and painting the pier, axis casings, and legs with a few coats. A few more wet sanding and coats will get it done. If you don't mind me saying, that gloss black looked good, even if it wasn't correct. I should acknowledge Turk, Tim, and PiSi for their help in causing me more work. Here's a few photog's of what I've been doing for the last few days, along with the Shop Steward: |
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Post by vincent on Mar 29, 2017 21:05:05 GMT -5
Everything is painted up. No clear satin coat yet, that will come later. At this time I need to press in the polar axis.
Found a ChiCom shop press. 12 ton, with a short throw, but I can use extensions. A lot cheaper than what I paid the local machine shop!
I can use the bottle jack for some other things too.
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