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Restoring and Repainting Classic Telescopes

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#26 Telescopeman54

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Posted 01 April 2008 - 01:55 AM

Criterion

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#27 Telescopeman54

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Posted 01 April 2008 - 01:55 AM

Criterion agaon

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#28 Telescopeman54

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Posted 01 April 2008 - 01:58 AM

Edmund, unfinshed. The green one in the middle.

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#29 Telescopeman54

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Posted 01 April 2008 - 02:00 AM

Celestron 80mm with Kameleon Paint. $365.00 PER PINT!!

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#30 BarrySimon615

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Posted 01 April 2008 - 03:55 PM

eStephen,

Great pictures and explanation of your technique. I do want to clarify a few things regarding the use of JB Weld. While this stuff does have a resin and hardener like an epoxy. It does not perform like an epoxy in respect to it's texture when hard. In that respect it is more like an automotive bondo. If mixed well it will sand very well when cured and it does not have a tacky feel. Going beyond a bondo, it has stayed in place for years now, many years without any signs of cracking or shrinking on repairs that I have made.

I do agree that any surface to be repaired should be leveled as well as possible before anything be it a putty or JB Weld is used. A hammer to tap out dents is just not practical when you have a 2.5" to 3.5 internal diameter tube. I have used the hammer technique on larger tubes like my 6" f/5 Jaegers with a 7" diameter tube.

I think the best advise with any of these repairs is to take your time, do it right, and have patience during the curing process.

The attached photo shows the dewshield for the 4" Celestron Super Polaris. It did have a dent in the dewshield which I was able to tap out for the most part. Only a very small amount of JB Weld was used to smooth the surface. The dewshield was then fine sanded, primed and painted, followed by an oven baking. The baking not only cures the paint but also gives the paint job a lustre that does not seem to happen without the baking. The picture was taken of the dewshield in the same area where the dent repair was made.

Barry Simon

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#31 Awesomelenny

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Posted 01 April 2008 - 04:52 PM

Hi Barry!

I do the same thing with my Lionel Trains!!! I have them in a wall shelf that I made out of Cherry with a oak veneer rear panel! You have those beautiful Big Boys and other steamers. I have New Haven & Santa Fe F3's, a Pennsylvania #681 Steam Turbine etc... I also have HO's and a modular Steel Mill layout with a switching yard in HO.

Ok moderator...I know...off topic!!! :confused: :confused:

#32 Awesomelenny

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Posted 01 April 2008 - 05:24 PM

Stephen,

Your techniques are very well detailed. In fact, both you and Barry have already contributed a significant amount of information here. This thread should be saved for later referral. Especially interesting was the painting. I found it really hard to believe that it would take paint so long to cure. I always thought that a week was enough. I will now wait much longer since your writing about this.

Thank you both!

#33 BarrySimon615

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Posted 01 April 2008 - 05:54 PM

Stephen,

Your techniques are very well detailed. In fact, both you and Barry have already contributed a significant amount of information here. This thread should be saved for later referral. Especially interesting was the painting. I found it really hard to believe that it would take paint so long to cure. I always thought that a week was enough. I will now wait much longer since your writing about this.

Thank you both!


I once got a 70 mm finder scope that was put together in the U.S. It was rushed to completion and there was evidence that the paint was still not cured when it was bagged up and shipped out. The paint fumes were pretty strong in the shipping box.

I guess we will have to talk trains "off topic". But a quick few words, check out some other pictures I have in the "Just Trains" Section over in Off-Topic, under the heading "Cameras and Photography". Also check out one of the photos I just posted in the Cameras and Photography Section under the header "Water Towers".

Barry Simon

#34 mikey cee

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Posted 01 April 2008 - 05:59 PM

Barry....Any 4-6-6-4 Challengers to go with the Big Boys? You wouldn't have a UP 4-8-4 to go with that SP by chance also? Sorry I digress. :grin: :grin:Mike

#35 BarrySimon615

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Posted 01 April 2008 - 06:50 PM

I always thought that a telescope tube painted as a "spectral line would be very interesting. I have never tried but I don't think I quite have the skills to be truly happy with the result. A nick or scratch in a "transition area would also be very difficult to deal with.

Over in "Off Topic" under Cameras and Photography those of you interested in trains can find a happy, warm home. Just look for "Just Trains". I have a number of photos posted there and will meet anyone there for train discussions - real or model.

Barry Simon

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#36 Telescopeman54

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Posted 02 April 2008 - 12:09 AM

Barry:

As far as the picture of the dew shield is concerned, I have only one question about it. What dent? If there were ANY imperfections in that repair that metallic would show it! Well done!

Also, you are correct in stating that baking the finish helps to add a lustre to the paint. That's why I am building that OTA oven. If it works out I should be able to bake OTAs for 8" f/15 tubes.

I have been able to hammer and dolly smaller tubes. I used a modified tack hammer and extended the handle to get inside. Sometime it is necessary to make custom tools to do the job. That in itself can be pretty interesting and rewarding.

You do excellent work!

Now, about that spectral line paint job... Hmmmmm.... You are going to have me thinking about that one until I set off the smoke alarms! LOL

CS

Steve
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#37 Lew Chilton

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Posted 02 April 2008 - 12:28 AM

Steve, Barry, Preston, Lenny, et al,

Terrific thread. I'm learning a lot!

I am restoring my almost 50 year old home-built iron and steel Newt. mount and plan to have it powder coated. It was recently sandblasted, as you can see in the attached picture. I was about to use JB Weld to plug up some holes and smooth out some old welds on the iron legs, but instead I will use hi-temp Lab-Metal, as per Preston's advice.

Unfortunately, the declination bearing is made of babbit, so I can't have the dec. housing (actually, a pipe tee) powder coated lest the babbit melt in the powder coating oven.

The counterweight is made of iron pipe but is filled with lead. I think it'll be safe for powdercoating because of thermal inertial. Do you think I'm right, or should I also not have it powder coated?

Prior to sending the mount to the powder coaters, I will have to have some additional parts sandblasted and possibly have what's already been sandblasted, sandblasted again because some oxidation is beginning to form.

Question: To prevent further oxidation before going to the powder coaters - which may still be a few months down the road - can I prime the mount using an etching primer from a spray can? Will such a primer be compatible with powder coating?

Thanks in advance for any advice you can give.

-Lew

P.S. I also am a railfan and have a Lionel train collection as well as N-scale. No layout currently.

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#38 Telescopeman54

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Posted 02 April 2008 - 12:43 AM

Oh MY! Babbitt bearings! I haven't seen those in YEARS!! Where did you get this thing? Those are some small axle shafts! What kind of scope did it hold, originally?

Sand blasting is great, but, bead blasting is better. Sand can actually get stuck in the metal and can ruin a paint job when it breaks lose. Bead blasting material has less of a tendency to stick to the metal and leaves a better finish. You will still need to do some sanding to get the finish smooth, though.

As soon as you get the metal cleaned up, immediately after blasting it and sanding it. You can lay down a primer coat to protect it. However, that will only be good for short term protection since primer can attract moisture and eventually the rust will begin developing again.

I do not know if powder coat will work with primer paint. I kind of doubt it. For something like this, especially where lead and Babbitt material are involved, I'd stick with a good enamel paint and forget about the powder coating.

By the way, I still have some old lead counterweights that I cast on my mothers kitchen stove. They were never painted and work just fine. I never even painted them. LOL

CS

Steve
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#39 Mr Magoo

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Posted 02 April 2008 - 03:06 AM

Do not use JB Weld. Use Lab-metal:

http://www.alvinproducts.com/Products/ Alvin Products: Lab-Metal

It has aluminum pigment in it for current to pass through it (so the powder coat will bond).


Preston,

That's good to know. I talked to my local powdercoater and he told me that the powdercoat would not work with any kind of plastic body filler either like Bondo. You can even buy powdercoat kits to do at home. Sears sells one in their catalog. I've even known some guys who have done their own anodizing, but that's kind of nasty business. I did some nickel electroplating when I was in high school with the help of my mom who is a metallurgist/corrosion engineer.

I love reconditioning things. I love redoing old tools, furniture, bicycles, etc... There are a myriad of different spray colors and finishes available to us these days that we didn't have even 10 or 15 years ago. I'm building a solar newt right now and trying to decide how to finish the tube. It's a cardboard tube, so I have to deal with the spiral on the outside.

What I want to know is how you guys bake paint in the oven without suffering the wrath of wifey. My wife was just given a 1 year old Dynasty range that cost $6,000.00 new. No way she is going to let me near that thing with paint! :roflmao: I've been trying to think of a way to rig the old one up out in my garage. Bigget problem I can see is that it's a gas oven. Probably need to have the oven pre-heated and turned off before putting the parts in to avoid becoming the subject of a Mythbusters episode. Great thread BTW. Thanks Barry!
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#40 Lew Chilton

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Posted 02 April 2008 - 03:34 AM

Steve,

Here's my home-built Newt. in its entirety the way it looked in 1962. Cave figured the 8-inch f/7.4 mirror in 1959. The scope was finished in 1960. After I got my driver's license in 1959, I hauled it to star parties in a 1953 Buick Roadmaster. I sold it in 1963 upon entering the service and got it back in 2004, a rusted basket case with many of the OTA components missing. The shafts are 1-1/4 inch stainless steel. The counterweight is made from an oil well casing, is filled with lead and weighs 22#. The dec. and R.A. housings are pipe tees, the pedestal is made from a 5-1/2 inch diam. oil well casing. The legs were fabricated from scrap iron by my dad at the place he worked. My dad had it painted at his work with black wrinkle enamel. It is one heavy beast that could be upgraded in many ways, but I will leave it just the way it is because it has so much sentiment for me.

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#41 BarrySimon615

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Posted 02 April 2008 - 07:44 AM

Re- oven baking.

The oven we have is electric, not gas. Maybe because it is electric and maybe because I always have the vent on when I am baking painted telescope parts, there is very little in the way of lingering paint odor. To be on the safe side, odor wise, you may want to crank up the empty oven again after the painted parts are removed and run it again at a higher heat with the vent on to totally remove any paint odor.

Another back burner project of mine is an "oven extension". I bought some sheet steel several years ago and drew up some plans to bent it to make an extension on our oven. The whole contraption would rest on the open door of the oven which is stable and completely horizontal when open. This would allow me to bake/cure parts as long as 40". That would be long enough for the Celestron SP C102. That purple tube never got a baking and it does have one bad spot that was scratched and touched up. Maybe I will complete that oven project one day, but it is not a priority right now.

One restoration issue that I have that others may be able to give good advise on is what are the best (and safest) ways to straighten a bent shaft. I recently straightened a bent shaft on a Unitron #114 alt-azimuth mount. This azimuth slow motion was so bent that it would bind when turned so was essentially non operating. I removed it from it's threaded receptacle and with it between two metal plates, pounded it straight. (I tried a vise but had little luck with that.) There is another shaft on another mount, purchased used, that has a bent shaft too. That one is a chrome plated shaft that I think may have more tendency to fracture than would the nickel plated brass shaft on the Unitron mount. Anyone have a good recipe for shaft trueing?

Barry Simon
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#42 Telescopeman54

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Posted 02 April 2008 - 08:31 AM

Lew:

That was a nice scope. Even though it is now distressed, at least you got it back. How many people are lucky enough to recover an instrument from their youth that they later regret selling?

Just stick with the paint and keep it original. The extra effort and expense of powder coating, etc. won't be worth it. Also, if it gets a nick or ding you can fix it up right away and no one will ever know.

Hey! Magoo! What the Hell is a wife?!! My last one took her final breath in '04! :evillaugh: Been happily single ever since and HOPE to STAY THAT WAY!! :mrevil:


sbf

#43 Telescopeman54

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Posted 02 April 2008 - 08:36 AM

Bent shafts are a tough one. I could see where using a lathe to hold and spin the part might work. A device to apply pressure, slowly and constantly, from the cross slide MAY allow you to straighten it out. How long is the shaft and how thick?

sbf

#44 Jim Rosenstock

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Posted 02 April 2008 - 08:52 AM

Hey! Magoo! What the Hell is a wife?!! My last one took her final breath in '04! :evillaugh:


I'm sure the poor lady is better off now.

And I wondered why so few women post on this forum...

Steve, please limit your future posts to the topic of classic telescopes, and work out your evident problems with women someplace else. Please.

Jim
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#45 2manyscopes

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Posted 02 April 2008 - 05:25 PM

Barry, can powder coating be done after an epoxy (JB Weld, etc) repair? I would have thought the repair would show through?
Hubert


Simple answer is no. There are however two auto body fillers that are compatible with aluminum and the powder coat process. The names escape me but your powder coater should know. I used one to fill about a dozen holes in a 7" diameter tube with perfect powder coat results.
Bill

#46 2manyscopes

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Posted 02 April 2008 - 05:36 PM

Mr. Simon,
On your "Purple Planet Eater" scope, I think I see a sliding brass counterweight to the right of the laser pointer. Since it looks like there is little to no room for the weight to slide what is it for? Does it counter the rotational torque of the finder?

I've had a few scopes with sliding counterweights on very short rods and they have very little to no effect at all on tube balance.

Bill

#47 Don W

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Posted 02 April 2008 - 05:41 PM

Since I'm no longer a moderator in this forum, I have asked those that are to make this thread Sticky. There's such great material here, I'd hate to see it roll off the front page and be forgotten.

#48 John Jarosz

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Posted 02 April 2008 - 06:20 PM

This is a great thread as I am getting ready to paint and finish my 6" F5 refractor.

Some of my thoughts:

I made a mandrel so I could mount my 7" OD tube in my lathe. A belt sander running in the opposite direction of the lathe results in a very randomized uniform finish on the tube. Finish the sanding with the random orbit sander while the lathe is running. This is tough with those F15 scopes.

Tower Paint will match any sample and put the paint into a spray can for you. I've used them for motorcycle painting. Very good product.

If you do a lot of powder coating buy an electric stove for the garage. You can buy em for the cost of the scrap metal at a junkyard. I can't imagine the grief I'd suffer from powder coating in my kitchen. I'd have to sleep with one eye open.

Only trouble is, I can't decide if I want a white tube or some snazzy color.

Great stuff everyone.

John

#49 Pedestal

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Posted 02 April 2008 - 06:26 PM

Modest cost baking oven: (I used this setup in gun building)
A small electric hotplate.
About 6 feet of of 8" ordinary wood stove pipe.
A BBQ pit thermometer.
A piece of plywood bigger than 8" with a small hole in the middle and a suspension wire going through it.
Put the thermometer in about the middle of the pipe. Stand the pipe up on the hotplate, and suspend the piece by the wire on the top cover. At the low temp for this kind of stuff, a wooden top is just fine.
Shaft straightening:
Tough one. Up to about 3/4", (depending on lenght).
Two machinest's V blocks, a dial indicator on a stand, and a clamp with a short piece of angle iron welded to the screw side with the "V" down. Also need a sturdy workbench to set it up. You can get pretty close with this rig, though. When you find the high side, you'll have to run the clamp down a bit past center, it'll spring back some.
But then, I have also straightened rifle barrels by setting up the V-blocks and indicator, marking the high side, and then giving the nearest telephone pole a healthy whack with the high side! That works, too. Main thing, you got to know where high/low is...
:o
(I have some pretty neat pics of a Challenger that came to Houston a couple of years ago. If anyone is interested let me know)
Hubert
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#50 BarrySimon615

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Posted 02 April 2008 - 07:06 PM

Mr. Simon,
On your "Purple Planet Eater" scope, I think I see a sliding brass counterweight to the right of the laser pointer. Since it looks like there is little to no room for the weight to slide what is it for? Does it counter the rotational torque of the finder?

I've had a few scopes with sliding counterweights on very short rods and they have very little to no effect at all on tube balance.

Bill


Bill,

Yes, the small brass counterweight and support is there simply to offset the weight of the finder and bracket. The one in the picture, a 50 mm with solid bracket is pretty heavy, so the weight works out well with the finder and bracket being at about the 10 o'clock position as viewed from the rear, the laser and bracket being at the 12 o'clock position and the brass weight and support being at the 2 o'clock position.

Additionally the heavy finder and bracket plus brass weight and support both help in getting more weight to the rear of the scope to offset the weight of the objective cell. I will see if I have a good picture of the brass weight and it's support. The weight and support were made for me by Ken Dauzat.

Barry Simon

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