TAL-M refurb

[DaveL59]

Not sure if this is the right section but thought I'd start a thread on the TAL-M that I can update as I get on with stripping it down and refurb bits. I bought this 1996 scope a while back, perhaps a year or so and optically it's excellent, mirrors in good order etc. The paint though has suffered  during its previous life as a family scope and it only had the 3x barlow and 15mm eyepiece. Missing were the 25mm and extension tube and the spanner for the Latitude nut, though the TAL screwdriver and camel-hair brush (still wrapped in tissue) are present. It does also have the wood case which is in pretty good order and nicely fits in the boot of the car for transporting the scope around, still has the nice pine smell when opened too.

So first up was to replace the failed foam inside the box with felt, so that the parts are all held snug and to remove foam powder from getting all over the scope. I did this not long after buying the scope. I should give the finish a sanding down and re-coat of varnish at some stage but its fine for the moment. I've since sourced a 32mm diameter TAL 25mm Plossl (by buying an older TAL-1 scope) but no luck finding an extension tube so far.

One thing I did note was that unlike other reports where it was mentioned that you can set up with only the lower pier post, on this example the connecting thread is fixed in the lower segment. This means you'd have to fit the top half of the pier to be able to fit the mount head. Fine for me but was hoping to make this usable for the wee grandaughter so it could do with being lower.

So after not doing anything on overhauling this scope I finally took the first step this afternoon. No not starting on the paint but adapting the pier so that I can use this as a short-pier. No sense painting the tube then having to drill and tap it after all  So the 2 pier sections are connected by this impressive threaded part which is held in place with a 3.0mm set screw.


Having removed the threaded coupler, I measured to offset to the setscrew roughly and then drilled the upper pier pole in the same place. Luckily I had a HSS drill exactly the right size to enable me to then run a 3mm tap through the hole and viola, I've reversed the threaded section and can now use the TAL-M in full or half-height config.

 

Turns out I was slightly off in the offset so I used a dremel-a-like to make a nick in the thread so that the set-screw secures the coupler in the new location, a cludge nobody will see so no matter  

So I guess next job will be to strip the OTA, pier posts and the mount head so I can clean up the tatty paint back to a smooth surface and then respray with smooth hammerite white. Haven't decided on the OTA inner whether to flock it or try flat blackboard paint. I recall astro-baby finding flock wouldn't stick on her TAL-1 refurb so I guess I'll find out when I get to that stage.

Edited April 24, 2020 by DaveL59

[DaveL59]

so feeling in a slow lazy mood, decided I really should get a start and paint that upper pier section since it's not in use. Have sanded it down to smooth the scars in the paint and washed it off with plain water and dried. Using a spare length of plastic waste pipe across the worktops either side of the shed seems to work to hole it steady and make it simple to rotate the pole to get to spray all around. Here it is sanded and ready to paint, will look at adding the post-paint shots once I've been able to lay a few coats down. First coat still shows the bare metal area (expected) and its about due its second coat now. I reckon it'll need 5 coats or so to give a good finish, will see...

Assuming I can get a good finish I'll move on to the rest of the pier and then the OTA and mount casings over the next week or so. No rush after all  

[DaveL59]

so 2 coats in and it's looking ok, defo needs a few more but so far so good

Does make me think maybe a primer coat would've been a good idea even tho the can says can use direct to metal. Not that the local shop had any on the shelf of course, given the supply situation...

Edited April 25, 2020 by DaveL59

[DaveL59]

between layers of paint I've been mulling over the idea of converting one of the nice TAL 6x finders to be RA configuration. Looks like I could fit a diagonal into the main tube and find a way to fill the slight gap between the 1.25-in tube and the finder body. Downside is that I'd need to cut down the finder body in order to find focus but might be worth doing. I've 2 of these at the moment, one for the 100RS and the other for the TAL-1 so I'd leave one unmodified.

Looking about I'm wondering if a 45-degree erecting prism might work as opposed to a 90-degree mirror diagonal, any thoughts?

[DaveL59]

So checking the upper pier section, its looking pretty good, only one tiny pinpoint that looks to have been a bubble/dust and came away, so gave that part a quick respray and left to dry while I strip the lower section and the AZ-EQ knuckle down.

Starting with the AZ-EQ knuckle, the cover plate unscrews to reveal a 17mm nut that holds the knuckle at the set latitude. Its very tight so I used the car socket set for this while still on the pier post.

Once undone we want to remove the bolt, but it doesn't just slip out, there's a hidden cross bolt that limits the latitude movement that you access from under the pier thread area:

Once done you have a few parts to clean up for paint. I'm thinking I might see if I can highlight the raised latitude marks  by touching over the relief part somehow.

For those unfamiliar with this little scope, the head can be set to latitude=90 to use it in AZ mode, or to your latitude angle so that the head operates in EQ-style mode (well probably more like an EQ-wedge in fact).

Edited April 26, 2020 by DaveL59

[DaveL59]

So on to the pier tube and feet. The feet are retained by thumbscrews that bolt into an inner ring inside the tube, which itself is held in place by 3 screws. Nice and simple

 

One foot had lost the plastic insert when I bought this so I'd bought some replacements but they need trimming to fit far enough to sit flush

 

First go I cut 2 rings above the foot, not quite enough so redone as per the red mark so only one of the collar rings is left, fits perfect now  

Guess its time to go sand these bits down, degrease and paint...

Feels like I used 3/4 can of white on just the upper pier post though, and I still have the OTA and mount head to go after these bits, so it's already feeling like an expensive restoration! Maybe powder coating would've worked out better. Will certainly look further into that for the TAL-1 when I get around to doing that one.

[sloz1664]

Looking good so far Dave. Can't wait till you have completely restored it. Great to see the Tal scopes being resurrected to their former glory.

Steve

Edited April 27, 2020 by sloz1664

[DaveL59]

Thanks Steve, it'll take a while but I think worth doing. Considering its age they were built like tanks and I've no idea what they used for mirror coatings but they just seem to last forever! At 25-26 years old you'd think the mirror coatings had just been redone and all I've done is give them a clean  

They do seem to perform really well too, very stable with the main limiting factor being the small slo-mo range before you need to unwind and then unlock the clutch and move the OTA back to target before you continue. I find the 110mm TAL-1 every bit as good as the SW130 in terms of view presented at the eyepiece even with 20mm aperture and 20 years age difference.

[sloz1664]

Yep, the Tal mirrors are fabulous. Tal make the optics for the military and that is why they are so good. I haven't cleaned the mirror on my Tal 200k and probably never will. My first true scope was a Tal 1 and I loved it, then aperture fever kicked in and I upgraded to a Tal 2 with the motorised mount. I would have been content with this until the Tal 200k came up at a really good price. I couldn't turn it down. The Tal 200k will never be sold.

Steve

[DaveL59]

while waiting for the last couple bits to dry I thought I'd sand the feet so they're ready to paint. Wow that was fiddly but only a couple bits where the paint had lifted tho over years they do seen dirty in the crevices. Am almost tempted to run them thru the dishwasher before painting  

[DaveL59]

so with things having slowed a little waiting on paint to dry and wet weather, not to mention a couple kind spiders who decided to sacrifice themselves making patterns in the wet paint of the knuckle I'd not long sprayed, decided I'd do the feet. A couple bits where the paint had been scraped/chipped showed some usual ally scabbing so all sanded down and prepped the other day waiting on the other bits to dry.

Of course the feet will have to cope with being in contact with the ground so I've reconsidered spraying these and I've decided to hand painted in black hammered effect hammerite, hope this turns out well and proves durable and those brush marks flatten a bit.

So having brought the poles and other parts indoors I carefully placed them inside the box for safe-keeping. Not carefully enough tho as I nicked the middle of one pole on the screw post that the braces fit onto  Oh well I'll touch that back up later... doh! Can see I'll need to find a solution to those interior fixings in the TAL wood box or all this repainting ain't gonna last long.

[DaveL59]

Home baking??? mmmmm

decided that after >24h the knuckle parts are still a bit soft and tacky, so thought I'd give this a go. Will see how they come out tomorrow after a 30 mins bake at gas mark 1...

[DaveL59]

ok so I decided to take a peek, all cooled down and paint nice and hard now  

I'd say a slight colour shift too, I guess we could call that oven browned  

Fair result though, wonder if I could do the same with the pier tubes, might look at how to suspend those tomorrow. For sure the OTA won't fit though.

[DaveL59]

hmmm not sure if this really was the colour I'd have chosen, certainly the oven browned things, quite a contrast to the colour it went in

 

if I do the whole thing I'll have a TAL-M in that 80's PC Beige!

 

[DaveL59]

hmmm so inspecting those baked parts further in daylight, the paint has set very hard. very! Brass wire brush in dremel-a-like hardly makes any impression at all. So I've decided that after going over the latitude markings with the brush (hopefully improve the relief a bit) to just try giving it an overspray with fresh white and see how it takes. If that works then at least I know there's a good hard layer under the white to help with chipping down the road once its back in use.

If this works then it just might be worth trying the same on the pier posts to give them some improved durability but an unsure, one to mull over later I think. Besides which, I'll have to figure a way to lay them in the oven on wires to get that idea to fly. Just as well I live alone huh  

Checking on the feet they came out OK, still show brush tracks to a degree, but being hung they developed a drip on the end as the paint settled while drying, figured that'd happen. Plan is to let them cure a while and then clean up and lightly sand the long flat surfaces and add a second coat. Again a durability thing since these are the bit that sit on the damp ground so will scuff most. The brush on paint does at least seem to have cured faster than the spray even with the lower temps we're currently experiencing.

[DaveL59]

Decided to do a bit more on the OTA, strip it right back to bare metal as the thick original paint is hard to get feathered nicely where it's gotten war wounds through use. After my first sanding I noticed some ripples under the paint after washing the tube down too which says the paint isn't well attached. Rough wet+dry and a block and it came away reasonably easily, even managed to get most of it done before a rain shower and the last little bit completed once it passed and before the next sprinkle hit  

So when I've space in the shed it'll be primer and paint and hopefully get a neat run-free finish that I can leave curing for several days while I make a start on the AZ-EQ mount head.

I expect the scarring was down to the plastic caps used in the tube rings to bear against the OTA, of which a couple have failed (domed head sheared away), so once the paint had chipped it's just scarred away as the OTA was rotated/moved. I think when I get to the OTA carrier I'll remove what's left and go with just felt/flock linings on the rings which should be kinder on the paint. More on that later when I get to this part.

 

[sloz1664]

I used felt linings on both my Tal 1 & 2. The felt came from a snooker hall I used to frequent. They refurbished the tables & I commandeered the offcuts.

Steve

[Alan White]

An interesting thread.

Never owned a Tal scope sadly, they were 'the' starter scope when I started,
so of course I bought a Bresser 90mm Refractor instead,
But I did use a Tal-1 a number of times at my local Astro Centre and loved it, but clearly not enough to buy one.
Wish I had as the Bresser is now long gone, the Tal would still be sitting here of course.
 

[DaveL59]

Thanks Alan, the TAL-1 was the first scope I'd tried to obtain not that long back in fact, but the seller went silent and an SW130 came up so I picked that up for a reasonable £70 complete. Then I found this TAL-M not far from me with the older wooden box so bought that as well, only thing its really missing now is the extension tube to get up to x138 with the supplied eyepiece and a bit paint scarred but I figured I'd restore that in time. Hankered after the TAL100 refractor too and got lucky there with the 100RS which came on an EQ5 rather than the lovely wood tripod, I've since upgraded that to GoTo..

Then a couple months back I bought the TAL-1 locally, in truth just for the older 32mm diameter 25mm plossl eyepiece to use on the TAL-M, the scope was in fact just a bonus part  That said, considering its age its in reasonably good nick, paint a little yellowed but not many scars, bought from the original first owner in fact. I've since shifted the mirror up on the TAL-1 using longer screws and springs and swapped to an OEM 1.25-inch focuser on it, so its now fully usable with regular eyepieces and performs nicely. If I were to sell one scope it'd be the SW130 as I find the TAL-1 as good even with a little less aperture and a lot more solid and stable, just no RA motor like the SW130 has, but that's not so big of a deal.

[sloz1664]

A nice product review on the Tal 1.

tal1.pdf

[DaveL59]

ah yes, I'd read that and one on the TAL-M hence deciding I'd aim for those going into the hobby. I quite like the older gear and being able to fix them up and keep them going. The only real limitation seems to be the slo-mo controls having only a few degrees travel before you need to wind them back and then re-adjust the RA/DEC and start over. But you soon get used to that.

Just had my DOH! moment for the day too, putting some laundry away - the airing cupboard, ideal place to cure the paint in a warm environment where they won't get disturbed. Pity I didn't think of that before my baking attempt lol Still, having spritzed those parts with a fresh coat of white they look ok so now in the airing cupboard to fully harden while I make a start on the OTA with some primer...

[DaveL59]

So I decided to go ahead and primer coat the OTA, of course we had a torrential hailstorm kick off just before I'd finished my coffee and biccies before going out to do the second coat. Forgot about the puddle that forms in front of the shed as I made my way out under a brollie too, so cold wet feet for my troubles grrr. Still OTA now has 2 coats of primer so can start the white hammerite smooth tomorrow and pray I get a nice flat no-runs finish

I'll re-tap the screw holes for the focuser/guide scope once the paint has cured, easier than trying to mask them off since I already have a tap/die set  

Figured I'd rub down the feet too and get rid of the bubble on the end, so I've now given the top edge and the end a second brush coat. Will give the underside another coat once that's dried off. I see a couple runs in the flat segment between the narrow part of top/lower sections but not really going to worry too much about that I think.

Plan is to use some self-adhesive flock on the end that butts against the pier post to protect the white paint once this hammered paint is cured.

So far so good, I think...

 

[sloz1664]

Coming along real nice, Dave. I hate using Hammerite smooth paint, I could never finish it without getting runs of some kind.

Steve

 

[DaveL59]

yeah been reasonably lucky so far, thin sprays every 30 mins or so to build the coat. But still did get a couple runs. Followed Astrobaby's method when she did her TAL-1, where she found brush/roller just left a poor finish. I was thinking a tin of smooth and paint pad but after reading her work decided it'd have to be spray paint as the way to go.

The feet though I felt were fine to brush and they've come out reasonably well. Am currently warming the OTA tube on the radiator so it has some residual warmth for when I hit it with the first coat of white. Seemed to work well for the primer so hoping will do the same for the topcoat. It'll be cooled by the time I do the following coats of course but they'll be going onto the tacky first coat so should be ok  

The focuser I've been thinking, will use a regular black spray as it doesn't look like it'll need much if anything. Having thoughts to drill and tap a 4mm hole into it to be able to add a securing thumbscrew for the eyepiece, since I've bent the spring-clip in the tube to allow easier insert of the TAL-1 eyepieces, so of course it no longer grips the eyepiece barrel that much. Will ponder on that a while and decide later. Can always do it much later since its easy to remove to work on.

[DaveL59]

so having warmed the OTA tube on the radiator, out it went to the shed and first top-coat applied.

Had to remind myself sternly too, light thin coats, don't go mad and try for a nice even white colour or it'll just run and you'll be starting over from scratch!  Plan to gradually build to maybe 5 coats over the next couple hours to get a nice finish, fingers crossed. Then tomorrow it can go sit in the airing cupboard for a few days to cure with gentle warming while I make a start on the ALT/AZ head which I've yet to strip down.