My 14" AstroSystems Telekit

Construction of a 14" Dobsonian telescope from an AstroSystems Telekit.

To start...

July 15, 2007

It all began last January (2007) when I purchased a fused quartz 14" blank from eBay vendor Recolabs for $175. 7/8" thick and flat both sides. I had been grinding away at a 12" plate glass thin blank and it was about to the polishing stage. But I gave it all up for the fused quartz. Such is love...

The 12" plate glass blank looking lonely and unattended to.



In March I began to think about a mount that would do justice to this fine piece of "glass". Telekit is the brand to beat in the market, so I ordered a 14" DIY kit from them. Randy Cunningham knew what customizations would be required for a thin but strong quartz mirror.

Come July, the first pieces began to arrive and the blank was a 90% polished f/4.7 mirror.

This is the saga of the construction!

Grinding & Polishing the Mirror

July 16, 2007

This is my grinding and polishing workshop. Yes, an honest to goodness 50 gallon steel drum in the basement.

My 14" fused quartz blank has been in polishing with Cerium Oxide (CEO) on 55 Gugolz pitch (basement was a bit nippy when I started polishing!). The mirror now has 25 hours of polishing and it's nearly finished. The very center continues to show just a little too much reflection from a laser for my tastes.

To get the blank to this point, which is f/ 4.9, it took

1 lb #60 SC and 4.5 hr of coarse grinding
5 lb #80 SC and 25.0 hr of coarse grinding
.6 lb #120 and 4.5 hr of coarse grinding
.25 lb #220 and 3 hr of medium grinding
.25 lb #320 and 2.5 hr of medium grinding
1 oz #25 WAO and 3 hr of fine grinding
1 oz #15 WAO and 3 hr of fine grinding
1 oz #9 WAO and 2 hr of fine grinding
.5 oz #5 WAO and 1.5 hr of fine grinding

I would definitely use more #60 or #40 SC next time, but I didn't have much #60 to start and didn't want to wait on it. Shoulda! All the coarse grinding was performed with a 25 lb flat barbell weight on top to provide extra pressure.

The FL was a bit under my intended f/5 but I couldn't lengthen it with #120 and #220 doing exclusively tool-on-top (TOT) grinding. Probably, that's due to not having weight on the stack.

I did 2 hrs of CEO with polishing pads on the tile tool just to experiment with. Although the inner 9" looked polished, a laser revealed a whole lot of scatter from the center areas.

It can take all of my 210 lbs of body weight to push the tool over the mirror when the pitch tool and mirror are well-mated and getting dry. Hard work! At most I can polish for 120 minutes continuously, then I just have to rest.

The mirror spends its free time in a little coffin I made for it. Keeps it protected from dust and dogs. I am paranoid about mirror scratches!


The pitch tool also has its protection. It's some sort of artist's portfolio that my wife scared up. Good for keeping the tool in a moist atmosphere and not having anything touch its surface. The down side to both storage containers is that they have to lay flat...and take up lots of surface area.


This is the pitch tool's second incarnation. The first lasted 25 hours; then the pitch squares started to pop off. The "potholes" result from pressing the channels with a warm steel bar. That puts ridges on the squares and then pressing with the mirror creates the potholes as it flattens them. It's only temporary. After an hour of polishing, the potholes start to close up.

Here's how I spell "good contact"! Fifty pounds of weight for 30 to 45 minutes, rotating the tool a little every 15 minutes. The temperature in the work area is about 70F now in July. When I remade the tool last week, I added some harder pitch because the 55 Gugolz is pretty soft at higher temperatures.

mid-August update on mirror

It's been HOT. Even in the basement. Given the soft pitch, I chose to work on the Telekit mount rather than the mirror. Once the weather consistently cools, I'll figure the mirror.

Telekit Arrives!

July 17, 2007

The Telekit pieces started arriving the week of July 7, 2007. The sages at Telekit wisely kept the instructions from me in the initial boxes so I wouldn't jump the gun! Or so I thought. Unfortunately, there was a mix-up and the instructions didn't arrive until the second week of August. Box #1 contains the upper cage rings, the bottom of the mirror box, ground board, other parts of the mirror box, spider, etc.


Box #2 contains lots and lots of parts - wheels, charger, covers, filter holder, glue, fan electrics...too much to list! Boxes 1 and 2 came the same day. When the instructions arrived, I unpacked everything again and did an inventory.



Box #3 arrived after another day. Full of stuff! Bearings, feet, cage parts, baffle, tubing clamps, and a mystery "Bottom Counterweight System" - a little surprise from Randy, I guess, for my light mirror! But no tubes or transport handles. I would continue to wait until August 13 because of the order mix-up.

Forward 3 weeks

August 11, 2007

After several emails and even a visit to the AstroSystems office in LaSalle, CO, (I was in the area for another reason - not to harass them!), Randy and Alan finally got my order straightened out. BTW, the office is NOT easy to find, even though the address is 100% correct. If you're ever in LaSalle to look them up, go to where you think it should be and don't move more than 50 yards from there. Kinda like finding an 11th magnitude fuzzy bit in the sky. Despite the small hobbit door pictured here, Randy and Alan manage to get everything out and shipped around the world (there's got to be another door, eh?)


I received a manual for a 18-22" Telekit a couple days ago (no 14" manual??) and it covers the basics of assembly. But, it's easy to see that the kit has evolved a bit from the original manual written in 1997. But things are changing - here's a top-secret new developments - Randy and his ultra-nano-portable Telekit! Pretty impressive, right? It's got the light gathering power of Bambi! Hope I don't get in trouble with them for publishing this photo!

Sat down with all the boxes and the parts list in the 18-22" assembly manual and checked all the bits off their lists. Since this is a new and improved 14" kit, the list in the manual is not 100% accurate. But major differences are covered in the parts list in each component's plastic bag. Now that I've got everything put away again, I'm wondering if I actually saw an azimuth brake assembly. Hmmmm...

After that, I made a supplies run to Home Depot for paint, finish, some extra fine sanding supplies, contact cement, etc. There's not enough time to continue this afternoon since guests are expected, but I hope to start work tomorrow, then go see the Perseid shower in the night.

The AstroSystems computer controlled router.

Work area & cage

August 12, 2007

Not a lazy Sunday! Spent most of the day cleaning and rearranging the garage to make a decent work area and work surface. Problem is, the garage is pretty small (it will squeeze in two compact cars) and is in use for my wife's painting assemblage, my two motorcycles, and lots of hand and power tools. But I think this arrangement will work well.

By about 5pm, I collected all the Telekit part boxes and moved them into the garage. I'm thinking I'll follow the construction order in the manual. The cage has all the essential requirments for the construction but in small bites (sanding, glueing, alignment, etc).

The cage parts got sanded to 220 grit by about 7pm and then it was time to quit. I'll be using just hand sanding on everything because it's so easy to wear though plywood veneers with a power sander. As it is, hand sanding a part takes very few strokes (maybe 10 or so) and you can make the strokes parallel to the grain.

Hoping that I'll be able to construct the rings and spacers on Monday.

Cage assembly

August 13, 2007

I had all the wooden pieces for the upper cage ready to go, sanded to 220 grit. First thing to do was mix up some epoxy. How much? Duh, dunno. No guidance provided. So I took 10ml of each and mixed up 20ml. Way Too Much! About 5-8ml total would be plenty for gluing in the dowels and ends of the spacers. Too bad you can't save that stuff after it's mixed!

There was a part problem at this stage involving the spacers. They have two holes drilled in them to accept part of the 1.5" dowel. But those holes were drilled a little too deep, as only 1/4" of the dowel projected out when fully inserted. The assembly directions say 1/2" should project to be inserted into the rings. In addition, some of those holes had a bit too much wiggle room. I'm hoping that enough epoxy was present to fill the gaps.

After the spacers with dowels are connected to the holes in the bottom ring in the correct orientation, the free ends are epoxied up, then the upper ring is connected. This is a bit of a 3 hand job because the holes in the upper ring and the dowels in the spacer are not precisely cut. Fortunately, it's wood! which is amenable to a little bit of controlled pushing, squeezing, and bending.

After that, I applied a bar clamp over each spacer and slowly applied pressure (not too much!). It's important at this point to have acetone and Q-tips available as the inevitable bit of excess epoxy will magically appear at the joints. Acetone does a good job of cleanup when this epoxy is still soft and will even allow you to salvage the mixing cups and brushes for re-use (and you only get 3 of each so either re-use or buy more!).

Now it's time to wait 24 hours for the epoxy to set up. Geez, I could be ambitious and sand more stuff...NAH! Good for a Monday!

Cage Truss Clamp Blocks

14 August 2007

The clamps were removed and the rings seem securely held together by the short dowels coming from the spacers. Yeah! First assembly finished.

Next up, putting the 4 truss clamp blocks on the lower cage ring. The holes drilled into the pieces were too deep again. Only about 1/4" of dowel sticking out. But the good news is that everything lined up well and went together easily. I figured about 1 teaspoon of each epoxy component was enough for this job and I still had some left over, about enough to glue up another of the block...if there were more...

Clamped them with some thin plywood over them so things wouldn't go askew when they are tightened. Everything has to sit tight for another 24 hours. In the mean time, I need to go get some oil-based, sandable, birch-colored wood putty. The Minwax stuff is not sandable and I have some that needs to go back to Home Depot. The good stuff is coming from a WoodCraft store in Oregon.

Cage and slide box varnishing

15 August 2007

This evening was the start of finishing of the cage assembly. Got out the wood putty and the sanding tools (#220 and blocks) and went to work. The color of the putty was a bit more red than the Baltic Birch but the defects to fill were pretty small. Getting the ring edges smooth took a lot of attention. After the first cleanup I felt things over and mulled over sanding more or starting to varnish. Heck, there's really only this chance to get a smooth surface, so I went back to sand some more. Then out with the vacuum and the tack cloth again, gave a critical look, touched up a couple rough defects, and called it GOOD.

I'm using AstroSystem's varnish recommendation - MinWax Helmsman Spar Urethane, both brush on and aerosol. For the first coat, I thinned it 50-50 with mineral spirits. That sure helped get the finish into the wood and it also decreased the drying time, allowing me to flip the cage to paint the other end. The wood color became slightly more yellow and the contrast increased. All in all, this product is doing a nice job.

Tomorrow - light sanding and full-strength coat. Should I call that the first coat or second? Hmmm...

16 August 2007

Gave a nearly full-strength coat with brush of varnish this evening with some fine sanding with #320 before that. Cut varnish 1 part spirits to 10 parts varnish. I did the clamp blocks first and worked slowly. By the time I had everything that was visible coated, the blocks were dry enough to turn over onto some wood strips. I think tomorrow I'll do another coat with brush, then follow that the day after with aerosol.

18 August 2007

Saturday...after fine sanding the brushed on varnish on the cage, I strung it up using the pre-drilled holes in the spacers to apply aerosol varnish. Three coats spaced 30 minutes apart and it's done...except for some post-finish #0000 rubbing with steel wool and maybe some wax. Hmmm, wax...might defeat the purpose of the satin finish. Have to try that out on something else first.


Next up - locating and gluing the baffle retainers onto the filter slide box. I thought this step was kinda weak in the instructions. Because the retainers are very small in cross-section, it was impossible to use a clamp on them without having them slide around under pressure. The box had to be stood vertically so the retainers wouldn't ooze away while the epoxy set up. In retrospect, temporarily tacking them to the slide box with a small brad would have been the way to go. Oh well, I'm sure the epoxy will hold them just great.

19 August 2007

A couple coats of brush on varnish and a couple of aerosol on the front surface, some Ultra Flat on the back, and the finishing of the slide box is complete.

Finished cage assembly

20 August 2007

All the finishing of the filter slide and cage completed, I gave it a quick rub-down with #0000 steel wool to remove anything just on the surface. It all looks great. The slide has a slightly nicer finish since it was hard to get a good shot of varnish spray on the narrow cage rings...but I'm happy.

Assembled the filter slide to the cage but had second thoughts about the deck screws that AstroSystems provided. They're supposed to be 1" long (according to the BOM), to match the 1 and 1/8" width of the rings. However, the provided screws were 1 and 1/4" long and made me real nervous. So I substituted some of my own #8 1" wood screws and that all went together well. In photo, supplied screw, left, and my choice, right.

After the slide was connected, I went ahead and rolled out the light baffle and sprayed its outside face flat black. Hope the paint gets into the fabric enough so it won't crack when it's rolled around the cage interior.

28 August 2007

Had to take a few days off for personal reasons. After returning on Sunday, it was time to put the baffle into and attach it to the cage. Disaster! Within a few minutes the baffle cracked and was good only for scrap. It is brittle stuff.

Someone in RCA had suggested awhile ago that ABS sheet from Tap Plastics is a good baffle material. It's glossy on one side and flat black with a pebbled surface on the other. I ran down to Portland and picked up a 13" x 96" piece for just $11. This stuff is not going to crack from brittleness and is easy to cut with a blade, even though it's about a 1/3 thicker than the Formica that AstroSystems ships. Last night, I got it cut to length and installed. Just a note, the 12 5/8" that AS cuts the baffle to could be 12 7/8", it's just a little short and can show some tape or wood on either end.

Tonight, I attached the spider, 2nd mirror holder, focuser and adapter plate. Wow! that Feathertouch focuser is phenomenal! It is well named. All metal work at this point is top-notch. Now, I've put the cage assembly to bed and will be moving on to the lower parts.

But first!, a confession. I was looking through my desk on Sunday night when I discovered a Telekit assembly manual for 10-16" kits. Randy must have sent this right after I ordered in February and my multiple trips to Asia in the winter and spring must have wiped my memory of it clean. So my sincere apologies to Randy and the AstroSystems crew. I won't go back and edit out my mistakes and bitching from my earlier blogs...just know that it was my bad! The manual for the smaller kit is much more accurate so you can ignore my bitching on that score, too.

Ground Board

August 29, 2007

Started on assembly of the ground board tonight. Started by laminating the 3 sections of each foot together with epoxy and dowels. I decided to attach the Formica bottoms to the feet at this point, figuring it would be much simpler to trim the bottoms, sand, and rout the feet without them being attached to the ground board. And I think I was right.

August 30, 2007

Took the glued up feet into the shop at work to use the stationary belt sander on them, 'cause a bit of epoxy was squeezed out of the joints. I think that the belt on that sander was #120. Anyway, it made short work of the epoxy and did a decent job of rough sanding the joints. As with any high velocity sander like that, you have to be aware that the edge that the belt hits first will sand much faster than the other edge.

Back at home, I put the feet topside up on my router table and used a Bosch round-over bit (with bearing) to finish their bottom edges. I just moved the bit back just enough under the fence and then held the feet against the fence opening as I rotated it.

The fence came off and a pin and guard were put in place on the table top to round-over the top and bottom surfaces of the ground board (after marking on the board where to stop rounding the bottom edge where the feet would attach).

I further finished the feet and the ground board at that point with #150 and #180 on a handheld finishing sander, cleaned up a bit, and got some epoxy ready. After painting some epoxy on the top of the feet, they got attached to the bottom of the ground board and then clamped. By the way, the dowels were about 3/16" too long and stood proud of the top surface, so the clamps had to be jiggled around a little. Those stumps will require some work tomorrow to get them flush with the board's top surface.

August 31, 2007

Took the stumps down with a sanding wheel on a Dremel. Fast! Then tried to sand down some of the poor fit between the edges of the board and the feet. I don't know if these were specifically fitted, but some had about 1/8" gap. Lastly, I put some of the wood putty into the router tears that came on the ground board, let them dry for 10 minutes, and sanded them flush.

After cleanup and dust removal, put a 50-50 mix of the MinWax Helmsman and mineral spirits onto the surfaces. Hope to be able to get a second coat on tonight, then use some aerosal on it tomorrow. That will complete the groundboard except for miscellaneous hardware installation. Good thing, too, as I leave for a week on Sunday to visit my ancient parents, then return to Portland for a few hours before leaving for 2+ weeks in Singapore. I don't suspect I'll be able to do anything else on this project until nearly September 28. I'll miss it!

September 2, 2007

Yesterday, I did manage to get some finishing work done on the ground board. I hit it with 2 coats of aerosol Helmsman urethane and it looks pretty completed (especially since it's not visible in normal usage!).

Between coats, I looked into getting the parts together for the mirror box. I wound up kinda mystified by the "cage rests", as describe on page 35 of my 12-16" (new!) assembly manual. I neither had the plywood parts nor the slots in the box parts that they were to be epoxied into. So, I sent an email off to Randy and Allan to find out what's up with this. Good thing that I'm already in Memphis, on my way to Florida, and I'll only have 12 hours or so at home next Saturday before leaving for Singapore.

But I did have time to fill some edge defects with putty and get that sanded down with #120. But no time and no extra hands around to get the box glued up.

September 6, 2007

Randy replied that this 14" kit was the first of a new design (for this size) using mostly 1/2" Baltic Birch ply and that the cage would not need any rests within the box. I'm to let him know if that is not the case and AstroSystems will make things right. I like that - "Don't Worry, Be Happy"!

Mirror Box

September 26, 2007

Finally got back to work on the kit after returning from Singapore! But I've only a limited time because I'm off to my parent's home at the end of the week, for at least a week. [as it turned out, for 2 weeks].

As noted above, I had already fixed edge defects with putty and did some sanding.

Next up: prepping the wood strips that have to take the clamp pressure and resist the epoxy (don't want any nasty strip permanently attached to the box!). I used some scrap 1/4" ply for the strips and wrapped them in light paint drop sheets.

I mixed up about 60ml of epoxy (and still had some left when done) to use for the joints and the feather on the inside corner. Oops! I had run out of acetone and had to quickly go get some. [I never made a good Boy Scout.]

Although I had been planning on performing the glue-up with my wife, she was still at my parents without any clear return date; so, I decided to do the corner-by-corner glue method and hope for the best.

Painting the finger joints with epoxy was pretty tedious but it went right along and I was soon finished. I applied the required 2 clamps along each side, 8 in total, and then checked for square. Not a perfect first try - the two corners were about 1/4" different. I had a long clamp in reserve and put it across the top (by necessity) of the long diagonal and applied just the slightest pressure. I had two equal diagonals virtually instantly.

I then used most of the rest of the epoxy to feather in a fillet on the inside corners, using my fingertip as a spatula. Then, cleanup and waiting for 48 hours for the epoxy to fully set.

October 23, 2007
I stayed away from home for 2 more weeks, helping my parents. The box was left with clamps on, so it was 'good and set' when I got back! No ill effects of being clamped up that long, as I had protected the wood with scrap very well.

I went to work at routing the edges flush, getting rid of the small raised portion of the finger joints (planned in by Astro Systems) and the extra epoxy. Initially, I tried doing this on a router table but quickly decided that the way to go was to make an edge guide from scrap and use the router "by hand" with a long straight bit. Since that worked well, the next step was to use a similar setup and round over the edges with a guided round-over bit. Finally, the machining marks on the edges got sanded down with 120, 180, and 220 grit paper, on an orbital finishing sander.

One more item for the mirror box right now - the cover. I thought this step was misplaced in my instructions, but that is probably due to the fact that this was a custom kit. Anyway, I did sand and finish the cover now, but I haven't put any of the hardware in place yet.


Dec 22, 2007

My fears were justified about the fitment of the Primary Mirror Cell into the mirror box (see below). I'm thinking that because AstroSystems switched to 1/2" plywood for the mirror box, that there was some warping inward due to the clamping pressure when the box was assembled. I did that just before I left for Asia and the box was left clamped for 2 weeks or so. That made the side panels take a bowing set inwards. The box was also slightly out of square (maybe 1/16") but the bowing of the sides was much worse (contact and needed about 1/8" sanding).

So, long story shortened, there had to be considerable sanding done to get the PMC to fit reasonably well into the box. I didn't want to sand the edges of the PMC, so, instead, the bottom of the box was sanded down a ply layer in a couple areas. There is still a little contact, but I'm sure that screwing the PMC into the lower blocks will help square things up.

Today, I glued up the bottom of the lower truss clamps to the main body of the clamps and set them aside to dry in a warm room. The epoxy is very reluctant to flow when its cold so the containers are set in a pot of warm water for 30 minutes before I use it. It also gets very stiff after mixing if it's cold, so glue-up is being done in the house rather then the garage.

Dec 23, 2007

With the epoxy on the bottoms of the lower truss clamps well cured due to the overnight in a warm room, it was time to epoxy the clamps to the top of the mirror box. I took the advice of the manual and put some 3/4" brads through both arms of the clamp. It was necessary to make a pilot hole using a brad in a power drill because nailing into the edge of the plywood is difficult with a light nail like this. I set the brad's head below the surface with a finishing nail set.

Working one corner at a time, I spread the epoxy on the outside of the arms, placed the template across the corner, pushed the clamp body in and up against the template, worked some gymnastics to tap the brads with a hammer in one hand while keeping the clamp in place with the other, placed the inner part of the clamp in place, and, finally, applied a woodworking clamp around the entire corner assembly. You can see that two of my clamps were applied with the clamp screw inside the box; this was because the screw-end clamping surface for these particular clamps is gimballed and won't work against the outside box corner.

The glue-up for the clamps took about 1.5 teaspoons of mixed epoxy. I had about 0.5 teaspoons left in the mixing cup, so I went ahead and glued the dowels into the tops of the truss poles, as per directions. Here's one about to be stood on its end for the epoxy to cure. Don't neglect to test the fit of the dowels into the poles before you start gluing! One of my dowels was a bit oversized and required a little sanding to get it inserted.

Mirror Cell

29 October, 2007

I'm starting to feel that I'm at least half way finished. Starting on the mirror cell really re-inforced that. The only major assembly piece after this is the rocker box. Then bits and bits and bits.

Since I have a very light mirror, there are some oddities to my kit. Another one was noticed with the cell base - there are some extra holes. I'm not exactly sure what these are for yet, but I suspect they relate to the counter-balance system that A.S. included. You can see these counter-sunk holes to the side and above the the lower travel posts in this picture:

Tonight, I filled the edges of the cell base and then sanded them and the two surfaces. Not too tough! The base is a sandwich of two pieces of BB and, naturally, there are some small places where the surfaces didn't quite get matched up. Additionally, there are some router machine marks on the edges, so it's important to fill and sand those edges first.

Mixed up the recommended volume of epoxy. Again, the directions specify way too much, at least for my 14" kit! You can easily do this job with 3/4 the amount (I'd say 1/2 but I don't want to get anyone into trouble). There are several pieces to glue up but the epoxy sets so slowly there are NO worries! In this photo, you can see my first try at the "right" amount of epoxy on the post and its hole. A bit too much. The travel support was done just about last but it's a surface mount. You should be able to get the correct amount easily, unlike me. Aim low - if you end up light, just pull the dowel out and add some more! Besides, it all gets painted black, so why worry??

Can't do anything more tonight, the epoxy needs 24hrs to set.

Cell finishing & Transport handles

Oct 30 - Nov 5, 2007

There's a lot of finish work to perform on the mirror cell. Both sides have to be sealed, the "up" side has to be painted black, and the "down" side has to have additional finish coats of clear urethane applied. All this takes time, especially with the spray Spar Urethane because it requires so much drying time if you can't re-coat it within 90 minutes (then you wait 72 hours!).

So, while working on the cell finishing, I thought I'd grab the transport handles and finish them at the same time. Might as well, it's all the same type of work - sand, sand, sand, paint, paint, spray.

Things are pretty far along today. The cell is done except for a final rub-down with #0000 wool and the handles need one more painted coat or urethane. Then, it will be time to put the goodies onto the cell.

Nov 25, 2007

Wow! What happened to November? I'm sitting in Tokoyo airport (Narita) looking at this last post and realizing that the only work I finished on the mount in November was to complete finish work on the cell and handles. And they're not fully assembled yet, either!

In my defense, there were some major house projects to get done and then my son arrived with his fiancee for the Thanksgiving holiday. He's on his way for another tour with the Army in Korea.

Darn it! I won't be back from this trip until about December 6th. I'm seriously considering sending the mirror out for figuring since I seem to have so little free time to work even on the mount.

Dec 9, 2007

I'm back and finishing the cell and handles up! The handles only needed the wheels, bolts, and pads attached. I decided to just finish them up with a #0000 steel wool rub-down because they look good already.

The mirror cell needed a bit more than just bolt-ons - there's a final touch-up coat of flat black involved and some time delay for the battery tape to set up. Well, at least I get to work this indoors instead of the garage. It's gotten cold in Portland since I was last here.

The kit for the PMC was good but I was missing the wire tack-downs. I just used what was on-hand in the garage - not great but functional. This is the way the primary mirror cell looks like with everything except the pivot pins attached. I was a little nervous about securing the pins onto the PMC with the substantial lag bolts but all was well in the end. They have to come out and go back in at least twice more, so I'll probably have to re-coat them with black at the end.

Those shiny pivot pins, lag bolts, battery terminal connectors, and whatever else has gotten scratched or reflective during assembly must now be re-coated with flat black. Bother - another masking job. But anyway, here's a picture of a hinged corner after the touch-ups.

I'm hoping that I'm in the clear with the PMC at this point. Disconcertingly, there's a note in the next section of the assembly manual about fitting up the PMC into the mirror box before its final finishing because you may have to sand the PMC's edges if the fit is too snug. Yikes! Maybe that text should come a little earlier in the manual??