Dome Internal Mounting Plates

Lots more dome work in the last few days. Focus was to get all the internal stuff mounted – Holo Projectors, PSI and Front and Rear Logics.

I wasn’t very happy with my previous attempt of drilling holes through the inner dome and using counter sunk screws. By the time I’d counter sunk them enough the holes had gotten so big that the screws could pull through easily. Attempts to JB Weld the screws on the inside of the dome didn’t work so well either.

Here’s what my old mounting system looked like

Didn't work so well

It really looked like I may have to do what most other builders do and that’s goop the crap out of each part – Locking them in place for good.

But a quick visit to see my friend Richard resulted in a cool solution that I’d not seen done before. He came up with the idea of having a single mounting plate for each side of the dome which would hold everything and be easily removed if need be.

After a bunch of prototypes this is what we came up with. Just 3 screws holds everything in place. I can’t believe how simple the design is.

New Dome Mounting Plate

The PSI’s are inserted into a cut down pipe fitting secured with a screw, the HP’s just press fit to the dome by the plate and the logics are held on using the bracket/box.


We still needed to secure the plate in place, and the only good way to do it was to bolt it to the inner dome – which hadn’t worked too well previously. We tried JB Welding the screws to the surface of the dome but they came off easy.

Richard remember the trick of pulling aluminum into a cone/dimple like on the side of a home made Luke Graflex lightsaber – the tool used to be called a “Shoulder Puller” back in the day when people still made their own Graflex’s. Here’s what Richard used.

Dome Hole Puller

Simply drill a hole in the dome and insert the screw and tighten down on the collar which is on the inside of the dome. I think we started it off with a thinner screw then switched to the final size. I should name it the Dome Hole Puller.

In the end we used 1/2″ 10-32 screws which are much bigger than what was originally holding things in place a few months ago. No chance of things pulling through now.

Plate is somewhat flexible, so if someone pushes on things then it’ll give a bit rather than failing or things popping out of place.

I also decided to switch back to the old style logic surrounds. Not having the front outer plate on the new version was bugging me. I’m hoping to get the panels cleanup and painted tomorrow.

A couple of screw ups/lessons learned along the way. JB Weld didn’t want to hold the screws in place, even when going through the dome. So in the end I notched the underside of each screw a bunch of times and scored the hole with a dremel. As of right now things seem very solid and once the outer dome goes on there’s no way for things to move…hopefully.

Screw all JB Welded and sanded down

A big notch was also cut in the dome ring by mistake while making room for a PSI. I’ve tried to fill it with a piece of aluminum and JB Weld and I’m hoping it will not be noticeable once the outer dome goes on.

Patched Dome Ring

The marks in the top band will be covered by the blue paint, but behind that is the patch which is visible. It wouldn’t be so bad if the dome touched the dome ring at the bottom, but there needs to be a slight gap.

I also had one hole from my previous attempt of mounting things that needed fixing. It fell on a panel seam line and I ended up plugging it with a aluminum rivet I filed down. You can hardly notice it with the outer dome on.

Hole filled by rivet

And tonight I finally got all the pie panels cut out, so I’m very close to being able to glue the two domes together.

Pie Panels Cut Out

Posted by Chris on May 15th, 2007 in Dome | 2 Comments

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2 Responses

  1. Matt McCormick remarks on

    Nice work, as usual Chris. Good to know that the JB Weld won’t work on these details. I’ve been having trouble with it too. So what exactly is this little collar/shoulder rig you’re using here to dimple the dome for the screw head? Is it made for this purpose, or you just rigged something up? I can imagine making something like it with washers and a nut. Is the aluminum pliable enough that it will deform ok around the screw head?


  2. Chris remarks on

    It’s a pipe reducer, so a found item. The trick is to have enough of a dimple to “pull” the hole. My R&J dome was definitely pliable enough, but your mileage may vary (e.g. 300MM dome).

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