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Model Railroading > Rotating Backdrop? Too Much Time on my Hands?

Date: 02/23/24 17:42
Rotating Backdrop? Too Much Time on my Hands?
Author: wabash2800

Before I get into this, I'll admit I may have too much time on my hands since I retired. And I may or may not use this idea on my layout. But it was fun to draw up and think about. And I'd love to hear your input.

I am planning a new layout for a large spare bedroom with a door in the corner. The layout is an around the wall, walk-around design with a peninsula in the middle. After much practical deliberation I have decided on a lift-up-gate at the doorway and flipping the door hinges so the entrance door swings out in the hallway. A nod-under, drop-down-gate, swing-out-gate or vertical drawbridge style of entrance all would not work for some very good reasons.

Anyway, one feature of the layout is a 24 in. tall photo-backdrop around the perimeter of the layout and down the center of the peninsula. What would I do for the backdrop at the entrance way? Most modelers would probably just leave it out. But I would like to incorporate it with the gate.  The simplest solution would be to mount the backdrop on the inside of the entrance door, provided you can open and close the door from the inside. However, I have an antique door and don't want to modify it. (I suppose I could substitute a cheap door and hang onto the antique door until I sell the house and re-install it.) Another simple solution would be to put a  track under a movable overlapping (or under-lapping) piece of backdrop and just slide it over when the gate is to be opened or closed.

Note my first illustration. The distance from the floor to the top of the rail with special cabinet hinges is 54 in. (my hinge point). My ceiling height is 92.5 in., and though it seems if I attach a rectangular piece of backdrop 24 in. tall and 36 in. long onto the back of the lift-up, I won't exceed the 92.5 in. clearance. But what would seem to be a need for just a 90 in. ceiling clearance (54 in. plus 36 in. at a 90 degree opening) is really a need for perhaps 97 in. ceiling height! (There is probably a geometrical formula in there somewhere.) On the way up the rectangular piece of backdrop will clear the backdrop to the left, but look what happens on the way up when the overhang exceeds 92.5 in. clearance height! Also, once you get to the vertical position of the lift-gate you overlap (or under-lap) the backdrop on the right. (This could be remedied with allowing the overlap and having one of the two backdrops in front or behind each other.

Note my second illustration. But if I cut a radius into the backdrop equal to the width of the lift-gate I can still have a layout height of 54 in. (or taller) and have a 36 in. long piece of backdrop 24 in. tall. A careful observer would note that if I made the lift-up gate narrower than 36 in, I would have less of a clearance issue. However, even though my door width is only 29.5 in., I want my lift-up 36 in. width, because I don't want to anchor screws into the antique molding around my antique door. Also, note that there is a little bit of overhang for the fixed part of the backdrop in the top left corner of the door. This shouldn't be an issue with the door height about 6 ft. 6 in. and the width almost 30 inches.

Caveats Well, the fact is I think this would work, but I can already see some caveats. The radius cut into the backdrop has to be perfect for the movable backdrop to slide smoothly in an arc without binding. (I'll assume a slight gap would be necessary.) Also, the material used for the backdrop here has to be very stiff or supported to keep it from flapping in and out. Expansion and contraction might be an issue, so I would rule out any kind of wood product. (A glass shop might cut you some 1/4 in. styrene or Plexiglas.) A roller track or some kind of curved track that would have a male and female component could be used to align and support the moving arc with less stable material. Another issue is that getting this thing set-up and perfectly aligned might be a PITA. The other thing is that the weight of the whole 7 ft backdrop section might require an axle at the pivot point rather than hinges, though Blum cabinet hinges can be ordered heavy duty and perhaps three would work.

Victor Baird

Edited 11 time(s). Last edit at 02/24/24 00:26 by wabash2800.

Date: 02/23/24 20:06
Re: Rotating Backdrop? Too Much Time on my Hands?
Author: dragoon

Looks like a clever idea that will work! Maybe a counterweight will help in the rotation?

Date: 02/23/24 21:11
Re: Rotating Backdrop? Too Much Time on my Hands?
Author: wabash2800

That's a good idea.

I also redid the second image as I made an error in coloring my image. The backdrop (light blue) is supposed to be on the backside of the gate and bench-work (brown). 

Edited 1 time(s). Last edit at 02/23/24 21:11 by wabash2800.

Date: 02/23/24 21:54
Re: Rotating Backdrop? Too Much Time on my Hands?
Author: PHall

Curved lines going through an image might be tough to conceal.

Date: 02/23/24 22:11
Re: Rotating Backdrop? Too Much Time on my Hands?
Author: bearease

Just my 2.5¢, but I kinda like your sliding panel idea. Just brainstorming here, but what if you mount the drawer tracks, rollers, or whatever mechanism you chose on the back of the stationary layout bench work, not the room door or frame. The motion would be similar to a sliding screen door - the door opens out into the hallway, then you slide the backdrop panel, then lift up the... "lift-up-section." Have the sliding panel roll back behind the stationary segment (to the right in your drawing.) You might even be able to model a structure or scenic element (Mountain, rocks, etc.) in such a way as to hide the area where the two panels overlap, eliminating the empty curved section that appears when you lift the curving panel as in your drawing. Keep in mind here, woodworking is NOT my strong suit, so I'm not sure if what I'm describing is even feasible - I've got a lot to learn as I start this process. But it is fun to brainstorm!
I'm interested to see what you come up with as I'm in the "drawing board" stage of my future (retirement) layout. And while I won't encounter a situation like yours, I'm grappling with the concept of a long removable, flexible backdrop that can be slid off of the layout and rolled up for portability, if so needed.

And yes, the design process is just as much a hobby as the railroading itself -- and all a part of the retirement experience!

Date: 02/24/24 00:22
Re: Rotating Backdrop? Too Much Time on my Hands?
Author: wabash2800

True, though that's not my greatest concern. Perhaps a durable photo paper could overlap the seam ever so slightly to help conceal it?

PHall Wrote:
> Curved lines going through an image might be tough
> to conceal.

Posted from Android

Date: 02/24/24 00:44
Re: Rotating Backdrop? Too Much Time on my Hands?
Author: wabash2800

That was basically what I considered as a option with the backdrop panel sliding to the right behind the stationary backdrop. How would you push and pull that section? A knob? Hole? Recess?

I plan on using tall 2x4s on the wall side of my L Girder benchwork to attach my backdrop. But the only ones that will be screwed to the wall are the ones near the lift-gate.

Victor Baird

Wait till you see what my idea is for overhead lighting without attaching it to the ceiling.

Posted from Android

Edited 3 time(s). Last edit at 02/24/24 00:47 by wabash2800.

Date: 02/26/24 11:52
Re: Rotating Backdrop? Too Much Time on my Hands?
Author: wabash2800

I mentioned reference my first illustration that there must be a geometric equation in there somewhere to figure what the max height would be for the rectangular 24 x 36 in. backdrop.

There is. It's been about 50 years since I took geometry in high school, but it's the good old Pythagorean Theorem reference triangles. Remember that?  Therefore see this third illustration.

The calculation computes that the distance btw the two points (corners) would be 43.27 in., and it would overshoot my 92.25 in. ceiling by about 5 in. 

So,.... If I knew my ceiling height was 92.25 in. and the backdrop would deflect to 43.27 in., what would be the max benchwork height? We don't have to do algebra but just subtract the 43. 27 from the 92.25 ceiling height and come up with 48.98 in. But, of course, I would round that down. to probably 48.75 in.  As I mentioned before, making the lift-up narrower would get your benchwork higher. But now you have the formula to figure that out.

So, you can see that given my 92.25 in. ceiling height, cutting a radius equal to the lift up width (shown in my second illustration), all things being equal, I can maintain my 54 inch benchwork height and still maintain my clearance. (I actually could raise my benchwork height to about 56 in.)

Caveat: Where your hinge point is (and what kind of hinge you use) affects the calculation. Comments, questions or corrections welcome.

Victor Baird

Edited 13 time(s). Last edit at 02/26/24 17:33 by wabash2800.

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