Tuesday, September 6, 2011

Palmer Industrial Backdrop

The backdrop for the Palmer Industrial Park goes down the middle of the layout, which sticks out into the middle of the room.  I didn't want the backdrop to change the feel of the room from one big open space into a sort of maze.  So I decided to keep the top a bit below my eye level.  A nice convenient height seemed to work out to 10 inches above the foam.  That seems like it should be quite high enough to provide a good backdrop for relatively flat N scale scenes - none of my buildings will be anywhere near 10 inches tall, and even tall trees won't quite make it to the top (10 inches is 133 N scale feet).

I described the backdrop supports in Foam on the Palmer Industrial Park.

Order of operations is always a good debate.  I wanted to get the foam painted a reasonable earth color, the backdrop painted sky blue, and the fascia painted dark green.  It seemed to me that the best way to do that and have the least potential for getting a color of paint somewhere it shouldn't be was to do things in this order:
  1. Paint the foam.
  2. Tape down the paper track plan, to transfer it to the foam and then to use it as a drop cloth to keep backdrop and fascia paint off the foam.
  3. Put up the backdrop and paint it.
  4. Put up the fascia and paint it.
  5. Rip off the now paint splattered, pounce wheel punctured paper plan and stand back to admire it all.
Without backdrop or fascia to worry about, painting the foam is fast and easy.

Foam painted a light tan
I used a color from TrueValue called "Benefactor" (number 14D4).  It's not quite what I hoped it would be, but it serves the purpose of being at least somewhat ground colored, and still light enough to easily see pencil and marker lines on.

With the foam painted, getting the paper plan back down over the backdrop supports turned out to be fairly easy, with only a bit of fiddling around to get it positioned properly again.

Track plan back over painted foam
As I mentioned previously I decided to try a roll of vinyl flashing for the backdrop, so I wouldn't have any seams.  The flashing is fairly thin, which is why I used sheets of plywood to support it.  The open question was what glue to fasten it with.  I didn't want to have to try to clamp the vinyl in place while the glue dried.  I wasn't sure I could do it without denting the vinyl.  And I didn't have any clamps with long enough reach anyway.  So I read the fine print on the the tubes of glue in the glue aisle.  After rejecting the ones that had dire warnings about ventilation, I found Loctite Power Grab for tub surrounds.  The fine print says it has "very high initial tack which reduces the need to brace".  I clamped a plywood scrap vertically to a support column in the basement, spread some of the stuff on it, pressed on a chunk of vinyl, and sure enough it stayed put.  After it dried, I couldn't see anywhere that the glue had damaged the vinyl.  And I couldn't pull the vinyl off without exerting enough force to wreck the vinyl anyway.  So I bought another tube (and later discovered I should have bought two more tubes), and started on the real backdrop.

Glue spread into thin layer on support
I used a plastic scrapper to spread the beads of glue out into a more or less solid thin coating on the plywood backdrop supports.  Then very carefully press the vinyl into it.  You can pull the vinyl back off, and even slide it around a little to get it exactly where you want.  The only really tricky bit for my backdrop was the bulb around the end.  I used an extra thin bead of glue up the single post at the end, and let the curve of the vinyl do most of the work, pulling it around until it just squished into the glue bead on the end vertical a bit.  Here's the backdrop completely glued on, with the remainder of the roll sitting on the O scale layout at the far end, waiting for the glue to dry.

Backdrop glued in place
At the far end the backdrop curves out to the wall with a pretty tight radius.  I didn't actually glue the backdrop to the wall, I slipped a sheet of thin (1/16 or so) model aircraft plywood I had lying around in and glued the backdrop to that.  Saves messing up the wall.

Once the glue was dry, I trimmed off the remainder of the vinyl roll and applied the first coat of paint.
First coat of paint
I used valspar EB6-4 Sky Blue.  I chose the one color actually labelled "sky blue" after bringing home hundreds of those paint sample strips with exotic names for various shades of light blue.  I'm very happy with it.  I'd always thought the backdrop on my O scale layout was a bit to intense of a blue, this one seems much better.  In the above photo you can see a couple blue marks on the track plan, so it is serving it's new purpose as a drop cloth.

So, if I was to do the backdrop over, I'd make a continuous strip of plywood down the center, cutting a series of vertical saw kerfs deep into it where the shallow curves are to make the bends.  But I'd do the big blob at the end the same way.

Monday, September 5, 2011

Transfering the Plan

On both my new N scale Palmer Industrial Park and my older O scale No-Name Industrial Park I drew the trackplan in a cad program (Ashlar Vellum, for reasons I won't bore you with here).  The cad drawing has very accurate turnout locations with point, frog, and center lines marked, and also easements.  The challenge then becomes getting the drawing onto the layout in a form that helps you lay track.  I described the process of getting the full size printout in Mocking up the Palmer Industrial Park.

Once you've got the full size plan taped down to the layout (and in the case of foam, if you're going to paint the foam paint it before you get to this stage) you can transfer the plan from the paper to the layout.  I use a pounce wheel, which is a sharp pointy wheel in a handle.  You can get cheap ones at fabric stores, but they don't have the sharpness necessary to do a good job.  I bought the 3-piece pounce wheel set from Micro-Mark, and I mostly use the largest of the three wheels.

Using the pounce wheel is simple.  Try it out on a scrap with however many paper thicknesses you have to see how much pressure you need to get a good line of dents.  It needs a lot more pressure on plywood than it does on foam.

Using the pounce wheel
At intervals while you're doing the pounce wheeling, take a break (your hand will need it anyway), and very carefully peek under the paper without moving it to make sure you're getting a good line of dents - not too deep, and not too faint.

Once your done, make sure you've got decent lines of dents everywhere.  For laying track, you want the line to be clearly visible between ties and through a thin layer of glue, so you need to go over the dents with a pencil or permanent marker.  If there are places where the dents get a bit faint (it happens), shining a flashlight along the line will bring them out.

A flashlight makes tracing dents easy
A bit of care and patience, and the cad drawing is transferred very accurately to the roadbed.

I've done all the pounce wheeling on the Palmer Industrial Park, but I haven't yet done all the tracing.  The printed plan is now serving as a drop cloth to keep backdrop and fascia paint off the foam, after which it will be discarded and I'll finish the tracing.

I should note that an alternate approach I've seen used on the North Shore Model Railroad club layout's newer areas is to simply glue the printed track plan to the plywood, and glue the roadbed and track to the plan.