Scratchbuild Project - Sperry Detector Car in N Scale

[Ike the BN Freak]

It was a company that made rolling stock. Atlas bought them a year or 2 ago.

Atlas purchased BLMA in 2016

[rodsup9000]

Atlas purchased BLMA in 2016

It sure doesn't seam it's been that long ago.

[BCR 570]

The Atlas/BLMA drill template is part #57 and is currently listed as in stock on their website.

The 18" drop grab irons are part #60 for 20 or #61 for 60 and are currently listed as "pre-order".

https://shop.atlasrr.com/c-1405-blma-n-parts.aspx

Tim

[NorthWestGN]

Thanks for keeping us up to date on this project Tim, I especially appreciate the crisp macro photos and concise descriptions.
 
I’m glad you haven’t retired from the Railwire!

Brent

[BCR 570]

Carbody Sides (cont.)
The next section to be made for the sides is the galley section, which is relatively short in length.  This section has a blank panel and a panel with a small horizontal window on the left side, and a door with window and a blank panel on the right side.  I would presume that the right side door would be intended to facilitate loading of groceries directly into the galley, and garbage out.  As this door is the most challenging component for this section, I thought I would tackle it first.

The galley door measures 24" wide x 5'-0" high, with a 12" wide x 24" high window towards the top.  I selected a strip of #107 .010" x .156" styrene for the door, which gives me a close enough width of 25".  This was cut long for now.  I drilled two holes to start the window opening, and then a small chisel blade to connect the holes for a rough rectangular opening:




I then used small files to work towards a rectangular opening of 12" wide x 24" high.  I used a block of #157 .080" x .156" as a gauge for filing out the window opening:




This photograph shows the block fitting tightly into the window opening, confirming that I am at the correct size:




The window opening will be framed with Plastruct #90709 .010" x .010" styrene.  Here I am cutting two identical lengths for the sides:




A strip of .030" x .030" styrene was used as a shim to locate the first side frame piece parallel to the side of the door:




Same procedure for the opposite side piece, with the gauge block used to align the two side frame pieces vertically:




The bottom and top frame pieces were cut to length and glued in place:




Another strip was cut to length for the centre divider.  This was glued in place with medium CA rather than styrene cement:




The door above the window was cut to length using my NSWL Chopper:




The door below the window was trimmed short but not yet cut to exact length.  The angled cut is reminder to self that it still needs to be cut to exact length:




Glad to have this item built.


Tim

[mmagliaro]

Every little subassembly is a conquest.   A whole bunch of very accurate cuts and accurate glue joints.  A big part of expert model making is taking the time to make every little part with precision, no matter how small it seems.  That's how great models are made.   I am enjoying this thoroughly.  Onward!

[BCR 570]

Carbody Sides (cont.)
The galley section now brings me to the point on each side where we have a bottom side sheet, a belt rail and a top letterboard extending for much of the carbody sides.  While these would be helpful in aligning the parts along the window strips, I am a little unsure of their precise length and am thus hesitant to glue them in at this stage.  I could cut them long but trimming them later would be difficult as they are laminated to the backsheets.  This photo of my test side section shows the typical arrangement above and below the window strip:




I will instead use the correct strips of styrene for the components above and below the window strip as shims, and then cut them to the exact length and glue them in later:




Here are those shim strips positioned on a side:




The challenge with this approach is keeping them fixed in place during the installation of window strip components.  I believe I have come up with a method which will work.  I will use my Micro-Mark magnetic gluing jig.  This tool allows me to block an assembly against a wall with magnets:




Here is the right side in the jig with shim parts aligned correctly.  These parts are now blocked in place and unlikely to move, and I can install just the window strip components:




Hopefully this approach will allow me to install the various window strip components, and then add the strips above and below when the exact length is finally known.


Tim

[BCR 570]

Carbody Sides (cont.)
Starting on the left side of the galley section, I need to add a separator (#120 .020" x .020") and a narrow blank panel (#125 .020" x .100").   These were cut to a length of 36 inches to fit inside the height of the window strip.  This photograph shows the left side held inside the magnetic gluing jig with the various blocking pieces in place, and the two pieces described above ready to go in:




This image was taken after the separator and narrow blank panel have been glued in place next to the motor compartment vents:




The panel containing the small horizontal galley window is next.  I cut two separators from #120 .020" x .020" styrene 36 inches tall.  The window opening is surrounded with #120 .020" x .020" above and #125 .020" x .100" below, both cut to a length of 30 inches, and two strips of #120 .020" x .020" left and right, both cut to a height of 16.5 inches.  Those parts are seen at the top of this image ready for installation after test fitting:




The resulting window opening will be cut out and framed in with pieces of .010" x .020" styrene, but not yet.  I have two more windows like this one coming up when we get to the washroom section, so I will frame in all three at the same time:




After removing the various blocking pieces, this is what the left side of the galley section looks like:




The right side of the galley section is next.


Tim

[BCR 570]

Carbody Sides (cont.)
There are a lot of window openings coming up in my build, and these are separated by vertical posts (separators) which must be installed perfectly perpendicular to each other.  I need a block which fits into the 36" high window strip for aligning the separators, and which also fits into the 31 1/2" distance between them.

I assembled this block from six pieces of strip styrene to get close to the 36" x 31 1/2" dimensions of the window openings:




The first three pieces were glued together to get the 36" height:




And then the next three pieces to achieve the 31 1/2" width:




The end of the block was then sanded square using my True Sander:




It was sanded gently until it fit snugly between the blocking pieces used for aligning the window strip components:




This little tool will allow me to achieve perfect alignment of the vertical separators, and it can slide along as the separators go in.  Later, it will also be used as a block when cutting out the window openings.


Tim

[Dwight in Toronto]

I’m really liking this thread.  I’ve just barely scratched the surface of N scale scratchbuilding, so this is hugely insightful wrt tools, materials, techniques and discipline.  Tim, please continue with the wonderful closeup pics and comprehensive dialogue.

Having been duly inspired, I’m contemplating a scratchbuild of CP’s theatre car “Sandford Fleming”:




At this point, I’ve been gathering photos and historical poop, and will launch a build thread if/as/when I start cutting styrene.

[BCR 570]

Hi Dwight:

Tim, please continue with the wonderful closeup pics and comprehensive dialogue.

Will do if people are interested.  Your car makes for an interesting subject; reminds me of the Devon Belle observation cars with the large rear window.


Tim

[John]

Absolutely interested

[BCR 570]

Carbody Sides (cont.)
With all of the window separators and blanked out panels coming up, I thought it might be efficient time wise to fabricate some parts in bulk.  I need about 25 window separators which are 36 inches tall, and a number of blank panels same height in various widths.

The full width panels for blanked out windows need to be 31 1/2 inches wide.  These were cut from #129 .020" x .250" styrene to a height of 36" to fit inside the window strip.  I made a stop gauge to position my square 36" away from the cutting blade on my Chopper, and then cut the styrene strip into 36" high pieces which you can see on the left of the square.  The 36" dimension is indicated with a check mark to avoid confusion:




These pieces were then test-fitted on the carbody side with the alignment strips above and below the window strip in place.  I am aiming for a nice comfortable fit with no gaps:




I need six of these panels so I cut eight.  I also cut a narrow infill panel from #122 .020" x .040" for the first right hand side bedroom window which is noticeably narrower, and two panels from #127 .020" x .156" for either side of the right hand freight door adjacent to the mechanical room, which I estimate to be about 25 inches wide.  All of these are seen on the left of the cutting mat in the photograph below.

Next up are the 36" tall window separators, of which I require about 25.  These were cut from #120 .020" x .020" styrene using the same method shown above.  To save time I cut five strips simultaneously which yielded batches of five separators:




One separator from each batch of five was test-fitted in the window strip on the carbody side:




I cut eight batches of five separators for a total of forty.  The cut parts are seen at left in this photograph:




Turning back to the full width blank panels, I now needed to trim them to a width of 31 1/2 inches.  I made a stop block of the desired width and then trimmed the panels:




The panels were checked against my window gauge for the correct width of 31 1/2 inches:




And they were also double-checked for the correct height of 36 inches:




Here are all of the parts from this work session - from left to right:  full width blank panels, window separators, and narrower blank panels:




And here are the alignment gauges which I will rely on to achieve correct installation of the parts:




With these parts and gauges now on hand, the next sections should go fairly quickly.  Now onto the bedroom section!


Tim

[Tad_T]

I’m definitely following along.

[randgust]

OK, I just rolled through this thread top to bottom.... looking.....

Your fabrication precision and approach is extraordinary.   This is a wonderful thread.

I've done virtually all my resin molding masters out of styrene materials.  It's worked pretty well, similar precision needed.

But I've learned a couple really painful lessons.   The big one is the selection and use of solvent-based cement.  I may be the only one with this issue, because I'd been using Testors tube orange since I was a kid.   And I've tried the liquid stuff with a pipette, even needling it in.  Plastruct gray stuff in particular is completely resistant to Testors orange.

But with every solvent cement I've tried, at least on Evergreen if not Plastruct,  if you're laminating flat material to flat material, it's going to warp.  Not right away.  Not bad if it's heavily reinforced behind... But over time, it wants to curl and warp, usually in the direction of the thin material cupped upward.
I did a bunch of deck conversions back in the 80's of Trix container flats to Piggyback flats, making new decks of styrene, scratchbuilding everything above the original frames with Evergreen.   Looked great.  Then they started to warp after a couple years.  Worse and worse.   You can guess the rest.   And I've had several similar glitches, the older it gets the worse it gets.   Plastruct doesn't do this.

My solution, simply is that I quit using any solvent cement on any flat styrene material laminate to another flat material styrene laminate.  I use thin ACC. That never warps.  Getting it aligned properly is tricky though, you get one shot at it.   I've learned to do stuff oversize, laminate, then cut things to size in case you're off a bit.

Now if somebody has a different solvent that doesn't do this, and has stuff five years later that still isn't warping, lets talk about that. 

When you make a resin master out of styrene, the laminates and joints literally have to be watertight, because the molding rubber will crawl in there and you'll destroy the master getting it out.   I started using ACC as a sealer on edges, and discovered later that it worked just as well for laminating if not way better than solvent cement.

I've got styrene masters now that are coming up on 18 years old and they aren't damaged or warping by using ACC.   Styrene will brittle a bit, my  scratchbuilt Heisler shell I did in 1976 was all styrene, and it's had to be repaired quite a bit, but never destroyed.

I just did six scratchbuilt houses out of all Evergreen, and I'm not kidding, they are reinforced inside with .25x.25 'beams' on the edges.  I use the biggest material that won't show on the outside.   Siding was all .040 clapboard, all solvent joints.    But when I did my tannery, that was .010 brick material laminated on .030 evergreen to get the wall thickness I wanted, and I used all ACC for those sections.