Best metal to use for etched details for N scale?

[jdcolombo]

Hi everyone.

I'm working with John LeMerise on a project to create an NKP 1000-series caboose in N scale, using a combination of a 3D-printed body and etched detail parts such as grabs and end rails/ladders.  I've never used etched parts before, and am wondering if I should go with stainless steel, brass, phosphor bronze or some other metal for this.  Remember it's N scale, so the parts are going to be small and thin.  And yes, they will need to be painted, so any suggestions on the best paint to use on etched parts is also welcome.

Thanks!

John C.

[peteski]

In my experience dealing with photoetched railings etc. stainless steel and phosphor bronze are stiffer and more springy or durable than brass. Brass also comes in different hardness, but the other 2 metals are still likely better for very thin cross sections items.

[garethashenden]

It depends on how its going to be assembled. Stainless steel can't be soldered, or at least not easily, so it would need to be glued. With a 3d printed body its probably safe to assume you're planning on gluing things, but its a consideration for future projects. Etched grabs also don't really look right to my eye, they should be round in cross section, which isn't possible with the etching process. There are ways of designing an etched ladder to use etched sides and wire steps, but its complicated.

Stainless can usually be etched from thinner sheet, which may be an advantage in this situation.

As with most metal painting, use a self etching primer, then the paint of your choice.

[bbussey]

I use brass for body panels and roofwalks, and stainless steel for stand-alone details such as railings, grab irons and ladders.  The methods have worked extremely well with the Made In America kits.

[thomasjmdavis]

First, let me applaud your adoption of metal details to use with a 3D printed model.  Having done some kits built this way (ATSFNscalemodels) or older cast resin kits (Fine-N-Scale and others), I think this is the best option.  The finished models are much better than those that use 3D printing alone.

My preference has been to use wire for grabs.  Some kits come with a jig to enable bending the wire at the correct points to result in proper size and shape.

My only complaint with stainless steel is that it is difficult to cut. (including stainless wire) and sometimes puts small nicks in the cutting tool.  The upside to stainless steel is that it is...steel.  So, for parts like grab irons on a stainless passenger car, or other stainless or bright steel detail, it is ideal.

That said, I don't know that I have a real preference between metals.  I think brass is the easiest to work with. Stainless and phosphor-bronze are tougher, and hold up to handling better.  So, it is a matter of how you anticipate the model will be handled.

On painting the etched parts... remove any coating using an appropriate solvent. Soak in household vinegar for 5 to 20 minutes, then mix a paste of water and baking soda and gently brush the parts using this mixture and a toothbrush (the baking soda will neutralize the acid in the vinegar to stop any further reaction, and is also very mildly abrasive). Rinse with water and dry. The key to painting is to use a good quality primer.  I've been using Badger's Stynylrez primer (the name is short for Styrene-Nylon-Resin) and while it is not a metal primer per se, I've had good luck with it, and it takes acrylic paints very well.  But consult the paint company for whatever brand/type of paint you are planning to use on their primer recommendation.

[jdcolombo]

Hi everyone.

Thanks for the replies so far.
@garethashenden - yep, glue.

@bbussey - thanks; it was the Lackawanna caboose kit that first interested me in using etched parts for grabs, end rails & ladders.  That's the look I want for the 1000-series project. BTW, I'm intrigued by your decision to use a 3D print as a master for a resin-casting kit body.  Was that a cost decision?  Given that I'm going to need at least a dozen of these on my layout (and I think other N-scale NKP-ers will want some, as well), maybe I should look at going the resin casting route after John completes the design work and I get a high-quality print from somewhere?

@thomasjmdavis - I know that the cross-section of grabs/handrails should be round, but as I note above, I'm looking to build a fleet of these things.  The 1000-series was the iconic NKP caboose; they had literally hundreds of them and used them everywhere on the system even up to the merger with the N&W in 1964.  So the idea of bending wire (and soldering wire for end rails/ladders) isn't really where I want to go.  I'm willing to give up a true round profile for some simplicity in construction.  Again, that Lackawanna Made in America caboose from Bryan I think looks awesome, and I can imagine assembling a dozen such kits without going completely crazy .

John C.

 

[thomasjmdavis]

@thomasjmdavis - I know that the cross-section of grabs/handrails should be round, but as I note above, I'm looking to build a fleet of these things.  The 1000-series was the iconic NKP caboose; they had literally hundreds of them and used them everywhere on the system even up to the merger with the N&W in 1964.  So the idea of bending wire (and soldering wire for end rails/ladders) isn't really where I want to go.  I'm willing to give up a true round profile for some simplicity in construction.  Again, that Lackawanna Made in America caboose from Bryan I think looks awesome, and I can imagine assembling a dozen such kits without going completely crazy .

John C.

I probably over-edited my previous comment.  I wasn't thinking to use wire for end rails or other complicated  parts (I would not try to solder together a ladder, either).  I just meant to use wire for independent grab irons. 

[jdcolombo]

I probably over-edited my previous comment.  I wasn't thinking to use wire for end rails or other complicated  parts (I would not try to solder together a ladder, either).  I just meant to use wire for independent grab irons.

Nah.  I over-interpreted your comment.  You did say "grabs" and my brain converted that to "grabs, end rails and ladders" because I think of all these things as being prototypically round in cross section.  But I think for my purposes etched grabs will be OK.  And thanks for the instructions on painting.  All this is new to me.  I don't do 3D printing; I've never used etched parts in my life, although I HAVE been known to sneak in some .010 brass wire on a couple of models that needed it.  I suppose that if one had a jig to get the curve and length correct, it wouldn't be so bad.  But the idea of doing this for 16 grabs per model (they're everywhere on that caboose . . . see photo) gives me the willies.

John C.

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[SAH]

Hi John.  Good project to work on.  Here are some samples to consider

Mostly stainless with some .008" pb wire for grabs.  A bending guide was etched with the stainless parts. Cast resin body.


Brass etched parts.  Modified injection molded donor shell


3D printed shell.  Phosphor bronze .008" iron work.


AMB Laserkit with .008" pb iron work


And STILL the finest set of etched parts ever included with a kit.

[bbussey]

@bbussey - thanks; it was the Lackawanna caboose kit that first interested me in using etched parts for grabs, end rails & ladders.  That's the look I want for the 1000-series project. BTW, I'm intrigued by your decision to use a 3D print as a master for a resin-casting kit body.  Was that a cost decision?  Given that I'm going to need at least a dozen of these on my layout (and I think other N-scale NKP-ers will want some, as well), maybe I should look at going the resin casting route after John completes the design work and I get a high-quality print from somewhere?

The KV Caboose design pre-dated affordable personal 3D-printing. I needed a master for rubber molds of polyurethane castings, and one constructed entirely of brass would have been problematic because castings had to be extractable from the rubber mold. A master entirely of Shapeways FXD wasn’t viable because the resolution wasn’t fine enough. So the core was printed via Shapeways and brass panels were etched and inset into recesses in the body and roof components. The floor/underframe master was entirely 3D-printed. All the free-standing etched details purposely were stainless steel because it could have delicate relief and hold up to handling. I learned a lot from that design. With the advent of 3D-printing, I do things differently now. But the remaining constants are etched details in brass and delicate stand-alone etched details in stainless steel.

[bbussey]

Regarding cutting SS — you just need SS nippers.

[jdcolombo]

@SAH
Very nice!  The AMB NKP 1000-series was very well done, but of course not available any more.  Hence my foray into the current project (although I probably would have hesitated trying to build a dozen of the AMB's anyway).

@bbussey
Thanks for that explanation.  I actually have some 1000-series cabooses that I had done via a guy who had a Shapeways store about 8-10 years ago.  They are serviceable, but used printed grabs/ladders/end rails that were WAY too thick (and even at that, still very fragile) and have always been a bit of an irritation when I look at them in photos of my layout.  The advances in 3D printing since that time and the use of etched detail parts will produce a much better model, I think/hope.

John C.

[jdcolombo]

Regarding cutting SS — you just need SS nippers.

Do you have a link to such a tool?

John C.

[peteski]

Train Cat's Wilson Auto Ramp kit has stainless steel railings and deck.  I was worried about soldering SS railings I was able to tin the stanchions using TIX Flux (Zinc Chloride), to make it easier to solder them to the brass frame. 

[Sokramiketes]

I'm at the other end and avoid Stainless Steel for soldering and painting reasons. 

I switch to nickel silver for etched stand alone details, including all the signal etchings we've done over the years.  PPD LTD has nickel silver available.