Anyone tried custom valve gear?

[peteski]

A lot of etched valve gear components in N scale are etched from stainless steel. It is very robust. Some Kato locos and other manufacturers use it. Fleischmann is another example.

As for plain nickel, I have not ever encountered a solid nickel sheets. Usually nickel is used as a part of an alloy with another metal or as plating metal.

[pjm20]

Having built a few of these in O Gauge, you definitely need nickel-silver (not nickel-plated steel or nickel). If you have a small jewellery rolling mill, you could actually just take a length of track and roll the slide bars on that. The brilliant Albion Alloys make nickel-silver rod and bar.

https://www.scalemodelshop.co.uk/albion-alloys-nickel-silver-rod-nsr06/
https://www.sundwiger-mw.com/en/strip-products/nickel-silver/

\thread_drift I definlty would be interested in a seperate thread on your techniques for valve gear \thread_drift

[TechnicalATSF]

This makes me curious.  I did indeed use nickel silver for the rods I have made, mostly because I knew it had to be something hard, yet shapable and solderable.  But why not nickel or nickel plated steel?  Aren't they both harder than nickel silver?  And you could still file and drill them (although I wouldn't trust soldering to a plated steel).

Good question. Nickel-silver is basically brass with nickel added (typically 60% copper, 20% nickel and 20% zinc. Brass is basically the same alloy with a higher zinc content and no nickel. Both are corrosion resistant, very easy to work and solder. But nickel-silver just looks so much nicer when used in valve gear. It also seems to hold lubrication better and be slightly harder, without being difficult to work, making it perfect for your slide bars. I made my entire valve gear out of the stuff, using brass only for the balance weights and any castings. BTW, nickel-silver contains no silver, it just looks silver.

Nickel and its alloys are completely different beasts. A modeller would find them difficult to work, machine and solder. The alloys bring no beneficial properties that a modeller could use that aren't available elsewhere, unless you want a high-temperature flame can in your locomotive. 

Mild steel is a softer low-carbon steel that is cheap, easy to work, weld but would be difficult to use in small sizes (apart from maybe screws). Nickel plating just adds a hard surface and a nice shine and is the foundation layer for chrome plating. You could make slide bars out of mild steel and then nickel plate them, but you don't really want that mirror shine.

[TechnicalATSF]

A lot of etched valve gear components in N scale are etched from stainless steel. It is very robust. Some Kato locos and other manufacturers use it. Fleischmann is another example.

As for plain nickel, I have not ever encountered a solid nickel sheets. Usually nickel is used as a part of an alloy with another metal or as plating metal.

Etching brass and stainless steel are similar processes, with Ferric Chloride being used for both. However, whereas brass is nicely reactive and will readily etch, stainless steel will take a lot longer (and only 304 really works with Ferric Chloride). For the more resistant grades of stainless steel, you'll have to start using hydrochloric or even phosphoric acid, both really nasty and require specialist professional handling. Definitely not recommended for the average modellers workbench. BTW, nickel-silver is nice to etch too....

[peteski]

I have been etching my own copper-clad PC boards (and more recently) small metal parts from brass and nickel silver for over 45 years.  Yes, I use Ferric Chloride. As far as metal parts go, I have never etched anything thicker than 0.010".  My home-brewed process is not advanced enough to evenly etch thicker parts (yes, I know there are methods I could use to make more even etching possible but I just use straight immersion in warm FeCl solution. I usually float the etched item on the surface, etched side down (single sided).  I have done double-sided too, but that is much more hassle.

I simply mentioned that stainless steel etchings are used by "real" model RR manufacturers (not that  it is something suitable for home-etching).

[JeffB]

I have been etching my own copper-clad PC boards (and more recently) small metal parts from brass and nickel silver for over 45 years.  Yes, I use Ferric Chloride. As far as metal parts go, I have never etched anything thicker than 0.010".  My home-brewed process is not advanced enough to evenly etch thicker parts (yes, I know there are methods I could use to make more even etching possible but I just use straight immersion in warm FeCl solution. I usually float the etched item on the surface, etched side down (single sided).  I have done double-sided too, but that is much more hassle.

I simply mentioned that stainless steel etchings are used by "real" model RR manufacturers (not that  it is something suitable for home-etching).

So you do mostly single sided etchings Peteski?  I'm considering doing some home etching.  Purchased a Micro Mark etching kit many years ago, but never used it.  I've been researching using a laser to burn away etch resistant paint off thin brass (rather an using resist film) to make some thin (0.005" wipers in phosphor bronze and small 0.010" brass details).  Just curious how well one sided etches work in thin material.  I would imagine well enough as etching copper clad is wholly on sided and that seems to work pretty well, even with home etching.

Jeff

[peteski]

Jeff,  PC boards are fairly easy and forgiving to etch at home.  The copper cladding is only about 0.002-0.003" thick and Ferric Chloride (etchant I use) really works well on copper.

Here are some examples of parts I have etched for various projects.



One of my earliest attempts was etching steering wheels and canopies for N scale golf carts.  0.005" brass, single side etching.



Finished models.



Weather vanes and lighting rods for N scale barn. Again 0.005" brass single side etching.





Installed on the barn.



Corel Draw artwork for a photomask.



Etched mirrors, again 0.005" brass, sinle side etching.  THe fret on the right side has finished mirrors. I applied solder to the back front of the mirror to give it a thicker 3D look, then airbrushed dark gray.  I painted the  back side with silver paint.



Installed on the N scale FedEx van.


This is my attempt to double-side etch emblems for a model of Mazda Miata.  0.010" nickel-silver. It yielded usable parts.



After polish and paint washes.

Main problem with etching thicker sheets is the uneven etching action. I need to leave the sheet for longer to complete the etching process, which then causes more than expected undercutting of the etched parts.  I started warming up the etching solution (on a temperature controlled hot plate set to 60 deg. C) and that helped to speed up the process and make etch more evenly.

On single sided sheets I spray-paint the back side with any type of organic solvent based paint which will protect the sheet from the etchant.  Then on the front of the sheet I apply photoresist, expose it through photo-mask, develop it, and then I float it on the surface of the enchant. That lets me monitor how the etching process is progressing (the etched-through areas will become clearly visible on the solid painted side).



Another project was Peterbilt emblems  for a wrecker.
This was coupler of decades ago, before I kept thorough record of my builds. IIIRC it is 0.005" brass relief-etched.  Basically it is a single-side etching but I took the sheet out of the etchant about half way through the process and filled the inside of the oval with paint (etch resists), then put it back to complete the process.  That gave me oval logos with relief around the letters.  I tinned the pieces with thin coating of solder and then flooded the relief parts with red paint. Then I polished the emblems and gave them few coats of clear nail polish.

This is all very basic stuff - I never purchased any etching kits.

[JeffB]

Thanks a ton for the photos and write up Peteski!  Very much appreciated. 

I definitely think it's worth a shot for what I want to do.  I need to use 0.010" brass or nickel silver for the what I have in mind (and the parts will have to be a laminate of two layers), but they're relatively low detail and I can fudge with overall width to allow for undercutting.

The tip on using solvent based paint on the back side is a good idea.  Some articles I've read, the individual used paint on both sides. 

I have the Micro Mark photo resist film, but I'm sure after the 17 odd years I've had it, it's probably gone bad, even though it's stored in the box, in a relatively cool basement.

I plan on using photoresist paint and burning it off with the laser to form the etching contours around the part.  If that fails, I suppose I'll give the film a try, even if I have to buy new stuff.

Thanks again...  Once I give it a shot I'll post photos to the Forum of the results.

Jeff

[peteski]

I'm not sure about painting both sides of the etched piece. If you did then noting would get etched!    But if you will use laser to expose the bare metal then a paint layer itself might actually work as photoresist to get burned off (not need to use some special photoresist film).  I would try this first.  Photoresist is needed for when a photo-mask (transparency) is used with UV light along with developer solution to do this task.

I use spray-on positive photoresist spray PRP200D from Electrolube in UK, but last time I bough it I had a hard time finding it in U.S.

Also make sure that the bare metal is perfectly clean, free of oxidation and any oily substances. I clean my metal sheets and PC boards with a househild copper cleaning powder. It works really well as it cleans chemically and also with a mild abrasive.

[JeffB]

I'm not sure about painting both sides of the etched piece. If you did then noting would get etched! 

The individual(s) that painted both sides (as opposed to using photo resist on one side) were using a laser to burn the paint off around the periphery of the part, exposing the metal to be etched.

I plan on using photo resist paint on the etch side...  You can purchase it online from a few sources, but it is not easy to find for sure.

Thanks for the advice on making sure the metal is very clean.  Matches what I've read and seen in videos.

Jeff