what's the possible resolution for high-res etching?

[mark.hinds]

Not really N-scale, unless I use some of them to represent R/C aircraft, so I'm not posting an image here, but just a link:  https://lh3.googleusercontent.com/bJZ1iln2wkdJdEI1tCyIF3SinttEsB_dLVXRLiwrYT-RdnhJyYKAeO3iZa_SoRsW6j-YPg0KN4N0AUqQcwbWO_8eGNidKDagdJ_ixzI196BS9Fi2kgD1EPIOVsEwN2BFryednLkOhw=w2400 .  Note the coin is a USA dime, about .7" across. 

I am hoping that someone here has first-person experience with high resolution etched brass or stainless steel.  These are really small, hence my question. 

The prototypes are 2 layers of plastic, with the main layer being .01" styrene card, and the upper layer being a angled slice off a .015" styrene rod, glued on top.  So I figured one could etch this, either as a 2-part etch (ideal) or in 2 pieces, with the fuselage piece folded back on the wing silhouette.  The metal sheet would be .01" or less in thickness. 

My main concern is whether etching resolution is good enough to capture the silhouettes of the different aircraft.  I found this Youtube video for example; note the leaf shape on the model ironwork:  https://www.youtube.com/watch?v=NntLi4KcLlI&feature=youtu.be

MH

[wpsnts]

This outfit comes with high recommendations.
https://www.ppdltd.com/

[wazzou]

This outfit comes with high recommendations.
https://www.ppdltd.com/

Seconded.

[mark.hinds]

Thanks for the recommendation, guys.     One good thing about hiring this company is they do it for as little as 30 pounds (UK) and can do full-etch and half-etch combinations. 

Just to clarify, my main concern is whether the technology can handle the resolution.  We are talking about a model here which is only a couple of millimeters across, in the smallest case, and it needs to retain its distinctive appearance.  For example, a Spitfire (elliptical wing) should look slightly different than a Hurricane (less curved trailing edge to wing). 

I will see if Railwire lets me change the subject of the thread to emphasize this. 

MH

[mmagliaro]

"A couple of mm" is .078"
The thickness is .010".
As long as you don't try to etch smaller in length or width than you have thickness, you can do this.   Think about it.  While the etchant is burning DOWN, through the sheet, it starts eating sideways because it is under the layer of protective resist that only protects the top surface.  But in your case, the figure is still much wider and longer than it is thick (.078" vs .010", so you should be fine.  Heck, I had some super tiny steam loco pipe hangars etched out of brass a few years ago.  They were .010" thick with .009" diameter holes in them, and the whole piece was only about .100" long, and they came out well.

I don't know about that rounded profile for the fuselage.  You say the prototypes were done with a little piece of rounded styrene rod stuck on top.  I don't see how etching is going to manage that rounded profile.  Would it be sufficient to just have the fuselage end up like a thicker section of flat metal on top?  You would still have the correct rounded outline of the aircraft as viewed from above.

[mark.hinds]

(text removed)

I don't know about that rounded profile for the fuselage.  You say the prototypes were done with a little piece of rounded styrene rod stuck on top.  I don't see how etching is going to manage that rounded profile.  Would it be sufficient to just have the fuselage end up like a thicker section of flat metal on top?  You would still have the correct rounded outline of the aircraft as viewed from above.

The rounded profile probably isn't necessary; just a center ridge.  These things are really small (1/6000), and are intended to be viewed on a stand of several aircraft, not individually.  Also, they would be painted, which can substitute to a certain extent for detail.  It's a miniatures gaming thing (this is going to get the mods after me...).  Example: 

[peteski]

PPD Ltd. has lots of helpful documentation (including the thinnest part that can be etched). I recommend diving into the info on their website.

[mark.hinds]

PPD Ltd. has lots of helpful documentation (including the thinnest part that can be etched). I recommend diving into the info on their website.

Good advice.  This statement of theirs concerns me a little, however: 

we can resolve fine detail as low as 0.1mm

.  Given that the smallest model has a wingspan of about 2mm, that might or might not be acceptable.  I'm imagining the top-down view resolved into a bunch of .1mm squares.  OTOH, given the etching process, these probably wouldn't be sharp-edged squares...

[wcfn100]

  I'm imagining the top-down view resolved into a bunch of .1mm squares.  OTOH, given the etching process, these probably wouldn't be sharp-edged squares...

I don't think you should look at it this way.  From what I remember, the minimum is just how small they can go and still get the masking material to stick consistantly.

Jason

[peteski]

Mark,
I don't think you will have problems with etching those airplanes, but you might have to go with thinner metal due to undercutting during the etching process. Best would be to do a sample design of couple of the airplanes (in one of the formats PPD accepts), then send the artwork to them for evaluation.  They should be able to inform you whether what you want is within their capabilities.

[daniel_leavitt2000]

Features on my recent job was half the thickness of the sheet. I am using .15mm nickel silver so I could get down to.07mm resolution for some parts.

Big thanks to Keystone Details for amazing artwork that was probably a much bigger project than either of us realized at the time.

Can't wait to get the parts in.

[prbharris]

I don't think you will have problems with etching those airplanes, but you might have to go with thinner metal ....send the artwork to them for evaluation.  They should be able to inform you whether what you want is within their capabilities.

I will echo the support for PPD. We have had 100's of sheets etched by them. They are now running well, after their shutdown, and are getting back to full production. Very helpful and efficient folk.

PPD will examine your files, and will give advice on how acceptable etching will be. We have had finer than 0.1mm wires on thin brass [for wire panel fencing], but it started to fail, so we agreed it would be at our risk.

The profile is more of a V on thin metal due to their methods, and this is more noticeable on thicker metal.

Bear in mind that shipping costs to the US from Scotland have doubled since July 1, as the US Government have hugely increased inbound postage costs, in some cases doubling the cost. Shipping to the US by Royal Mail - still the cheapest method for packages of etches etc. - is now a separate price band. Folks have been very surprised at the costs now!

I hope that the project goes well

Peter

Peter Harris
N Scale Kits
www.nscalekits.com