Best Of Pennsy Position-Light Signal Head - Shapeways Project?

[peteski]

Interesting. Did you use the FUD resin?

[nscaleSPF2]

Peteski, 

No, these were printed using their "black detail" material.  As nearly as I can tell, black detail, like FUD, is a type of acrylic, but it contains a black dye.  I thought that this material may direct the light from the LEDs a little better.

Jim

[Philip H]

We have several forum topics here on Shapeways cleaning - and for FUD Bestine/rubber cement thinner seems to be the leading contender.  Not sure about the black stuff - no one has ever tested it for us.

I think what the SPF's here will be really interested in is what does it look like painted.  So posting additional in process photos will be a good idea, as will detailed descriptions of your lighting and installation process.

Nicely done.

[peteski]

Peteski, 

No, these were printed using their "black detail" material.  As nearly as I can tell, black detail, like FUD, is a type of acrylic, but it contains a black dye.  I thought that this material may direct the light from the LEDs a little better.

Jim

Ah, that probably explains the very rough (for N scale) surfaces and soft edges.

[robert3985]

Although I appreciate the work and effort gone into this, I'd say the protocol should be DETAIL, not DIRECTING LED LIGHT.  A can of flat black Krylon will solve the light "directing" (whatever that means) problem fairly quickly.

I'm not going to sugar-coat it for you.  This piece looks like crap...literally.  Have Shapeways do it again and make sure you specify the highest resolution FUD material they've got to minimize (not maximize) the layering.  That should either eliminate the problem or greatly minimize it...the problem being really poor surface quality...really.

If I were an SPF, I would not consider this part for inclusion on my layout in its present form.

[nscaleSPF2]

Thanks for your opinion, Bob.  I appreciate it.

Jim

[nscaleSPF2]

Well, this phase of the project is officially over.  The "black detail" material is far from opaque; the light from the LEDs shine thru it.  Even thru the 0.8mm wall thickness.  Overcame this with a coating of black paint, but then I lost even more detail.

Next step is to order parts made of FUD, so we can start with a little more detail in the parts.  I'll start by spraying them white (to prevent the light from entering the plastic) then cover them with weathered black, unless anyone has a better idea.

Stay tuned.

Jim

[SkipGear]

Base coat with silver first. It will reflect light.

[peteski]

Well, this phase of the project is officially over.  The "black detail" material is far from opaque; the light from the LEDs shine thru it.  Even thru the 0.8mm wall thickness.  Overcame this with a coating of black paint, but then I lost even more detail.

Next step is to order parts made of FUD, so we can start with a little more detail in the parts.  I'll start by spraying them white (to prevent the light from entering the plastic) then cover them with weathered black, unless anyone has a better idea.

Stay tuned.

Jim

Jim,
my first suggestion is to re-do your artwork to make the signal head and hoods thinner. FUD process allows for thinner parts.  As far as making the head light-tight, my suggestion would be to airbrush couple of layers of silver paint (which is pretty opaque), then few layers of black paint.  The black has to be built up slowly as wet coats tend to pull away at the edges of the piece, allowing the light to shine through.

Here is an example of making a "light pipe" totally light-tight:
Here are 4 LEDs installed in a plastic light pipe of a model car.  As you can see, the light is visible all over the light pipe.


I masked off the ends using liquid mask, then I sprayed it white . That is to reflect more light into the light pipe. Since your signal head is not used as a light pipe, you can skip this part.  Paint your signal head silver instead.


Last step was to airbrush the ends of the light conduits with black paint to prevent any light from being visible anywhere except at the ends of the light conduit. After each paint application I hooked up the power to check for light leaks. I had to apply few layers of black paint to stop all the light leaks.


I don't have a photo showing the lit assembly after painting it black but you can take my word for it that the light only shines through the ends.

[nscaleSPF2]

Thanks for the input, Tony, Peteski.  Will post again when I have more to report.

Jim

[nscaleSPF2]

So here begins Phase 2 of this project.  Following are some parts made from FUD, with the hope of improving the level of detail.  I'm going to do a step-by-step for anyone who is interested.



The part is covered with a waxy substance that needs to be removed so that paint will adhere to the surface.  I used Bestine, which is available at some artist supply stores, and a toothbrush to remove the wax.  Did I mention that Shapeways does not tell you how to do this, you have to search their forum?  They also don't tell you what kind of paint to use.

A part cleaned with Bestine follows.  By the way, this is really nasty stuff, so use adequate ventilation and be careful.







The light hoods are .012 inches thick, which is the minimum allowable with this material.  Don't ask me why the part turned white.  I don't have a clue. 

I tried to scrape the light hoods, to make them smoother, with mixed results, as shown in the next photos.  Paint is Floquil Old Silver.





I used a lot more silver and Weathered Black on this next part than I would normally, in an attempt to prevent the light from the LEDs from bleeding thru the part.  Some of the detail was lost as a result.







The level of detail is getting better.  It's almost acceptable to me.  For a sense of scale, the end of the toothpick holding the part is 1mm in diameter.  Next step is to install the LEDs.

[Dave V]

Now that is looking quite a bit better!

[robert3985]

Mucho Better!  What's the next step?  Will a change in orientation make it smoother?...although with paint, the finish is acceptable.  Any possibility of decreasing the cross sections overall?  What is the actual measurement of the cross section on the signal face, and the shrouds?

[Mark5]

Hmm ... gettin there.

Mark

[superturbine]

Looks really promising... you should get it perfect then cast the master and save the money you would be spending Shapeways