New brass Milwaukee Bipolar EP-2 clinic- part 2

[u18b]

Yikes.

Sorry.  Not sure what happened.

It is Reply #118 on page 8 of this thread.

Here (I hope): https://www.therailwire.net/forum/index.php?topic=36215.msg484308#msg484308

[u18b]

Spent a couple of hours today on a couple of small parts-- the handrails to the cabs.
They have to be masked and painted in THREE different colors.
So if I'm going to that much trouble, I decided to do a bunch of them for future locos.

Instead of air erasing them, I just sanded them lightly.




Masked and painted.  These are amazing lost wax brass castings.
Oh... and since I was painting black, all my photos show the wind deflectors to have black frames.  So these BLMA parts are not painted and waiting to be installed.




Test layout.




These are NOT easily to get it.  Something must bend in order for the rest to slide in place-- risking chipped paint of course.




Once in, I straightened them as best I could without risking damage.   Macro shot shows little imperfections, but you can't even tell with your eye from normal viewing distance.
I superglue the posts from the inside.
It's possible I might make a slight adjustment later.  But maybe not.   

[u18b]

I took the BLMA wind deflectors that I had painted black and trimmed the posts.  Instead of drilling holes in the brass (and risk damaging something!  ) I just mount them on the surface.

The way I "glue" them down is with the same clear coat that I use.  Model Master gloss clear Acryl.




I add just a tiny bit to the back, let it dry a second, and them put it in place.  The tackiness holds it in place.
I then use a fine wire, dip in the Acryl and then place a micro drop in the wind deflector.  Not too much!   This is just the first application to get the part to stick to the shell.  If you apply too much, it leaks out too much.




When that dries clear in a couple of hours (or less), then I go back and add a larger micro drop to more or less fill the wind deflector.   This will require drying overnight.




I like this technique for a couple of reasons.
1.  When you have wind deflector projecting out from a loco, they are easily damaged, and sometimes it makes storage of the loco harder.
2.  Laying flat is prototypical.  Sometimes they are out, sometimes flat.
3.  The Acryl serves two purposes.  It glues the part on the shell, but it also serves as the "glass".  I think it's a better look than leaving them empty.




These don't show up as well on this loco (black on black).
But they really stand out on other schemes.

[u18b]

Then I installed the window glass one pane at a time.  Used 5 minute epoxy to glue the edges down.

[u18b]

I've begun to worry about the long term use of the micro plugs in the vestibules of the Cabs.
When you install the jumper wire through the boiler room the sockets rock back and forth a bit.




I want these to last for years of heavy use.  So I thought I would stabilize them with glue blocks to remove the side-to-side play.
Here I test fit them.




After all the four blocks were cut and fit (2 per Cab), I then decided to paint them orange.   This was a little more professional looking than leaving them white.  Also, these sockets are so tiny, they are actually hard to see when setting up the loco to run.  So black on black was worse for seeing.  So I thought to paint the support blocks orange so that the black sockets would show up better visually.




Much more stable now.  Mission accomplished.

[u18b]

Yay!   With the windows and most of the detailing done, I can install the cab weights.
Each weight is modified slightly.
A groove up top is cut for the red wire that runs from the vestibule socket to the wiring harness at the motor.
The underside of the weight lip is filed and curved to give extra clearance for the flywheels.
The corners are painted black so the grey won't show through the windows.




Weight is installed.




One thing I learned to watch for is the red wire blocking the hole on the roof.  This hole is for the mounting pins on the pantographs.




The shell is almost finished!

[u18b]

I thought I would post the new way I'm casting my own low temp weights.

When I needed to cast a gearbox, I had to use a higher temp alloy because of the mechanism heat.

But here, I need to cast a weight for the boiler room which has no heat issues.  So I can use low temp alloy.

Here is all I need.  The alloy melts at 136 degrees.  I bought it off ebay. 




I was a little disappointed in the mold.  You can see it has a flaw since it was not totally cured when I broke the master out.  I like the product Oomoo by Smoothon (https://www.smooth-on.com/product-line/oomoo/)  but my hobby shop supply is not suitable for small projects.  It makes a LOT of molds- but it spoils once open.  So you must use it or lose it.

So this time I bought a kit from Allumilite from Hobby Lobby.  The RTV was much smaller.  But the ratio is 10 to 1.  That's a lot more tricky to mix well than the 50/50 mix of Oomoo.

Long story, but this bad spot is what I got after curing of at least 18 hours.  It probably needed 36 or more.
Anyway, not the end of the world.  It just means I'll need to mill the weight a little.





Aside from the weight mold, I also need a lid for the mold.  Notice all the halves are pretty thick to give more stability for alloy pouring.




One of the tricky things about pouring an alloy is keeping the mold halves together (and not burn myself).  With relatively thick molds, I use a plain old C clamp. 




I take the lefovers from the previous casting and add some more to a metal spoon.




I use a torch to melt the alloy.  It doesn't take much.




Fully melted.  Ready to go.




The pour goes in the big opening in the middle.  Note the outside air holes.  As alloy goes in, air and bubbles are allowed to escape.


 

Once poured, I quickly rap the mold on the table a couple of times to loosen any stubborn bubbles.
Then I leave it alone to let it cool.



Once the metal is cool (usually only in about 5 or 10 minutes max), I can take the C clamp off and inspect the cast.




Bending the mold a little helps things break loose a bit.




The cast then comes out.




A little work with a file and a little milling (repair of the mold flaw) and the weight is ready.




THIS is why I do this.  Saves a lot of time in the future.




I mount my new weight in the boiler room floor.  Since it is totally out of sight, I don't worry about painting it.

[peteski]

Ron,
when I make small RTV molds I cure them in a food dehydrator. Same one that I use for speeding up paint cure.  The elevated temperature also speeds up cure time of RTV and will likely cure it even if it wasn't mixed really well.  That dehydrator sure comes in handy!

[u18b]

That's a great suggestion.
Wonder if I could find a used one at a thrift shop or yard sale.

And I would get better molds... and beef jerkey out of it!

[peteski]

That's a great suggestion.
Wonder if I could find a used one at a thrift shop or yard sale.

And I would get better molds... and beef jerkey out of it!

Yes, you should be able to find one at a thrift store or at a flea market. But even new ones aren't very expensive.

But (at least in my case), I have permanently converted it for hobby purposes.  Mine had several stackable rings of drying trays. I cut out the inside part of the trays, leaving just the outside rings. That gives me a larger (higher) open area inside, but now I could only dehydrate a single layer of snacks on the very bottom.   

I have been using mine for probably about 30 years now. It is a very basic unit with a 40W heater on the bottom, with adjustable air shutters (top and bottom) to control the air flow (and temperature).  I also bought an inexpensive cooking thermometer (the one with a small dial and a long metal probe you stick in a cake or your turkey), for monitoring the temperature.  I have the probe stuck through a hole in the top lid into the dehydrating chamber to monitor the temperature. My unit runs around 100-120 F which I find is optimal for speeding paint dry time, or resin or RTV cure, without melting or distorting plastic or resin shells.

Nowadays many dehydrators include fancy temperature control. I still would buy and use a thermometer to verify  the temperature stays around 100-120 F. Last thing I want is to melt my freshly painted model! 

Dehydrators have been quite popular for this unusual application for quite a while in the model car builders circles (another hobby of mine).

[u18b]

Spent a good deal of time this week working on video editing and posting.

I figure that since these EP-2 locomotives are uniquely my design....at present, I'm the only one who knows how to work on them.
How to take them apart, etc.

So a while back, I made some videos covering topics like opening the package, how to clean, how to oil the motor bearings, and the most important-- how to take one completely apart and how to put it back together again.

I figured these would be a great resource for those that buy these. 
(Don't you wish Kato had instruction videos on how to take apart their locos?   They've had some doozies.)

The videos are a bit amateurish... but I think they are adequate to help someone see what to do.

It was an interesting experience.  I discovered how hard it was to model slightly sideways with a camera over my right shoulder.
Screwing a screw is a whole new challenge in that situation!

I discovered that if I were going to do this a lot more, it would be best to get a Go-Pro camera to wear on my head so that it naturally points at what I'm looking at.

Anyway, if anyone here has insomnia, these might help!   


Intro Video:

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Cleaning Wheels.

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How to take one apart.

(19 min)

[u18b]

And how to put one back together again.   

[narrowminded]

Those are perfect, Ron.   Very clean, properly explained, just what's needed for a technical advice video.  I hope when it's my turn to do one I can do half as well.