I was told that it’s the area where they lift the frame off of the trucks for repairs.
I finished putting the grab irons and door handles on the long hood. I also filled in the overly-wide panel lines and scribed new, thinner ones; and replaced a couple of molded-on pipes:
(http://www.raydunakin.com/Site/IRR_RS3_Conversion_files/Media/IMG_1333/IMG_1333.jpg)
(http://www.raydunakin.com/Site/IRR_RS3_Conversion_files/Media/IMG_1334/IMG_1334.jpg)
I scribed some lines into the smoke stack, and replaced the molded details:
(http://www.raydunakin.com/Site/IRR_RS3_Conversion_files/Media/IMG_1332/IMG_1332.jpg)
One of the reference photos I found included a close up view of the horn, which inspired me to go nuts and add all the little details to the horns on my loco:
(http://www.raydunakin.com/Site/IRR_RS3_Conversion_files/Media/IMG_1359/IMG_1359.jpg)
The sideframes of the trucks have a lot of molded on detail, including the brake cylinder. I’m cutting those off and making my own, completely 3-dimensional brake cylinders. I haven’t finished that yet, but here’s a pic showing how I’m altering the shape of the steel arch-thingy (pardon the technical terminology!) to more closely approximate the prototype. I used epoxy putty to fill out the shape. Since this piece must be able to move up and down, I just put a piece of wax paper between the two parts before adding the putty:
(http://www.raydunakin.com/Site/IRR_RS3_Conversion_files/Media/IMG_1362/IMG_1362.jpg)
That’s all for now, more later… .
Ray, nice work. Almost makes me want to build a diesel… almost. 
Ray Dunakin said:
Does anyone know what this thing is… it looks like a small step hanging down from under the side of the deck, directly above the center of the truck: [url](http://www.raydunakin.com/Site/IRR_RS3_Conversion_files/Media/RS3Mystery2.jpg)
[/url] There’s one over each of the trucks, on both sides. I don’t think it’s a step though, because in some photos the face of it is flat.
Thats known as a Jack PAd…used for lifting the body off the trucks…
I finished making a master for the brake cylinders. It just needs a little touch up, and then I’ll use it to make a silicone mold. I need eight cylinders, and I really don’t want to make them all by hand, so casting is the most efficient way…
(http://www.raydunakin.com/Site/IRR_RS3_Conversion_files/Media/IMG_1374c/IMG_1374c.jpg)
The grill over the radiator fan isn’t totally accurate but it looks pretty good, so I want to keep it. Unfortunately the holes are much narrower on the back then on the outside, in fact they’re barely open. So I’m carving them out, one by one, with the tip of an X-acto knife. Very tedious, so I can only stand to do a little of it at a time. I’m halfway finished so far:
(http://www.raydunakin.com/Site/IRR_RS3_Conversion_files/Media/IMG_1380/IMG_1380.jpg)
Ray,
Why not use one of those drill bit thingies?
I did use a drill bit in a pin vise to put holes in the two areas that are extra thick and completely sealed. I used the knife blade on the rest because it’s tapered – this makes the hole wider on the underside, without altering the square grid appearance too much on the top.
Ray - Is that an 'early" or “late” model RS-3? I ask because I think they upgraded that screen on the later model. I have 3 of the “late” model RS-3’s and I don’t remember the tiny holes. I’ll have to look at home tonight.
It’s an early model, probably second generation.
Today I made a mold of the brake cylinder master. Because of the complexity of the shape, a two-part mold was needed. I built a form out of styrene, and filled half of it with sulfur-free modeling clay. Then I pushed the master into the clay, and worked the clay in around it to make as clean an edge as possible. I pressed a few dimples into the clay to make “keys” that will keep the two halves aligned:
(http://www.raydunakin.com/Site/IRR_RS3_Conversion_files/Media/IMG_1382/IMG_1382.jpg)
Next I poured in some silicone rubber mold compound. I use Smooth-On brand “Oomoo 30” because it’s easy to use and doesn’t require a precision scale. It mixes by volume, not weight, and is pretty/ forgiving. When this set, I pulled off the bottom of the form and removed the clay. Leaving the master in place, I then coated the face of the first layer of silicone with a very thin coat of vaseline as a release agent. I also used a spray on release from Michael’s:
(http://www.raydunakin.com/Site/IRR_RS3_Conversion_files/Media/IMG_1388/IMG_1388.jpg)
I poured in some more silicone, let it set, then removed the form and pulled the two halves apart. Then I started casting. The initial casting came out rough, which is typical. The rest came out better. I had also made a simple one-piece mold of another part that will be used on the side frames, and cast that too. Here’s how they look after cleaning up the flash:
(http://www.raydunakin.com/Site/IRR_RS3_Conversion_files/Media/IMG_1390c/IMG_1390c.jpg)
And here’s one of the brake cylinder castings after being painted with a coat of primer. It’s a little bit rough but not bad:
(http://www.raydunakin.com/Site/IRR_RS3_Conversion_files/Media/IMG_1400c/IMG_1400c.jpg)
BTW, the silicone mold compound and the urethane resin both have a very short shelf-life after they’ve been opened, especially in a humid environment. But you can greatly extend the shelf-life by shooting a bit of anti-dust spray into the containers before closing them. This is the stuff typically used to clean electronics, etc.
It’s been almost a year since the last time I made a mold but my mold compound is still good; and I’ve been using the same gallon jugs of casting resin for at least 4 years.
Ray, are those air bubble holes prototypical? 
Ducks and runs for cover.
I wish I had your persnickitiness.
A little more progress… I finished casting all the brake cylinders and install four of them on the rear truck. The brake shoes on the original model are removable plastic pieces, and include a curved shape that is supposed to represent the sand line. As-is, these brakes look pretty anemic. So I reworked them, adding on new styrene bits to make the brake shoes a little larger and thicker, and also made the hardware stouter and more accurately shaped. (In silhouette, anyway. As on the original model, a lot of liberties have to be taken in this area.) I cut off the original sand lines and built new ones that are much more realistic looking. Here’s a shot of two remodeled brake shoe assemblies next to one of the unmodified parts:
(http://www.raydunakin.com/Site/IRR_RS3_Conversion_files/Media/IMG_1420c/IMG_1420c.jpg)
Here’s a couple shots of the modified parts temporarily installed on the truck. You can also see how the brake cylinder castings fit into place:
(http://www.raydunakin.com/Site/IRR_RS3_Conversion_files/Media/IMG_1429c/IMG_1429c.jpg)
(http://www.raydunakin.com/Site/IRR_RS3_Conversion_files/Media/IMG_1431c/IMG_1431c.jpg)
I still have to make four more brake shoes pieces, for the loco’s front truck. .
Very nice work Ray.
Nice
Man, that baby is really shaping up to be something.
Doh!
Rather than making the four remaining brake shoe assemblies individually, I wanted to try molding and casting them.
I spent a considerable amount of time figuring out a way to make a two-piece mold of the brake shoe assemblies. This was not an easy task, because they are a fairly complex shape. Got the first half of the mold cast. Added some stuff to form the fill channels, then poured the second half of the mold. All of this was done piecemeal, between numerous interruptions, which also meant a lot of it was done in a rush. (You can probably guess where this is heading…)
Pulled the mold out of the form this evening and discovered the Big Mistake. I had forgotten to apply any kind of mold release between the two halves of the mold. So now I have one big block of (expensive) silicone rubber with two master brake assemblies buried somewhere in the middle.
< sigh >
Oh no!
OOh! OOh! OOh! [raises hand] Done that!
hehehehehhe done that couple times myself…Estimate the demarcation line and start slicing in twith #11 blade…I got lucky once…