Coach 9 - Official Work Thread

[Jeff Schumaker]

Excellent work, Harold. What's next on your list?

Jeff S.

[Dave Crow]

Harold, the "cups" in the ends of the carbody in which the ends of the truss rods and tensioning nut go - are those castings?

Dave Crow

[Harold Downey]

The truss rods on Coach 3 terminate with washers and nuts.  So - no castings.

[Dave Crow]

Harold, thanks for the clarification.

[Harold Downey]

I am starting work on the patterns for the Hale & Kilburn seats.  This is the window side casting that supports that side of the seat, and where the flip-over mechanism attaches as well.   

It is very challenging, even though it doesn't look too complicated.  I also need to make a complex core box to form the back side cavity.  This is just a warmup for the aisle side casting -- that one is giving me nightmares.   

The first picture is the pattern in process. I am gluing on the first level of core prints in this step.  You can see the actual part just above it.

The second picture is showing something I am trying out.  The original casting has a part number on  it - 71M-3.  The letters are very similar in size and detail to the Hale and Kilburn lettering that definitely needs to be reproduced on the aisle side casting.  I got some mold making silicone rubber.  I poured this over the letters.  Once that hardens, I can peel it off and use it as a mold to make letters out of epoxy.  Then I can glue the epoxy letters to the pattern.  I hope this works!

I'll update as I get further along. 

[Harold Downey]

Silicone mold making

[Wayne Laepple]

Hi Harold --

We have had very good luck making silicon casting patterns at the Railroad Museum of Pennsylvania. We've made builder's plates, number plates and quite a few small bits of hardware. Good luck!

Cheers -- Wayne

[James Patten]

It looks like Hale & Kilburn's successor is the Kustom Seating Company.  Did you talk to them to see if casting pattern 71M-3 (or any other pattern) still exists?  Doubtful, I know.

[Stephen Hussar]

Wow.

[Harold Downey]

A couple more pictures: 

The silicone mold peeled off the letters.  It seems to have worked really well.

[Harold Downey]

And with the epoxy letters placed on the pattern.  The pattern is a little further along.   The core box for this is taking a lot of time.  I will have a picture of that to post in a day or two.

[Jeff Schumaker]

Fantstic work, Harold.

Jeff S.

[Harold Downey]

This pattern is a one-sided pattern with a cover core.  It will be molded completely in the drag (bottom half of the sand mold flask).  The cover core forms the back side indent and takes care of the offsets in the parting plane. 

On top is the pattern -- the darker wood backing is the core print.  Below is the core box. 

Still have lots of finish work to do -- filling holes, fillets, etc.

[Harold Downey]

I've started on the biggest seat part, the main side frame.   Since the silicone mold making seemed to work well for my first try with letters, I thought that it might allow me to make the most intricate part of the side frame pattern, the open basket weave.   I backed up the weave area with a waxed piece of acrylic, and brushed on a thickened silicone mixture to make the mold.   After curing and peeling it off, it didn't seem all that great, but I decided to go ahead and make an epoxy casting with it, to at least learn something.  The basket weave is on a curved surface, which doesn't lend itself to making an epoxy casting very well.  So I flattened the silicone mold, and put plaster on the back side to keep it flat. 

I made a dam around the silicone with molding clay, mixed up epoxy and poured it yesterday.  I unmolded it today, sanded down the back side to get it to the correct thickness, and did a little clean up with a paring chisel and files.    I am very pleased with how it turned out.  No need to do it again. 

[Harold Downey]

Here is the silicone mold I made to reproduce the Hale & Kilburn lettering.   I am stoked about how well this is working.  The new seats will look very authentic.