Building the Southern Railway PS-4 Frame

[Greg_Lewis]

was treated like a kink by the local members.

Everybody treats me that way. With time you'll get used to it.

[Cary Stewart]

Sam's last name is Calderwood. He was the clup Pres. 3 years ago. Cary

[kvom]

Nice report. I also visited LALS last summer and was treated royally. Super outfit there.

[Pipescs]

I would like to be able to say the trailing truck castings are coming along with no problems but to say the least it is an on going battle of education. I have finally admitted the need for a pyrometer so that I can quit guessing at the temp on the metal. It should come by monday I hope.

I have made various attempts at the various parts but most have been failures due to the pour being too cool to get a good flow. The Pyrometer was 135.00 from Budget Casting.

In the mean time I am mounting the patterns for the Journal Box Castings to a match plate and building up a flask. It will be my next attempt.

The largest challenge to date has been the long arms. I have made them scale to find that thin sections tough to cast.

With luck the pyrometer will solve the last of my problems.

[Pipescs]

I had originaly thought that I would do the castings for the jornal boxes with small recesses in the pattern. After talking with Trainman and having had Fender give me a little experiance with cores I decided to retrofit the patterns with core prints and make up a sand core box. These could have been made up of wood but as I am on the road a lot I decided to add them on as RP parts

Not having any time in the shop due to my travel but also a little extra spending cash I went ahead and drew up the parts to have glue on prints that would match up with the existing pattern holes. I drew the core itself as a possitive with the idea of doing a two part core mold box using a plastic that Trainman recommended called Kwick Cast II. Have yet to find a supplier close to me so I may end up using something such as Plaster of Paris. this will make Trainman cringe, but I only need four cores to make up the two sets I want.

One set to machine, the other in case I screw it up.

The two halves of the core and the prints were a little more expensive than I would have spent if I had made them from scrap wood. But as I say my time is hard to come by in the shop until I get retired. Total cost on all of the parts was $70.00. I ordered them ont he fifth of July with a forcasted date of arrival being the seventeenth of July.

[Pipescs]

Core Prints and Core Patterns were ordered from Shapways on the fifth of July. Came in the mail today. Very happy with their service and product.

Wish now I had developed a negative of the core so I could use it for the mold itself. Well you live and learn.

The prints will simply glue into the existing holes on the pattern

The pattern for the core was done in halves with daft to be able to pour a molding material around it in a box. Once the pattern is removed the core box will be waxed up and sand cores made from it.

While cleaning out a closet I stumbled on a PS-4 Pacific in O Gauge that we bought for my son when he was four. It has been in the closet so long I forgot we had it. Will put it out on a shelf in the Man Cave for Motifvation.

[Fender]

Very slick pattern work! What RP material are these?

I'll have to say you are providing us some classic typos, what with making your patterns with "daft" and being treated like a "kink".

[Pipescs]

In my defence I have been typing without contacts. I had to take them out for ten days to be evaluated for cataract surgery an have been blind

[Pipescs]

Also I learned to spell in the USMC by taking spelling for Marines MCI course.

About to pour a plaster mold to see how it works.

[Pipescs]

RP was Sandstone

Rougher than normal. I filled the pores with lacquer putty from the autoparts store.

[Pipescs]

The first half of the core box attempt in Plaster came out acceptable on the first attempt but as I layed in bed last night I decided to redo the attempt with deeper sides to give them a little more durability.

I will make them about two and a half inches thick. After they have dried I will paint them with auto primer and wax them.

When we made up cores at Fenders we also sprayed them with PAM as a parting agent to help get the sand out of the mold.

[LivingLegend]

OK.... Here's the scam on plaster molds made from patterns.

Don't try to completely fill the mold box the pattern is set into in one pour.

First, coat only the pattern and the immediate surrounding surface of it's mounting board with a thinned, less viscus coat of plaster to make a thin "shell" around it's surface. This will allow the plaster to worked onto the pattern for complete coverage and fill all pattern recesses. Give time for the shell to set, then pour more plaster to fill the mold box for re-enforcement and to give strength to the mold. This method will give a finer surface finish to the mold. For larger patterns, sand can be added to the plaster backing the shell to give more overall strength to the mold.

A bit of trivia.... A number of plaster molds were made of various patterns for Tom Miller's Big Boy by Severn-Lamb when they were building it back in the late 70's and early 80's.

EDITED (for clarification).... 2012/07/13 @ 0922 hrs CDT

LL