I know it is hard to save old wood patterns that have "been around for a while", but I was curious to hear success stories from people and how they saved old patterns

Also related, what is the red paint typically used on the wooden patterns?

In our shop's attic, we have patterns for casting three different cylinders, various valves, other random pieces, and new patterns and core boxes for our current restoration project. The old patterns have seen various storage locations, but are all in fairly good-great condition for being 60-80 years old!

We are lucky in the fact that foundries in Denmark are willing to take our old patterns and work with them. They view it as a chance to re-learn old history and view it as an educational experience!

So in all means, I would like to save and restore the patterns now before they get to the point of no return! Would be nice to have these when somewhere down the road we need to cast a new pair of cylinders for two of our locomotives!

Hi,

FWIW, there is a soft metal foundry in East Point GA (Near the Atlanta Airport). Thye cast aluminum, brass, and so forth but not iron or steel.

When I visited them in the 1990's for live steam truck castings, the owner told me much of their business was from the airlines for wheels on the luggage carriers and small items that they needed fairly frequently.

He told me that the wood pattern was built to double shrikage size. Then they would cast 20-30 wheels in Aluminum. These would be mounted on a plate and set up for casting 20-30 at a time. The pattern used for the casting was cast in aluminum. and the wood pattern was kept just in case.

Interesting idea even if it was not for railroads.

Doug vV

I haven't ever worked with an old pattern than needed repair- but having made quite a few, I might be able to offer some insight.

To me, "Save and restore" is a very different end goal than to "fix them for possible use". For an in-service foundry pattern, the only question is whether or not it can produce a casting which can yield the desired finish part. This largely involves making sure it's dimensionally correct, and structurally sound enough to withstand the molding process. If I needed an old pattern to produce a slightly different casting than originally intended, I wouldn't think twice about adding material to the pattern to make it suit, and I have heard of this being done before. If it's falling apart, or the fillets are coming undone, I'd reattach them however suits it. Leather fillets were usually glued in place, and the wax fillets are applied using a heated metal ball on the end of a rod- and can be re-attached the same way they went on.

Conversely, if the goal is to stabilize and present the patterns, then I'd do as little to them as possible to make them presentable. Reattach anything falling off, clean them up, and keep them in a space which is at least out of the weather- hopefully somewhat climate controlled. If it's meant to be preserved as an artifact, I wouldn't dare be putting bondo on them, and would only replace missing parts with something exactly like what would have been there originally.

No idea what the red paint is called, but I would be curious to know. Instead, I use something totally different these days. I typically use floor polyurethane, because it goes on thick, hardens, and I can build up a decent coating to wet-sand totally smooth. Probably overkill- but I haven't heard any complaints.

If the red is not a complete coating of the pattern but only on selected areas of the pattern(s), it may signify the locations for placing the chunks of sand used to create voids within the interior of the casting. See the yellow pattern for the core used to create the hollow within the counterweight in this thread from the WW&F Railway forum:

http://forum.wwfry.org/index.php?topic=11.150

Nice work as always, Bernie!

Dave Crow

Yeah, there was a standard (or several standards over the years) color scheme that gave the molder an idea of what each part of the casting did, and therefore what surface finish was required. Core prints, which simply hold other pieces of the mold and don't see metal at all were one color; surfaces that would be machined after casting were another. That allowed the molder to concentrate on good surfaces that would be used as cast.

The Society for Preservation of Carter Railroad Resources has 300+ patterns in its collection, about half old patterns salvaged from the West Side Lumber Company pattern room, the remainder produced for our restorations by both traditional pattern makers and by members using a variety of methods (some traditional wood patterns, some cast from resin, and in one case molds taken off an original seat end, used to make aluminum patterns) We have used a number of the WSLC patterns successfully.
Of course in cases where a pattern needs a specific core, you need to find the matching core box... and keep them together. Our pattern collection represents 19th century California narrow gauge rolling stock.

Separately, I have been involved in a foundry preservation project... a foundry full of patterns going back to 1875... Mostly mining equipment but also some cast iron building parts, some logging and sawmill parts, some construction equipment parts...

There are a couple of issues we have identified...

1) (in the case of an old pattern) identifying the what the pattern was intended to produce... and finding someone with a need for that casting... so many castings were unique to a specific locomotive or machine... and

2) getting them cast... our patterns are a mix of loose patterns (with a flat face) patterns with a follower board, and boarded patterns... All are meant to be used in hand rammed sand molds... and we have fewer and fewer foundries willing to do that. We have encountered foundries that will only do boarded patterns... we have encountered foundries that need patterns boarded in very different ways. We have found that different foundries need different board sizes... some are more willing to work with you...

On the issue of red paint... we have patterns that are natural wood, some are black, some (modern) are silver, with cores marked with hash marks, a few are green... and one or two are red... I suspect that the paint and paint color are of local significance.

Back in 1990 I created a catalog of our patterns... In part to catalog what we had, in part to aid other museums with similar technology and let them know what we had, and in part to create a record of the systems used... It now needs to be updated, and that is "process"...

Randy

Besides patterns, core boxes are often required. These create the voids inside of a metal casting. On core boxes I have seen different colors used to indicate what part of the sand mold would be in contact with the metal and what part would be connected with the rest of the greater sand mold for the pour.

From the MACHINERY HANDBOOK(22nd edition, page 2184)

The generally accepted standards for pattern colors from groups such as the American Foundrymens Association and The Steel Foundries Society of America are as follows;

Some brief Google searches indicate these are not universally used though.

The color black denotes an unfinished surface(as cast)
The color red denotes a surface that will be machined (post casting)
The color yellow denotes either the seat for a pattern core or the core pattern itself(referred to as the core print)
The color red stripes on yellow background indicate the seat between multiple core prints(where they seat together)*
The color black stripes on yellow(diagonal) indicate a casting stop-off(a feature added to the part to prevent distortion during casting that is subsequently removed)

* this is my interpretation of the description given in the text and is subject to correction.

Merry Christmas to all RYPN members!

Mike