Filling rough spots in white metal castings

[bpickering]

I've got a MDC Harriman Consolidation kit I've been putting off working on for lack of enough dedicated time. [:(]

I was doing some general grinding/cleaning of flash on a bunch of metal hopper & flatcar undercarriages last night (once I get out the airbrush, figure to primer a whole mess of them at one time...), and decided to clean up the Connie boiler as well. While it was fairly clean of flash, I noticed two rough spots on the top of the boiler (IIRC, immediately aft the smokestack, and immediately aft the steam dome.) Instead of raised flash or remnants of a sprue, it looks like removing a sprue actually might have taken a small chunk out of the boiler itself.

So... I'm going to have to fill this in then file/sand it clean (they are just a >little< too obvious to leave as-is [:D]). The question is, what should I fill it with. The depressions look sufficiently rough that plastic modelling putty might have enough "tooth" to get a grip and hold, but I'm wondering if there would be something better.

TIA,

Brian

[mcouvillion]

bpickering,

I'd try the Squadron Green putty. I think it would work well. Are you sure there isn't supposed to be a piece of equipment (bell, whistle, generator) attached at either location?

Mark C.

[bpickering]

QUOTE: Originally posted by mcouvillion
I'd try the Squadron Green putty. I think it would work well. Are you sure there isn't supposed to be a piece of equipment (bell, whistle, generator) attached at either location?

Mark,

I just had an unexpected stop to my LHS today (wife locked out of her car a couple of blocks away...), so asked this question. They recommended the Squadron putty as well.

I now remember that there is already a bell cast just to one side (making the order something like stack ... rough area ... bell? ... rough area ... steam dome). Also, IIRC (I'm at work right now, writing while re-imaging servers), the generator is a separate casting that will be mounted under the floorboards. Yes, I'm pretty sure these are casting imperfections.

Maybe I'll try to get a pic up tonight, but I'm pretty-comfortable filling these areas in.

Brian

[bpickering]

As promised, here are some images:
Whole view:

Med-Zoom:

Forward deformity:

Aft deformity:


As I said, in the forward view, one can clearly see the bell (although I botched the order, having been working from my typical spotty memory...). The aft view shows the steam dome and, I guess, the generator (corrections, if ya got 'em).

Anyway, these definitely look to me like casting imperfections, and I'll be planning on filling them, probably with the plastic modelling putty.

Thanks,

Brian

[Anonymous]

Those look like mould feeds to me, judging by where they are (on the centreline of the boiler) - these are where the molten metal is poured into the mould.

[bpickering]

QUOTE: Originally posted by Railroading_Brit

Those look like mould feeds to me, judging by where they are (on the centreline of the boiler) - these are where the molten metal is poured into the mould.

Yeah, exactly what I thought.

Too bad I can't cover them up with gaffa tape. [:D]

Brian

[orsonroy]

File 'em smooth, but keep the filings. Once you've got the contours where you want them, add a puddle of cheap superglue th the area, and dust the ACC with the metal filings. Sand smooth and repeat as necessary. This will work MUCH better than Squadron putty, since it'll adhere better and won't shrink as much.

Bondo works too.

[mcouvillion]

Brian,

I was going to suggest plastic automotive body filler (Bondo) too, but thought that it was out of the realm of reason, since 1) you probably don't have any at home, 2) even a small can would run you several bucks, 3) you wouldn't use enough to justify the expense, and 4) it takes a little practice to know how to work with it properly. The suggestion to save the filings is a good one. I don't know that I would use ACC, though. I would probably dust the putty with the filings. You're only going to use a tiny bit of putty, anyway.

Take your time filing. I have a white metal caboose that I had to clean up and it is easy to get carried away. You might knock down the big, then use fine sandpaper strips to get it to the right contour. You might even consider roughing up the sprue area a little so that you get a better "bite" with the filler material. Just a thought.

Mark C.

[bpickering]

I've used Bondo before (and was even satisfied with the results), so experience wouldn't be a problem. You're right, though, that I don't know if I want to put out several bucks for a one-time (?) use.

I won't get much in the way of filings out of this- the two holes are already pretty-much below the surrounding level. Too bad I didn't remember the AC/filings tip (remember seeing it in one of the forums a couple weeks ago...), since I >might< have had enough if I added up all the frames I cleaned up that night.

Anyway, the openings are relatively recessed, and I don't think they'll need to be high-strength (that is, they're well-protected by the surrounding details), so I'm likely to try the modelling putty. If that doesn't work, maybe by then I'll have some more kits ready to clean up/prime.

Thanks for the advice,

Brian

[dknelson]

There are many tube-based products at the local hardware store that would seem to work, including one that is like a paste metal -- the important thing is something that will bind to zinc alloy and can be filed. I have used plastic wood for this and was surprised that it worked. My use was on a Mantua Pacific boiler
Dave Nelson

[Anonymous]

You might stop by your local auto parts store and pick up a tube of spot putty. Same as Squadron Green. Just that there are a lot more auto parts stores so it will be easier for you to get some thing that will get the job done quickly.

Joe