Brass tender truck corrosion?

[ATSF_Ron]

This is a pic of my Oriental Limited UP 2-8-0.  I have several of these in UP and SP, but I've never seen this on any of my brass locos.  I HAVE seen it on older models for sale online and in hobby shops years ago.  It looks to be some kind of corrosion or tarnish possibly "leaking" through paint, but I don't know.  This model was factory painted.  I'm hoping a light bit of airbrush weathering will take care of it and stop the corrosion or tarnish.  It looks to be fairly mild compared to other older brass locos I've seen.  I believe mine is from the mid-80s.  Brass folks, do I have anything to worry about here?  Thanks.

Ron

[robert3985]

I worked on an old brass Hallmark (?) NP engine 4-8-4 that had a similar problem, but was much worse, a couple of weeks ago.

I assumed the corrosion was from the flux used to solder the truck side frames to the bolster, so I dismounted the trucks, took the wheels out (keeping track of which side the insulated wheels are on)...took a small brass wire welding brush I got at Harbor Freight and brushed the Hell out of them, taking most of the paint off at the same time.

Then, I mixed up a small batch of warm distilled water with several spoonfulls of baking soda, and put the trucks in it...swished them around for a few minutes, then took an old toothbrush to 'em while they were in the plastic cup, wetting the brush with the water/baking soda mixture.  I let them sit in the solution about half an hour.

Next, took 'em out, rinsed well with hot water, then took my airbrush to them set on 75psi.

Then, I de-greased 'em, and repainted them.

I don't want to take chances of corrosion ruining any job I'm doing sometime down the line, both for customers' projects as well as the models I'm keeping.

Just painting over it isn't a good idea.

Photo (1) - NP Tender Truck much corroded by what I think was solder flux that didn't get washed off at Samhongsa before the trucks got painted:


Photo (2) - Thick bits of corrosion that fell off of the NP engine's tender trucks when I removed them:


Your Oriental Consolidation is worth the effort to "fix".  Mine is one of the finest running engines in my roster, as are my Key U.P. Consolidations.

Cheerio!
Bob Gilmore

[ATSF_Ron]

Yep, that's some serious corrosion.  It's funny that it's from an Oriental NP Northern, as that's the loco I saw online with the tender truck corrosion.  Wonder if it's the same one?  Anyway, I'll try your method.  It doesn't sound too tricky.  I have a small brass (I think?) brush I got from PBL years ago along with a stiff nylon brush from a weathering kit of theirs.  That should do the trick.  Thanks!

I definitely love my Oriental and Key connies.  Great runners with great details!

[thomasjmdavis]

I worked on an old brass Hallmark (?) NP engine 4-8-4 that had a similar problem, but was much worse, a couple of weeks ago.

I assumed the corrosion was from the flux used to solder the truck side frames to the bolster, so I dismounted the trucks, took the wheels out (keeping track of which side the insulated wheels are on)...took a small brass wire welding brush I got at Harbor Freight and brushed the Hell out of them, taking most of the paint off at the same time.

Then, I mixed up a small batch of warm distilled water with several spoonfulls of baking soda, and put the trucks in it...swished them around for a few minutes, then took an old toothbrush to 'em while they were in the plastic cup, wetting the brush with the water/baking soda mixture.  I let them sit in the solution about half an hour.

Next, took 'em out, rinsed well with hot water, then took my airbrush to them set on 75psi.

Then, I de-greased 'em, and repainted them.

I don't want to take chances of corrosion ruining any job I'm doing sometime down the line, both for customers' projects as well as the models I'm keeping.

Just painting over it isn't a good idea.


Your Oriental Consolidation is worth the effort to "fix".  Mine is one of the finest running engines in my roster, as are my Key U.P. Consolidations.

Cheerio!
Bob Gilmore

Bob, on your model, if I didn't know those were brass trucks, I would have guessed zinc pest... yikes.
While you are probably right about the flux, I've seen similar problems on a couple brass models where the painter (end user, not the factory) gave the  parts a soak in vinegar (or maybe something stronger) to give them more "tooth" to promote paint adhesion, and then neglected to do a baking soda bath to neutralize the acid.  Apparently believing that as long as they were "dry" he could go ahead and paint.

In any case, I would follow Bob's instructions up above to clean up the trucks prior to painting.

[Steamblood]

Yep, that's some serious corrosion.  It's funny that it's from an Oriental NP Northern, as that's the loco I saw online with the tender truck corrosion.  Wonder if it's the same one?  Anyway, I'll try your method.  It doesn't sound too tricky.  I have a small brass (I think?) brush I got from PBL years ago along with a stiff nylon brush from a weathering kit of theirs.  That should do the trick.  Thanks!

I definitely love my Oriental and Key connies.  Great runners with great details!

My Oriental limited NP A2 and three A3 had the same issue, that it's true also for the ones listed on the net I had seen with that tender, but strangely no toher parts of the locomotives neither the A4 and A5 with centipede tenders develope that issue.

[ATSF_Ron]

Well, thankfully it's just a truck and not the loco or tender body!