Another 2900 project...

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Harold_V
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Re: Another 2900 project...

Post by Harold_V »

If you've read on anodizing and dying, you understand that the anodizing process creates a huge number of miniscule holes (pores) in the anodized aluminum surface. These holes absorb the dye that is used, which is applied by immersing the part in the dye solution for a prescribed period of time. The part is then removed from the dye and sealed, which is accomplished by immersing the part in a heated solution, although just plain water, heated to the prescribed temperature, will seal the pores. This process is reputed to close the pores, so the dye should be stable, and not bleed.

I can't help but wonder if, maybe, the parts were not sealed properly. I had masked areas on my parts (wall plates for the lighting system in my house) that are absolutely clear of color. Frankly, I've never seen a properly dyed anodized finish that did any bleeding.

Might not hurt to determine how the parts were dyed. Rit dye has been known to be used, but that's not what is used in industry so far as I know.

Were all areas of the part anodized, or were they masked, so only the area dyed black was intended to be anodized?

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.
SF2900
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Re: Another 2900 project...

Post by SF2900 »

I have never had anything anodized prior to these parts and have very little knowledge of the process or methods used. Its been a while since the parts were anodized but I believe that the entire part was anodized with nothing being "masked off". Since a friend of a friend performed the work I have no idea of the process or procedures used. I had just never observed this kind of discoloration before in other anodized things that I have seen and want to avoid this pitfall should I choose to anodize more visible parts.
- Ward
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I was considering anodizing this piece as it is aluminum
I was considering anodizing this piece as it is aluminum
SF2900
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Re: Another 2900 project...

Post by SF2900 »

Started on the pilot beam. Cut a couple pieces of angle iron to approximate length. Made some paper templates and started cutting and welding. Also installed the Teflon rings on the pistons and fit them into the cylinders. Also started on the reverse gear but forgot to take pics...
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Cutting the angle iron
Cutting the angle iron
Welding it back up
Welding it back up
Looks pretty good so far
Looks pretty good so far
Ready for a home...
Ready for a home...
SF2900
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Re: Another 2900 project...

Post by SF2900 »

She is alive! After finishing the reversing gear we were able to attach shop air to the engine and see the locomotive operate for the first time. After a 10+ year journey to get to this point it was indeed a major milestone.
A friend who has a laser cutter cut out the gaskets
A friend who has a laser cutter cut out the gaskets
Running on air
Running on air
Close up of gear
Close up of gear
Rob Gardner
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Re: Another 2900 project...

Post by Rob Gardner »

That is just awesome! Any video footage?

Rob Gardner
Asteamhead
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Re: Another 2900 project...

Post by Asteamhead »

Congratulations, SF 2900!
Your running gear looks awesome from any angle :) !
You may be able to run your engine on steam to the same schedule as the prototype 2926 will do! :?:

Best luck to you by
Asteamhead
Kimball McGinley
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Re: Another 2900 project...

Post by Kimball McGinley »

Regarding the cylinder and valve heads; that seems to be way too many fasteners, especially for the piston? You will never get that many on the backside.

On the valve, there has been some trouble using set screws for studs; a failure was reported because the nut was only threaded on the hollowed- out portion, not on the solid.
SF2900
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Re: Another 2900 project...

Post by SF2900 »

@Rob - I will try and get the video posted at youtube and post the link.
@Asteamhead - Thank you for your kind words. I think the prototype 2926 will be under steam before I will.
@ Kimball - Number of fasteners was per the prototype. I suppose that this may be a case of some of the things that don't "scale". The backside head is welded on as was done on the prototype. The set screws will be replaced with bolts in final assembly. This was a case of using what we had at the time.
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Harold_V
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Re: Another 2900 project...

Post by Harold_V »

SF2900 wrote: Tue May 08, 2018 1:17 pm I suppose that this may be a case of some of the things that don't "scale".

I don't agree. If one's goal is to replicate the prototype in miniature, it is perfectly acceptable to use an equal number of fasteners, assuming they are available in the given size. Makes the model look all the more faithful, and satisfies the rivet counters. I like such detail.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
rkcarguy
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Re: Another 2900 project...

Post by rkcarguy »

I think what SF was trying to say, is that the fasteners are larger than the prototype when scaled?
A #4 screw for example, scales out to about a 7/8" thread and a 2" hex head at 1-1/2", or 1/8th scale.
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Harold_V
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Re: Another 2900 project...

Post by Harold_V »

rkcarguy wrote: Tue May 08, 2018 5:39 pm I think what SF was trying to say, is that the fasteners are larger than the prototype when scaled?
A #4 screw for example, scales out to about a 7/8" thread and a 2" hex head at 1-1/2", or 1/8th scale.
That makes sense. It's the reason I said "assuming they are available in the given size". They do start looking "out of place" when too large.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
rkcarguy
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Re: Another 2900 project...

Post by rkcarguy »

It's a catch 22, because any smaller than that and they become very hard to tap, especially blind holes, and don't have much for strength.
I had an HO scale steam engine I had to repair with some 00-80 screws and that was pretty ridiculous work.
The OP's work is amazing though, I'm excited to see it run on air.
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