Another 2900 project...

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Harold_V
Posts: 16867
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: Another 2900 project...

Post by Harold_V » Wed May 17, 2017 1:06 am

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
Posts: 64
Joined: Thu Dec 02, 2010 4:40 pm

Re: Another 2900 project...

Post by SF2900 » Thu May 18, 2017 11:17 am

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
Attachments
hangar bracket.jpg
I was considering anodizing this piece as it is aluminum

SF2900
Posts: 64
Joined: Thu Dec 02, 2010 4:40 pm

Re: Another 2900 project...

Post by SF2900 » Fri Dec 08, 2017 6:15 pm

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...
Attachments
pilot beam 1.jpg
Cutting the angle iron
pilot beam 2.jpg
Welding it back up
Pilot beam 3.jpg
Looks pretty good so far
piston.jpg
Ready for a home...

SF2900
Posts: 64
Joined: Thu Dec 02, 2010 4:40 pm

Re: Another 2900 project...

Post by SF2900 » Fri May 04, 2018 10:34 am

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.
sf2900 2.jpg
A friend who has a laser cutter cut out the gaskets
sf2900 1.jpg
Running on air
sf2900 3.jpg
Close up of gear

Rob Gardner
Posts: 371
Joined: Sun Oct 23, 2005 9:27 am
Location: Southwick, MA

Re: Another 2900 project...

Post by Rob Gardner » Fri May 04, 2018 11:22 pm

That is just awesome! Any video footage?

Rob Gardner

Asteamhead
Posts: 339
Joined: Tue Jul 31, 2012 1:59 pm
Location: Germany, Duesseldorf

Re: Another 2900 project...

Post by Asteamhead » Sat May 05, 2018 5:07 pm

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
Posts: 682
Joined: Wed May 31, 2006 2:13 pm
Location: Laguna Niguel CA

Re: Another 2900 project...

Post by Kimball McGinley » Mon May 07, 2018 7:11 pm

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
Posts: 64
Joined: Thu Dec 02, 2010 4:40 pm

Re: Another 2900 project...

Post by SF2900 » Tue May 08, 2018 1:17 pm

@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.

Harold_V
Posts: 16867
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: Another 2900 project...

Post by Harold_V » Tue May 08, 2018 3:41 pm

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
Posts: 636
Joined: Tue Aug 22, 2017 10:33 am

Re: Another 2900 project...

Post by rkcarguy » 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.

Harold_V
Posts: 16867
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: Another 2900 project...

Post by Harold_V » Wed May 09, 2018 1:46 am

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
Posts: 636
Joined: Tue Aug 22, 2017 10:33 am

Re: Another 2900 project...

Post by rkcarguy » Wed May 09, 2018 10:25 am

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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