Kozo A3 in 1.5" scale - new project

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NP317
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Re: Kozo A3 in 1.5" scale - new project

Post by NP317 »

kvom wrote:Assessing the reassembly and piping project. Club member said copper tube in the smoke box is liable to corrode away, so I just ordered some SS tube and fittings from McMaster. [snip]
I assume this will be a coal-burner? Thus the corroding copper.
~RN
kvom
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Re: Kozo A3 in 1.5" scale - new project

Post by kvom »

My stainless compression fittings and tube arrived from McMaster. The fittings are longer than I imagined, and a quick fit to the loco revealed a few problems.

Image

The one on the steam port on top would interfere with the petticoat, and on the bottom is a tight fit to the blower nozzle. The connection to the blower nozzle is close the inside wall of the smokebox and would mean a tight bend on the tubing.

Using various fittings I came up with this:

Image

Seems to fit with no issue, although an elbow at the blower nozzle might be good too.

What's the crew's advice on using brass fittings (nipples and elbows) here? They're a lot thicker than copper tube. It's a coal burner.
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Harold_V
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Re: Kozo A3 in 1.5" scale - new project

Post by Harold_V »

I'd suggest you avoid brass, but bronze, I would think, would be acceptable.

Nice looking EE I see in the background.

Harold
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Kimball McGinley
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Re: Kozo A3 in 1.5" scale - new project

Post by Kimball McGinley »

Can one actually find BRONZE commercial pipe/tube fittings?
I have seen a wide variation in the length of the "Nut" in compression fittings. You might be able to shorten that portion that extends along the tube, so that the tube can begin its bend earlier.
The pipe/ female end might also be shortened, and the threads extended towards the hex. These are usually made to easily handle pressures that are far higher that Live Steam loco pressures.
We home machinist types could also easily make our own compression fittings, except for the ferrule (ball part) which would be difficult. Sometimes you can buy those separately.
mikeehlert
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Re: Kozo A3 in 1.5" scale - new project

Post by mikeehlert »

You might find Bronze from Wholesale Plumbing Supply or a Marine (boats) dealer. Think $$$

Mike
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Fender
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Re: Kozo A3 in 1.5" scale - new project

Post by Fender »

Kimball McGinley wrote:Can one actually find BRONZE commercial pipe/tube fittings?
These seem quite affordable:
http://www.jmesales.com/catalog/product ... gQod5gYCHA
Dan Watson
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kvom
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Re: Kozo A3 in 1.5" scale - new project

Post by kvom »

I found and ordered a quantity of SS hex nipples on Amazon that can replace the brass ones used in the prior photo. No luck looking for a 45 degree with mail and female like the brass one. I think I can make one with 2 female threads and use a nipple for the male end. OTOH that 45 degree brass nipple is quite thick, and even if it were to corrode it should be easy to remove/replace.

I am reluctant to modify the SS compression fittings at this time, as they are $20 each. The steam supply setup seems pretty good as it needs only a short curved piece of tube. The blower side is more awkward, but there is plenty of room forward in the smokebox to make a fairly wide curve. I'm not going to finalize it until everything else is set, including the valve piping from the turret.

Speaking of which I'm wanting to use brass pipe for the blower valve connection vs. the copper tube I had before, which I felt was unsightly. The valve (I believe it is from Locoparts) has a female thread on one side and a male solder connection on the other. To use threaded pipe on both sides I needed to duplicate the tube end piece that had been soldered on previously. Fairly easy lathe job starting with some 7/16 brass rod.

Image

Spent the rest of the afternoon setting up the CNC mill to thread the many pieces of 5/16 brass pipe that will be needed. First attempts will be hooking up the blower valve and the whistle.
marshall5
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Re: Kozo A3 in 1.5" scale - new project

Post by marshall5 »

kvom wrote:Assessing the reassembly and piping project. Club member said copper tube in the smoke box is liable to corrode away, so I just ordered some SS tube and fittings from McMaster.
I must admit I'm a bit puzzled by your aversion to using copper piping in the smokebox as, to my mind, it is much neater and simpler. Of course it will eventually corrode away but in my experience you're talking 20+ years and I can live with that. When I re-boilered my coal fired Milner Hunslet (built 1989) a couple of years back I made new steampipes from 1/2" O.D. copper, not that the original ones had corroded away but it was just easier to cut them when removing the old (non-spec) boiler. I made the unions from hex brass as I had some the right size in stock. The main reason I prefer copper piping rather than a series of unions and elbows is that you can shape it to follow the side of the smokebox and leave the flues clear for sweeping. Just my 2c worth.
Cheers,
Ray.
kvom
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Re: Kozo A3 in 1.5" scale - new project

Post by kvom »

After much fiddling plus discussion with a very experienced builder, I decided to use brass compression fittings along with the SS tube.

Image

Tube bends were relatively straightforward, and there's no interference with the petticoat. Then I have basically finished up the redo of the piping. Other than the turret being replaced, I redid the connections for the blower, whistle, and water glass.

Image

A few minor tasks left before next attempted steam up.
kvom
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Re: Kozo A3 in 1.5" scale - new project

Post by kvom »

Passed hydro today. No leaks from boiler even though new piping has a couple of leaky pipe thread joints (will tighten). Left the loco at the track and am thinking to light a fire next Wednesday if the weather cooperates.
Pontiacguy1
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Re: Kozo A3 in 1.5" scale - new project

Post by Pontiacguy1 »

You won't be disappointed with the Brass fitting/stainless tube combo. I actually use brass flare fittings instead of compression fittings and ferrules, but they both work fine. I've had mine in the locomotive now for about a dozen years, and a lot of hard running. Took them out a year or so ago to do a repair, and they came out fine. The brass fittings were fine. Cleaned it all up with a wire wheel, and it looked almost like new. When done with the repair, I just put them back in place. Before, I had been using the same brass fittings with copper tubing, and the copper lasted all of about 3 to 4 years under those conditions before one of them cracked in the middle of the bend.

I don't expect that I will ever have to replace these.
kvom
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Re: Kozo A3 in 1.5" scale - new project

Post by kvom »

Short update: last week I took it to the track for a hydro test on the boiler, which passed. However, several pipe joints had seeps and need to be tightened.

This week I returned to the track and attempted a steam up. Still some small seeps, but I had problems in firing. First issue is that my stack blower is to fast, pulling so much air that the fire gets blown out. Since I don't have a speed control I restricted the flow by blocking the best part of the output. Got it heated uop with the needle off the peg, but couldn't get is past 20 psi. Adding some more coal put the fire out!

Post-mortem is that I likely had too much coal, as it wants a thin bed on the grates. I found some unburned wood I'd supposedly added to help start the blaze.

I'll try it again soon.
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