Steam Tractor 3/4" (Rudy K)

[Kim]

You need not rely on the pump check. For testing you can put a shut-off valve in the line...

Pete

That's a brilliant idea Pete!  (Duh, he says, why didn't I think of that?  )

Just a thought - have you checked to make sure there is no leak at the gauge end of the tubing, or in the union from the pump to the tubing?

Well, I have check fairly well.  When I saw water beading up here or there next to a connection, or dripping from somewhere, I'd find out where it was coming from and tighten things up or fix the leak somehow.  I don't THINK there's any leaks at the gauge or connections, but I could be wrong.

That's the reason I've been assuming it was the check-ball leaking, because I'm not seeing water anywhere, so the only place I could think of that is going is back through the check valve.

Anyway, its working much better than before.  I must have an out of round hole in my bronze pump casting.  Or something...

Kim

[b.lindsey]

Kim, you are a lot better off than you were yesterday for sure. Still puzzling though why the original seat didn't work better. Maybe the spring was the critical component in the new design.

Bill

[Kim]

Kim, you are a lot better off than you were yesterday for sure. Still puzzling though why the original seat didn't work better. Maybe the spring was the critical component in the new design.

Bill

Thanks Bill,
Yes, definitely better than yesterday!

I don't think it was the spring - I changed the spring with various lengths and tensions in the original one and it never seemed to alter the behavior.  And with this new check valve I made today, this was the first spring I tried (probably one I'd tried in the casting valve too ).

Who knows...

I think if I'd had better lapping compound and stuck with that, I might have gotten there.  But I gave up after a try or two and went with making an external brass valve.  Seems to have worked for me! 

Thanks,
Kim

[Kim]

My plan today is to hydro-test the boiler.

I had to start by making a plug and jury rigging my piping together.  The shutoff valve I had had a 1/8” NTP fitting on one end, and a 1/4"compression fitting on the other.  Unfortunately, everything else was setup for 1/8” tubing.  So I silver soldered some 1/8” tubing to 3/16” to 1/4" to get there (you can see this between the pump and the boiler).  It seems to work fine.

Here’s my test setup. The pump is sitting in a tub of water, and the boiler is in a dry tub.  I wanted to make sure that I didn’t dribble water everywhere when I found a leak.


I filled the boiler up using the top opening (this will be for the pressure release valve).


With the boiler full, I put a plug in that hole and pumped up the pressure.  Sure enough, it went down slowly – I had a leak somewhere.  “Ah… its leaking around the plug I just put in.”  So, out it comes, and I used PTFE tape on it and reinsert.

Great!  No leaks there, but now the front seems to be leaking.  I was worried that I had a leak there, around the bushings.  But it turned out, again, to be the threaded joints for the test hardware.


So I use PTFE on both of those, and try again (you can see all threaded joints have tape now).



I pump it up again and close the shutoff valve at the boiler input, and here is my pressure reading:


I set my timer to check on it later, and after 30 min, no detectable leaks anywhere.   The pressure went down a couple of pounds, but there was NO water anywhere.  No weeping at any joint or seam – the thing was bone dry.

I repeated the test – pressure up to just over 60lbs, wait 30 min, and again, no water anywhere, but the pressure had dropped from, say, 65lbs to 62lbs.

I’m wondering if this could just be my cheap cut-off valve leaking a little?  Or if I need to do a better investigation for a leak?

Like I said, I can’t find ANY moisture anywhere on the boiler.  I dried it off really well after filling (and fixing the thread leaks) and it just is bone dry, which is what makes me think it is sneaking back past the shutoff valve.  But you guys with more experience, is this acceptable?  Or do I need to do more sleuthing?

I’m still quite happy with the results!

Thanks,
Kim

[crueby]

Excellent test. Not uncommon for the metal to stretch a little bit, coupe of pressure up and down cycles and it should stop. Possible that there was just a little air at the top that bled out. Try trurning it on it side if you can, or at least tip the whole tray. Nice!

[Kim]

Thanks Chris!

I ran one more test last night while I was watching TV with my wife.

I pressured up the boiler to a tad over 60 lbs (maybe 65? - hard to tell since there are no marks above 60).  And checked on it about 2 hours later.   It had only lost about 1 lb.  so I'm saying that is pretty good! 
I'll call the hydro-testing phase complete and will move on with the build.

Thanks,
Kim

[steamboatmodel]

Hi Kim,
Your rig looks good, but there is one thing you should improve. When working with pressure gauges the middle third of the gauge scale is where you want your readings to fall. For the gauge you are using this would be between 20 and 40 psig.
Gerald.

[Kim]

Thanks Gerald,

Well, in practice it should be running around 30 lbs, which would be right in the center of the gauge.  maybe I should have gotten a bigger gauge for my testing.  I was hoping that I could get by with one, but maybe that was a silly place to economize.  Would you generally suggest a separate gauge to use for testing? One with twice the range of the one you intend to use in practice?

Thanks for the advice.  As you can likely tell, I'm quite the novice at this!
Kim

[Don1966]

Just catching up on your bulit log Kim I been falling behind lately. Very nice work and looks like your silver soldering Skills are really looking great. Test results on your boiler looks great and I agree with Gerald on the gauge. Very nice work all around Kim even with the mishaps which are common to all of us.
 


 
Don

[Kim]

Thanks Don!
Nice to know you're still following my slow progress
Kim

[steamboatmodel]

Thanks Gerald,

Well, in practice it should be running around 30 lbs, which would be right in the center of the gauge.  maybe I should have gotten a bigger gauge for my testing.  I was hoping that I could get by with one, but maybe that was a silly place to economize.  Would you generally suggest a separate gauge to use for testing? One with twice the range of the one you intend to use in practice?

Thanks for the advice.  As you can likely tell, I'm quite the novice at this!
Kim

Yes defiantly a separate gauge for testing. I usually try to find one with as large a dial as possible,  and with the max test pressure anticipated in the centre of the scale. Worked at a Hydraulic service shop once and there test pump had five different gauges from 180 to 6000psi, they would not let me test my boilers with it though as it was filled with oil.
Gerald.

[Kim]

Thanks Gerald,
I do appreciate the input!
Kim

[Kim]

Now, to mount the boiler in the boiler casing!

But wait…  it doesn’t fit
 

The water pipes hit the boiler casing about 1 1/2" too soon!


Duh… of course, I should have checked this before the boiler testing and probably even before soldering it up. Ah well, you live, you learn.

So, I annealed the copper with the torch, trying to be careful around the joints – hoping to leave those alone, but soften the tubes and the boiler right around where the tubes join.  Then I use a hammer and a piece of aluminum as a soft punch, to help decrease the diameter of the boiler right around where the tubes go in.


And there you go, now it fits!


But, since I got it all hot and banged it around, it seemed prudent to repeat the hydro test on the boiler.

The test seems to be going well, once I got the fittings not to leak again!

While the boiler test is going on, I made the Firebox Backsheet. This will hold the boiler in place from the cab side.
Here I’m drilling 1/2" holes for the bushings on the back of the boiler.


And the completed Firebox Backsheet.


When I’m happy with the boiler hydro test, we’ll get back to mounting the boiler!

Thanks for stopping by,
Kim

[Dave Otto]

Looks good Kim!


Dave

[b.lindsey]

Very nice save Kim. That would have been a bummer to have to do it all again.

Bill