We're trying to get the throttle removed from our 2-8-2T, Coos Bay Lumber #11. We need to get all the crud cleaned off the inside of the boiler to evaluate it for possible restoration. Right now, I'm the only guy in our group who can squeeze by the throttle to get inside the boiler. And, I really don't want to to all the cleaning myself!

The problem is scale. There is a heavy coating of scale on the "j-bolts" that hold the throttle to the dry pipe. Even though, with a lot of effort, I've been able to back off the nuts that hold the bolts in place, the bolts won't move because of all the crud that has built up between the bolts and the "ears" on the throttle body that the bolts pass through.

I've tried heating with a rose bud torch, hitting the end of the bolt with a small sledge hammer and an air chisel. Any further suggestions? My next try will be going at the end of the bolt with a rivet gun, but just how physical can I get, without risking cracking the throttle body casting?

As a last resort, I can cut the bolts. But, I'll still have to get the remaining parts of the bolts out of the throttle. I guess I could soak in in HCl for a while.

Thanks for any suggestions.

Jim Baker, PSRM

Got pictures? That may help with ideas.

Here's a couple of pictures. I've gone over the area with a needle gun since these were taken, so the scale now isn't quite as bad. In one picture, A and B are nuts. I cut off A with a cutting wheel, and have been able to back off B several turns. D is the "ear" on the throttle body. The area from C back through the ear to where B is is so full of scale that I haven't been able to loosen the bolt.

In the other picture, D is the throttle body, E is the joint between the throttle and the dry pipe. According to the ALCO blueprint for this engine, there should be a ring with a hexagonal cross-section that actually forms the seal between the throttle and the dry pipe. F is a collar that is welded onto the dry pipe. G is the dry pipe. H is the j-bolt that hooks over the collar to hold the throttle to the dry pipe. And K is the same place as C in the first photo.

There are two of these bolts, in the same condition, located at 9 o'clock and 3 o'clock around the dry pipe.

Jim

How about a nut splitter? If your nuts are 3/4" or less across the flats, a manual nut splitter (McMaster-Carr 3742A11) might work.

Bigger ones (hydraulic) are also available from McMaster, but are about ten times more expensive.

If you start hitting the scale with a sharp cold chisel, will it pop off?

Acid cleaning with HCl should remove the scale. But if you use acid cleaning be sure you use an inhibitor like Rodine 214. It will protect the steel from acid attack. The acid will need to be heated to maybe 140 degrees F. A solution of 5% to 10% will be all that is needed. This process may take several hours. Depending on what the scale is, you may release some nasty gasses, so becareful. The entire boiler should not be acid cleaned. On a riveted boiler, scale helps seal the joints and rivets. If the scale is cleaned out of the crevices, there may be leakage problems. Also, it is hard to flush and neutralize these small cracks.

I managed to cut off the outside nuts (A) with a small cutting wheel. They are 2" nuts, and there wasn't enough clearance to get a nut splitter between the nut and the throttle body. So, now the second nut, (B) is backed off several turns.

I can knock the scale off ok on the outside of everything. The problem is at (C). There is scale between the bolt (square in this area) and the "ears" (D) that the bolt has to slide through.

Thanks for your suggestions, though.

Jim

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I have also used small rotary tools like Dremel or air grinder with small cut off disc or carbide cutter/endmill bit to eat away deposits so that a decent socket or wrench can be put on the nut and bolt. This is only slightly faster than the sharp chisel and punch scratch method.

I personally would not recommend the acid, while it should work, it exposes you to a potentially unsafe confined space work environment where you have no rapid egress if things go bad. I second Kelly's suggestion, new bolts are a whole lot cheaper than new castings.

Mike Tillger

Jim Baker, myself and a few others have been trying to get that throttle out for a while now.

We just had a rather serendipitous event - a sharp-eyed former RR guy found the Alco blueprints to the Coos Bay #11. He had enough sense of preservation to look up the engine's history and found the engine at our museum - Pacific Southwest Railway Museum and sent the large pile of prints to Jim. !!

http://www.psrm.org

Here's the engine :

http://www.psrm.org/roster/steam/s-11/index.html

I'm one of the guys who can't quite make it into the boiler. Can get in up to my breastbone, but no farther. So that throttle has got to come out so others can share in the joy :) of needle gunning the boiler.


Kelly - that does seem to be the simplest and most expedient way right now. We now have the blueprints to those j-bolts and the whole throttle assembly, so making them shouldn't be a problem (would need to find out what material/heat treating needed/etc), plus that's a loooong way off.

Another concern, after we cut those bolts, how much the crud/scale is holding the throttle to the dry pipe ? I'm assuming the joint is a press fit, maybe with some kind of gasket/ferrule between the 2 pieces ? Think we'll have to look at the prints and see what else we will be dealing with. Also make sure the dry pipe is supported adequately. Think we'll have to get the engine moved underneath our big crane to support/lift the throttle as it comes out.

Thanks for everyone's advice/suggestion so far !!

Mike Lucek

Mike: According to the blueprints, there is a ring "gasket" between the throttle and dry pipe. It has a hexagonal cross section. The ends of the dry pipe and throttle are beveled to accept the ring. And, the engine is already under the crane.

Of course the best solution is for you and a few other guys to lose about 20 lbs each, then we won't have to remove the throttle!

I'll add my thanks to Kelly and the others for all their suggestions. We'll let you know how things turn out, probably in about a month.

Jim Baker, Steam Foreman, PSRM

Where do you get HCL?

Hardware stores should have it. Look for it under the name "muriatic acid". (*EDIT* it's used for cleaning concrete)

Swimming pool supply store, sold as Muriatic acid.

Jeff