So we are replacing a few top or radial staybolts. Apparently, this is the best method we could come up with to support the drill.

What do you do? Any better suggestions?

physically holding that drill can be rough especially if it cogs up it'll wrap you around.

.

We used oxygen rods. You use a 12 volt battery to energize them. It is just like stick welding.

I have no previous boiler (and torch cutting) experience, so I am not much help. The use of the drill seems decided by, "that is the way we do it". As shown in other posts, we using a cutting torch on the steel bolt in copper firebox, but we only drill the bolt on the steel boiler shell.

I think the other problem is we only have one really skilled professional welder. I do not know personally what his certification level is (pressure vessel?), and I do know we are prohibited from welding on this particular boiler. Or, maybe if we had a certified welder and a plan we could weld, but it would require inspections, etc.

We have a number of guys (some in the pictures) who are pretty good with a torch and do things like repair cast iron, etc. all the time. But they seem cautious about taking the torch to the steel boiler shell.

So, it might really be a matter of lack of experience and fear of making a mistake. Sometimes my information is not as complete as it could be, because not everyone in the shop is strong in English.

How does one practice cutting a bolt out, before working on the real boiler?

Cutting isn't welding... and you're not taking the torch to the boiler, but rather the bolt, which is scrap anyway. You have to just be VERY careful to control your heat, so the sheet stays cool enough that it won't burn, because you don't want to nick the sheet. But the guys at the local muffler shop know that you can skin one piece of steel off another with a torch, if you are careful with your heat.

"How does one practice cutting a bolt out, before working on the real boiler?

You thread a bunch of holes in a piece of scrap, screw in stubs of bolts, and stand at a vice and practice piercing through the center of the bolt without nicking the sheet.

.

Thanks. This summer I will get some practice in and then wow-em next winter as I cut those staybolts out! Yankee ingenuity!

I took a course in welding, did some car work, not on any locomotives. The biggest advice from my professor...be patient. slipshodding won't work. Cutting you heat up your object to cut then you hit the oxygen valve which highly accelerates the burning and heat, localizes the heat where you want it.

Welding is technically fluidizing the metal where 2 pieces meet and intermixing the metals together...think water to ice, except your using high heat, adding more fluid metal as needed to make the weld.

Differrent techniques of welding may work better than others, gas welding works good on small parts but large pieces like boilers will drive the heat away where you are trying to heat up to make a puddle to weld with.A hot torch is key to this, why arc welding may be better on large pieces. The point is heating the metal where you want to make that puddle to weld to and join your pieces fast. Soldering isnt that far off from welding but you are not melting 2 pieces together than making one metal stick to another.

Perhaps some more discussion is in order. Let me preface it by saying that it's been years since I've done anything useful with a cutting torch...

The novice view of cutting (and welding, for that matter) is the worker brings the instrument close to the work, there is a flash and a shower of sparks, and magic happens. One can't hope to develop the skill unless one is able to look into that shower of sparks and see what is going on... then begin to learn what one should be seeing, and finally develop the skill to make what one wants to see happen.

It's easiest to cut starting from the edge of the work. The corner heats fast, comes up to pre-heat temperature... you press the lever to start the stream of oxygen flowing, and you can watch a bright yellow line develop as the oxygen not only consumes the steel, but also drags the adjacent molten steel into the stream and blows it away. Start learning to cut with some heavy scrap plate... set it hanging off the edge of a steel bench at a comfortable height, and just cut one inch slices off it. You'll learn to see the cut, to make it move where you want it to go, that moving too slowly lets the cut go out as all the steel in range of the oxygen stream is consumed, and how moving to fast over-runs the ability of the torch to blow through, and you end up with a face full of slag. The most important thing you will learn is what steel looks like when it's too cold to burn. That's how you keep from damaging things you don't want to damage.

Then practice piercing. Piercing sucks. When the oxygen stream starts burning the steel, there is no place for it to blow the slag, so it blows it up the sides of the bowl shape it's excavating, and back in your face. It also tends to blow slag back into the pre-heat holes in the torch tip - keep your tip cleaner handy, you'll need it.

Piercing plate, you can angle the torch somewhat to blow the slag to the side until you burn through, but this won't work with burning out bolts or rivets, since you are trying to not burn the adjacent plates. As Kelly mentioned above, you just have to grit your teeth and pierce almost straight down until the well you are excavating in the end of the bolt is deeper than the thickness of the plate, then you can angle the torch so it blows out the side of the bolt past the plate. After that, it's more or less like cutting plate... watch where the cut is going, and keep it away from the threads.

Good luck.

All pretty good advice for anybody really. I am always nervous of causing more work when I am piercing a bolt/rivet. I do not do that much torching on a regular basis so the my concerns are warranted. Kelly's suggestion of drilling a pilot hole works for me when I am concerned. In removing frame bolts which are tapered and usually froze in place permanently I like to drill a hole and then cut from the edge of the predrilled hole. This is different as the depth of the burning is more than angling a cut on staybolt. It is the reason I absolutely hate removing saddle bolts. It is so hard to concentrate on not damaging things when your getting burned all over. The bigger pieces of molten steel turns in to BBs that roll under your knees, down your shirt and into your stomach folds. No matter the protective gear you wearing it will get behind it! The trouble with the pilot hole way of doing it is the time it takes to drill the hole. A boiler maker or mechanic who is adept with a torch will just go at it and make it look easier than it is. When replacing big pieces of firebox you can nip some of the excess staybolt out of the way making the piercing easier, but removing a single in place bolt is much trickier unless you do a lot of this kind of work on a regular basis. Dennis nailed it, "piercing sucks". 1/2" depth cut is short and sweet on a bench. It is a skill developed with time and experience. Doing it more than once or twice every 20 years helps too. Being in practice is often a big help. Good luck and smooth sailing. John.

I would think that a drill with a magnetic base might be very handy too?

Radial stays are installed into curved plate and not at right angles to the tangent of the outside curve. Setting up a mag base drill with some form of beveled platform, perhaps......

edited once for clarity

I probably worry to much about nicking the threads when cutting out old stays. The few jobs I was involved with, the holes were reduced for small stays either by bushing the hole down and re-tapping or welding the hole shut and re-drill and tap. Often the idea is to replace stays back down to smaller diameter anyway. Nicking the old hole wouldn't be a total end of the world thing. This would probably apply to a different scenario than the OP replacing only a few radial stays in a foreign land? I think as old stays are removed the hole is opened up to the next size up so new threads are being used. Hence eventually having to reduce the size back down? Just trying to learn here and see if my thoughts are way off base or not.

If the holes / threads wear out, it was common to ream and tap to the next size diameter, which is fine up to a point. I don't think I have seen a stay larger than .125" more than its sisters, so that could have been the largest allowable before welding and reaming and tapping the hole back for the original size. Of course, we can and do weld stays in today with great success and robustness.