Boiler woes

Dennis Kunkle

During a routine P/M, the round plates on either end of the Burnham cast iron boiler were removed for replacement. Trails of minerals were hanging down from them. The one end it went by the book. On the other end, 2 bolts snapped off. The one drilled out and tapped normally. On the other one, the drill snapped off in the hole. And to make matters worse, the machined surface for the plate is severely pitted in this area. The tech, just to see, reassembled everything with the new plate and gasket. Well, steam was getting by and it was shut down. This is a 20 year old boiler (I remember when it went in!). So, to put on a new cast iron end section is expen$ive. Massive dismantling, welding, etc. A new one, of course, is even more. Any other options? (It runs 24/7 for heat in winter and reheat in summer)

STEVEusaPA

Dennis Kunkle said:

...So, to put on a new cast iron end section is expen$ive. Massive dismantling, welding, etc. A new one, of course, is even more. Any other options?

Are you the contractor or the homeowner? If you're the h/o, why is this your problem? If the contractor said, or had you sign off on something like "I'm going to try to drill this out...if I damage it the cost to replace will be..." then you're on the hook. Otherwise, it's up to them to fix/replace.
Proper drill bits, cutting oil, proper method, taking your time, the drill bit shouldn't snapped off. Maybe he can go in with a smaller bit, next to the bit. After that gets through, bigger and bigger to get the bit out. If the threads cant be fixed, maybe a little bigger and tap for a bigger bolt.
Maybe I'm lucky in 25+ years I've always used the best bits, and never snapped one (Oh Karma, don't get me on the next one )
But seriously, if I ended up in your exact situation, I as the contractor, would make it right.

Dennis Kunkle

I'm the Director of Facilities at the museum where this boiler is located. I am a hands-on director, though. Change filters and belts, replace steam traps, etc. My volunteer (retired engineer) was a little more forgiving than you, "It can happen". The service manager is checking it out tomorrow. I'll get his take. I do appreciate your insight!

GreenGene

Sounds like a commercial boiler, many times getting a section is better, be forewarned and double check, I have had new Burnham sections NOT FIT older boilers, these were push nipple sections with 3 nipples, one of the three would be off by a fraction so you end up not being able to use the back section and have to get a new one.

They claimed some of the old machining was off but now it's perfect and that's why, either way it was not good to find this out after pricing the job and getting 1/2 way into it.

Anyone else seen this? Any more info?

Sailah

Weld a nut to what's left of the bolt/bit and try backing it out. I do this all the time on bolts that break below the surface. Just lay a nut on top and fill in with a weld puddle. I prefer TIG but MIG can work. The heat will also help break the rust.

If you now have a broken hardened drill bit, redrill with a carbide bit, tap for helicoil/timesert. You might need a carbide burr to get a center in the drill bit. Don't try without a center or the bit will walk off center and be fragged.

If it were me, I'd try to rig a mag drill to drill straight, if not I'd be setting up 90 degree guides to ensure I was going in there straight. If the bolt is still there use a **** punch to get a good center. Light rap, check it, another rap check it. You can correct a bad punch by angling the punch in the direction you want to go and "massage" it with a series of angled hits to correct it back to center. Once you are sure it's centered, give it one good hard rap. Now drill with a center drill to get a starter hole. Switch to a shorty drill 1/2 the size of finished hole. Finish with tap drill size. Retap or insert helicoil. Use cutting fluid for the drilling operation, no cutting fluid for cast iron.

As far as the pitted surface I'd use Loctite Metal Master 98853 (http://www.mcmaster.com/#7489a26/=12qj39x) repair stick. Feather it over the pitted area. "Machine" the surface by wrapping sandpaper over a dead flat bar and sanding it to the same height as the surrounding machined area.

Reinstall plate.

That's what I would try before I bought a new boiler.

FranklinD

I'd go with Sailah's recommendations to start with. I can't say I've done it on boilers, but I deal with broken nuts and bolts and broken drill bits in my field all the time.

I'll second the carbide burr to get a good starting center on the broken bit. And the MIG welding a nut on has saved my bacon from much more labor many times...sometimes it takes a few tries but when it grabs, it's like magic.

A magnetic-base drill is also amazingly helpful. I don't own one but our shop does, and oh my lord does it make life easier for stuff like this.

Best of luck!

Paul48

Yes...What Sailah said......Broken bolts require a BIG bag of tricks.

Dennis Kunkle

The latest on this situation is that the service manager and the original technician are going to "get that bolt/drill out". Since there was a can of WD-40 left behind and a broken 1/8" drill bit on the floor the colors of the rainbow, it doesn't look like the most professional job..

Sailah

Ask them if they know what Kroil is. If not I'd be nervous that their attempted fixes are potentially worse than what you have currently.

Can you post a pic of the problem area?

Dennis Kunkle

You can see the black round plate on the boiler here:
http://www.burnhamcommercial.com/products/atmospheric/5b/index.php

Paul48

Is the broken bolt visible on the inside? If so, heating it slightly, will pull penetrating oil in. The same way solder goes to heat. Be careful...don't burn the joint down. Kroil (the oil that creeps), or PB Baster are good.