ARCO Ideal Round Water Boiler (1920’s)

Those two tapping were probably for an external tankless heater for DHW.

I'd use bolts and washers. I wouldn't want to try to thread anything into those due to cracking risk.

Then close nipples and caps might be a better look.

Back in the day that your boiler was operating, a piece of galvanized pipe went thru those openings. The water jacket or coil or heat exchanger of some type that hovered over the coal fire was connected to those pipes. At some point in the life of that heater, the DHW HX was removed and the openings were covered with asbestos cement. Thus was to match the asbestos cement that insulated the rest of the boiler's exterior as seen in Art Taylor's photo.

Since no one sells Asbestos insulating cement for this purpose any more, I would say that you can just use furnace cement to do that job. If you are actually going to try to commission this with a real fire at some point, you may want to try to find some way to insulate the boiler as shown in Art's photo. If I were going to do that as a museum project, I might start with sections of semi rigid fiberglass (like duct board) and carve some ridges in the fiberglass to allow it to conform to the curves of the boiler as needed. Once the boiler is covered with the fiberglass I would wrap the fiberglass with chicken wire in order to hold a coating of a plaster sub base. Something like a Structo-lite brand of plaster wall base coat. You may need to get someone that can sculpt the coating of plaster to conform to all the ridges, peaks and valleys of the boiler This was an artform in itself back in the days of boiler builders and steamfitters of the 1800’s and early 1900’s If you want to take the time to learn that skill, it would be a nice touch.

With the furnace cement in the holes, the fiberglass and plaster coating, those openings will not be of any consequence when it comes time to fire that boiler.

From what I remember of those boilers, that coating of asbestos insulation was about 1½” to 2” thick. So to get the look as realistic as possible I would start with 1” duct board for the base of the insulation and use Structo-lite as a glue to hold the pieces of insulation in place. As soon as you get a section completed I would wrap a 12” wide section of chicken wire around the boiler to hole the fiberglass in place. Continue to add insulation and chicken wire as you go up to the top barrel of the boiler . Custom pieces of fiberglass can be cut to form the base of the insulation on the boiler, with the chicken wire acting as the outer strap to hold the fiberglass, and as the support for the last outer coat of the plaster. I have had great success with Structo-lite when securing vent connectors of boilers to the chimney base. There is very little shrinking and cracking of the Structo-lite after it cures. It also dries very fast, usually within 20 minutes of initial mixing, allowing for multiple coats to be applied in the same day.

Once you get it close to the form you want, it can be sanded , and any high spots can be reduced to a very smooth finish. Since it is used for plaster walls, it will accept white wall paint for a professional look. That is one ides that I would try if I were in your shoes.

ArthurTaylor said:

This boiler is heating the home today and was installed the year her grandparents got married and built the house. 1923

This car was also built in 1923. I wonder if her grandparents owned one back in the day?

Those sound like standard 4" push nipples. I would order them from Utica. Thru a local supply house that sells utica boilers

Let me make some inquiries. Probably won't here from my source until Monday or Tuesday

Are you going to wrap it with insulation? That will make it look original for sure. I just thoight of another insulation trick. After you chicken wire fiberglass insulation in place you can mix some Struct o lite with some vermiculite to make an insulating filler for any of the larger voids you may have between the fiberglass pieces that will do the bulk of the work. After you have the thing looking like a snowman, then you place the last coat of Struct o lite with no vermiculite on about 3/8" thick, after that drys you ca nskim coat with drywall compound to make the smooth finish the boiler installers of the 1800s and early 1900s would do. They were real artists. A coat of whitewash as a sealer to keep the dust from flying around every time you bump covering. Nice job with what you have done so far.

Not vermiculite it contains asbestos or used to.

I can remember taking those boilers out those horizontal sections were something else.

Cut the ty rods drive some wedges in to get the sections up and tip them onto the floor hoping they fell the right way. Put some pallets or something on the floor like and old mattress for them to land on so you wouldn't bust up the floor. Rubber tire didn't work too well they would bounce off. Roll them like a car tire over to the stairs and haul them out. Bust up the bottom section with sledgehammers nasty job.

Must have been fun picking those sections up to assemble the boiler. Most basements the ceilings were too low to use a chain hoist

i think i've seen pictures f houses being built with the boiler in the basement before the floor was built.

i'm not so sure people are concerned about asbestos contaminating vermiculite used in gardening. i think it is one of those things that they just stopped talking about and it never got addressed. like the asbestos wiring in most light fixtures from before the early 70's or so and heating appliances with asbestos wiring. or friction materials that it isn't clear even today if some formulations contain asbestos.

i thin structo lite comes with vermiculite aggregate.