Gas engine restorer learns to cast with a 1909 4 hp Baker Monitor.
Manufacturer: Baker Mfg. Co., Evansville, WI
Serial Number: 3742
Horsepower: 4 hp @ 400rpm
Bore & stroke: 5in x 7in
Flywheel dia: 28in x 2-1/2in
Cooling Capacity: 7-1/2 gallon
Ignition: Jump spark
I’ve restored many engines over the last 12 years, so when I bought a 4 hp Monitor that was missing a water hopper and muffler, I knew it was going to be difficult, but I wanted a new challenge. You know the saying, “Be careful what you wish for, because you just might get it”? I truly understand that saying now!
The 4 hp Monitor is a relatively scarce engine, so I knew that parts for this engine would be hard to find. However, I already had a 4 hp Monitor in my collection that I would be able to use to make duplicate parts. It was time for me to take on a new skill – sand casting!
Sand casting is a process of making parts by duplicating the original parts, using sand as the mold to form the liquid metal. I had heard of sand casting, but had never done it. But I knew if I learned how to sand cast, I could make parts for this engine as well as others as long as I had an original part to copy. Parts are difficult to obtain for 100-plus-year-old engines, so I knew this skill could come in handy in the future!
I decided to learn this new skill working from library books, and I also purchased two books from ads in the back of Gas Engine Magazine (Metal Casting: A Sand Casting Manual for the Small Foundry, Volume 1 and 2). The books were great for reference, but YouTube videos were what really taught me the process! Videos give you almost hands on education, and I’m a visual learner. If school were as good as YouTube, I would have gone to college!
To get ready to sand cast, I had to find a furnace, a crucible, make the frames (called flasks), and make “green sand,” which is a fine sand mixed with clay. And, most importantly, safety gear. What I didn’t know was how labor-intensive it would be, from getting the moisture content in the sand correct to pulverizing the sand after sand casting: I wish I had been more organized before I started.
My first couple attempts at making the muffler failed. When I opened the frame and pulled out the muffler, a portion of the muffler wasn’t forming to the mold – there was a big hole. “Why?” I asked myself, and I’d try again. The problem was that the molten metal traveled through the narrow passageways in the sand and cooled too quickly; it hardened before it reached the other side of the mold. I was doing this outside and the air temperature was still below freezing at night, so I brought the cold sand from the unheated shop into the warm house for the next pour. That did the trick. Finally, I cast my first engine part!
The next challenge was how to make the water hopper. Close inspection of the original hopper showed a seam in the middle, so it appeared to be made in two pieces (top and bottom) and welded together. I didn’t want to cut the original hopper in half, so I made a plaster mold from the original. I copied one half at a time by packing green sand so I would have the outside shape to lay the plaster bandages in. Then I would have a plaster water hopper that was in two pieces to use as a form to put in the frame, and put the green sand in to create a mold that I would use to pour the molten aluminum in. I had a plan, and I was excited to get started.
Now that I had a sand mold of the outside of the hopper, I needed to make plaster bandages. I got the idea thinking about when I broke my arm at the age of 12 and got a cast made of plaster bandages. Before working with Plaster of Paris, I coated my hands and tools with petroleum jelly for easy cleanup. I chose burlap as the fabric for the bandages, and cut it into strips and dunked the strips into wet plaster. Then I laid the strips in the sand mold before the plaster set up. I followed the advice from a YouTube video that recommended adding about 20 percent joint lapping compound to the plaster to slow setup time, otherwise the plaster sets up within minutes.
Success! Finally, the new hopper was born. Both top and bottom were poured with the help of two good friends, Dennis Jensen and Jim Allen. I needed extra hands because the crucible was filled with a gallon of molten aluminum (about 1,300 degrees F), and it was not safe to hold the heavy crucible with one hand and pour with the other. After pouring the aluminum into the mold, we let it cool for about 30 minutes before eagerly digging it out to see if it was complete. We successfully cast it on the first attempt!
I was thrilled to see the complete hopper! This was a grand finale to my “labor of love.” All of the prep work, finishing the molds nice and smooth to ensure a perfect finish on the hopper and making more green sand (about 30 gallons total) had all been worth it. Digging the new hopper out of the sand that day, I was as proud as a new father (without having diapers to change)! I decided to name her “Beautiful.”
The Monitor’s first show was at Edgewater Haven nursing home in Port Edwards, Wisconsin. I drove there in my 1931 Ford Model A, with Beautiful bolted in a small trailer I was towing. I had the front screw jack in place, but needed a jack stand for the back of the trailer. Every time the engine fired, the back of the car bounced up and down. As I ran the engine, I received one of the funniest comments, made by a sweet, gray-haired, little old lady: “You know, sonny, if that thing (the running Monitor) was not hooked up to that car, I’d say that there was some funny business going on in that car!” My friend Joe Terry and I almost fell over laughing!
The feeling of accomplishment and pride in making parts for this 4 hp Monitor is second to none. While I know there may have been easier ways to do this project, this is what worked for me. I hope I have inspired you to try to make your own parts. Good luck!
If you enjoyed this article and wish to see the many challenges and videos I had with this project, you can find me on www.SmokStak.com; my handle is “B Kedrowski.” Watch the running engine at http://bit.ly/baker-monitor