Category: Hacks

Electric Steam Boiler – Base

Wherein we are reminded why dead trees suck.

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I’ve often said here on this blog that I am not a woodworker. I don’t particularly enjoy it, largely because the associated tools are all extremely noisy, make incredible messes, and are frequently terrifying. Machine tools, by comparison, are stately and civilized things. Don’t get me wrong, a lathe or mill will happily pulverize your meat into meatloaf if you stop paying attention, but they are not the subject of nightmares and horror films the way table saws are, and I have never seen a human contraption that can make the kind of mess that a router does. The splash-damage range of the dust is measured in meters, because all other units are too small.

All that said, wood is just the thing in many situations. One of those situations is the base for a model steam engine or boiler. Properly finished, a wooden base is an attractive compliment to all the machined metal, and copes well with the potential onslaught of water. My electric steam boiler is at the point where it needs a base. All the major components are coming together, and they need somewhere to live.

Allow me a quick sidebar on sequencing. Normally here on Blondihacks, I work hard to create an interesting narrative from these projects. That’s usually possible, because I build them start to finish and then move on to the next thing. The electric steam boiler project has been so complex, however, that I’ve had multiple tracks of work running in parallel. One track was constantly getting stuck while I waited for parts or needed to figure out a problem, so I would work on something else in the meantime. While building the base is the next logical thing to show in this series of articles, I can’t avoid showing you pictures of the progress without spoiling some future parts. Consider it a behind-the-scenes sneak peak of upcoming posts in this series. Of course, if you follow me on Instagram or Twitter, you’ve already seen some of this stuff, although without context (which I hope keeps some of the surprise alive). Okay, here we go. Spoilers or not, the blog must go on.

 

I started by laying out the base on butcher paper. I needed to get a sense of all the parts that need to fit here, so I mocked up the electrical box on one end with gaffer tape and cardboard, and laid out an electrical conduit needed on the other end. I opted for a one inch border around everything, which felt pleasing.

 

Seeing as how no part of me is a woodworker, I don’t have much good material on my junk pile for this sort of thing. I called a lumber supplier and tried to order some rectangular cellulose bar stock, and they acted like I was crazy. I dunno, what do woodworkers call this stuff? Planchettes? Tree slices? Anyhoo, for nice bases for my steam engines, I usually go to my local woodworking shop, which has a nice off-cuts bin. There’s usually treasure in there, in the form of convenient loins of mahogany, cherry, or other attractive butcher’s cuts of dead trees. No such luck this time- the bin was pretty much empty.

I thought about buying a few board-feet of something nice, but the width I needed meant that no single board would do. I don’t have a jointer or a planer, so gluing up a slab from smaller pieces was mostly a non-starter. I decided to try high-quality plywood instead. They had really nice small pieces of birch, so I grabbed one of those. I hoped that with the right stain and finish, I could make it look like the nice hardwood base I was going for.

With the size determined, I cut the plywood down to size with a circular saw and straight edge. Speaking of nightmare tools, circular saws are high on the list of things that I’m convinced are going to put me in the hospital some day. They sure are versatile though, and it saves me owning a floor-space-eating table saw for the minimal woodworking that I do.

 

With the base dimensions established, I laid out the components. I took plenty of time doing this, because I only got one shot at it, and the finished look depends on getting this right. Pretend you don’t see the brass electrical box that is already partially finished on the end there.

 

With the major components arranged the way I wanted, I traced the outlines of all the parts so that I could recreate this layout later. I needed everything “fully assembled” to establish the relationships, because (for example) the end of the boiler fits inside the electrical box in a very specific way with little margin for error. However, I needed everything unassembled to mark mounting holes. Tracing outlines is how I reconciled these competing objectives.

 

Note the traced outlines of the base and electrical box.

 

The next logical step was to establish the mounting holes for everything. For the main boiler, this was easy to do, because it has a removable brass base plate with holes in it. This brass plate ties the legs together for stability, and also serves as a heat shield for the wooden base. I decided to use the same screws that mount the legs to this brass plate, and simply run them all the way through the wooden base as well. I lined up the naked brass plate with my traced outlines, and used a transfer punch to mark the holes. These were then drilled through on the drill press, using a backer of scrap wood to prevent tear-out (which plywood loves to do when drilled).

The electrical box was an interesting problem. The mounting points are brass blocks silver-soldered to the inside of the shell, and there’s no way to get a marking pen or transfer punch in there. The box is not exactly square because of my limited sheet metal skills, so measuring wouldn’t work well either. Luckily, there’s a specialty tool that I love which is perfect for this situation- transfer screws.

A transfer screw is a screw which has a point on the end instead of a head. Just behind that point is a hex profile which can be grabbed with a special tool. The screws are hardened like a punch, so you can hammer on them. All you do is thread the correctly-sized transfer screw into the hole you want to transfer, line up the object, and tap it to mark the locations. Since there are no heads on the screws, you then need the special tool to fish them back out of the hole. They are a marvelous tool, and I learned about them from years of watching Mr. Pete on YouTube. His channel will teach you more about shop practices than just about anything else, so go watch! While you’re over there, tell his viewers to come and subscribe to the Blondihacks channel too.

 

If you look closely at this photo, you can see the transfer screws inserted into the electrical box’s mounting holes. The special tool shown is used to insert and remove them. It also stores the screws in its handle.

 

With the transfer screws inserted, I just had to line up the electrical box with the outline I traced earlier, then press down on it. I’m marking holes in wood here, so no hammering is required.

After all the mounting holes were drilled, I also countersunk them with a larger drill bit so the cap screws would be flush with the bottom.

 

As you can see, the drilled and countersunk holes ended up in the perfect spots, thanks to transfer screws. The cap screws are installed in this photo, though they are difficult to see.

 

With the basics accomplished, I couldn’t help myself – I needed to get a little fancy. I didn’t love the way the brass plate on the boiler sat on top of the wood. I felt it needed to be inlaid so the top was flush. Time to bust out my least favorite power tool- the router. I am not skilled with this thing, and it has a unique ability to make a colossal mess, no matter what dust remediation methods I try. It is, however, the right tool for this job, so we shall press on. Press On.¬†How about that power switch pun I just made? Did you appreciate it? Good.

The outline that I had traced for aligning the holes was also conveniently the exact area I needed to recess. I used a clamped straight edge with the router to get the edges crisp, though I did still manage to make a couple of mistakes. Routers are difficult beasts to control. This process is tedious because you have to get the distance between the straight edge and the edge of the router bit just right such that it ends up cutting right up to your line, and remains parallel the whole way down. This setup needs to be repeated for each side of the rectangle, and if your desired depth is enough that multiple passes are required, you may have to repeat all this setup work. A router table would be the perfect tool for this, but the tedious-setup method gets the job done.

 

I started by routing the outside edge to the correct depth, which took a couple of passes. I then routed the center area free-hand, making sure it was as deep or deeper than the outside edge where the brass plate would sit. The corners were squared up with a chisel.

 

I made a bit of a mess of the center area because of a rookie router mistake. The recessed area is larger than the base plate of the router, so I lost the ability to control depth in the middle. What I should have done was left an island in the middle to support the router, and done everything around it. Then the island could be removed with a chisel. Luckily, it doesn’t matter that the middle is a mess, because the brass plate covers it.

 

Despite my best attempts at setting the depth on the router accurately, I didn’t quite get it deep enough, and the brass was still 1/16″ proud of the surface. I knew this would drive me nuts, so I set it all up again and repeated the whole routing process, a little deeper this time.

 

That’s better! If you look closely, there are mistakes, but I’m pretty pleased with how it turned out.

 

I also brought out a decorative ball-bearing bit and did a filet on the edges. This fancy look is a bit of an odd thing to do to plywood, since you can really see that it’s plywood around the decorative edge, but I hoped it would look nice after staining.

The next task was to handle the wiring at the far end. By necessity, the thermoswitch is in the opposite boiler head from the heating element, where all the electrical stuff is. That means we need to get those wires from one end of the boiler to the other. I want to hide the wires, so I decided to run them inside a copper pipe, then through a channel under the base. I carefully lined up this pipe, and marked the location on the base for drilling. The pipe is a press-fit in the wood, so I drilled it slightly undersize and opened it up to fit perfectly, using a round file.

 

It was easiest to position the pipe where I wanted it, trace the outline, then use a pair of dividers to find the center of the circle from the outline.

 

There’s a tricky order-of-operations to make this all work. The vertical pipe slides in from above, further than needed, then the wires are fed through the elbow and down the pipe, then the pipe is slid back up into the elbow. It took some gray matter to figure out how to make this happen such that it was all still removable for servicing!

 

Here’s the final wiring cover. The brass knob provides access to the adjustment screw on the thermoswitch.

 

You might have noticed that I completely glossed over a pretty interesting part there- what’s that whole deal with the copper elbow and the fancypants brass knob running through it?! Well I’m glad you interrobanged, because I have a video explaining that whole situation! As you may know, I’m now producing private video content for my Patreon supporters. However, to give everyone else a sample of what you’re missing, here’s a public video of the making of this feature. If you like it, subscribe on YouTube and pledge on Patreon to catch all the rest!

Okay, moving right along. At this point, I was very happy with the inlaid brass plate, but now I had a problem. The electrical box had been sized to line up with the end of the boiler¬†before I recessed the base plate. Whoops. I couldn’t rework the electrical box without messing up the carefully planned internal dimensions (more on that in a later post), so what to do?

 

It was back to router yet again, and I recessed the electrical box by the same amount.

 

It actually looks really nice, because the recess hides the crimes of the not-so-square bottom on my sheet metal contraption.

 

While I had the router out, I also cut a channel in the bottom of the base plate to run the thermoswitch wires from the far end back to the electrical box. I didn’t show that in photos because I did it super half-assed. At this point in the day I never wanted to see the router again, so I regret nothing.

After some light sanding to tidy up all the edges and corners, it was time for finishing. My other steam projects are all red-toned woods like mahogany or cherry, and I wanted the boiler to kinda match. This birch plywood was not going to do. I opted to use a colored stain, then coat it with polyurethane for protection from water.

 

The stain I chose called itself “burgundy” and they were not kidding about that. It looks a lot more like something that fell into a wine barrel than I intended, but it’s fine. It’s no longer blonde plywood, which was the main problem I was solving for.

 

I did two coats of polyurethane with a light sanding in between, and for my first-ever wood finishing project, I’m pretty happy with the result. It’s very smooth to the touch, and water beads right off it.

 

Here’s the underside, so you can see how that wiring channel works. Note the really precision router work there. That’s the trained hand of a journeyman router operator. The finish is an uneven mess under here because I experimented with the stain and polyurethane to learn how they work before doing the part everyone can see.

 

Here’s a closer look at the finished top. You can see that it’s plywood, but it actually came out a lot nicer than I feared it might. It won’t fool anyone into seeing fancy hardwood there, but for the low amount of effort, I’m pleased.

 

The last thing I wanted were feet for the underside. Steam engines and boilers are a wet environment. Things are going to get damp, despite best efforts. Valves drip, steam condenses, blowdowns happen, and so on. If you’re working with steam, water is a thing that will be everywhere. If water gets down around the base, that high-voltage wiring underneath will be sitting in water. I’m not crazy about that notion, so I want to lift the base off the deck.

I decided to make some feet out of scrap brass stock with felt furniture pads on the bottom. Good news Patreon Patrons- I made a video of the making of these feet just for you! Check your Patreon feeds and email boxes for that. Yes, that’s TWO videos for this one post! The public sampler and a second one just for you Patrons because I heart you so very much.

 

The feet are brass blocks with felt pads underneath. Watch the video linked above to see how these were made. Sometimes the simplest parts are the most satisfying to watch!

 

That’s all for the base! I believe the last thing to do is finalize the electrical, so stay tuned for that! This epic project is very nearly complete!

 

 

 

 

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