Boiler Failure

At long last, I'm back to putting pieces on the boat. Now that I have identified the type of wood I'll be using I can really see the day when I will have an actual boat and not just a pile of boards in an unsightly pile in the back yard. With the help of my brother in law I had put in the forward pieces of the chine log (both sides from frame 7 forward to the bow). I then wanted to put in the rest. To do that meant firing up the boiler for the steam box.

Normally the procedure is to load the boiler, fill it with water, lite it and wait for the steam to come up. Loading it isn't a problem as I had chopped and cut a fair amount to wood and have lots of oak shavings and sawdust to get it going. Filling it proved to be more of an adventure.

As many of you know from previous posts, I've been running the boiler over the winter. I've had some trials and travails trying to stay ahead of the frost and keeping the water in it from freezing and have been more or less successful. Or so I had thought.

The normal filling protocol for winter operation is to use my little electric pump to take up the water stored in my tank/hot well that I had made (see previous postings). But because I hadn't fired the boiler in a few weeks, I had drained the tank after it had mainly drained by itself due to some 5200 failing in the cold. So I had to hook up the garden hose. Not a big deal as the hose in the back handily reaches to the boiler and it's already equipped with 3/4" fittings for just such.

Now, the old boiler holds close to thirty gallons of water and it takes a while to fill, even with the hose running full, so I hooked it up, turned it on and started doing other prep work, coming by every so often to check on where the level was. The other check I have to keep doing is keeping the relief valve open to relieve the back pressure as it fills. It's spring loaded and doesn't take to being held open and has a tendency to close it shaken even the slightest bit.

Well, I wasn't as attentive as I should have been and it seems that we have some fine water pressure at the house here. As I was walking up to the boiler from across the yard, I happened to notice that the pressure was up to almost 30 lbs. I wasn't concerned for the boiler at that point but for the hose as I had run the boiler up that far in the past. I thought the safety relief valve had closed itself and was going to kick off by itself soon (it opens at 30) but hoses are expensive and I didn't want to over stress this one. As I was nearing the boiler at a hurried pace, disaster struck! I heard the sound that strikes fear in every steamers heart, the tell tale PAHHSHSHSHSHHHHH of boiler failure.

I quickly ran the other way, not out of fear of any steam, the boiler was still cold, but to shut off the water. Even as I did so, I knew that that boiler's days were over. The person who made it, while a good designer and a genius at upcycling (look it up) was not a great welder. I mean, I'm not a great welder either, but even my beads are better. I really didn't trust it much before, but now it was nothing but 800 lbs of scrap. This wasn't just some pin hole that wept under pressure, this was a full scale blowout. If it had been hot, it could have been fatal.

Further investigation showed that a seam in the roof of the firebox let go, no doubt weakened by a winter of going from ice cold to steam a few times, plus the corrosive effect of boiler mud that no doubt must have collected there.

On the bright side, I've learned a lot about boilers from it and it will fetch me a few dollars at the scrap yard. The weather is warm enough now that I don't need heat in the boat barn any more so that's no hardship. The downside was, I still need to make steam to bend wood. So I made a new boiler!

And here it is. This obviously isn't the one for the boat but it serves it's purpose. It's made from a pot I had in the basement, fittings reclaimed from the old boiler and, like the brakes on my first car, JB Weld and lamp parts. The wood on the top is the high tech clamping system I designed just for this application. It's fired by propane, so its way more convienient to use, but it cost more. The hose out of the top runs to the steam box. The hose out of the bottom serves both as a fill (note the handy funnel at one end) and as a sight glass. The hose is clear so I can see the water level in it. It gives a distorted reading because of the back pressure but as I'm really only interested in it not running dry, its good enough. It works like a charm too. I steamed the aft sections of the chine later the same day and they bent right to. I have pictures of the completed form but that will be for the next post.