SRS Blog > Grit blasting my hands

Published 15th January 2006

I managed to do something stupid in the workshop before Christmas. A large traction engine had come in for boiler test which was done by my inspector. A couple of days later, having put it back together, I needed to run the motion to test a modification to the lubricator drive. Rather than push it out into the cold December afternoon and steam it (I was short of time, light and motivation for same) I took the blowdown valve out intending to replace it with a air fitting so that I could run the engine from the workshop compressor. I had a root around in the boiler plugs box to find something suitable, but to no avail - the nearest thing was the right diameter but wrong pitch and would only screw in half a turn. At this point it should only have been the work of five minutes to turn up another plug from a piece of hex bar and screwcut the right thread on, drill for an air fitting and job done...

Unfortunately, at that moment the phone rang, I talked for twenty minutes, then went off to find the subject of the conversation, then noticed the time and adjourned home for supper. Next day I was out delivering a locomotive, it was two days later I got back to the job where, early in the morning and with a mind only half on the job, I saw the fitting screwed into the boiler and put the air line on it. It took some time (it's a large boiler) but as the pressure rose to 50psi, I noticed air leaking from around the plug so put my hand down behind the back wheel to tighten it. As soon as it turned, the plug disengaged from its half a thread of engagement and, with a mighty bang flew about eight feet across the workshop, after first making hefty contact with my middle finger. The dog leapt out of his skin at the noise and I went dizzy - for the first few seconds I was convinced I'd lost my finger, such was the pain. When I did finally have a look, the brass plug, which probably weighed a couple of ounces - had raised a great lump at the base of my finger, after which all the grit and rubbish on the foundation ring had been evacuated at high speed and shot blasted the rest of the fingers, resulting in a constellation of little blood blisters. Sitting typing this a month later, they are just fading and I can still feel gritty bits under the skin. Yuk.

Apart from being three parts deafened (the dog as well probably, although he often pretends so I have no way of knowing for sure) and losing the use of my left hand for a couple of days until the swelling went down, I got off very lightly. It did rather focus the mind on the stored energy in a boiler - this happened at 50psi on air, if it had happened at working pressure (which is three times that on the engine in question) with steam I am sure that I would have lost at least one finger (and probably had a poached arm as well). So I'll keep telling people not to fiddle about tightening up boiler fittings when they're under pressure (as I always have done) whilst trying to remember the advice myself in future.