Recently I needed to blow some test bubbles so that I could see what certain colors looked like when they were blown thin. Unfortunately, in 1999 I had a virus that damaged the facial nerve on the right side of my face and consequently I can no longer blow glass with my mouth. Therefore, I had to devise a way to blow by using some sort of pump.
I came up with this idea after hearing about some Russian glass blowers who use a foot pump attached to their blow pipe. That seemed a little awkward to me for the size work I wanted to do, so I decided to try making a small hand-pumped blowpipe that can be used in conjunction with my torch. What I came up with is simply a pump bulb and valve set from a blood pressure apparatus, a 13" length of surgical tubing, and an 18" length of 1/4" heavy wall stainless steel tubing.
I bought the pump bulb, valve, and surgical tubing at a local medical supply that serves the public. I ground a taper on the end of the blow pipe that the surgical tubing slips onto. This allows the tubing to be pushed on quickly if necessary. If I'm starting out working at the torch I start with the pump already attached. However, if I'm starting by taking a gather from my crucible furnace, I leave the pump and tubing on my workbench and slip it on when I'm ready to blow.
I support the left end of the blowpipe with my left hand and I hold the pump like this (figures 3 and 4). As you can see, I'm able to twirl the blowpipe back and forth with my finger tips while keeping the pump bulb held securely in the palm of my hand.
If I need to pump air into the pipe I use my two middle fingers like this:
The valve is operated by my thumb and forefinger. When the knob is closed, the valve operates as a "one way" valve. This allows me to pump air into the pipe without the air escaping. The pipe stays pressurized as long as the valve is closed. This simulates what a glass blower does when he blows into the pipe and then caps the pipe with his thumb. When he wants to release the pressure he removes his thumb. When I need to release the pressure, I simply open the valve.
This is what it looks like when I'm operating the valve.
The pump works surprisingly well! I was able to blow small to medium size bubbles right away and I'm sure Christmas ornaments are once again in my future. As with all things, it just takes practice. The only thing that would make it better would be a swivel adapter between the pipe and the hose. However, it's not at all necessary. I simply rotate the glass back and forth (figures 7 and 8) in the flame rather than allowing the pipe to go around and around. The hose just flops over and back, over and back.
This method does have one distinct advantage over normal blowing... You can actually watch from different angles as you're blowing, rather than straight down the pipe!
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