Fuse Making Machine

This is a fuse making machine that operates nearly as well as a factory machine would. Have you figured out what exactly this is yet? It’s not an electrical fuse, it’s a Visco Fuse. Still not totally clear? Don’t worry, we had to look it up too. Visco Fuse is a high-quality safety fuse used in fireworks.

[Robert McMullen] built the machine as part of his degree in Mechanical Engineering at Olin College. But there’s a hobby twist behind its genesis. When he has free time he participates in Olin’s Fire Arts Club and we’re sure this stuff comes in handy. The fuse is made by encapsulating a stream of gunpowder in a tube of woven thread. Twenty spools of thread wrap their way around the nozzle of a fine funnel. Once the casing is in place the machine coats it in a waterproof lacquer.

The image above only shows the base of the machine. All the fun parts (and test burns including one underwater) can be seen in the video after the break.

19 thoughts on “Fuse Making Machine

      1. Being as I did not see ANY English (or even a recognizable letter of the Latin alphabet), I am certain this factory is not within OSHA’s jurisdiction. But I think we all know what you were meaning.

    1. He simply needs to adjust his powder mix. If he cannot find a slower burning smokeless powder, he could mix the powder with something inert (such as talc, or maybe a add additional carbon powder). The fuse itself (and the fuse making machine) works fine, he only needs to work on fine tuning the rate of burn.
      The only other comment I might add would be to replace the gravity fed funnel with some type of constant feed rate system. But assumeing that Robert isn’t planning to start produceing thousand foot spools, the funnel should work just fine. Actually, if this was my machine, I would add the constant feed rate setup ABOVE the funnel. That way, you could do several short batches (in batch mode), to check different powder mixes. When you have the mix you like, you mix and load the hopper, and away you go.

      No, this is an excellent build, and if I were making my own fireworks, I would DEFINATELY be looking into building one of these for myself.

      1. Hi Brian. I’m aiming at using Robert his design to create the above mentioned 2s/inch burning fuse. From what I read in your comment I assume that you think this can be done with Robert’s design, without modifying the design? So the fuse doesn’t need to be thicker then this, for instance? I am also going to replace the constant cycle motor by a motor that changes in speed. Will the funnel then still be sufficient, or will variable motor speed then also create variable qualities of fuse? Any comments on my questions would be very welcome. Anne-Jan

    2. Actually, there is no set in stone standard for the speed at which visco fuse burns. Visco is produced in many speeds for different specific fusing applications.

      Brian, it’s not smokeless gun powder but instead black powder, 75-15-10. And to adjust the speed of the fuse requires adjusting the burn rate of the powder. That is typically done by changing the powder grain size.

  1. I’ve been involved in the Pyrotechnic business now for over 50 years. I have been involved in most every part of the business there is. My expertise is making Visco fuse machines and fuse for the fireworks industry. I was just looking on line at what the latest was in in the way of Visco Machines when I came across Robert McMullen’s machine and I was quite impressed. Although small in size, it looks as if it would be a great little device for the amateur pyro. The machines I build produce the standard ⅛” double N/C coated Visco all in one step by the same machine. The machines can be adjusted to produce both larger and smaller diameter sizes fuse depending on what the customer requires. I have built many of these machines over the years and can say that all are still producing the highest quality Visco and some of these machines are over 45 years old. I’m sorry but I cannot post pictures of the existing machines due to contractual agreements with the owners, but I can say they are very different in design and operation than the Chinese versions and what people are building on line. I am now 68 years young and in process of writing a book on the pyrotechnic business and have included a lengthy illustrated chapter on Visco fuse and the American design machines that produce it here in the United States. Hopefully it will be published soon after my contracts expire with my customers.

      1. I am having machine for making safety using the same process as displayed in the photograph that you have shared. These are Japanese machines and we imported them in the 70’s. Now, they are un-economical and we would like to upgrade them for bulk production. How can you help?
        Rahul Jain
        +91 9927660060

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