They’re affecting their effect there.

J/P=?

Thank you. After reading through that I’m much relieved. I’m sure that video was edited for maximum viewer impact and not as a documentation on your equipment and procedures, because none of that caution comes through on the video.

As a little background on myself, I’ve spent the past 20 years or so on and off in the semiconductor equipment industry, including eight years at Applied Materials. I worked on etch chambers that not only had multi-kilowatt RF generators, but high pressure air operated devices and used some of the deadliest gasses known to science (silane, anyone?). It wasn’t enough to have safety pounded into us enough on a daily basis, we also had to take an annual “hazmat” training class to have the fear of death re-instilled in case we’d slacked off.

In addition to that, I help run the largest model rocket club in the country, and have to oversee the safety of launches where we send 200 to 300 rockets skyward during a four hour launch. Procedure is everything.

Thanks for the clarification,

- Jack

Thank you. I really shouldn’t try to do that in my head! I always drop an exponent somewhere. I had 1F equaling 1,000,000 uF (which is true), but I used the “million” instead of the “one” when multiplying out the energy.

I was also going to point out that at 12V it didn’t pose a lethal hazard, although it can give you a nasty burn across your fingers. Plus we discharge it a lot slower. Our firing leads are 14 ga and they mention 12 ga, plus it’s about 15 feet of cable from the firing relay to the ignitor clips compared to a few inches for their setup. We probably have at least an order of magnitude more resistance in the discharge path (if you include the ~1 ohm in the ignitor itself).

That still doesn’t excuse them for their shoddy safety practices.

- Jack

Well, the “does the coin melt?” question seems ripe for an episode.

There are some non-obvious safety systems in place which don’t make it into the video.

- Before operation, a safety perimeter is established keeping personnel at a safe distance.

- The chamber which contains the coil has been tested hundreds of times. HDPE turns out to be one of the few materials which are up to the task of absorbing the shockwave and shrapnel. In addition, the walls are made out of nearly 2 inches of the stuff, and built way over spec. The shrapnel penetration depth is less than 1/4 inch into HDPE.

- the 2ndary spark you see emits UV, however, all staff are wearing UV blocking safety glasses, in addition to earplugs. 132db is quite loud.

- The operation of the chamber is as follows: Clear the area, Unsafe it, Charge it, discharge it, remove the balance of the charge (about 1kv normally), safe it. If any time during this cycle one of the spotters sees someone enter the danger zone, the operation is stopped. Keep in mind that after a charge is put into the cap bank, it is in a very dangerous state. The only way to safe it would be to discharge it.

- Regarding the tubing in use on the trigger: Best practices require a simple explanation of safety. The mechanical triggers, while ‘crude’ can be easily inspected for proper operation, and their safety level and function can be determined at a glance. This was a design requirement which I believe we implemented very well.

- Use of high voltage gloves – we are dealing with 10kv DC charge. high voltage gloves have many failure modes, and our safety policy demands that we simply do not interact with the device while it has a charge. Honestly, even if you had gloves, a bump of the elbow would likely cause death anyway, so they provide very limited protection.

- The operators of this device have practiced handling failure modes – the only real tricky one is if the bank has a charge and we don’t have a way to discharge it. The yellow 2ndary switch, if it fails, still has exposed contacts. We have a method for manually safely discharging the bank remotely should our safety switch fail.

If you have any further questions, please don’t hesitate to ask. you can email me at 3ricj ATTY hackerbotlabs DOTTY com

As for mythbusters, I have not seen any of their work, but we built stuff for ourselves, not for TV. Thanks for watching.

Thanks!

As far as X-rays go, just a reminder that Scotch tape peeled in a vacuum can create X-rays, Lightning also generates them.