MPCNC Not Fireproof

I would not have thought of that i thought the air was how it burned. Does the size of hole matter or is it to just contain?

Makes sense, if itā€™s self-oxidizing. If you try to fully contain it, all youā€™ll end up doing is creating a pressurized vessel full of self-oxidized burning embers. When it blows, you end up spraying them all over. If you allow venting, the pressure is released, but you contain the combustion. Hence the SS scrubby filter (you want something hefty enough NOT to catch fire itself, Iā€™ll wait while you go light some steel wool to prove my point). Heck, probably, just some overlapping, offset plates would probably do. Something to prevent the combustion (or I suppose chunks) from having a direct path out, while allowing the hot air/gasses to escape.

To Timā€™s question: It would depend on how quickly the volume of air could be heated to the point of vessel failure vs the rate at which the gasses could be vented. Weā€™re not talking about oily rags, so youā€™re not trying to prevent oxidation (these things are self-oxidizing), so youā€™re not trying to prevent airflow. Youā€™re trying to prevent flame spread and chunk mobility. Both of which are actually enhanced in the case of unplanned vessel over-pressurization and failure.

WaterHeater

Yes, thatā€™s actually a hot water heater, but it exemplifies the effects of unplanned over-pressurization of a vessel.


Thatā€™s why I mentioned a stainless scrubbing pad. Bigger pieces, and the stainless doesnā€™t burn as easily as steel wool. I accidently dropped a 12v lantern battery into a big box of steel wool my grandpa got at an auction once. Luckily it was in the barn, and was over 20 feet to the ceiling. Shit got hot quick! Iā€™d think a couple half inch holes would be enough. Just want it to vent.

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Iā€™ll add that this experiment is relatively safe. It can be done in say the middle of your driveway without wind. Itā€™s especially cool to watch the spectacle at night time. If you havenā€™t seen this beforeā€¦ you owe it to yourself to try.

I will second the thought about holesā€¦ another experiment is filling a tennis ball with match headsā€¦ a bit more dangerous and explosive but displays how self contained oxidizers can react much faster when compressed. So thereā€™s additional hazard physics involved beyond just a ruptured pressure vessel.

Cousin lost 2 fingers and a thumb packing match heads into a CO2 container so be careful

To avoid this next time you may check something like this fireball

Btw, even metal cnc probably will lose conditions after a fire because dur high temperature it could change geometry and stiffness, and anyway all expensive electric parts will be damaged.

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I should have said it is a VERY DANGEROUS experiment that should generally not be tried at home. Please keep it safe everyoneā€¦ the purpose of this discussion is to share understanding of the science behind fire safety, not to encourage dangerous experiments.

Yes safety first ! I agree with you combinations can be not what you expected. The steel wool is a boyscout firestarter trick always had It in my pack

Ah, the things I missed out on not doing Boy Scouts. My older brotherā€™s experience left me not wanting to try it. This was unfortunately when I was too young to fully grasp my brotherā€™s ā€œuniqueā€ mindset on things. I have one of those cheap magnesium+flint sticks from HF. It takes a few minutes of shaving magnesium with the attached 3ā€ long piece of hacksaw blade before you have enough chips to get a fire going. Steel wool would take less work I bet.

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You just push a 9V battery straight into the steel wool. Instant fire. Not a ton of heat though, you need kindling.

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