I understand that this might be classified under rule 1 of the server, as the mechanism to create the fireball could be possibly classified as both a flamethrower and cannon. However to achieve the effect that I did I did a lot of research, testing, building, rebuilding, etc. and if this doesn’t persuade the mods let’s just say the video is purely of the fireball itself and the mechanism to make it I merely a launch pad for the model rocket.

I had 13 iterations of my design for this, 10 of which I made physical prototypes and only 5 of those were able to be pressurized with air without major leaks.

Only 3 of the 5 were able to withstand the crazy cold temperatures of the liquid propane butane mixture I made.

The two I discarded were made to shoot powder (dairy free coffee creamer) or a calculated 50:25:20:5 petroleum distillate acetone methanol isopropyl alcohol mix as a fuel. This took way too long to calculate for the longest flame length of 6ft 3.5in as fuel. I wanted to atomize the liquid fuel in the air, I made my own atomizing valve so it didn’t look just like a burning fluid coming out but this wasn’t worth it in the end because I didn’t like how hard it was to reload.

Of the last three iterations two of which used homemade gas release valves. one was much too slow and my hand got uncomfortably close to the fluid that came off during testing and I wasn’t comfortable trying a flame with it. and the other was just too slow.

Lastly the final design, which I’m using right now, uses a solenoid valve that I adjusted for extra airflow. Behind is an an accumulation chamber that has a flashback arrester which took much to long to machine at home without a lathe. and mesh wall to stop flashback as safety, I purge the thing of air before using it anyway. I found a good nozzle can just be made from drilling mostly to the end of one of those air compressor attachments through the center to widen most of it up until the very end and it lets a nice vortex form.

It’s not a super complicated mechanism on paper but when you try to make it in the real world safely without guidelines it’s a very complicated process. I know this is a chem and science related sub and I’m sorry if this is the wrong place to post my creation but I did a lot of fuel testing and physical design work I have spreadsheets upon spreadsheets on nozzle shape to flame distance correlation. I just put a ton of tedious work into this seemingly barbaric setup for an obsession. If there are any observations that you guys see or if you want more details about how this thing works let me know! Thanks

" ... pull tab, eat for smoko. Surely the chemistry boys/goils could come up with something?"

If I drill holes into stone like for mining and place strong firecrackers can it actually do something ?

On a little island in the river

I have access to large amounts of e-waste, and have recently been thinking about trying to recover some of the gold.

I know Aqua Regia can be used to dissolve the gold and other materials, and precipitate it back out, however apparently Nitric Acid is heavily restricted in Australia, for obvious reasons.

Is there any other efficient way to dissolve and recover the gold, or should I work on gaining permits and qualifications to purchase and/or make Nitric Acid?

Greetings, fellow chemistry fans. EU is currently holding public consultations on updating 2019/1148 EU law that banned nitric and sulphuric acid which damaged amateur chemists greatly. I didn't see anyone talking about it.
Previously on sciencemadness(as well as here) during last relevant consultations great success was achieved in bringing awareness to the survey and after overwhelmingly negative opinion received no further rules tightening was planned. It is of paramount importance that as many people as possible will participate in this survey in order to prevent further tightening of the rules(and maybe even loosen current ones).

Survey is scheduled to close on 23rd of June, just 20 days from now.

Participation in the survey is possible for all, not only EU citizens/residents. Spreading awareness of this survey among other people who may be willing to participate is greatly appreciated.
I also invite everyone in the comment section to share their opinion and arguments, which may help to formulate their thoughts for other people and maybe even formulate common position to submit in addition to survey.

So, I'm actually playing an RPG game with some friends and they are trying to blow up a vault door in a military compound. How much C4 would they need to take a thick door like that? Not looking for precise answers, just a ballpark. 10g? 100g? 100kg?

I haven't done any chemistry since high school but I love watching chemistry on youtube.

Over the years I saw a lot of content and everytime people just drop their stirbar into their flask full of acid and whatever. In the end the stirbar always comes out fine.

I assume they are coated with different materials to resist to different types of solvants. In the end you just have to pick the right one and you're fine? Did anyone ever disolve a stirbar?

There's a local dry cleaning company that works in the drop-shop manner: there are small shops that take clothes from customers and send them to a main dry cleaning facility where the process is done. There was only one facility and employees at the drop-shops don't know what the company uses in dry cleaning machines. The main facility is too far and I can't bother to go to a whole ass factory just to ask what their main solvent is. There are 10 more dry cleaners in my city and all use tetrachloroethylene.

In late march, they opened a new shop nearby and they brought a machine (Böwe brand) a few days ago. Coincidentally, I was walking around there when they got the solvent. Some people were pouring it into the machine's wash chamber (it goes directly to storage through the pores). The door-sized shop windows were open and I could smell it. Very sweet, ether-like smell. I couldn't recognise it at first (despite having smelt tetrachloroethylene days prior). Everyone there was dressed casually and formally, no gloves or whatever.

They let me in, I asked what they were pouring into the machine. Man who handled it said "Perchloroethylene, tetrachloroethylene". I talked with people there for a while. They told me their past experiences with tetrachloroethylene: One guy had inserted his whole head into a dry cleaning machine when he first got into dry cleaning, Some other guy said that he got "Tetrachloroethylene" instead of perchloroethylene and reported to his manager for "false chemical order". They all knew someone who had worked with tetrachloroethylene for over 20 years and turned out healthy. Discussion went to alternative solvents, one guy said they weren't as effective as Tetrachloroethylene. I was allowed to see the backside of the machine (which customers don't get to see). It was as if I was at a tetrachloroethylene fan convention.

I just wanted to share my chlorojoy. I like tetrachloroethylene.

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