Hide your sulphuric acid (2023 Update)

Everybody should keep a little bench power supply around the house, along with a DVM and a thermocouple meter, and some test leads and junk.

24 volts, 1 amp supply is fine.

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John Larkin      Highland Technology, Inc 

The best designs are necessarily accidental.

Stupid policy. Since there are ways to make concentrated sulphuric acid, it won't prevent terrorists from getting it. But it will encourage non-criminals who need it for other purposes to engage in dangerous processes that wouldn't otherwise be required.

What next - ban Nitrogen? Let's see how well that would work out.

Sylvia.

I have a can of Extra Strength Acetone. That must really be dangerous.

I'm not sure it is all that stupid there have been a spate of acid attacks using concentrated sulphuric acid in the not too distant past.

The big problem is that quite a few of the chemicals they want to ban have important and legitimate uses in gardening and agriculture. Sulphur, charcoal, potassium nitrate, ammonium nitrate for example.

When I lived in Belgium I was very surprised to see conc HCl, HNO3 and H2SO4 on sale in the local supermarket and the shelf they were on corroded to hell. Caustic gels are still on sale as drain cleaner.

Only if you mix it with H2O2 carefully at the right temperature and live to tell the tale. Strangely when I last bought some maximum UK permitted strength peroxide Amazon helpfully suggested that I should buy some acetone too! "Most people who bought this also bought that"...*REALLY!*

I can think of a profession that uses both substances.

I keep a bench power supply at home and in the cabin. It will charge a battery and do lots of other things.

And you *can* charge a zero-volt totally dead car battery. The auto parts stores sell electronic chargers that won't, so that they can follow up by selling you a battery.

I let a car battery go dead because the car was not driven enough. My best charger would not let the battery start to charge. I have an older very simple charge that is only a transformer, diode and meter that I hooked to the battery for about half an hour and then I could use the better automatic charger.

I once had to use 120 VAC and a diode and a hair drier ballast resistor to bootstrap charging a car.

Some devices with a 2-step dimmer have the necessary diode inside.

Do you have to water it down before use, like IPA? CARB rules and all.

california is so f****ng stupid.

...

I refer to coders as typists.

In our state a friend of mine was forced to change the name of his small business because it contained the word "engineering" in it and he wasn't a licensed professional engineer. But you can do that if you have a PE on staff (which may be a part-time consultant). He replaced "engineering" with "designs," and that was acceptable. It is also interesting that you can become a professional engineer here without an engineering degree.

It is also interesting that you can become a professional engineer here without an engineering degree.

I have only known one PE and how he got that I would like to know. Maybe good at taking tests, but he did not show me or anyone else at work much. We were always doing his work and all he did was carry our work to the blue print office for them to print out .

Sort of like me. Around 1972 I thought I wanted to get a job working on

2 way radios. Took the test for that and for one dollar more got to take the test to work on the radio and TV stations. I had never seen a radio or TV transmitter but passed the test to work on them.

A friend was stuck with a flat battery at his cousin's place. He used an old halogen lighting transformer to get going :) They have called him McGyver ever since...

CH

Was it called an "FM License" or something along those lines?

At that time it was a Second Class Radiotelephone to work on the 2 way radios and after you passed that you could take the First Class radiotelephong license to work on the radio and TV stations

About 1980 or so they changed it all to the General Radiotelephone license. I don't think one has even been needed for about the last 20 years by the FCC.

Strange, HOOH is the most corrosive substance on the planet there is. The more pure, the more corrosive.

Not even close:

It seems like most of the weird permits were dropped. Does anyone know if pilots (air to air, air to ground on VHF) in the US ever needed radiotelephone permits, like in other countries?

IIRC, yes permits were needed. No test of any kind and it was just an operator's permit, no station license. Just fill out a form.