Hydrothermal reactor

i would say, if you are not going to invest in a real hydrothermal pressure vessel, go with a nipple and caps, nipples are thicker than normal pipe, and are pretty cheap, the only drawback is that they are small.

what pressure they can withstand? it's pretty thick metal, at least 3mm in the thinner areas (it's the threaded part, so the cap is adding another 3mm at least).

just be safe to begin with, i tried this experiment on my hotplate, set for maximum 180°C, staying far away from it while hot, and with a thick wood cage around it (not in the picture) to hopefully catch flying pieces in case of explosion (sandbags are better, but heavier).

my pipe leaked anyway, so the pressure never got too high

[Edited on 7-6-2020 by Ubya]

Stay safe: Any pressure vessel made from random and unknown pieces SS by an armature welder should only be pressurised in a hole in the ground with a paving slab covering it. That should probably include any experiments with any high pressure bottles.

In the UK Soda Stream bottles can sometimes be found in charity shops and purchased cheaply. OK the charity shops may be closed at the moment so you could try a recycling sites like one of the Freegle sites.



They are tested to 30bar (from memory) and have a burst disk set to about 100bar (thats the item sticking out of the side of the brass valve). The brass valve can be removed for modification with a big spanner and at least 3ft of pipe for leverage.

Quote: Originally posted by wg48temp9

Stay safe:

Absolute terms, relative perception. I have a friend who is a "know-it-all-guy" but actually goes wrong even on some basic stuff. These are the people who blow things up by just putting some pressure generating substances in a closed vessel and wait for things to happen. Materials can withstand surprising stresses, but when they fail, the more damage will occur. A vessel bursting at 500bar is not far from an actual fragmentation device.

I'm not to say anything, but I've worked with pressure vessels and welding and could confidently say that if I were to make a vessel to withstand static 100bar pressure, it would be no trouble.

When you proof things, you fill them with water and add pressure with gauge-meter. In this manner, if the vessel fails, it has only few cubic cm of gas to expand. If it withstands 300bars, you can confidently use it at 100bar. Other factors, aka material and gasket compatibility, temperature etc. must be taken into consideration.

But for example, a reaction that is done with ethanol as solvent at 100C, will generate pressure inside the vessel. One manages the pressure by just immersing it in boiling water.

Quote: Originally posted by wg48temp9

Stay safe: Any pressure vessel made from random and unknown pieces SS by an armature welder should only be pressurised in a hole in the ground with a paving slab covering it. That should probably include any experiments with any high pressure bottles. In the UK Soda Stream bottles can sometimes be found in charity shops and purchased cheaply. OK the charity shops may be closed at the moment so you could try a recycling sites like one of the Freegle sites. They are tested to 30bar (from memory) and have a burst disk set to about 100bar (thats the item sticking out of the side of the brass valve). The brass valve can be removed for modification with a big spanner and at least 3ft of pipe for leverage.