What is Reddit's opinion of GreatWhip 615 gram Whipped Cream Charger 0.99 Liter Nitrous Oxide Tank Pure N2O Whipped Cream Cylinder (2 cylinder)?

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High Test Peroxide monopropellant rocket fuel is more dangerous than you might think.

Here's the peroxide rocket body count (incomplete list):

• On July 16, 1934, in Kummersdorf, Germany, a rocket engine using hydrogen peroxide and alcohol exploded during a fuel mixing test, killing Dr. Kurt Wahmke and two assistants.

• On March 18, 1980, at Plesetsk, USSR, a Vostok-2M rocket exploded on its launch pad at during a fueling operation, killing 48 people. An investigation into a similar - but avoided - accident revealed that the substitution of lead-based for tin-based solder in hydrogen peroxide filters allowed the breakdown of the H₂O₂, thus causing the resultant explosion.

• On July 22, 2010, Erik Bengtsson, founder and co-owner of rocket propellant company Peroxide Propulsion (archived web page here, videos here), suffered a near-fatal accident at their production facilities in Gunnilse, Sweden. Erik was working at the plant with a routine procedure when hot hydrogen peroxide steam exploded in his face. The plant subsequently burned to the ground. All stock of propellant grade hydrogen peroxide was destroyed in the fire. After being temporarily blinded, Erik's vision returned. Peroxide Propulsion, however, ceased operations.

I toyed with the idea of using HTP as a monopropellant or oxidizer in the early 00s, but research into the dangers and Erik's accident turned me off to it.

You might want to look into a pressure-fed propane/nitrous bi-prop instead (as seen here and here).

You can get a bottle of propane [for less than $10 from Walmart](goto.walmart.com/c/60286/565706/9383?veh=aff&sourceid=imp_000011112222333344&u=https%3A%2F%2Fwww.walmart.com%2Fip%2FBernzomatic-14-oz-Propane-Cylinder-1-Pack%2F17128612) and a couple of 0.95L nitrous oxide whipped cream chargers for less than $100 on Amazon.

Launch of the University of Waterloo's Eridani Propane/Nitrous bi-propellant rocket here.

Project page here.

If you keep safety first during design and test, this is an affordable and (relatively) low risk propellant combination.

Hope this is helpful, Godspeed and good luck!