Does 55 gallon drum off gas when heated?

Hi there, I'm sure this is already discussed in depth somewhere, but after searching for a while I could not find it.
My wife and I are building a 6" style rocket mass heater for our small house.
My wife had concerns about the 55 gallon steel barrel, have they been tested to not be toxic? Our home is 200 square feet so we don't want any harmful fumes coming in from the heated barrel. I already had a 55 gallon steel barrel that I can use, but we can always buy a stainless steel one if we have to. Just wanted to save the money of it was indeed safe.
If you could direct me to any studies done by Paul or other forum posts discussing this that would be great.
Thanks!

Braden, your barrel needs to be burned before getting in the house. You make a pocket rocket with it, Wrap it in rock wool or glass wool, even below, set fire inside.

Thanks for the reply!

Does anyone know if there is an article or literature that explains the process and proof of it not letting off any bad chemicals of fumes?
Just wanted something to be able to show to people when they ask for a source.

Thanks again!

All you need to know is the volatilisation temperature for the stuff that has outgassing potential: oils, solvents, whatever was in the drum. By doing a good preburn and getting the steel up to a decent cooking temperature (200-300C) those will be the first molecules to get the hell outta Dodge. What's left behind will be mostly carbon, with the possibility of some metals and salts and really tough long-chain polymers that require kiln-like heat to break down. Those can be sanded off if you're really worried (or for aesthetic reasons, like old paint), and then painted over with high-temp stove paint. This should reduce any further offgassing to minimal or zero once the paint has cured.

Lots of drums we get our hands on were used to hold lubricating oil or grease. Here's a link to how the fractional volatility of motor oil is determined:

http://www.pqiamerica.com/Testdescriptions/Noack.html

I guess it goes without saying that it helps to know what you're dealing with...if the drums were used to store pesticides, then any burnoff could be a hazardous operation and you could make yourself (and any downwind neighbours) really sick. Hotter is better, and if you could do it inside a retort that would be ideal (it's ok to dream, isn't it?).

I reckon if you really wanted to have some fun you could do the pocket rocket and put a mixture of sawdust and potassium nitrate in there...but whatever you do, don't succumb to the temptation to try thermite. You'll ruin a perfectly good barrel.

Thank you for your replies! That helped a lot.
Got it completely burned yesterday and painted this morning and just did a test firing up the RMH for the first time and it ran beautifully!
So thankful for this technology, I was blown away at watching the flames move sideways and the rocket sounds.

Braden, just to clarify... you burned the barrel, which should have burned off any paint on it, then you repainted it?

Correct, thanks!

That new paint is going to off gas, or burn.  I think the idea is not to have any paint or anything left on the barrel, just bare steel.

Hi-temp paint, like the stuff used to finish woodstoves, should be fine. It will offgas on the initial heating and then that should be all she wrote.

Burra Maluca wrote:That new paint is going to off gas, or burn.  I think the idea is not to have any paint or anything left on the barrel, just bare steel.

I'm with Burra here. Oil the barrel on a regular basis, it's all you need, if even that. Heat keeps the moisture away. So it doesn't rust much.

I'm a fan of oil finishing myself, but have run across people who are attached to that painted look. The log burner in our house has a nice looking matte charcoal paint job, but after a few years of cooking on it the top is getting splotchy. If it were an oiled finish it would be a cinch to rub it out and smear some more tallow on it.

Any particular oil that is commonly used to season the freshly cleaned metal for the RMH barrel? I'd personally rather season it, than let a thin layer of rust accumulate during the hot/humid months when it's not in use.