Old Coffee Dispensers
Posted: Tue Jun 03, 2014 7:12 pm
I tend to accumulate a lot of stuff. I'm not sure how this happens but inevitably it does. A while back I picked up some real nice old 10 gallon military coffee dispensers with the intention of reselling them.
However as often happens one thing led to another and that hasn't happened yet. Then one day an idea started bouncing around in my brain, I started thinking these things might just make some pretty nice boilers. This was the start of a process that others may find themselves in with potentially catastrophic results so I decided to let everybody know the potential danger these things pose.
On the surface these coffee dispensers are almost ideal for a boiler. They are 2 layers of stainless steel with insulation in between
and have a nice big 6 inch opening at the top which would allow you to reach inside for easy cleaning should the need arise.
They do come with lids that lock down and seal but use rubber, however if you remove the seal and lid you can easily clamp a 6 inch stainless steel bowl to the opening and adapt it to whatever size takeoff you want.
And they just look cool.
Of course there are some things that are less than ideal but most of them are easily dealt with. The first is that the inside diameter is only 10.5 inches. This makes fitting it with a heating element a bit restrictive and limits you to a short element. The biggest I could find that would fit was 3500 watts. To me that's not really a big deal, I could always install 2 elements for a total potential of 7000 watts, which should heat up 8 gallons of wash pretty darn fast. So no big deal there.
Of course you need to mount those elements and that brings us to obstacle #2. Although a problem, this is also one of the things that make them seem ideal, the double wall. My thought here was to cut a 3 or 4 inch diameter hole in the outer wall, remove the insulation from that area then drill a hole in the inner wall the right size to fit a 1 inch fitting and solder, braze or weld a fitting in for the heating elements. I thought about maybe using the method of putting a nut on the element from the inside but think that wouldn't work due to the diameter.
The last obstacle is the one that I found insurmountable and is the reason this post is in safety instead of somewhere else and that is the insulation itself.
Now obviously this insulation makes these impossible to use with a banjo burner but you might think that the insulation is what makes these ideal for an electric boiler. That might be true if it weren't for one thing. That one thing came to me at 3AM one morning when I woke up and couldn't get back to sleep. I started thinking about the label on the outside where it proudly boasts that the insulation was blown in using DuPont freon.
I know what some may think, "so they used freon to blow it in, that was a long time ago". but that freon IS a HUGE deal, some of you may know this already but living in a largely post freon age many of you may not know that when you heat freon you can get Phosgene gas! Again some of you may know this but for those who don't, Phosgene gas is a very potent nerve agent. A small puff of it can have toxic effects that will last a lifetime which may turn out to be a very short time or make you wish it were.
Why be concerned about something that was only used as a propellant? Well a quick Internet search revealed that "Most of the Freon remains in the foam’s cells." So most of the freon remains in the foam and there is risk of heating that foam to the point of releasing Phosgene gas using welding, brazing or soldering with your face in close proximity to any toxins that may be released. Even if it is a small risk it is not worth taking. So the coffee dispensers are destined for resale once again or maybe use as fermentors or storage but they will not be used as boilers.
A few people on here have come across the 5 gallon version of these containers and cut the bottom out and removed some of the insulation then used them with banjo type burners. In some cases the insulation is fiberglass, in others it's foam. The labels are only thin foil and over time may be worn off, so be careful if you come across these and be mindful that this foam exists and holds the potential to ruin your health or even kill you in a single breath of a little puff of smoke.
On the surface these coffee dispensers are almost ideal for a boiler. They are 2 layers of stainless steel with insulation in between
Of course there are some things that are less than ideal but most of them are easily dealt with. The first is that the inside diameter is only 10.5 inches. This makes fitting it with a heating element a bit restrictive and limits you to a short element. The biggest I could find that would fit was 3500 watts. To me that's not really a big deal, I could always install 2 elements for a total potential of 7000 watts, which should heat up 8 gallons of wash pretty darn fast. So no big deal there.
Of course you need to mount those elements and that brings us to obstacle #2. Although a problem, this is also one of the things that make them seem ideal, the double wall. My thought here was to cut a 3 or 4 inch diameter hole in the outer wall, remove the insulation from that area then drill a hole in the inner wall the right size to fit a 1 inch fitting and solder, braze or weld a fitting in for the heating elements. I thought about maybe using the method of putting a nut on the element from the inside but think that wouldn't work due to the diameter.
The last obstacle is the one that I found insurmountable and is the reason this post is in safety instead of somewhere else and that is the insulation itself.
Now obviously this insulation makes these impossible to use with a banjo burner but you might think that the insulation is what makes these ideal for an electric boiler. That might be true if it weren't for one thing. That one thing came to me at 3AM one morning when I woke up and couldn't get back to sleep. I started thinking about the label on the outside where it proudly boasts that the insulation was blown in using DuPont freon.
Why be concerned about something that was only used as a propellant? Well a quick Internet search revealed that "Most of the Freon remains in the foam’s cells." So most of the freon remains in the foam and there is risk of heating that foam to the point of releasing Phosgene gas using welding, brazing or soldering with your face in close proximity to any toxins that may be released. Even if it is a small risk it is not worth taking. So the coffee dispensers are destined for resale once again or maybe use as fermentors or storage but they will not be used as boilers.
A few people on here have come across the 5 gallon version of these containers and cut the bottom out and removed some of the insulation then used them with banjo type burners. In some cases the insulation is fiberglass, in others it's foam. The labels are only thin foil and over time may be worn off, so be careful if you come across these and be mindful that this foam exists and holds the potential to ruin your health or even kill you in a single breath of a little puff of smoke.
I'm not sure how that is made but I know they have to go rapidly from hot to cold, which is why they also need to use old pyrex, and I think maybe some TV shows show them using liquid nitrogen for that.