Well we got a cold snap the past couple days which just happened to coincide with a project I needed to do in my sort-of insulated shop with a decent size propane heater, however I'm too cheap to go buy a 100lb bottle or rent a bulk tank. But I do have a good collection of 20lbs bottles that I've been using to run my forge and heater.

After running both the heater and my forge all day on 2 seperate bottles I got wondering.
If I setup a manifold to tie all my my bottles ( i got 6 of em) together would I be able to draw more gas for longer just like if I had a larger tank?

Has anyone tryed this?

Yup... and Yup. It will work.

Manifolding quickly costs more than buying a bigger bottle, unless you have all the parts already. A bigger bottle also costs less to fill in the long term. Manifold 2 together and put in a tub of water, restrained so there is no stress on the manifold. You will drain those bottles quite nicely unless you freeze the tub solid.
Phil

Phil, I am not doubting you. Just trying to learn something new. Why put them in a tub of water? Just curious and had to ask. Thanks. :)

All about heat transfer, phase change, and gas laws, PV=mRT. As pressure drops, cooling occurs, as fuel evaporates, cooling occurs. This cooling causes evaporation to take place less quickly until the bottle is said to "freeze" which really means that it is too cold for evaporation of the liquid fuel to keep up with use. This temperature is below the frezing point of water and causes a lot of frost on the bottles.

In a tub of water, the bottle is held at a higher temperature, and since the water contains more energy than air, heat energy is transferred safely into the fuel so you get more evaporation, and more pressure helping use a bottle completely. Ice still forms on the bottle, but it stays warm enough.

With my 2 burner forge and two 20# bottles manifolded together, I start forming ice after about 30 min, but have not run long enough to have noteworthy pressure loss as I get at most 2 hours of forge time at a shot. With one bottle, at about the 1 hour mark I was loosing pressure due to freezing. If I started in a tub of water, at the 2 hour mark there would be a 1 inch or more shell of ice on my bottle, but I could run the bottle dry causing my forge to rather abruptly shut off, instead of slowly loosing temperature.

Phil

Thank you. See, an old dog can learn new tricks. :D

A bigger bottle also costs less to fill in the long term.

I'm not sure that this is true anymore where I live. 20# tanks cost around $11 to fill and the cheapest I can find to fill my 40# tank is $26. So I am loosing $4 per fill at the cheap place. It's $29 at the place right by my house which is where I usually go to avoid driving across a town populated with lunatics with a propane tank.

Lunatics, In Effingham?!!! Nawwwww!!! LOL

Are they filling a full 20# or exchanging you for 15#?
Phil

It's funny,scary now that R40 is getting a bit scarce that some folk are putting propane in their cars A/C systems as a substitute. Nothing like driving a bomb around.
Even out here in Phoenix you can freeze your gas bottle on a nice 110F day and need to thaw it out with a hose.

I use to take my bottle and exchange it. Went by the feed store and had them refill it one time. Only put two gallons into a five gallon bottle before it was full. Now, I never exchange. I just wait for the feed store to open and have them refill what I have used. Only ran me about 6$.

I know you said you were to cheap to buy a 100lb, but it is not that expensive. Definately not worth the hassle to me. The only reason I would not have a 100lb bottle would be for portability. I dealt with freeze ups on my first fill of the small bottle and immediately got a 100lb. Walmart has them for $117 shiped to their store for pick up.

Walmart.com: 100# Refillable Propane Cylinder: Grills & Outdoor Cooking

hmm walmart sells bottles eh
I'll check that out.
Although I do have most of what i need to build a manifold
and with my current setup my forge wont run a 20lber after it down to a 1/4 full so if I exchage Im getting ripped off
bigtime.