Propane Dilemma

[01tundra]

I decided to add a propane forge to my arsenal yesterday and am now in the process trying to figure out what to do fuel wise in preparation for its arrival.

The forge is a Chile Tabasco single burner. I will only be heating mild carbon steel in this forge, 1/2" diameter max and will reserve any heavier work or forge welding for my coal forge. The sole purpose of the new forge is for doing ornamental projects with 1/4" - 3/8" diameter range stock and some 1/8" - 1/4" x 2" wide (max) flat stock. It will be located in one spot and will not be portable, per se.

I currently own a 250-gallon below-grade propane tank that serves my house. The tank is only plumbed to our gas grill on the deck and to the fireplace, that I've since converted back to a wood-burner. So basically I have a 250-gallon propane tank serving a 2-burner gas grill. In the 4 years since I completed construction on my house, I've only used 40% (250 gal x 0.80 = 200 x 0.40 = 80 gallons used), which include 4 winters burning a 38,000 btuh gas log set and doing 85% of our cooking on the gas grill. So to say the least......I have spare capacity.

The tank has a regulator on it the knocks the service line pressure down to 10 psig, then a second regulator takes the pressure down to 7-11 in. wc. prior to stubbing into the crawl space under the house. Where the second regulator sits under the deck, happens to be adjacent to my garage/shop and is run with the yellow polypropylene piping.

My original direction was to use a 100# cylinder for the forge due to safety concerns of running 10 psig gas into my garage, but the more I think about that.....it's a stupid thought process that got me there and I know better. I would rather have 25 ft of gas piping route into my garage with a shut-off valve outside the garage prior to entering the house versus 100 lbs of propane sitting in a tank in my work space around my welder, plasma cutter, etc. I would adopt a shop procedure that requires the outdoor isolation valve to remain normally closed, the only exception being when the forge is in operation.

As I'm currently ignorant on the operation of gas forges, I'm not sure what the optimum operating range will be for this particular forge, coupled with the material I'll be heating, if under something like 8 psig maximum is required to make steel yellow, then I'm golden. If more pressure will be required, an alternate solution may be to increase the leaving pressure at the tank within the limitations of the current tank regulator and within the range of the secondary house (gas grill) regulator to be able to adjust it back down to a 11 in.wc. delivery pressure.

If need be, I could set another secondary regulator downstream of the new isolation valve (still located outdoors), in the event that I can lower the delivery pressure even more after up and operating. The piping system would start at a tee on the existing polypropylene exterior piping above grade under the deck, then convert to 1/2" Sch. 40 A36 thread & coupled steel piping (or 3/4" if necessary to minimize system pressure losses). Then would pipe to a brass ball valve and possible a secondary regulator, prior to stubbing into the garage/shop. Once inside, the steel pipe would be routed up the interior wall and across the ceiling, spanning one bay of the shop prior to turning a 90 degree elbow down for connection to the forge gas hose (about a 12' rise & 12' span). The forge will have a second isolation valve on it from the factory.

Am I wrong to want to attempt to use a huge tank that I already own and that's hardly being used currently? I feel like I may be missing a larger point, but it's not coming to me offhand.

Other considerations, I can have my big tank refilled at bulk rates, which around here are currently $2.29/gallon versus retail rates on the 100 # tanks that are currently in the $3.70/gal range. Plus, they drive to me, instead of my dragging two 100# tanks around town.

Side notes - I do understand the effects & hazards on products of combustion and safety requirements necessary. I have three 10'x10' garage doors and a 3'x7' walk-in door in my garage and a decent amount volume as well (45'x25'x12'). My plan is to crack a garage door (or however many necessary) and open the walk-in door while forge is in operation, such to create a cross-draft of fresh air for combustion & breathing purposes. It will be a little bit of trial & error figuring out the balance between keeping the garage above freezing temperatures (water heater located in garage) and still maintaining a safe & healthy work space. I will also have a CO monitor locate in the shop area.

I understand that some people feel uneasy making recommendations when life safety issues are present, so I'm not asking anyone here any opinions on what I should do or what they recommend that I do, I will be the only person that makes the decisions and will be the only person responsible for any outcome.

But what I would like to know is if you were in a similar situation at your house (or have been), how would (did) you set your system up?

And if anyone would care to take a "guess" at whether 8-9 psig gas pressure "may" suffice for the particular forge and type of work I'm planning on doing, that would be very, very much appreciated as well, I understand if it doesn't work, it was my choice and my problem to make right. I'd just hate to be working around 100# tanks if I can avoid it.

Thank you for your time and I apologize for the rather long read, but I'd rather have too much information than be vague :)!

[ThomasPowers]

So what did the manufacturer and seller of that forge say when you asked them about common working pressures for it?

I don't have that brand/model but the gauge on my propane forge for general use was about 8-10 psi---given that gauges are notoriously prone to being off by substantial percentages.

I'd talk with your propane supplier about running a line to the shop. My supplier is always happy to discuss the customer using *more* gas. They also inspected my work when we put in a propane stove for our kitchen.

[01tundra]

So what did the manufacturer and seller of that forge say when you asked them about common working pressures for it?

I don't have that brand/model but the gauge on my propane forge for general use was about 8-10 psi---given that gauges are notoriously prone to being off by substantial percentages.

I'd talk with your propane supplier about running a line to the shop. My supplier is always happy to discuss the customer using *more* gas. They also inspected my work when we put in a propane stove for our kitchen.

Just said it varies, depending on various factors, such as type of work I will be performing, ambient temperature, elevation, etc....all of which are true - Heating small stock - 1/2" diameter & smaller, 580' above sea level, 40 F - 100 F ambient temperature operating range. They seemed hesitant to offer me a possible operating pressure range, which is understandable. I explained that I wasn't trying to drill down an exact pressure, just looking for a possible range.

The manufacturer's website states "Operating pressure range from 1 - 30 PSI" for the burner.

Already spoke with the gas company and they're all for it, for obvious reasons that you stated above.

So far, from searching this site, I've seen 3 psig to 15 psig range for normal forging operations (non-welding). This range was from one person that appeared to be more of a hobbiest like myself, versus a full-time professional blacksmith that was operating at a high production rate and wanted to heat the metal as fast as possible. Based on that information, I would say that I'll be OK with 3-10 psig.

I'm leaning toward installing a tee prior to the sencondary regulator, dedicated gas cock outside, then in to the forge. Since the tank has a regulator on it, as does the forge, another secondary regulator at the new runout would only cause additional unnecessary pressure drop and reduced gas flow rate.

[HWooldridge]

I am not familiar with that particular forge but venturi burners typically require higher gas pressures - up to 15 lbs in some cases - in order to pull in enough air for proper mixing. Going to a needle valve and electric blower lets you dump more volume and run down to 3-4 lbs. Overall usage is similar - just the way it's delivered is different.

I have a similar setup to yours - 250 gallon tank mounted near the shop - but have not plumbed it yet and am still using 100# cylinders. However, I stopped using venturi burners several years ago and have no doubts I can plumb the propane to a blown forge and make it work.

[wpearson]

I'd use the 100lb tank and see what you need first

[Frosty]

Plumbing the 250gl tank to your shop may cost more than buying a 100lb tank. Simply put the 100lb outside, plumb it through the wall or whatever and put a 1/4 turn ball valve first, then the regulator, then the gauge, then lastly another 1/4 turn ball valve as close to the burner as reasonable.

This gets the tank outside, the first ball valve is so you can open the gate valve on the tank itself without charging the rest of the system, it's a simple precaution. Normally the regulator goes on the tank itself but it's really handy having it inside so you can adjust it while watching the forge's performance. The gauge isn't so much to get the pressure exactly to manufacturer's spec, it's so you can duplicate performance. The PSI YOU find good is what counts, NOT what the guys at Chili say is good.

Lastly the 1/ turn ball valve at the burner allows you to kill the fire instantly if something BAD happens. Shutting off the 1/4 turn ball valve at the wall still leaves the propane in the lines, regulator, gauge charged though not being replenished, still, this is lots of propane that's going to bleed out and burn if a fire is the problem.

I run a 100lb tank in the shop, within about 6' of the forge. My shop is a long way from air tight, sits on a little rise and I'm always right THERE when there's a fire going. Sure, it may not be the safest way to do it but leaving a tank outdoors in potentially -40f winter is a good way to NOT have a forge running at all.

Frosty The Lucky.

[01tundra]

Running the pipe from my 250-gallon tank will actually be very inexpensive and the savings on fuel cost would be substantial.

I was planning on having an isolation valve outside the shop, then an adjustable (lockable) in-line regulator (3-35 psig) with gylcerin filled pressure guages on both sides, once I penetrate the shop wall, a second isolation valve inside for emergency shut-down. Then run 1/2" Sch. 40 piping overhead to above the forge location. The forge has a regulator and isolation valve on it with a 8' hose that would be connected to my steel delivery piping.

The outdoor in-line PRV would be to satisfy the International Fuel Gas Code by limiting the line pressure to 5 psig (in theory) and the PRV furnished with the forge will be used for fine tuning delivery pressure.

I get all of my plumbing supplies very near cost, hence the overkill, which would still be way cheaper than one new empty 100 gallon tank. Piping within the shop is a wash either way.

I'm almost positive that the two 100 # tanks my father has are way outdate as far as testing is concerned, so I would have to purchase a new bottle. The nice part about my 250-gallon tank is that outdoor temperatures don't really effect it since it's underground.

[ThomasPowers]

My old 100# tank was purchased for US$25 and tested by my propane company for free. They replaced the valve on it and I was good to go.

However I would go with piping off the main line as the cost difference will make a big impact over time. A good shut off outside the shop and one by the forge should be sufficient---as would a regulator at the forge and not one back in the line.

[01tundra]

Agree on all accounts.

I've decided to run 3/8" Type K copper with brazed joints within the shop. My current challenge is sourcing a female POL x 3/8" NPT adapter fitting. 1/4" copper would more than carry the load, plus three more forges just like it.......but someday I may want an entire fleet of forges.....who knows :)!

I've sent Chile an email asking if there's any way they can provide the connection hose with a 3/8" NPT swivel male/female fitting in lieu of the POL tank fitting. That would do away with an unnecessary pipe joint and a hard to find (an fairly expensive) adapter.

[Frosty]

Testing my freeby 100 lb tank was free if I filled it there so . . .

I have a 3/8" rubber hose running from my gauge to a manifold made of 3/8" pipe. There are 4 1/4 turn ball valves with 3/8" FPT X 1/4" flare fittings. From there I run 1/4" copper to my burners. The rubber is safely away from the fire and the copper doesn't get hot enough to matter.

I don't particularly like swivel fittings, slight as the chance may be I don't like adding a chance for a leak I don't have to. I've posted my forge enough times I don't want to bore the guys with another but if you check my posts from my header you can find all the pics, heck more than enough, to see what I did. There are pics of my "T" burner design as well.

Frosty The Lucky.