Boiling wood - with natural gas question

[Hugh]

Hi there Everyone,
OK - I boil some of my wood before and after turning. I have a propane tank and a burner for heating my large stainless steel barrel. I have been wondering about hooking the burner up to natural gas. I have a natural gas line going into the shop for heating and the line is only a short distance away from where I boil the wood.

So the question is: will the burner that is made for propane, work on natural gas? Would I have to change the regulator? Anything else I would need to do?

I am getting cheap here. It costs me $3.05/gal of propane. It takes me almost 5 gallons to do a boil. I use a 5 gallon tank for the propane. I think the natural gas would be much cheaper to run.

Any ideas or help?
Thanks.
Hugh

 

[Fred Belknap]

All you need to do is change the orifices in the burners. Natural gas will need a larger hole in the orifice. Stoves use to come with orifices for both.

 

[Gil Jones]

Natural Gas 1,030 Btu/cu ft.....100,000 Btu/therm
Propane 2,500 Btu/cu ft...........92,500 Btu/gal
It would be helpful to know how much of each fuel you would use (in common units) to boil an equal amount of water and wood. Then figure the cost per common unit. It looks like propane has over twice the BTU s per cu/ft.

 

[Bill Boehme]

As mentioned, natural gas requires a larger orifice. Since I have a complete set of numbered drills from #1 through #80, I just started with the size that fit the original butane size and then incrementally increased orifice size until the flame would stay lit and also burn cleanly with a blue color. Since you can't go back to a smaller hole, stop when the flame is satisfactory.

More information is needed in order to translate propane and natural gas usage into real world conditions. Even with more information, it is hard to get a good handle on the cost without going into a lot of data collection that is not easily done. In general, the cost of natural gas is pretty cheap compared to propane or butane. Here is a PDF document that sheds a little light on the subject.

 

[Hugh]

Thanks Everyone for the info.

Good info. I am doing a boil right now so I can not check the size of the orifice. I got into a bunch of wood and I have been trying to keep the pot boiling.

Gil - you made me go run down an old utility bill - I pay about $1.25 for a therm of natural gas. The gallon of propane costs me $3.05. So it looks like I would save a bit of money. I know it would be a lot more convient to just hook up to a natural gas line than to run around trying to get propane everytime the 5 gallon tank runs out. I run off to swipe the BBQ tank.

With the gas line right there already - I would just have to add a small extension - it just seems like a good thing to set up.

Bill - lots of good stuff in the PDF and the advise about drilling the hole out.

Thanks.
Hugh

 

[Mark Mandell]

Danger!!

Hooking a portable device into a natural gas line is, in most places, unlawful; reason being, in the event of a leak at the device or in the line, the gas never stops. Before you tap into that line, you should contact your gas company as they don't take lightly to modifications to their delivery systems. Do things right, and they'll be happy to sell you all the gas you want.

Yes, you will have to re-port your burner and, depending on where you put the tap, you'll need a new regulator/vaporizer.

 

[john lucas]

forgive me for asking this but I have always wondered about the expense of boiling. How much does it add to the cost of a bowl? I think I understand why people do it. Faster turn around and possibly less warping but have always wondered about the cost when you add the time involved in doing it along with the cost of fuel.

 

[Bill Turpin]

There is a lot of good info in Bill's PDF. BBQ tanks are usually 20 lb tanks , not 5 gallons. This correction may effect your cost analysis. You might be able to change the spring in your regulator. This will require getting your gas supplier involved, which you have already been told to do if you hook to your house gas plumbing. You will have to have a 100% gas shut off valve if you have flame failure. This will add at least $200 to your conversion. If you ever have a fire/explosion your insurance will deny ALL claims once they find a non-code installation! Propane is much denser than natural, that is why the orifice difference. Almost like water vs air.

 

[Tim L]

The last time I got a 20# propane tank filled the guy told me they hold 8 gallons of propane. Just thought I would throw that in to try and help you guys figure out the costs.
Tim.

 

[MichaelMouse]

Some strange things, what? Seems most figure 4.1 or 4.2 lbs/gallon for liquid propane. http://www.liquidpropane.net/ So 4.7 gallons per 20# cylinder.

 

[Hugh]

Hi there Everyone,
Good stuff. Enough to almost throw out the idea of converting. I thought it would be just a simple change over. Not sure I want to get the building inspector and PG&E involved. And I do know that I do not want to have anything to do with my insurance company.

The last time I filled my 20# tank (5 gallon?) - I went with a totally empty tank - one of the newer type of tanks - and it registered 4.6 gallons. I had two tanks and ended up with 9.2 gallons - cost $31.00 to fill the two tanks. I can get 2 1/2 barrels of wood boiled up with that.

For John - I boil Madrone wood - it is the only way I have found that I can use it. I have a stainless steel barrel that is about 40+ gallon size. 22" in diameter. When I rough out bowls, I can get about 12 - 15 large - medium sized bowls in the barrel (more of the smaller size). So the cost of the propane would add about $1/bowl. There is the time involved but I do not figure that in I am afraid. I do not boil wood to speed the process as I have enough roughed out bowls that does not factor in.

I recently lucked out and found a bunch of Madrone trees removed from a piece of property. I picked up a bunch of burl from those stumps. That is what I am in the process of boiling up right now. I chunk up the burl into moveable pieces (I have to be able to lift them into the barrel) and then boil the chunks - and then dry in chunks. I can not turn fast enough to be able to process the wood unless I do this. And I have found that if I have chunks of burl around - I find a project to use it for.

Thanks again to all who answered. It is always good to get a good reality check - and no one was hurt in the process - good stuff all.
Thanks.
Hugh

 

[Tim L]

I should have checked the net before I posted about the gallons of propane in a 20# tank. Either he told me wrong to charge me more or my memory is crap. I thinks its the latter. lol

 

[Sean Boyle]

I am fairly new to turning so I have one question Why Boil your wood

 

[MichaelMouse]

I am fairly new to turning so I have one question Why Boil your wood

In this case, to help relieve stresses in the wood. Lignin will flow and perhaps degrade a bit as the wood boils. Wood with bad nature like madrone will relax a bit and be more tolerant to drying stress after boiling. Steaming and microwaving, which boils from within, are also used to relax things enough to allow some spatial rearrangement.

Boiling or steaming are also used to help equalize color in woods with very light sapwood like cherry, walnut or beech.

 

[Sean Boyle]

I live in Northern Ontario and do not have a variety of green wood to turn around where I am my choice are oak maple and birch. I have tried turning green maple with out a lot of success therefore I turn kiln dried wood. I take it that there is no need to boil kiln dried wood and had I tried boiling my limited attemps at green wood would it have help in reducing the large cracking

 

[Hugh]

Sean,
Not sure what would happen in boiling the Maple wood. I have not tried it.

I only boil Madrone wood. I have tried to turn it and dry it normally but without luck. When I boil the wood I can get a bowl out of a roughed out blank.

I have tried to boil up Eucaliptus, Valley Oak bowl blanks without any luck. Now I just stick to boiling the Madrone wood.

Good luck.

Hugh
p.s. Everyone - I am going to stick to the propane tanks I believe. Thanks for the discussion. Good stuff all.
Hugh

 

[john lucas]

Thanks Hugh. Having never turned Madrone I'm not aware of it's problems.

 

[wnnelson]

Do it right

Hi Hugh You have been given mostly good information and some not so good. I work for the other large Gas Company in California and have done BBQ conversions from propane to NG as part of my job when I was a service tech. The process is very easy and will be even easier for you if you call PG&E and have them come out and evaluate and convert the burner for you. They will measure the propane orifice and them convert it to NG with a very convenient chart which will tell them what size drill is needed to drill out your propane orifice. (I can get a copy of this chart if you need it) If you have a convertible appliance regulator they will take care of that too. Propane is delivered at 11 inches of water column and NG is at 8 inches. If could be as easy as flipping the spring around inside the regulator, or turning down the pressure. All this does come at a cost but they will tell you that before they do any work.
As far as things being illegal I think that Mark has it a little wrong. Any pipe that is on your side of the gas company's regulator belongs to you and you can change or adapt it at will subject to your local building code. Portable appliances are allowed with a flexible hose as proven by all the BBQs that are all ready installed in California (this is BBQ land by the way). This is a BBQ hose and not the standard flexible stainless steel line for hooking up a standard appliance. If your boiling tank is mounted in a permanent manner you can use the stainless steel connector or hard pipe it directly. As far as I know I have never heard of a 100% gas shut off valve having to be installed for appliance protection. In California we use them for earthquake protection but not because you have a certain appliance.
Don't forget to figure in the gas for your car or truck for hauling the propane as that adds up fast too (over $4 here as you know). After you have found out how much it will cost to convert to NG you may find that you can burn propane for years before the conversion cost to NG has a payback.
Call PG&E and your local building department if you want to do it right, if not you could have a potential problem on your hands. It all can be done by yourself safely but you really need to know what you are doing.
Good Luck

 

[MichaelMouse]

I live in Northern Ontario and do not have a variety of green wood to turn around where I am my choice are oak maple and birch. I have tried turning green maple with out a lot of success therefore I turn kiln dried wood. I take it that there is no need to boil kiln dried wood and had I tried boiling my limited attemps at green wood would it have help in reducing the large cracking

Not sure how far up you are in Ontario, but Acer saccharum and A rubrum, hard and soft maple, are pretty friendly when turned green and allowed to cure. Shape and thickness are players. Don't get too thick, don't get to broad at the bottom, and you can count on 'em surviving. Yellow birch can be a problem, because it's irregularly swirled and stressed. Sometimes it moves too far to make good round even at thicknesses that would crack maple. Makes for smaller bowls, on those pieces, but few are that bad.

I'm north of 47 myself. Beech,birch and maple are the climax hardwood forest.

 

[Hugh]

wmnelson - Thanks for the info - good stuff. I would not want to do the conversion if I thought it would be a problem and cause a fire. Right now I came upon the wood and need to process it - which will take boiling up a pot of wood 10 - 12 times for what I have. Hopefully later this summer I will need to do it again another 5 - 6 times. Not sure if the cost would be worth it. I need to work on it a bit more. I will keep investigating and one of these days make a decission.

What I would like to be able to do is use wood for fuel. But there are too many problems with that.

Thanks for the info. I will check with PG&E and see what they say. In the past they have been a good source for electrical info for me. We do a bit of BBQ in the north part of the state also.
Hugh