First forge

[Holeshot86]

Yes I know I need to find ridgedizer so let's get that out of the way. 

Just picked this up last night. It is set up for low pressure gas and has a variable blower fan. I will have to convert it to LP grill tanks. Will the fan work or be usefull with a high pressure set up? Or how would I go about setting up a 40# LPG into a low pressure system? 

The Smith says it works great as it sits but got rid of it because he built a bigger one. I know I need to ridgedize the fiber. I need to brick the openings. There are a couple welds that have broke free in transport home I believe. And the plaster/concrete on the bottom slides around in the forge.

Anyone know the best spots to go to to get what I need to convert this to LPG? Will Home Depot sell the fittings and long hose? 

[ThomasPowers]

B y "low pressure gas" do you mean Natural Gas at household pressures or Propane at low pressures? If it's propane at low pressures; that is just dealt with by using a regulator to meet the pressure(s) it is designed for.

Since the burner is NOT designed as a NA burner; you gotta have a fan!   Will that one work for the BTU's you plan to shove into the forge---Maybe.  My blown propane burner uses a 150 cfm blower considerably choked down, what is that one rated at?  Propane and NG work a bit differently due to the base energy content of the fuels. All those bends in the mixing tube makes one think it was designed for propane anyway. My best suggestion is to try it and see!  I hope you know how to tune a burner by varying both air and gas to get a good burn.

I get all my propane stuff from a propane dealer, they have it to hand and KNOW how it should work! I live in a rural area and so propane is common here---we have a propane kitchen range for instance.

Have you thought of building a Frosty T Burner NARB?  Naturally Aspirated so you can move the forge away from a plug.

[Mikey98118]

Why so many (and so large holes) in your proposed ribbon burner?

[ThomasPowers]

(If it was running on natural gas wouldn't greater volume be needed?)

[Irondragon Forge ClayWorks]

As far as the supplies to finish the interior of the forge, everything is right here in the IFI store. Important note I would not fire it up until I had it rigidized and the blanket coated with castable refractory.

https://www.iforgeiron.com/forum/254-gas-forge-refractories-and-supplies/

[Frosty]

I've never seen a build quite like that one but the multiple 90* turns in the supply pipe assure the fuel gas is well mixed. Yes, as you say the interior needs to be rigidized and a coat of hard refractory applied. A final kiln wash will improve effectiveness too. 

BBQ regulators tend to be too low volume to adequately supply a propane forge. 0-30psi high pressure regs. are reasonable money online and provide enough volume to run more than a reasonable fellow needs. My old obsolete 0-20psi regulator handles four 3/4" T burners easily.

Everything you  need is available online "Propane Warehouse" has about everything but if you search Adjustable propane regulator" online you'll get hits fro other suppliers. I've bought from the above mentioned warehouse but with today's supply issues I can't say what they have in stock but you aren't looking for anything exotic or weird. 

I hope the floor in your forge isn't REALLY "plaster/concrete"!! If it's loose just slide it on out and replace it with something appropriate to a propane forge environment!

Frosty The Lucky.

[JHCC]

IFI member Latticino is our local expert on low-pressure NG forges; I'll send him a message that he's needed here.

[Latticino]

Sorry folks, down with COVID so not as on top of things as usual.

All advice here has been very good to date.  I expect the original hookup was for residential pressure natural gas, which is what I run here at home as well, based on the apparent size of the gas feed.  I've not converted one to high pressure propane (or wanted to as NG is so much more convenient), but it shouldn't be that hard. 

I would definitely keep the fan assist configuration, but you may want to neck down the gas feed to something like 1/2" with a 1/4" orifice to avoid having a flame thrower if you regulator fails for some unknown reason (not critical, but a good safety measure).  Of course doors, proper rigidizing and coating with a refractory are also a good idea, as is a good quality gas regulator.

The other safety recommendation I have is to install a gas rated solenoid valve on your propane feed that is connected tot he same circuit as the fan.  Not quite as good as a flow or pressure switch, but if the power to the fan shuts down it will shut off the gas.

The chamber size is a little small in diameter for a typical fully developed flame, but having a multi-outlet burner should help with that (shorter, well spread flame).  You will have all the typical issues with multi port burners (characteristic optimal operating range and potential for preignition in the mixing chamber during turn-down), but these are more easily dealt with in a fan assisted configuration IMHO.  I'd be careful with the fan speed control, as conventional ones tend to burn out synchronous motors, and I think that Dayton may have such.  The blower may be a little small for the forge size in NG configuration, but could be fine with propane.  

As Mike and Thomas mentioned you get a different BTU output from propane than NG and the quantity of air needed is different as well.  Not firing on all cylinders now, so not going to do the stoichiometric combustion calculations, but you may need to adjust the number of outlets to get a good burn at the temperatures you are looking for.  Most likely fill some if you have a problem with preignition once the forge is up to temperature (all a matter of matching the flame front location to the temperature of the forge interior, as I have written about in the past).  Note: if you hear ANY pop-back, close off the gas immediately, but keep the air running to cool the burner.  After a minute or so you can usually turn the gas back on.

Floor and burner look to me to have been cast from Mizzou or some similar refractory.  Should be fine for flame and flux contact, but the floor may bleed a little heat.

[Frosty]

Sorry to hear the Covid got you. Get well soon.

Frosty The Lucky.

[Mikey98118]

Get well soon. We need for you to stick around

The problem with stoichiometric flame temperature calculations is that methane combustion suffers from a refrigeration effect, as part of the combustion byproducts recombine. I have never seen these figures posted anywhere; only estimates of how much they subtract from total combustion heat. It is clear that natural gas (mostly methane) still ends up as the clear winner concerning fuel costs, and also a clear winner for the cost of added oxygen for brazing. But, for highest flame temperatures, no. On the other hand, if we aren't torch welding steel, who cares?

[Holeshot86]

Hey guys, I appreciate all the help. I have no answer yet for the low pressure fuel system. I dont know if it was NG or LP. I only have access to LP and was going to pick up  100# tank. I do have a 0-30psi adjustable regulator with hose coming and should be here in a couple days. I still have to go online to get my wool coating. It is 2-3 layers deep if you recommend that I pull out half the thickness. 

As for the CFM of the blower I also don't know right now but will update as soon as I get home from storm duty (probably tomorrow night 4/19). The power cord for the blower and speed dial is pretty long 20-30'. I know this will be a lot of trial by fire for me as I've never had a forge. But every bit helps and I will use the knowledge given. And yes, the wierd plumbing set-up caught me off guard quite a bit as well.  I play with power all day on the poles but I've never been great as an electrician so the fuel solenoid may sit on the back burner for a while, atleast till I get comfortable with this forge and know that it is running well/ consistently.

I did get a picture of the tag. I could remember if I did. Says 50 CFM @ free air

[Frosty]

Nobody's born knowing this stuff, this is just another learning curve. The nice thing about a gun (blown) burner is how easy it is to tune. Put the speed control next to the regulator, well within easy reach and tune by eye and ear. If you need more heat, turn the propane psi up a little then gradually turn the air up until the flame looks and sounds right. Note the settings in the notebook you have handy so you can get close to THAT temperature again without having to hunt, next time. Yes?

That blower should make plenty of air. Free air or transparent mean air can move freely through it so blocking it off or choking it completely won't damage the blower or blow something apart. It's an impeller fan, it makes a LOT of air for the power you put in but won't stall if blocked off. they're good, safe blowers.

One of the advantages of a gun burner is how easy they are to tune, the disadvantage is needing to tune it every time you change temperature and being tied to a power outlet.

Naturally aspirated burners are harder to tune, you have to physically change the burner to alter the fuel air ratio but once it's tuned all you have to do to change heat output is change the psi. It stays tuned regardless of it's output and a NA burner doesn't need electricity so it's more portable.

Everything has plusses and minuses on it's score card. 

Frosty The Lucky.

[Holeshot86]

All you experienced smiths know the sound and look well. I on the other hand have the experience only with oxi-acetylene torches and the look of the flame in videos. But like you said, it will be a fun learning curve and with the guidance I've got here hopefully it makes the start easier. 

[Frosty]

You got it! None of us knew what a good air propane flame sounded or looked like when we started tinkering with the things. Well, I knew what a weed burner, commercial propane soldering torch or kitchen range flames looked like but not a forge burner. Mike might have I don't know but I sure didn't, Ron maybe better than I but maybe not. 

There are however, lots of folks who can evaluate a burner flame by sight now and we LIKE helping folks advance their addiction to hot steel and hammers. 

So go for it Bro, we have your back.

Frosty The Lucky.

[ThomasPowers]

By eye:  look at the flame impingement area and adjust the fuel *or* air to get it the brightest.  By ear: It should also sound the loudest. As I often do blades I tend to run a bit reducing and have MASSIVE ventilation to reduce CO risks.

[Leather Bill]

Reading through this I had a few thoughts,some maybe not exactly applical to this build but related.  If that butterfly on blower is origional I'd use it and lose the electric speed control until mfgr or motor shop says controler is ok.  As for shutting gas down via solenoid in the event blower slows/stops.  Draft induced gas furnaces have an air pressure switch,sail switch or other device to shut gas off.  For those like Thomas Powers and I that scavange junk yards,there's always gas furnaces in them to rob.  Safety measures/devices may not take a front seat when building the first or experimental burner but should certainly be on the short term to do list.  Even redundant measures/devices make sense for homemade burners.  Those junkyard furnaces have high quility safty valves in case pilot fails.  The gas valve, thermocouple, draft blower,air flow switch and 24 volt transformer can save some $$ and up your safty if you can take them.   While you are at it might as well grab the blower clamshell to vent the shop.  Holeshot has a gas pressure regularor on the way but also mentioned having oxy/propane torch.   Some torch regulators are capiable of enough volume to support small burners like these.  If building a burner and already have a torch there's advantages to using it.  The same regulator,hose,couplers,quick connects,flashback aresstors and backflow preventers can be easily switched between torch and burner plus are of high quility and reliability.  Acetylene accessories work fine with propane with a couple caveats.  Technically type R hose isn't approved for propane by some but have been used by many for years without incident.  Most hose on shelf now is type T anyhow.   The only reason an acety regulator might be limited is if it only registers 15 psi in the event you need higher pressure.  Most regulators go higher than 30 psi.  

[ThomasPowers]

The seals in Acetylene regulators will degrade with propane unless the regulator is marked "For All Fuel Gasses" on it.  Again it may take some time; but if you are worried about power loss---which has never bothered me, I just go over and cut off the gas when it happens; then possible leakage over time should be dealt with too.

[Frosty]

The problem I have besides old acet hoses, regularors, etc. degrading from propane exposure, is how cheap proper propane regulators are.

I don't know what the current inflation is doing to prices but last I looked they ran between $25 for moderate quality to almost $40 for top shelf. No need to adapt fittings, no worries about being safe, just screw it onto the tank and turn it on.

It's cheaper doing things right than trying to save money on a lashup.

Frosty The Lucky.

[Mikey98118]

Thomas,

I think you posted this in answer to my question to  Hoesshot86. Sorry not to answer promptly; it was just another Teflon moment on my part.

(If it was running on natural gas wouldn't greater volume be needed?)

Considered after I got my head out of my six...

You are correct. If I were attempting to calculate how much increase flame volume is needed between propane and natural gas orifices, I would set the total increase at 1/3 more. This is the estimate I read from people who had changed over. There were never many  comments on the subject back in 1999, when I was looking into it. Perhaps a better method would be to look up what gas appliance suppliers use to change out gas orifices between one fuel and the other to come up with the amount of increase. Then increase the gas orifices of known ribbon burner designs accordingly.

Frosty,

At today's prices, I would simply expect a $25 regulator to fail, sooner; not later.

[Holeshot86]

On 4/25/2022 at 10:54 AM, Leather Bill said:

Reading through this I had a few thoughts,some maybe not exactly applical to this build but related.  If that butterfly on blower is origional I'd use it and lose the electric speed control until mfgr or motor shop says controler is ok.  As for shutting gas down via solenoid in the event blower slows/stops.  Draft induced gas furnaces have an air pressure switch,sail switch or other device to shut gas off.  For those like Thomas Powers and I that scavange junk yards,there's always gas furnaces in them to rob.  Safety measures/devices may not take a front seat when building the first or experimental burner but should certainly be on the short term to do list.  Even redundant measures/devices make sense for homemade burners.  Those junkyard furnaces have high quility safty valves in case pilot fails.  The gas valve, thermocouple, draft blower,air flow switch and 24 volt transformer can save some $$ and up your safty if you can take them.   While you are at it might as well grab the blower clamshell to vent the shop.  Holeshot has a gas pressure regularor on the way but also mentioned having oxy/propane torch.   Some torch regulators are capiable of enough volume to support small burners like these.  If building a burner and already have a torch there's advantages to using it.  The same regulator,hose,couplers,quick connects,flashback aresstors and backflow preventers can be easily switched between torch and burner plus are of high quility and reliability.  Acetylene accessories work fine with propane with a couple caveats.  Technically type R hose isn't approved for propane by some but have been used by many for years without incident.  Most hose on shelf now is type T anyhow.   The only reason an acety regulator might be limited is if it only registers 15 psi in the event you need higher pressure.  Most regulators go higher than 30 psi.  

I've used oxy-acetylene torch because I used to do autobody as a profession. Love the ideas of scrapping an old furnace and I will keep a lookout for one. I'm still looking for a gas fitting shop and info from Irving or running a line from my home tanks. As they are only used in the summer for my stove top cooking and heat in the winter I should have plenty year round with 500# of fuel. When it comes to nozzle size installed, I have no clue what was already installed a d haven't had time to look it over or take it apart.  Was in New York all last week and had 2 home projects that took priority when I got home this weekend. Safety is definitely on my mind and it will be addressed as I can and hopefully before it ever becomes a problem. Not sure what you mean by the butterfly. And I will definitely test out the fan switch before running fuel through the system or firing up. I now have a fuel regulator that goes to 30psi and has a Guage and I have also got the itc100 reflective coating. Specs and reviews say I can just use that over my fiber mat without ridgedizer and refractory cement, so we will see if that is true.

[Holeshot86]

Sorry 100ht, not itc

[JHCC]

Rigidizing is recommended anyway, as it keeps the hard refractory firmly in place while it’s getting banged and bumped by workpieces going in and out of the forge. 

[Mikey98118]

Rigidizer also increases the life of the ceramic wool insulation quite a bit. Considering how expensive and irritating it is to replace, and how cheap and easy rigidizer is too employ...