New Forge: General Questions

[Andy98]

Hi,

I'm attempting to make (my first) forge, and I'm hoping to get some help and advice.

I have an old..metal box. I'd call it a tool box, but it doesn't have a top handle so I'm not sure what it was used for. It's 20" x 10" x 10".

This is probably not going to make any sense, but I'm thinking of making basically a 10" long tunnel forge right in the middle of the box (2" of kaowool) and I'll make a front&back (inside the metal box as well) out of either soft-firebrick or more kaowool. That'll leave a gap of about 3" between the forge and the sides of the metal box. I plan to cut holes in the metal box essentially to act as tool-rests.

I intend to mount the burner so it enters from the side, near the middle. 

My plan is that while operating the forge, I'll have the metal-box's lid open so that the dragon's breath can escape without melting the box. I'm *hoping* that the sides of the box near the entrance/exit don't get too hot - but if they do I can cut them away a bit as well. When I'm done with the forge, I want to be able to remove the burner, close the lid and store the box out of the way (with other stuff stacked on top of it as well. 

I intend to coat the top 1/2 of the forge with satanite, and the bottom 1/2 with bubble alumina (from  www.hightemptools.com). That should give me a roughly 10" long by 5.25" diameter tunnel.

My goal is principally knife making, including heat treatment. I'm really not going to use the forge a lot - just not a lot of spare time at the moment.

My questions are:

1. Is this crazy?
2. Do I need to worry about the paint that is already on the box? Do I need to strip/grind it all off, or burn it off, or just ignore it? At some point I would like to repaint the forge with high-temp paint to try and make it look a little nicer, but I figure high-temp paint over "regular" paint won't work since the "regular" paint will just bubble if it gets hot.
3. I intend to mount the burner horizontally, in the middle, entering near the top of the forge (e.g., forcing it to swirl, not blowing directly onto the work piece). Am I on the right track?
4. I am considering mounting the burner so it slightly points rearward. In my head this makes sense, but I can't help but notice nobody does this - any thoughts?
5. I plan to build either 3/4" T-Burner, or a Z-Burner. In my mind the T-Burner seems superior (more induced air) but for some reason I'm freaked out by not being able to adjust the mig-nozzle, and I'm also worried about being able to cut it cleanly). For all intents and purposes, difficulty of construction aside, is the performance of these two burners basically the same? 
6. Does anyone have a better idea of how to turn this box into a propane forge? Should I abandon the box?

I also have some questions about propane regulators, but I'll post that in a second thread - hopefully that's not contrary to accepted etiquette.

Any and all advice and guidance would be appreciated.

Thanks in advance.

 

 

 

[timgunn1962]

My advice is as follows:

1/ Work out exactly what you want to do in your first forge.

2/ Find a well-documented forge-and-burner design that has a proven track record of doing the result of 1/ above.

3/ Build EXACTLY to that design. Note that you want a "forge and burner" design, not a separate "forge" design and "burner" design. 

4/ Use it. Take notes. Look at other designs. Try to understand what is going on. Don't expect it to be easy: it's not particle physics, but it does have a fair bit in common with rocket science.

5/ When you are confident that you understand how all the many variables interact, reassess what you want to do and what changes need to be made to enable you to it.

6/ Only ever make one change at a time. Make notes. Photos and Videos can be useful too, but a notebook is indispensible.

Since you seem to be strongly attached to the box, I suggest you keep your forge, burner, etc. in it when it is not in use. A 2"-Kaowool-insulated knifemaking forge is unlikely to need a shell much above 8" diameter, so the box should be plenty big enough. 

My experience to date is that the most difficult thing to get a forge to do well is the heat-treat. All the hype is usually about achieving welding temperature and there seems to be an unspoken presumption that a forge/burner setup that will weld can do anything involving lower temperatures with ease. I am pretty sure it just ain't so, though others may have different experiences. 

 

 

 

[WayneCoeArtistBlacksmith]

First don't build a forge to a square design.  Second, go to the Forge Supplies page on my web site and study the attachments.  This will show how I like to build a gas forge for a long lasting, efficient forge.

Let me know if I can help you or if you have any further questions.

[Andy98]

48 minutes ago, WayneCoeArtistBlacksmith.c said:

First don't build a forge to a square design.  Second, go to the Forge Supplies page on my web site and study the attachments.  This will show how I like to build a gas forge for a long lasting, efficient forge.

Let me know if I can help you or if you have any further questions.

Just to be clear, the box is square (well, rectangular) but I intend the actual interior of the forge to be a round tunnel. Basically. I intend make a kaowool tube that just happens to rest inside a rectangular box.

I have explored your site (quite a few times!) but I will for sure go back and check again. I seem to forget 5 things for every one new thing I take on...

[swedefiddle]

Good Morning Andy,

Use that box to hold your Tools or other things in your WorkShop. It would be a pity to waste the storage ability and ruin it by making it into a "Kind-a-Forge", just because you can.

It is too large for a starter Forge. Start and learn with a Paint Can Forge or something similar. Some people use a large Coffee Can. A section of Pipe?

A real simple Forge can be made with 9 Fire-Bricks and one burner. Stack the Bricks on top of something. I use a 45 gal drum on end, with a cut out in the side. The inside of the Drum becomes your Slack Tub. When your Propane tank starts to freeze up, sit it into the water in your Slack Tub. The water acts as a Heat Sink and slows down the Propane Freeze. The Propane Tank in the water will cool the water, as well as your refreshment container. Start simple and learn what works. I also use an old Bar-B-Que stand (one that has wheels) as a Base.

The biggest mistake is to think you are going to become a Blacksmith, over night. Enjoy the Journey, there is no end of Learning.

Stay Safe, Wear your Ear and Eye Protection. You can make an apron from an old pair of Blue Jeans, the backs of the legs don't wear out so use that for your Material.

Neil

[Frosty]

Welcome aboard Andy, glad to have you. If you'll put your general location in the header you might be surprised how many of the Iforge gang live within visiting distance.

That was really well said Tim ad truer words were never spoken.

Sure you CAN build a forge in that box and it'd be a dandy. Unfortunately if it's the first one you build it's going to be filled mostly with mistakes. There a lot of "traps" folk fall into while they build experience. Feeling you just have to use a thing because you have it is a prime example. I have piles of "that's good for . . . x" stuff and it is, it's all good I just haven't gotten around to using it. The flip side of that coin is I HAVE this . . x I'll bet I could do X with it. Then finding yourself spending a huge amount of tie and resources trying to make it so.

Anyway, about the burners. The Sidearm and T are basically the same burner they're "jet ejector" type naturally aspirated induction devices. The device itself isnt or wasn't invented to be a gas burner they're pumps. Anyway, the Sidearm and T both work just fine, if tuned properly there's no significant difference.

Once tuned there's really no need to move the gas jet unless you make a change in elevation, you'll know if it needs tuning when you light it. Making a clean cut on a mig contact tip is easy, there are a number of methods. You can just cut it with a fine TPI saw, file smooth and clean the hole with torch tip files. A Dremel composition cut off blade works very well, clean with a tip file. One I've used a few times is to chuck the mig tip up in my hand drill and trim it down with a draw file by pulling the trigger and gently applying the mig tip to the file.

Just don't use a drill bit to clean the hole, copper alloys can be a stone Mother Bear about work hardening, galling and grabbing a drill bit faster than you can recognize the snap as the bit breaks. Torch tip files are designed to clean copper alloys and they do a much better job even if you don't jam the bit.

Another trap we all fall into now and then is. Bigger is NOT better in most cases. My shop forge is still WAY larger than I need, it's a good 20 years old and I've only ever fired up all four burners a couple times and that was when there were a number of people working in it. Well, I lit all four yesterday but I was heat curing some rigidizer on Kaowool for the new forge's liner. It's a MUCH smaller forge.

Just pick a design hopefully one with straight forward plans and follow just the ONE set. don't go looking all over the internet for help, every knucklehead with an unfounded idea will chime in with his/er can't miss "help." If you need help, ask the person who drew up the plans you're following.

Frosty The Lucky.

[Andy98]

Ok, thanks everyone for the responses.

I'm pretty surprised with the pushback on the metal box idea - which, probably means I have underestimated how much I don't know. Not it matters, but my overall plan was to essentially construct the thing per the 5-gallon-bucket forge from Larry Zoeller's site (http://www.zoellerforge.com/simplegasforge.html), again with the interior round even though the box is square. I did intend to have the burner enter sideways rather than from the top (which seems to be a common customization), and I'm lacking ITC/Plistix but hoping the bubble alumina helps enough.

But I'm happy to change gears - my goals are to have a forge where I could:

• Heat treat a ~10" blade I've already forged.
• Make additional, smaller, knives.
• Make some tongs.
• Possibly try to make a hammer. This is the largest thing I could imagine making in my forge.

I'd be happy to follow a single burner+forge plan - can you guys recommend one? If I include (what I judge to be) reputable sources, then my options seem to be:

• The standard propane cylinder forge - way too large for me.
• Two-brick forge - but all the plans out there are all based on soldering torches and I'm pretty sure I'll get limited use out of one.
• Paint-can / coffee-can forge - Too small to help me with my existing blade - plus all of the turn-key plans are also soldering torch based.
• Wayne Coe's plans - This is based on castable and for various reasons (short forging sessions, need to move the thing a lot, don't want to wait forever for it to be cool enough to pack away) I'm inclined to use kaowool instead.

..which leave me with a Freon tank forge, or a 5-gallon-pail forge both from Larry Zoeller's site. Are there others I should consider? I presume if I build the 5-gallon-pail forge but use a T burner instead of a sidearm, nobody will say that's too much of a variance (?). In either case, I'd be tempted to just buy some sheet metal and make a tube, since I don't have any access to either Freon tanks or metal pails.

Thanks in advance.

 

 

 

 

[Frosty]

My first real piece of advice is don't get in a hurry. My second is don't even TRY making the perfect forge, there isn't one. You have a pretty good idea of what you want to make which is a lot more than most of us had when we got started I think I wanted to make swords but that was a good 50 years ago. Maybe someday.

Heat treating wants an even temperature in the forge but home built forges don't usually have a very even temp, some pretty good but most okay at best. How most bladesmiths make sure the blade's heated evenly is by watching it and passing it back and forth through the hot spot. A number of guys have specialized heat treat forges but a number of the guys here make blades for a living, write books and are world names.

Okay, I'm drifting. The forge you want to build is one that will be good enough. Believe me in a few years you'll have built at least one and probably a couple few more forges before you get one that suits YOU.

Frankly you aren't "left" with a couple choices unless that's what you've narrowed it down to. Wayne has plans for forges insulated with Insulwool, or an equivalent ceramic blanket refractory as insulation (Backing) that has a hard castable refractory "plastered" on the interior for the Flame Face. Lastly the flame face is "Kiln Washed" with a zirconium silicate IR reflector, the ITC-100, Plistec, Metrikote, etc. Or in my stubborn Scottish soul making my own high zirconium kiln wash.

The outer shell doesn't HAVE to be anything in particular, your tool box WILL work though I can think of a number of things it'd be much better for in a knife shop. The shell only needs to contain the refractory, support itself and probably never more than a couple few lbs. of steel and lastly be easy to attach things to, say a burner mount, legs, perhaps a telescoping stock rest.

All that other stuff is cool but what you really need is something to hold your refractory and stock. The way I recommend a person chose their forge is based First on what they want to make, in your case blades up to maybe 10"-12". The diameter or width and height are a matter of convenience after you have your basic minimum. If you go with a 6" ID and 10" length you'll have a volume of around 283 cu/in. Make it 12" long and you're looking at about 339 cu/in.

The focus that matters is 2 fold, first if volume, the outside of the shell is irrelevant, what matters is the VOLUME of the chamber you're heating. I believe you have a handle on this but I repeat it a lot anyway just in case. The other factor is shape, the closer to a equal dimensions on all sides the better, a sphere or cube so to speak. A sphere is a FAR better shape than a cube.  Anyway, we rarely get the ideal: tool, job, materials, boss, situation, etc. the 6" dia. x 10"-12" long is long and narrow so a burner is going to make a HOT spot and the temp will diminish as the distance form the burner increases. It's going to do that no matter what but we can deal with it.

For a more even temp aligning the burners tangential to a chamber wall promotes a vortex which stirs the pot in an even manner. Aiming it directly at the opposing face causes turbulence in the forge so the flame isn't as evenly distributed. Aligning directly into an opposing wall especially only 6" away tends to increase the back pressure on the burner so it's not as efficient.

Another even better way to make even heat is by using multiple burners, in the above example two 1/2" NA burners evenly spaced in the chamber works much better than one. Two 1/2" NA burners has the same output as one 3/4" NA burner.

Remember, the numbers that count are length, cross section, "volume "   and shape.

The difference between varieties of well tuned ejector type NA burners is negligible. Larry's Sidearm is an excellent burner as is the T and those are the two easiest I know of to build. If you have good shop skills then build Mikey's Ferrari burners. They ARE observably and measurably more efficient burners because they are more precisely built and based on better knowledge of how the things work.

Anyway, I like two 1/2 burners in a 6"dia x 12" l. forge. 2" ok blanket, rigidized and plastered is going to want a shell roughly 10" dia and a little longer than your desired length.

Just don't think you HAVE TO use something you have, found, were given, etc. That's an easy corner to paint yourself into, especially for natural pack rats like blacksmiths.

There are so many different things available that are CLOSE ENOUGH to what the "designer" states as THE thing to use the tweaks to get whatever you have to work is insignificant.

Look around, talk to folks and take your time before you decide what to build then stick to THAT plan.

Frosty The Lucky.

[Andy98]

Ok - thanks again. After some ruminating, and realizing that (as Frosty said) that I'm almost certainly going to have to keep moving the blade around to evenly heat it, a very small forge is starting to seem really attractive. Being able to box it all up in that toolbox is just as useful to me as making it out of that toolbox (storage is a real factor for me!). I can also worry about making a hammer later (so this forge need not be big enough to accommodate).

So...

Questions relating to my actual forge:

1. On another thread (this one) - @teenylittlemetalguyposted about his 2BF with a 1/2" T burner, 2-1/8" ID chamber cut the full length of the brick. Is there any reason this shouldn't be my first forge? Or would a paint/coffee can with a backport be better?
2. If I do go with the 2BF should I bother coating the interior at all with my satenite & bubble alumina?

General knowledge questions not specifically related to my forge (meaning, don't worry about putting ideas in my head that'll cause me to mess up my actual forge):

• I'm under the impression that almost all of the heat loss for a forge will be through the doors. Most people describe their forge exterior as being warm, but not hot. Is that accurate?
• Is it true that in general, a forge with a larger cavity and small doors will be preferable to a forge with a straight tunnel design (assuming you've insulated well enough to make total heat-loss through the shell equal?

Thanks again.

[teenylittlemetalguy]

Obviously I like the two brick forge. It is ideal for a first because it is easy, cheap and provides plenty of heat.  Admittedly it's main limitation is width, but even many wider projects can be done if planned out.  I have made several hammer heads in one and a couple small 'hawks

 I wouldn't be surprised if a blade smith could point out an issue or two with its use for blades. I am not a blade smith but have made many blades in them and had no issues. 

 I have since made larger forges and the lessons learned on the little ones saved me from expensive mistakes on larger ones. I like to use full solid sides to support my bricks. The sides of the brick don't get hot but the metal does conduct back and the sides get hot using metal sides.

unless you plan on forge welding you would not have to coat the interior but it does help. If forge welding do coat the interior to protect it from flux. With heavy use plan on regular brick changes. solid side supports extend brick life as well.

 

 

[Frosty]

That little 2 brick forge is SCREAMING HOT, I've used it a few times. I only have two issues with it: it's a little too small for my tastes but only a little larger would suit me perfectly for most of what I do. Soft fire brick or the stuff we get here isn't rated above 2,200f so our burners tend to destroy soft fire brick pretty quickly. I THINK Tristan is thinking of casting his next one from Kast-O-Lite 97.

When I say a LITTLE larger that's what I mean, just a little. Visualize a brick, 2 1/4" x 4 1/2" x 9" I really like that volume as the chamber size. The shape isn't ideal, workable but not ideal, the volume is nearly perfect though. It's only around 91 cu/in and well within EASY range of a 1/2" burner. The shape isn't so long as to need special tricks to get even temps.

Casting a forge this volume in a little better shape would be a sweet little forge. Think a vaulted chamber. A capital D laying on it's flat side.

Frosty The Lucky.

[Mikey98118]

Andy,

Go back to Ron's burner pages and have a good long took at his mini forge. Then, down load a free PDF copy of Gas Burners for Forges, Furnaces, & Kilns from the Net; it will give you some improved construction techniques in its 5 gallon forge chapter. Then, ransack these threads to find your way to build a 1/2" Frosty burner to heat your little knife maker's forge with.

If, later on, you get restless and  decide you want to build something more than is quite good for you, than come back and ask me how to find your way to the deep end of the pool. I'm always happy to have another dissatisfied soul join me there

[Frosty]

2 hours ago, Mikey98118 said:

Andy,

 I'm always happy to have another dissatisfied soul join me there

You put it soooo eloquently Mike. I know I've been harvesting failures for I don't know how long in the hopes of a repeatable success or heck good enough. We'd be dangerous in the same neighborhood.

Frosty The Lucky.

[Buzzkill]

Andy,

Freon tanks are the same size (and probably from the same manufacturer) as the disposable helium tanks used for blowing up party balloons.  That's what I used for my latest forge.  A single T burner is more than enough for that size of forge with a couple layers of 1 inch thick kaowool lining it.  Assuming you put a pass through opening at the rear it's enough for forging fairly large blades.  If used for heat treating, ten inches should be no problem for a simple steel.  You may have to do a minor amount of pumping in and out to get an even heat before quenching, but nearly the entire blade will be heated with that size forge.  I hammered out, and brought to critical for quenching, a kukri style blade with a cutting edge around 15 inches long and an overall length around 23 inches in my forge.  If you wanted to ensure a more even heat then use more burners of smaller diameter (evenly spaced in the forge)  and/or place a piece of pipe in the forge then put the blade inside that to bring it up to critical.

If you don't have access to a tank then use something to make roughly the size you want.  Sheet metal rolled up to the diameter you want and cut to length, stove pipe, etc. will work just fine.  The nice thing about tanks is they are round, light, and usually thick enough (if only barely) to weld on things like burner mounts and legs, but there is more than one way to fasten those things in place.  If you have something that is slightly bigger in diameter than you want and you have some spare kaowool you can always decrease the diameter 2 inches at a time by adding another layer of kaowool.  There are lots of ways to get what you want once you figure out what that is.

[WayneCoeArtistBlacksmith]

To get a Freon tank just go to the local HVAC guy.  They use tons of them and can't get rid of them.  They can't recycle them.  Be careful when you go ask for one,  if you don't watch closely they will fill up the back of your pick up.  The same is true of auto repair shops that do AC work.

Let me know if I can help you.

[Mikey98118]

 

But we are in the same neighborhood, Frosty.

It's a cyber neighborhood is all. In person, I'm just a tired old man with a speech impediment. On the group I'm a revved up mind backed up with considerable knowledge of  its subject. It's a no-brain er. Working with you guys even gives me fresh ideas. Fresh ideas are so sparkly!

[Andy98]

Ok, totally excited about this approach now - thanks everyone for your comments. My thinking is that I'll build the two brick forge first, and then if necessary I can make a slightly larger forge down the road (probably along the coffee can/freon can style).

• For a two brick forge: Should I use K23 or K26 bricks? I couldn't seem to find that question being asked before...which is somewhat surprising.
• For the 1/2" T burner: If I swap the 3/4" x 1/2" (run x outlet) with a 1" x 1/2" - is that a problem? I can get the 3/4" T, it's just going to be a little harder than the 1".

Also, for mounting the mig tips: I understand that 1/8" sched 40 pipe is too thin (ID of the pipe is too large) to tap 1/4"x28.- but I see plans that have used various fittings:

• 3/8" flare to 1/2 IPS (mig tip going into the 3/8 flare end)
• 1/8 mpt to 1/4 flare (mig tip going into the 1/8 mpt end)

...so it looks like fittings must have a more narrow ID than pipe nipple? Is there any way to predict which fittings will have a suitable ID (e.g., any brass 1/8" mpt fitting is likely to work?) or is it really unknown and until you try/measure you can't know?

Thanks again!

 

[Frosty]

If you're going with brick buy the highest temperature rated ones you can. We have to special order soft brick with a greater than 2,200f rating so bricks in our forges tend to crumble pretty soon.

Do you  know what size drill bit to pilot for a 1/4"x28 tap? Take THAT drill bit with you to gauge fitting ID. There is variation in dia, some brass fittings are too open, come need chasing.

1/4" Scd 80 nipples, not scd 40.

Sure you can change the run diameter of the T but it'll bring more factors to tuning than sticking with the plans.

I'm thinking most guys who are asking this many questions regarding written and illustrated plans are going to have enough challenges getting one built to plans tuned. I'm betting you'll be up and working if you bought one online though I haven't been in a real hardware or plumbing store that didn't carry 3/4"x1/2" in the bins. Not talking about big box stores though most do carry them.

Frosty The Lucky.

[BlackMetalViking]

Andy,

I have found that a lot of the materials can be found at RONA in the plumbing section. The only thing I couldn't find there was the Flare x MPT fitting. I even found small rolls of a KAOWOOL equivalent, and a castable refractory good to 2600F, all resonably priced. Alternatively, in Mississauga, there is a Green Line Industrial Hose and Fitting store, they will have EVERYTHING you'll need for your burners(except mig tips and tools), check out their website greenlinehose.com. 

Viking  

[Mikey98118]

You use schedule80 1/8"  pipe nipples, if you want to tap 1/4-28 MIG tip thread directly into them. Any place you can get  schedule80 1/8"  pipe nipples  should also have a good supply of "T" fittings, as for instance McMaster Carr does.

[Andy98]

If you're going with brick buy the highest temperature rated ones you can. We have to special order soft brick with a greater than 2,200f rating so bricks in our forges tend to crumble pretty soon.

Hmm - I'm not sure where I got confused on this - I had consulted a data sheet that said both the K23 and K26 bricks had the same temperature rating, but I must have misread since I've now checked several mfg's sheets and they all clearly indicate the K26's are 2600oF vs 2300oF for the K23. Anyway, I'm straight on this now.

On 7/7/2016 at 10:23 PM, Frosty said:

Scd 80 nipples, not scd 40.

Understood - in my post I said sched 40 is too thin, and it's ID is too large.

On 7/7/2016 at 10:23 PM, Frosty said:

I'm thinking most guys who are asking this many questions regarding written and illustrated plans are going to have enough challenges getting one built to plans tuned.

Sorry - I know I'm asking a lot of questions - I just like to do a lot of research before I actually go and do something. Unfortunately, I have more time available to plan things than to actually do things.

The other factor is that the "real" plumbing or industrial-supply places I'm likely to go to are the order-at-the-counter deals, so I'm trying to walk into the store knowing exactly what I want - or as close as possible - I've never found them to be very friendly when you walk in unprepared.

That said - I have my contact-tip-holder: A 1/8" flare x 1/4" MPT. The 1/4MPT will be for my hose connection, and the 1/8" flare is narrow enough I can tap it to 1/4-28 to match my contact tips. 

Do I need to worry about the contact-tip-holder unthreading from the "T" every time I screw on/off the propane hose?

On 7/8/2016 at 0:35 PM, BlackMetalViking said:

Andy,

I have found that a lot of the materials can be found at RONA in the plumbing section. The only thing I couldn't find there was the Flare x MPT fitting. I even found small rolls of a KAOWOOL equivalent, and a castable refractory good to 2600F, all resonably priced. Alternatively, in Mississauga, there is a Green Line Industrial Hose and Fitting store, they will have EVERYTHING you'll need for your burners(except mig tips and tools), check out their website greenlinehose.com. 

Viking  

Thanks - I've never heard of greelinehose before, I'll keep them in mind - thanks for the reference!

Amusingly, I managed to find a Flare x MPT at Rona, but couldn't find a 3/4 run x 1/2 T. I know I can buy one from Acklands-Grainger (closer to me than Greenline Hose), so I'll probably swing by today to grab it. That T should be the last part I need for the burner.

There is also a (seemingly) good pottery place that I can easily get to: http://www.psh.ca/ - they seem to have all the kaowool, high-alumina-shelves, IFB, etc.. so that should do me fine. 

[Frosty]

1/8" flare? in my plans the fitting is 1/4" flare to 1/8" MPT. If you're going to connect a rubber hose to the "T" use 1/8" MPT x 1/4"  MPT.

Most supply houses that deal with professionals don't like spending a lot of time answering questions for people who are guessing. If you ask their advice about making a propane burner they'll likely stop talking all together unless you buy a burner and have it professionally installed. Too much liability helping untrained folk build their own fuel gas burning appliances.

I laid out a parts list in detail so you can print it out and buy those parts. Hand it to the guy at the counter.

Frosty The Lucky.

[Andy98]

On 7/20/2016 at 3:35 AM, Frosty said:

1/8" flare? in my plans the fitting is 1/4" flare to 1/8" MPT. If you're going to connect a rubber hose to the "T" use 1/8" MPT x 1/4"  MPT.

Yes - the 1/8" flare ID was small enough to drill+tap to accept the mig tip, and the 1/4" MPT is for my hose connection.

Here is the built burner: 

 

From top to bottom that is:

• 1/2" coupling (they didn't have any metal thread protectors) for an initial test outside-the-forge.
• 4" long 1/2" black pipe
• 3/4" run x 1/2" drop black pipe T
• 0.023 mig tip, cut down in length a bit.
• 1/8" flare to 1/3" MPT
• 1/4" ball valve
• 1/4" pipe nipple (supply house's best suggestion for getting a male fitting to accept my hose)

...then the hose connects on to that, which goes back to the regulator.

Are there any issues with my build? I put thread tape only on the connections that are outside the burner (e.g., none on the mig tip) - somehow I couldn't bring myself to skip it.

I gave it a first light, and the results were unspectacular. Running at about 6-10 psi, it wouldn't stay lit:

• I used a propane torch to try and light it and the flame would just never catch. It looked to me like the velocity was just too high...? It seemed like it was "blowing away" the propane torch's flame.
• If I blocked approx 90% of the air inlet ports, I would get a sustained and very rich flame (the kind of gently rolling burn sort of flame).
• As I opened the ports, I would get a more intense flame and then it would just blow out.

...my guess from this was that the coupling was insufficient as a flare. So I made a temporary flare, approx 3" long with a 1:12 ratio out of an aluminum tin can (the only thing I had handy) and that did light and burn intensely (for the approx 4 seconds it took for the aluminum to melt).

So, I took that as generally positive and that there was nothing more worth doing until I have the burner in the actual forge.

Does this all seem reasonable and normal? Or does any of the above point to a problem with my burner thus far?

 

[Andy98]

1 hour ago, Andy98 said:

From top to bottom that is:

• 1/2" coupling (they didn't have any metal thread protectors) for an initial test outside-the-forge.
• 4" long 1/2" black pipe
• 3/4" run x 1/2" drop black pipe T
• 0.023 mig tip, cut down in length a bit.
• 1/8" flare to 1/3" MPT
• 1/4" ball valve
• 1/4" pipe nipple (supply house's best suggestion for getting a male fitting to accept my hose)

...err, that should have read "1/8" flare to 1/4" MPT.

[Frosty]

The ONLY use I have for a 1/4" flare fitting on my burners is attaching to 1/4" copper tubing for heat proof fuel supply.

I don't know how it got started but a lot of people are drilling and tapping the T to receive the flare end of fittings. The ID of 1/8" MPT accepts a 1/4x28 tap as well.

It's not that something that works is wrong, I just don't know how it got turned around backwards. Youtube instead of asking me maybe?

If it works for you it's good but spreading a misdesign around isn't as helpful as it may seem.

Frosty The Lucky.