A few burner questions

[scruffy forge]

I got my forge from the guy who tought me how to make knives. He gave me all that I needed, forge, burner, and a little railroad anvil. It took me a long time to actually do anything with it. Since then I went back to him and bought his anvil from him. He threw in a bunch of steel for damascus and a better burner and set up. This is my forge. I know it needs a little work, I plan on rerelining it soon.   This is the first burner he gave me        . The 2 problems I am having with this burner is 1) I cant get it to stay on the pipe part. I tried to solder it and I also put a set screw in. It is brass so I cant weld it. 2) Since I have tried to solder it a few time the area by the valve leaks sometimes. The valve and pin hole assembly look like they are off a BBQ side burner. At least a lot like my BBQ anyway. This is it running 

 

This is the second burner I have      . The problem i'm having with this one is that in order to get it hot enough to really work with I have to turn the PSI up to 17-20. To get it as hot as the other burner it has to be 30 and up PSI. Here is a pic of both       .

 

Looking through this site and also on google I have seen pics were the burner is running out of the forge and it produces a amazing looking flame. Ive also read that its a good way to tune your burner. Neither of my burners will run out of the forge unless you turn it almost all the way off. This is what it looks like when you just crack it open barely, open it much farther and it blows itself out  . Any help, suggestions, and critcism would be greatly appriciated.

[Frosty]

Scruffy guy: I'm not sure what to say except that's a pretty crude burner. The flame in the last pic shows the jet isn't aligned and that's critical. The flame is also all secondary burn, no primary cone nor third stage flame. It needs help, lots, I'll see what I can do.

 

I need to know some more. What's the tube diameter? What's the jet diameter? We'll work from those basic numbers and get you to the tuning once we get the construction right.

 

Another problem that's probably tweaking the jet out of alignment is how the supply line is attached. The 90* elbow and nipple puts a lateral pressure on the mounting bracket, add the weight of the hose and it's going to be a real PITA keeping the jet aligned. The jet must direct the propane as straight down the tube as possible or it won't entrain sufficient air for the proper air fuel mix AND it won't mix properly. Propane is a gas but behaves like a mist of droplets making it hard to mix with air on short notice and burner tubes aren't long enough to mix them well unless everything is right. The propane hitting the side of the burner tube inhibits the mix to the point they don't, so even if it is entraining enough air it can't burn well. The pic of the flame distinctly shows the propane is hitting the tube pretty far up the tube so it's not mixing, producing a partial secondary flame.

 

Take a look on IFI under the gas forge/burner pages, there are a number of good burner designs, some excellent. Dave Hammer has an easily built ejector type burner and I have the "T" burner, both have directions and I think Dave has a video. There are two basic types of naturally aspirated burners, linear and ejectors. What you have is a linear burner as can be seen by looking up the tube, you can see the the tube, jet and air intake are all in a line. Ejector burners are similar but the air intakes are at 90* to the jet and tube. I have no idea why but ejectors are almost 30% more efficient induction devices so they're les susceptible to breezes or back pressure from the forge.

 

Ejectors are not only more efficient and robust in operation they're generally easier to build. Being stronger inducers they're easier to tune.

 

I can't really express a valid opinion about your burner, except it's being out of tune and the iffy supply line connection, till I know a little more about it. Don't worry, trouble shooting these things is about follow the steps and adjusting it one thing at a time. Oh, we'll have to talk about gauges and regulators for propane. <wink>

 

Frosty The Lucky.

[scruffy forge]

Frosty,

The outer tube diameter is 1 1/4" and the inner diameter is 1" for both burners. The flange on the first one's inner diameter is 1 3/4" and the second one is 2 3/4". I dont know what you mean by the jet diameter. Is a flare needed on the style of burner I have?

 

I did some looking through the gas forge/burner pages and found a really good example of what it should be like.  In a thread called "I pumped Frosty for information and made this". I think while trying to fix my current burner I will start making one of your T burners. I did a lot of reading on IFI today at work and I liked what I read about the Ejector burners. I have tried before to find a good blueprint of your T burner before but never found one until today. It will take a while to make due to my hobby money comes from selling knives. Unfortunetly I need a forge that works to do that.

 

On a side note. I plan on relining my forge soon. have you ever heard of or used superwool? Is it as good as kaowool?

Thank you vary much for the help.

Shon

[Frosty]

!" ID, the only thing that counts where performance is concerned are the IDs. ODs count for mounting ad such but not now. In general when folk talk about a 1" burner or a 3/4" or a 1/2" burner they're referring to the ID of the burner tube.

 

Your tubes are 1" ID. Properly tune that's enough burner to bring 1,500 cu/in to welding and even steel melting temperature. As a rule of thumb, one 3/4" ejector type burner will bring 300-350 cu/in to welding heat pretty reliably. Capacity is determined as a factor of the tube's cross sectional area. A 1" tube has 2x the area as a 3/4" tube ad pretty reliably has twice the BTU output.

 

In general terms, what is the volume of your forge?

 

When you say Flange" I assume you mean the "Bell Reducer" where the air is drawn in and the gas jet is mounted on your burners. Yes? For linear burners 2x the tube dia is a good number to work with but it isn't written in stone, tuning can make reasonable variation work just fine.

 

The "Jet" is the aperture the propane is forced through into the burner. I don't know what kind of jets your burners have but would guess they're holes drilled in a plug of some sort or maybe in a cap on a short nipple.

 

My preference for jets are Mig contact tips. My main reason for experimenting with them when Ron Reil and I were playing with the things was to make it easy to change jet diameters without having to drill a hole in another cross pipe like Ron was doing. Later I found out they work much better than a hole in a pipe, plug or cap, they make a much smoother stream of propane and raise the entrainment ratio significantly. So, when I talk about Jets" in my or one of several designs I'm talking about mig contact tips from the welding supply.

 

A 1" burner should have a 0.045" jet. though I don't know how much help your burners need so you might want to put that bit of info on the shelf for the time being.

 

About putting a flare on your burners, I don't know if that'll help as they are. I think they're so far out of working range we'll need to change a lot to get them in the zone. Then again as large as they, are properly tuned they may just melt the forge as it stands now.

 

I use Kaowool because I have a reliable source in Anchorage, E.J. Batrells, they give out club a nice discount ad always have lots on stock. I don't know about other ceramic wool products but you want to get as high a temp rating as is reasonable, 2,600f is pretty common and about as high as reasonable prices or availability goes. Here at least.

 

If you're going to be welding in your forge you need to  know fluxes tend to go through fire brick and especially ceramic blanket refractories like hot water through cotton candy. Borax is highly caustic at welding temps and silica dissolves in caustics. I coat my forges with a kiln wash, I used to use ITC-100 but it's become too expensive for my Scott blood. I've been experimenting with another alternative and mixing my own version. So far the experiments are good but it's too early yet to say for sure.

 

Have you checked out Dave Hammer' burner build video on Youtube ? He has a really together design that's easy to build with minimal tools and works well. Building a "T" burner takes some precision with tools, if you're up to it they're quick and easy but if you aren't up to doing precise work they can be a bugger. There's another popular version called the "Side Arm" and they're pretty easy to build and work well.

 

Sorry about not having better plans on the site, I should but. . . <sigh>

 

Frosty The Lucky.

[scruffy forge]

My forge is 17 1/2" X6" I plan on using 1" kaowool. I have never used or seen ITC 100 before but I do plan on using some. So that is about 220 cu/in. The hole I have cut is in the middle. I have a door on the front and plan on making one for the back.

 

Yes I did mean bell reducer. Will the 1 3/4" one I have do the job? or do I need to get a 2"? Is burner length a big factor? Both of mine are 10" long.

 

The jet diameter is the same size as my .030 mig tips. Since I already have ,030 mig tips would those work for a 1" burner? If not does a .045 have the same thread pattern and is it the same size? I have a tap that is the right size for the tipps i have now.

 

I just watched Dave Hammers burner build video and I have most of the parts to make the burner he has there. If my calculations are correct a 3/4" burner should bring my forge up to welding heat. Do you agree? I have used a similar forge to make a few damascus knives before. To help against the flux destoying the inside I will be useing fire brick to help slow that down as best as possible.

 

Thank you

Shon

[Frosty]

If your forge is 6" dia x 17 1/2" long that comes to around 480 cu/in. Okay, that's before reducing it by 1" for the kaowool. doors are a good thing but you still have to leave enough exhaust port to let the gasses out regardless.

 

the problem with using one burner to heat this length forge is it's length to width ratio, it'll be really hard to get even heat so one section will be  HOT while the rest will be significantly cooler. two spaced 1/2" burners will do it though.

 

The orifice on your jets is 0.030" Wow, no wonder it isn't burning well, that's small for a 3/4" burner let alone a 1" burner. Bump it up to a 0.045" jet and a little tweaking aught to make a HUGE difference. Once you get the jets right and aimed correctly a 1"x 2" bell reducer should be just right.

 

The general ratios for induction devices are. Tube length 8-9x throat diameter. Jet setback = throat radius, intake ports = 2x tube x section area. the jet dia depends on what the inducer is for and I never developed a ratio for propane burners. what works for me is 0.025" for a 1/2" burner, 0.035" for a 3/4" burner and 0.045" for a 1" burner.

 

And yes, as far as I'm aware all mig contact tips are 1/4"-28. Be aware I've only used Miller, Hobart and LIncoln mig tips so my last statement could be all wrong. Just ask at the welding supply or bring along a tapped something as a gauge.

 

Split hard fire brick make good floors as do kiln shelves. I know of some guys using SS trays to catch flux and preserve their liners.

 

What are you wanting to do? Are you wanting to rebuild the ones you have or build new ones. They're two different things and talking about both will just confuse you.

 

Frosty The Lucky.

[scruffy forge]

The door at the front only cavers about half the opening which should allow the gasses to escape. I want to rebuild the 2 I have, but after hearing how bad off they are im not sure that is the best way to go. I think making the jet larger wont be to difficult to do. Its attatching it and getting it to stay put centered and straight.

 

Were does the tip of the jet need to be? To make the jet bigger on mine I was thinking of useing a set up a lot like dave hammers. The only thing is it will move the jet farther down the reducer. And it would be a bigger set up along with a bigger bracket. Is this a bad idea? And do you recamend rebuilding or starting new?

 

Thank you

Shon

[Frosty]

I'm a little slow getting back, it's haying season and we're filling our barn and helping the gal who's helping us fill her's.

 

That much gap when the door's closed is fine, that's out of the way.

 

Rebuilding your burners won't be hard, it occurred to me I didn't now which we were working on and didn't want to confuse the issues. For consistency we want to keep both burners as much the same as reasonably possible.

 

Let's take the burner tubes first. they should be 8-9" long, longer without stepping them up in diameter will impart undue friction and bad turbulence. so, shorten them to 8" or 9". You ca buy nipples threaded on both ends, it will make adding a "flare" or a "thread protector" less hassle though adjusting it's depth a little harder. We can work with either so shortening the tubes you have or buying new is fine. We can work with either.

 

The bell reducers should be 1"x 2" for easier tuning later.

 

Now for the real changes, scrap those jets and mounts whatever they are. The easiest way to jet a linear burner is to either drill across the widest part of the bell reducers using a droll bit large enough to pass the gas supply nipple. Drill and tap one hole so you can secure the supply nipple to the bell reducer. Be careful drilling the large holes across the reducer so the supply nipple is centered. Another method is to use commercial clamps to  secure the nipple across the bell.

 

Th supply nipple needs to be threaded on both ends and long enough to be capped on one end and have a 1/4 turn ball valve on the other and still reach across the bell. Measure and mark the center of the supply nipple directly in the center of the burner tube. Remove the supply nipple and drill a 0.045" hole on the mark centered on the nipple so the hole is perpendicular to the supply nipple. You want the path of the drill bit to pass "NOTIONALLY, NOT LITERALLY" through the center of the supply nipple so the gas stream will flow evenly in a perpendicular line from the hole in ONE direction. I'm sorry about the "shouting" but I need to emphasize the point, it's important and I don't express myself so well any more. So please excuse the "shouting", if I'm not clear enough let me know and I'll try to do better. Okay?

 

Drilling the jet hole is the most finnicky part of the whole construction. Even though you can adjust the jet flow by rotating the supply nipple and moving it back and forth, if the hole isn't perpendicular the flow will be off center down the tube and can not be adjusted out. The bast way to make sure the jet hole is perpendicular is by using a drill press and "V" block with the drill bit centered in the block. A pair of pieces of angle iron angle up and touching, welded to a small flat plate will make a satisfactory "V" block that can be clamped to the bed of a drill press. Carefully lower the drill bit into the center of the "V" block before clamping. This will align the bit through the center of the supply nipple, when clamped in the "V" block.

 

All that sounds complicated and if you're high school machine shop skills are good you're reading this wondering why I'm wasting time doing all this writing. However if you haven't taken metal shop classes like so many folk today, that's what you need to do to get the jets drilled correctly.

 

Don't worry about the mig tips or any of the other stuff, adding them to a basic linear burner isn't helpful in a significant way.

 

Getting THAT hole drilled right is THE most important operation for making one of these burners work. Getting the gas jet aligned correctly is the most important operation in any naturally aspirated burner.

 

Mounting the gas jet this way will make adding a choke plate a little more hassle but the other jet mounts are more hassle it balances out to about the same amount of hassle however you do it just in different places.

 

There are other ways to do the gas jet, take a look around and if you see one you like, get back and link me to the version you like and I'll walk you through it. Okay?

 

I REALLY hope I haven't made this less clear that mud. <sigh>

 

Frosty The Lucky.

[scruffy forge]

I will be getting 1"x2" bell reducers and cutting the tubes down to 9". Attaching the jets is a little fuzzy. If i'm understanding you right, drill a hole all the way through the center of the bell, drill and tap the top of the bell above one of the holes for a set screw? Did I get that right?

 

To make the V block put one piece of angle iron down and the other against it upright so the V's point in different directions. Then drill the .045 hole. Is that a specialty bit? And small bits like that dont fit in my drill press. Do they make attachments for bits like that? What did you mean by "NOTIONALLY, NOT LITERALLY"? In the middle of the nipple length not the center of the tude? Just so I can line it up correctly down the burner right?

 

For the flare I can get a nipple and flare it, then drill and tap a spot for a set screw to make it easly adjusted.

 

For the choke plate, that goes on the back of the bell? I should be able to drill and tap that as well. That would allow me to swing it in and out as needed.

 

And I have absolutly no machine shop skills. My high school didnt have one. All that I do in this field is self tought with the help of a little reading, you tube, and people who are willing to work with someone who has no skill in this at all.

 

Thank you

Shon