Cast and Forge

Ribbon Burner Problem?

Recommended Posts

I can only see the top video so that's all I can comment on.  

For starters you have way too much fuel going into the burner at the start of the video before you start adding air, so as you add air to balance the burn you end up with a higher velocity of fuel/air mix than the burner head was designed for and that creates excessive flame lift.  Try significantly less fuel at the start and slowly increase the air to see how it behaves.  Or conversely after you add a little air decrease the fuel supply and observe what happens to the flames.

Did you build a baffle/diffuser into the plenum?  Have you tried a wide range of fuel and air combinations yet?

Another thing to keep in mind is that the burner will behave differently inside the forge due to the back pressure it will experience in that environment.  There's nothing I saw that should prevent you from being able to get that burner working well as long as you have a way to make small adjustments to both the fuel and air supplies independently, but in the top video even at the end it appears as though you are still running very fuel rich.

Share this post


Link to post
Share on other sites

Thanks Buzzkill!

Dumb me didnt built in a baffle plate. I thought for such a small plenum it would be alright. I dont think i can get one in now without casting a new burner block. So how bad is this for the burner performance?

Problem is my regulator is to rough. It shows 0 bar and i can still turn it down. But i dont know how much gas is going through. I will get a new one. 

I will test some more gas/air combinations tomorrow.

Share this post


Link to post
Share on other sites

It might be simpler than that on the regulator issue.  If you restrict the gas flow then pressure will show at the regulator (assuming you have a gauge there).  So, for your gas line input you can use a cap or plug with a drilled hole, a mig tip, or you can even squish a piece of copper tubing and solder it in the fitting - anything the restricts the flow enough to build up some pressure, but not enough to prevent the volume needed to run the burner.   You could also install a needle valve between your regulator and input to the mixing tube.  When you have a wide open line there is no opportunity to build up any pressure so it can register on your regulator.  What really matters in a blown burner is the total volume of gas and not the pressure.  However, we can use pressure through a given orifice to approximate the volume passing through.  A reading on a gauge is just a good way to easily return to a setting that worked well for you.   You can tune your burner by sight and sound without a regulator or gauge (although I do not recommend eliminating the regulator).  A needle valve gives fine control on the gas side, and I prefer gate valves for the air, but there are quite a few options.

I don't know how well your burner will perform without the baffle plate since the holes in the burner are lined up with the incoming fuel air mixture.  You would almost certainly get a better burn with a plate in place as that promotes extra mixing and helps even out the pressure before the fuel/air gets to the burner ports.  However, it may be ok for now.  You'll have to experiment a bit and see what happens.  You could potentially still install a baffle without recasting, but the cutting and welding required on the plenum could very well end up damaging or destroying the burner head.  If it were me I probably wouldn't risk it unless I was convinced the burner was a failure as it is.

Share this post


Link to post
Share on other sites

So I think you just pointed out the problem here. My gas inlet is a copper tube soldered into a fitting. I drilled 3 1.5 mm holes in the tube. I think this is way too muchafter reading your thoughts. 

Share this post


Link to post
Share on other sites

Welcome aboard Tim, glad to have you.

I'm not really a gun burner guy but they aren't really hard to get tuned. First, put a needle valve in your fuel line. Too much gas is better than to little, it's easy to restrict the supply with a needle valve. Do NOT try to adjust gas flow with the shut off valve they are NOT intended for the job and don't do it well while being damaged. 

For now forget a gauge, one won't really be much use until you learn how to tune and adjust your burner. Being home built it will be one of a kind and not operate like ANYBODY else's burner. Nobody CAN tell you how much pressure to use, no matter what THEY say. Sure we can say try more or less but nobody can put a specific number on what' good or not.

Sure buy a better regulator but without knowing the range of you reg I can't say yes or no. There's no harm having a spare regulator on hand if it turns out you don't really need a different one.

And PLEASE no videos! They take up a huge bandwidth and IFI has members in places where they have to pay for time on dial up connections. Still pics work just fine, I saw all I needed in the first and last second of the first video so 2 still pictures would've been enough for me to evaluate your burner. After more than 10 minutes and the second video was still blank and downloading so I killed it unseen.

Before you cast a new burner block let's get this one burning a neutral flame and then decide if the flames are uneven enough across the outlets to need a diffuser of some sort. Relax on that for a while, okay? So far, as out of tune as it is now the flames looked reasonably even, you may not have to worry about it at all.

How are you controlling the air supply? You MUST be able to control the air as well as the fuel gas or you won't be able to adjust the heat. 

Why all the plumbing? You only need to put ONE elbow between the gas jet and the plenum to assure good fuel air mixing. You can simplify that if you like, something like: Straight pipe (Nipple) from blower to (T and gas jet), short straight nipple to 90* elbow, straight nipple to the burner plenum. When you make your next ribbon burner try experimenting with holes drilled in a block of wood before casting it. It'll only last for 10-15 seconds before the wood starts burning and you can't see the burner flame for wood flames but that's long enough to evaluate the flame and it's so much less frustrating to throw a failed piece of wood burner block in the wood stove than have to scrap a cast refractory burner. Yes? 

For now and this burner. Close the air valve until you feel a modest breeze coming out of the outlets. Now with a lit flame, burning paper, soldering torch, etc. to act as the pilot light SLOWLY open the NEEDLE valve controlling the gas flow. Slowly increase the gas until you have a stable flame. IF it burns back into the plenum, kill the gas and open the air a LITTLE and try again.

Change ONE thing at a time a LITTLE BIT! If you're using a plumbing "Gate" valve for the air, 1/8 turn on the valve handle is probably WAY TOO MUCH! 

With some minor changes and experimenting you can have that burner working just fine. Remember though, it WILL behave differently in the forge than it does clamped in a vise. Get it close then put it in the forge and fine tune it. 

Also you'll need to tune it for a neutral flame every time you turn the heat up or down.

Frosty The Lucky.

Share this post


Link to post
Share on other sites

Thanks Frosty and Buzzkill for the input,

I experimented with the burner todSee the picture below on my setup and my regulator. I think theres still a needle valve on the regulator.

20191122_172359.thumb.jpg.04ec8a94b3cedac7771c3518cc6cb8a7.jpg

The blower is regulated by a power supply unit.

20191122_172347.thumb.jpg.fe8cc438d1402987bb96cf96155a452a.jpg

I turned on the blower and tuned the burner to a bright and rich flame. Then I slowly reduced the gasflow. I just adjusted the gas, not the air. I tried this procedure with several air/gas configurations. But it seems that the flames wont stay near to the burner head, if I turn the blower up more to some point.

See below the pictures of the blower configuration which will just hold the flames near the burner head. From there I turned down the gas to a point, where I cant turn it down anymore without the flames dieing. The flames are burning stable and quiet but are fairly small. I really dont think they can bring a forge to welding temps.

So what are you thinking about this?

20191122_190441.thumb.jpg.19d3526a774ca548738bfc6d62f5248e.jpg20191122_190743.thumb.jpg.bbc9f9dc966aff321f7fac58609d69b4.jpg20191122_190831.thumb.jpg.04bffecd3a6445659192ab47bd37ae1d.jpg20191122_191006.thumb.jpg.80ceae30913cca3b7177841010a9db5b.jpg20191122_190935.thumb.jpg.c2d4150c97b9bd36b65af83615ebdab1.jpg

 

Tim

Share this post


Link to post
Share on other sites

Don't worry too much about the flames lifting off the burner head when it's outside the forge.  It will behave a bit differently inside.  As long as you can get a good neutral to slightly fuel rich flame without backfiring or the flame blowing out inside the forge you are good.   Once your forge begins to glow inside you'll be able to turn the gas and air up enough to forge weld.  After the forge passes the ignition temperature of the fuel/air mix it will burn no matter how high you turn up the fuel and air (within anything approaching normal operation anyway). Then it's just a matter of adjusting the two inputs so that scale is not forming on the steel while it's in the forge and avoiding excessive dragon's breath which translates to wasted fuel.  

I think you will find that if you install it in your forge now you will be able to play around with the air and fuel a little bit to get used to the tuning and then you will have little to no trouble getting the heat you want.

Share this post


Link to post
Share on other sites

I installed the burner in my forge today. The forge is probably too small for the burner but it worked out very nice. I started slow on the air and gas mix and cranked it up further as the forge heats up.

A bright yellowish, nearly white heat was no problem! I just need to get used to the tuning to reduce scaling a bit more.

Thanks for all of the replies. You helped me very much.

 

Tim

 

20191123_172108.jpg

20191123_172111.jpg

20191123_172518.jpg

Share this post


Link to post
Share on other sites

Congrats!   We love success stories.  After spending a little more time with the air and gas controls you should be able to quickly tune it how you want.    This is where a pressure gauge reading can come in handy (but it's still not crucial).  Once you find a setting that works well for you, take note of the pressure reading so you can easily return to that spot and then you only adjust the air as needed.   If you can't get a pressure reading don't worry about it,  tuning a blown burner by sight and sound will become easy once you know what you are looking for.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.