Naturally Aspirated Ribbon Burner. Photo heavy.

[Leif Svendsen]

First of all I want to say thank you to Frosty and all the other contributors for the amazing well of information that this thread is.

I'm going with a NARB for the new forge I'm planning and I feel that I've ready to move out of the testing phase and start building the mold for the refractory.

I'm using a 1" burner with 0.8 mm mig tip and the wooden test block has 142 4mm holes. I've tested it up to 25 psi and It is burning really stable over the whole pressure range. No back firing or other issues at all.

I feal that I've gotten as far as I can without a proper forge to play with, so that's next on the agenda.

 

This is testing at 15 psi. What do you guys think?

 

[JHCC]

Very nice!

 Also, welcome to the forum! 

[Frosty]

Welcome aboard Leif, glad to have you. If you put your general location in the header you'll have a much better chance of meeting up with other members within visiting distance.

Your burner looks good but be prepared for it to burn differently when you put it in a forge, it might need a little turning. What are you casting the burner block from?

Frosty The Lucky. 

[Leif Svendsen]

Thank you, Frosty!

I have some Kastolite 30 that I bought years and years ago with this intended purpose. Never got around to it before now, though.

Thanks to this thread I've understood that it most likely will need some tuning when I mount it in the forge and I have built the burner with this in mind. I'm also playing with the idea of putting even more holes in the plinth and plug a few if I have too many. It seems easier than drilling into it or casting a new one if I have too few.

[Frosty]

Heh, heh, heh, my two NARBs both have a couple few plugged burner outlet holes. Plugging excess is WAY easier than trying to drill out more. 

I haven't built a burner in years, I have the T burner down to hardly needing to tune them so I don't consider the couple I've put together for the NARBS as counting. 

I'd really like to see someone come up with a way to keep the burner block cool enough to prevent burn back. I don't recall specifics but the hotter the outlets the higher the rate of propagation of the flame, IIRC Flame Front Velocity. Anyway, if the outlets get hot enough to raise the flame front velocity to the same velocity as the fuel air mix in the outlets it WILL burn back. 

Of course you can just turn up the psi and keep the outlets cool enough but at a point they break contact with the burner block and it stops performing. 

It's a balancing act. Wooden burner blocks like your test burner don't absorb energy or heat up like a hard refractory so you don't run into the problem until you start casting blocks.

I discovered that tuning by ear was more effective than by eye. Unfortunately wood blocks make long primary flames as seen in yours so there are possible surprises when you start casting blocks.

Listen to the other guys on the forum who work with and build multiple outlet burners, it's really old tech and many of them have been using the things for decades. I wouldn't have gotten close, heck even thought of a home build if it weren't for the glass people and glory hole burners. I just adopted and adapted other's burners.

Keep us in the loop please.

Frosty The Lucky. 

[Buzzkill]

On 6/29/2024 at 11:23 AM, Frosty said:

I'd really like to see someone come up with a way to keep the burner block cool enough to prevent burn back.

Well, so far my latest block doesn't burn back at all even after being at welding temperature and dropping back to under 1 psi.  It doesn't even pop when I turn off the gas.  However it has about 180 ports that are 1/8" diameter, and the ports are nearly 3 inches long.  It's a big heavy burner block and if I didn't have a 3d printer I wouldn't have even wanted to attempt the mold.  I think the distance between the outer burner head surface and the plenum is playing a significant role here.

I have less than 100 hours on the burner head at this point so I don't know how it will hold up long term.  Some of my previous attempts started out very promising, but showed degradation in the performance over time.

[Frosty]

Sounds promising Buzz, may we have a look at it running?

Frosty The Lucky.

[Buzzkill]

I haven't had very good luck getting pictures with accurate colors, but I'll give it another shot soon when I get a chance to fire up the forge again.

[Frosty]

Yeah, the colors aren't worth trying to judge forges with online. I'd sure like a look at the flames though. I can generally tell how hot a well made forge will get from how the flames look.

Thanks, Frosty The Lucky.

[Leif Svendsen]

Alas, had I only had a 3D-printer!

I've ordered some sprue wax from China that I'll try to make sense. That's one of the reasons I'm using 4 mm holes, I think 3 mm wax will be too bendy.

I'll try to go as thick as possible. Hopefully I'm have enough refractory to get close to 3".

[Frosty]

You can chill the wax before casting the burner head so they don't bend so easily. 

Frosty The Lucky.

[Leif Svendsen]

2 hours ago, Frosty said:

You can chill the wax before casting the burner head so they don't bend so easily. 

Frosty The Lucky.

My thoughts, exactly