Dry tuyere

[matt993fod]

So I am constructing a really small portable forge for my student backyard smithy.

Its basically an angle iron frame that holds four fire bricks, giving me a very small flat hearth. It sits on four legs, and its powered by a small electric forge blower that runs on a car battery. I need the forge to be lightweight, portable, and easy to disassemble. My design is good so far, as the bricks can lift out of the hearth, the blower will unbolt from its housing, the hearth lifts off of the legs, and whatever tuyere I use will be bolted to the frame, so will also come off easily. Because of the design, the tuyere must be side draft.

I still need to construct a tue iron. I can easily make a water cooled one, but that would negate the portability of my design. A dry tuyere is most practical.

Can anyone give me some suggestions as to a good reliable design for a dry tue iron that fits in with my design requirements?

[Wayne]

Have a look on the website for glendale forge, they sell dry tue irons which is basicaly a large block of iron with a flange to fix it in place.
You could fabricate on by building up from layers of pipe inside each other with a thick plate welded to the end for the air hole and a fixing point to the rear.

[matt993fod]

Glendale forge arent that expensive compared to some others, but I would rather make it to save money. Your pipe idea sounds possible. Do I have to insulate the tuyere at all? If I go covering it with fire clay I will surely sacrifice the portability of my forge. What actually stops dry tue irons burning up in the heat, besides the cooling action of the air flowing through them (which I can't imagine cools it that much really anyway)?

[Wayne]

When I first started out I had a simple riveters forge with a dry tue iron, it lasted me several years before burning out - I was fire welding and the high temperatures did not help so it is something you may have to view as a sacrificial item.
Instead of clay around the nozzle have you considered the board that is for sale as a replacement for fire bricks in stoves and fire places?
It comes in various sizes and is easy to cut so boring a hole through and sliding it over the tue iron may be an option, you can buy this stuff on e-bay.
Wayne

[matt993fod]

That sounds possible. So insulating the tuyere is the way to go if I want it to last then? I would hate to pay for a tuyere off of someone like Glendale and end up burning it.

[MLMartin]

you could make some simple tuyers out of some refractory cement/clay/ceramic. There are lots of people that cast hole gas and coal forges out of some type. I don't see any reason you could not just cast a brick out of it with a small hole running through it. Consider it a consumable. Might be cheep enough to make 3 or 4 a year and just use them till there gone.

Just make sure what ever you use can take 3000 plus temp

Lots of African smiths just have a large clay lump with a hole running through them, fan on one side forge on the other

[matt993fod]

Sounds fine to me. How about using a mild steel pipe and coating it with the clay? That way only the clay needs replacing when it eventually cracks up. I would like the setup to look as professional as possible, as I will be taking it on demos at some point.

[John B]

Dry Tue irons are sacrificial, and usually made of cast iron, if you have an electric blower and using coke instead of coal, I would consider using a bottom blast forge

However there are various alternatives you can use,

Obtain a large sphere/ball (F.H.Brundle's can supply) drill a 3/4" diameter hole through centre and weld a tube onto the rear of the ball to fit your blower

Or alternatively use a piece of 3" diameter or larger solid bar 4" long or longer, and drill a 3/4" hole through it then weld a tube on to fit your blower, or if you have a lathe, you could turn a boss on the end to fit your blower to

If you want plans for a small bottom blast forge PM me your email address and I will send you a copy

Good luck with the project

[Rob Browne]

Have you just tried some black pipe with a lump of clay on the end as you have said. Very cheap and simple and easily replaced.

[eric sprado]

You DO NOT need to insulate the tuyere. Jack Frost has one simply built that we use for hammer ins a lot. If you do want to make a portable water cooled one-I'm building one now that is an old cream can that I"m running the pipe through. Easily portable and will get lots of laughs and looks.You can set it up in the middle of a welding table or ANY metal surface and light er up....

[OddDuck]

Dont even need to get that fancy, if you are using bricks anyways, stack them to make the tuyere channel, just stack two about an inch apart and make a roof out of another one, place your blower pipe in the other end. Black iron will burn up, even clay-coated. If you are concerned with air loss, bring a small amount of clay with you, wet it until you have a paste, and use it to mortar the bricks together at the pipe end. When you pick up to go, wash off the clay and away you go. Easy peasy.

[matt993fod]

Thanks for the ideas guys. I think that I might use some sort of brick arrangement. I will make a permanent iron tuyere, but use a piece of refractory clay or fire brick with a hole bored through the middle as a capping piece which will take the brunt of the heat. That way, the main part will be permanent and fixed, but the part which will take most of the heat will be easy to replace. Sound any good?

[pkrankow]

Some side blast designs call for using excess pipe so you can push the pipe forward as the pipe is consumed.

Even a ceramic brick will eventually be consumed, so plan for this and make it take reasonable effort to remove.

Phil

[Tyler Cech]

I'm planning on probably making a dry tuyere by taking a small pipe surrounding it with clay so it fits snuggly into a larger pipe(an inch or two thick of clay) and then welding on a cap piece of metal at the end.

[Glenn]

And where did you get the plans for that? 

Make the first forge by following the plans and instructions provided. It is a known product that works. If you alter the plans and instructions, you alter the performance and who knows what you will end up with. After you get a working forge, you may alter it however you wish to change the performance, with the original as a known source to compare to.

[JHCC]

9 hours ago, Tyler Cech said:

I'm planning on probably making a dry tuyere by taking a small pipe surrounding it with clay so it fits snuggly into a larger pipe(an inch or two thick of clay) and then welding on a cap piece of metal at the end.

Why?

The biggest challenge to a side-blast tuyere is the heat of the fire burning up the outer surface; over time, this will erode away the tuyere and cause it to fail. A water tuyere combats this by keeping the tuyere well below the temperatures that will cause it to burn (or even start to glow); dry tuyeres either distribute the heat through a solid mass of metal (especially cast iron, which resists having clinker stick to it) or use a sacrificial nozzle (which, if ceramic, also acts to insulate the air pipe itself).

Your proposed pipe/clay/pipe arrangement will probably end up with the outer pipe burning up (since the heat won't be conducted away), leaving an inner pipe with a clay sleeve. That's time, trouble, and material down the drain, leaving you with something you could have made up from the get-go with substantially less bother.

[Charles R. Stevens]

If it’s a concern a 1” hole threw a brick of half carved threw each will solve the problem. Otherwise gas pipe is cheep. 

These bricks were carved with a rail spike, harder ones would benefit from a brush tool

 

[Tyler Cech]

That’s an idea Charles. I might have to try it. And JHCC I want to try using a dry tuyere because I was hoping to make it kind of compact. But please indulge me on how it works and how it is so important maybe you will change my mind? 

[Tyler Cech]

From what I know it sounds like it wastes water? Or Maybe i just don’t now what I’m talking about .

[JHCC]

A water tuyere (like the one I just built) circulates water within an outer shell and around the blast pipe to keep them both cool. This in turn both keeps the tuyere from burning up and keeps clinker from sticking to the tuyere. Some of the water evaporates, but not much. Just add a couple of gallons before a forging session, and you're golden.

A dry tuyere is simply any tuyere that isn't a water tuyere. If you use a pipe encased in clay or sticking through some bricks like Charles shows above, it will certainly take up less space than a water tuyere, as well as being easier to construct. I used a plain pipe in my JABOD, but I love the water tuyere and I ain't goin' back no more.

For a beginner, a simple JABOD with a plain pipe is the way to go. Once you have some experience and know a bit more about what you like, then you can start playing with variables.

[ThomasPowers]

I don't see any value in the extra pipe and clay.  The extra, larger, more expensive to replace pipe will scale away to protect the inner, smaller, cheaper one...

Anybody try one out of an alloy like inconel? 

[rockstar.esq]

I built a water cooled tuyere with a remote bosh.  It looks like a pig snout with hoses connecting to a plastic tub.  While certainly not as compact as the JABOD that Charles made, it is very portable.  The tuyere isn't actually attached to the sandbox so  I can store everything in a tighter footprint.  

JHCC is right about the clinker, it just sinks below the blast so the fire can go longer without cleaning.  It's easy to snag the clinker in one intact lump when it collects in the sand pit.

I've never used a dry tuyere, it's probably cheaper and definitely simpler to use sacrificial gas pipe.  I will say that 30 gallons of water gets steaming hot in about four hours of forging using coal and roughly 2.5 hours using coke.  I followed the tuyere design from Mark Aspery's website.  I ended up having to open the nozzle restriction so my hand-crank blower would work properly.  

I love the flexibility and cost savings of a side draft forge.  If I had to do it again, I'd probably spend more to make an integral bosh like JHCC's.