1st-Timer Forge Build Fun ( or 'Hey look, still not blowed up')

[Hoenirson]

Hi Folks.

Mike H here.

In the interests of posting build stuff in the right sub-forum (instead of my Introduction) I thought I would share my progress so far.

I have so far cut open a small water pressure tank measuring 9" high by 7.5" long. Assuming 2" kao-wool plus ceramic refractory I am NOT looking at a lot of volume in the forge. (147 cu in")

 

I have now also have a (mostly I think) working 3/4" Mikey Burner.

So I have concerns that

a - the burner is too big for the volume causing extreme back pressure.

b - the mouth of the forge will be a major obstacle to getting things in. ie coil springs for reforging, armour bits, curved s hooks and such.

I can roll my own forge body out of some 16g cold roll I have here...I was thinking a slumped oval profile might be an efficient yet wide style. Or I can widen the existing shell into an oval (the doors will be pain though) or I can length it (but then I wonder if the heat will get to a 12" long forge from just one burner)

Here is some video of the burner. (Audio is a bit low)

Here is a quick vid of the flame with lights out.

Thoughts?

ps. Pretty happy so far with this burner design. Thank you Mike.

Any feedback is most appreciated.

 

 

[WayneCoeArtistBlacksmith]

If you will study the Build a Gas Forge attachment at the Forge Supplies page at www.WayneCoeArtistBlacksmith.com you will see how you can cure the size issues you talk about.

Don't use fire brick for the floor.  It is a heat sink.  Cast it instead .  You can' tell anything about the flame of the burner outside the forge.  Enlarge the back door to help with back pressure issues.

Let me know if I can help you.

Wayne

[jcornell]

A 3/4" Mikey burner would be too much burner for that little amount of space.  I'd recommend a 1/2" Frosty T burner or comparable.

[John in Oly, WA]

Concern B is what I'd be focused on. The burner is fine, make a bigger forge body. Like you're already thinking, what you have is great until you start to bend the straight piece you've been heating up. Then all of a sudden it doesn't fit back into the forge for the next heat.

[Hoenirson]

Thanks for the feedback folks.

Wider mouth. Done.

• I am drawing up a 'slumped' oval shape 8" wide by 5" high

More Volume. Done.

• I am extending length of working space to 8" (12" external frame) gives 322 cu in.

Do not use firebrick for floor.

?

I thought firebrick was a good sacrificial material assuming it takes the brunt of the wear of

1. objects placed inside the forge
2. dropped borax flux from forge welding
3. direct flame hot spot

Am I off the beaten trail on this?

[Hoenirson]

Here is a sketch of new forge profile showing all elements and some dimensions.

Does the firebrick work in this configuration? Its surrounded by 2" kao-wool plus a thin layer of castable refractory cement.

 

[Buzzkill]

18 hours ago, Hoenirson said:

I thought firebrick was a good sacrificial material assuming it takes the brunt of the wear of

1. objects placed inside the forge
2. dropped borax flux from forge welding
3. direct flame hot spot

Am I off the beaten trail on this?

Yes and no.  Firebrick does handle the things you listed fairly well. The main drawback is it's a large heat sink, so it can reduce the efficiency of your forge a bit.  The simplest way to put this is that there are better materials to use which can still hold up to the things you listed, but don't suck as much heat out of the system.   Kiln shelf or castable/rammable refractories seem to be the generally accepted favorites at the moment.

FWIW if I were doing that general design I think I'd go with the clamshell option so that you could lift one side a bit to get odd shaped pieces in the heat if needed.  I'd still stick with the flat floor and the oval or "D" shape, but having more configuration options is not a bad thing.

[Hoenirson]

Ok, that makes a lot of sense.

Thank you.

Kiln shelf is indeed on my radar of the 'best' heat/flux/wear resistant material. I see me adding it later and replacing the fire brick with that. I just do not want to hold up the build while I source and budget for that.

Its pretty much lumped in with an IR reflective coating.....a purchase/order for NEXT month.

I am interested in the concept of replacing the firebrick with just more castable refractory...like the stuff I was going to coat the Kao-wool with?

I guess I could whip together a form to ram a brick like shape. If I 'dished' it a bit could it capture dripped borax?

In the meantime I have formed the new forge outline.

I have to call it for this evening...knee surgery first thing tomorrow morning...wish me luck!

[Mikey98118]

Personally, I prefer an oval shape supported completely off of any supporting surface,...but the way you shaped it's shell should work just fine. I would like to here more about your plans for the front and rear faces of the forge.

[Mikey98118]

Your positioning of the burner would be perfect it you leave its angle where it is, but move it further outboard by the width of the opening.

[Mikey98118]

It is understandable that people who have easy access to "hard" firebrick don't want to bother with refractory mixes; and it is just as obvious why people who have mixed a castable refractory already see it as utterly superior to old style--clay based--hard firebricks. They are old technology. Various castable refractory formulas are available in brick form nowadays. Such high tech bricks will only grow in market share, and will probably displace castable refectory as the main choice for tough hot face layers. We need to keep an open mind about this stuff.

[Hoenirson]

Hi folks

Knee surgery went well, but I will see how I feel in the morning. While I am too stiff to get to the shop this evening, I can at least acknowledge the advice given here. Thank you for your continued input.

1. Ok, sounds like firebricks are off the build list for several valid reasons. Instead a removable castable refractory pressed floor will be attempted.

2. For the doors I had hoped to show what I had in mind but for now a brief description as requested.

• Two side hinged flat faced 16g doors, shaped the same as the forge outline, given a 2.75" depth for 2" wool plus cement coating via a perimeter 2.75 strip of metal 1/8" thick on the outside of the face. This when hinged shut to the forge profile forming an overlap for a slightly better air seal and assist carry the weight of the door when closed. Nice little welding task.
• The rear door with a removable heavy metal 'flap' that covers a small rectangular opening to allow air pass as needed and long stock to emerge as well.
• Another larger opening for the front door. Not sure about a covering for this opening at this point. I will adopt a wait and see approach for this.
• Both door openings to be level with floor of forge and be framed inside the door (providing support for wool and cement) and outside of front door to provide a small lip for setting stock.

3. The forge frame as shown will be elevated, not resting as shown in picture. I definitely want some air flow under the forge...maybe a good use of these firebricks as well (smile). I am still waffling on a stand build or workbench placement. Which ever I go for will have to be stable enough to secure the plumbing and idler circuit on the right side of the forge frame.

4. The suggested outboard move of the burner would then point at the 'F' of the 'Fire Brick' label of the diagram? Or do I have that wrong?

I assume that is to assist with a swirl of the heat distributing to the entire forge volume?

[Frosty]

Here's to a speedy recovery. 

I only make the castable refractory a LITTLE thicker than 1/2" for the floor and it stands up nicely.

I'll let Mike talk about burner alignment, I'm more interested in what and why he thinks things should be in gas forges. We tend to do things differently each for our own reasons and his reasoning is sound.

Frosty The Lucky.

[Mikey98118]

How the burner is aligned is all about where the flame will impinge on the floor, and at what angle. You want enough angle to encourage the flame path to swirl, AND THAT IS ALL. You don't want to aim the burner so that it makes the most swirl possible, but you only want it to just barely allow the flame path to swirl, thus causing the combustion gases to slow down; but not to slow down too much. Also, slowing the flame down causes it to spend more time over the floor and lest time over the more delicate insulated wall, which helps the extra wide floor area to do its job.

As with so much else about burners and the forges they heat, the flame path is a balance of factors; Does this mean that you're going to nail it the very first time you try? Probably not,but you'll a do a lot better by try than by saying "aw shucks"!

On the positive side, the combustion gases have no need to swirl fast, fast, fast in  order to keep on going; they can't slow clear down to a stop, because the incoming flame is constantly pushing them out toward the exhaust exit.

[Hoenirson]

I appreciate you folks sharing your insight.

I take the point on the strength of slightly thicker cement on the floor. I will do that.

It is an interesting flow dynamic, almost a balancing act with flame/gas speeds.

Sadly the morning ends the last of the freezing and my leg is all about reminding me that its been opened (!) so I suspect I will be stuck on couch driving my wife nuts for at least this one day.

What I can do is brush the dust off of Sketchup and see if I can do better than a cardboard cutout.

Is this the angle you are suggesting Mike?  Or tighter to the wall? I will happily adjust the model based on your impression.

(small thin tube represents center of burner)

[Buzzkill]

14 hours ago, Hoenirson said:

The rear door with a removable heavy metal 'flap' that covers a small rectangular opening to allow air pass as needed and long stock to emerge as well.

Just a short word of caution on this.  If you go with this feature make sure you have some way to fasten it up or remove it when working with long stock.  If you just allow the stock to push the flap open you will probably find that the flap binds on the steel when you try to pull it back out, and that gets frustrating quickly.  Guess how I know. 

 

[Mikey98118]

Hoenirson

That will work just fine.

[Hoenirson]

Good morning folks.

The build is still going on, despite a brief visit from the knee surgery fairy. I just have to take a lot of sit down breaks.

I WILL see this running before end of the holidays.

I tried one liner and removed it as it was just too crumbly. It gave me a chance to fire it up though, and give me an idea of heat containment.

The new liner has a higher heat rating and seems durable and should protect the 2" kao-wool . It is dry enough right now I can keep going but probably needs another couple of days till its 100%.

Here is a quick video showing the lining.

 

So here is a quick mock up of what I am thinking. The base will attach to the forge bottom via bolt stand offs and extend to the copper bar for reasons of balance (forge was tipping toward burner) and supporting the fittings.

The gas fitting will be supported by the base and a couple extensions from the forge body as well.

I need to redirect the rear of the flexible line with a 90 away from the rear forge opening. I think I might move the entire fitting section further away, as well....just, cause.

Hmmm...what side to have the doors open. There will be access openings in both, so in use I see the doors being kept closed.

I might put a plate as a heat shield between the fittings and the forge openings as well. Not sure though.

Thoughts?

I will continue to post the progress till its complete and in use.

Thanks for all the feedback so far.

[stockmaker]

Hello Hoenirson.  I don't have any words of wisdom for you on the liner but I do have a question about your gas manifold. You have an interesting coupling of copper and steel pipe.  I have been planing to change mine and make it more functional and easy to use.  All the little parts and pieces needed have me worried about several trips into town. Did you have any problems getting everything to mate up?  Thanks

[Hoenirson]

The final fittings arrangement was definitely an evolution involving more than one supply run. A silver soldered solid copper version would have been cheaper, but the threaded option while more expensive allowed me the flexibility to change it based on needs and my learning. There was definitely a couple Lego moments there. The hardest part was getting the lengths in parallel to mate properly, thus the pressure fitted copper line. Testing for leaks was and then fixing them was ..... interesting.

The project parts purchasing started over a year ago, was put on hold til I moved, rebuilt and started at it again. It was also done via someone else, while I was house bound due to surgery healing.

Next one will be all soldered copper with galvanized iron pipe if needed. On the other hand I AM still learning AND its not operational yet...so take all this with a grain of salt.

Hope that provides some insight.

ps. I type this having just sent the wife in for another part (a 90 elbow) with the complete rig in hand. Its sort a nice to have a wife that WANTS this forge to get up and running.

[stockmaker]

Thanks for the reply, the soldering option is entreating, I will keep that in mind.  I once installed a deep double sink in my shop that was given to me, by the time I installed the drain pipe, faucet, sink drains, and spray hose I had made 9 trips into town, I kept the receipts!  And I have box's of spare plumbing parts before and after.  I hate plumbing and this looks like plumbing to me, lol.  Merry Christmas and a speedy recovering on the knee, go slow.

[Hoenirson]

Seeing as the doors slip OVER the end of the forge (potentially as much as an inch overlap) I think I might just bolt them to the body.

Do I really need to open them constantly?

With the needs for a variable sized front and rear port, depending on burner settings, a guillotine sliding vertical door seems like the way to go.

Here is a visual of another fellows forge that does a guillotine style door:

 

Will this door style be an obstacle(zero insulation) to achieving welding temperatures?

[Buzzkill]

There will be some heat loss, but whether it will be enough to keep you from reaching welding temps I don't know.  What you will likely find more problematic is the tendency of steel to warp when it's heated and cooled repeatedly.  If you have tight tolerances on your guillotine setup you will probably experience some binding within a few sessions.

[Hoenirson]

That makes perfect sense.

Ok, sloppy slide channel tolerances, it is!

I will use a threaded keeper to set the door height (as shown by example pics) and leave the door extra loose.

I guess I can always pull it out and re-flatten it when it exceeds even those tolerances. It is just a plate.

or

I could also build the plate as a lipped box, with ceramic and liner inside, facing the heat.

Hmm ... harder to correct if or when it distorted.

I will start with the plate and see if more is needed. I will create the door slide channels with a future lipped box in mind.

Thanks for the heads up, sir!

 

[Mikey98118]

Threaded, and even spring loaded threaded connectors are key  to making exterior fittings such as doors work properly, and be easy to modify on heated equipment.

Looking at your burner and and the portal tube it fits through I see no sign of a portal choke, to handle control of secondary air entrapment. Since you built a Mikey burner, simply stuffing the opening between turner and portal with ceramic wool would probably do fine, but you have done such a fine job on the forge so far, that I would like to see this option added, if you have the time for it.

Also, where you are planning to use plate steel doors, with their likelihood of deformation from thermal cycling, I would like to remind you of how superior high alumina kiln shelves would be, if cut to the same shape. Cutting, shaping, and drilling kiln shelf from you local potters supply store, is child's play with the low cost rotary tools and accessories available through eBay theses days...