Newb, fresh built forge, critiques please

[SeniorNugg3t]

I have zero experience with forging/blacksmithing. Looking to expand my abilities and learn from all of you.

I built this forge last weekend. I didn't really have any idea what I was doing or follow any rules of thumb that I'm now learning about. Just kind of common sense approached it.

This is a small mailbox style forge. Single propane burner i bought off Ebay. The design is my own and probably not the best...

Well, here it is and now I'm trying to make it work right. Seems to be okay but I know there's things I'm going to need to do to really get it going.

I have it sitting on a home-brew cart for now made of scrap wood.

The floor and seams are covered with a 3000* refractory cement slurry.  I may coat the whole inside with refractory cement for efficiency.  I think to help with the burner depth, I'm going to build up the wall on the right where the burner comes in with the refractory cement and form a bit of a flare to it around the hole. Or, i could build a stand off on the outer frame mounting straps to recess the burner a bit and grind away some of the brick in the hole to make a flare shape.  I may go with the cement method as it will reduce volume, and probably improve efficiency as it should keep the bricks from absorbing as much heat, or maybe a combination of both cement and stand off.  Burner is pointing just left of center and my thoughts are the heat will hit the floor where the work will be placed, and bounce around circulating the heat, also alleviating much back pressure.  The back wall is movable to allow for exhaust and longer pieces to be passed through.

So I fired it up the first time the other night and there's a few things I want to discuss.

For sure I have to address the burner mounting.  It's too deep in the forge and the flare is getting hot. I don't have the burner tuned very well either but it surely pushes some heat lol!

I have a lot of blue flame coming out of the mouth for the forge. Not sure what to do there. I've read it can be good and bad?

 

https://photos.app.goo.gl/29NewFGoKtem0iby2

I've got a lot to learn...  Please let me know what you think and what I can improve upon.

 

Thanks!

 

 

[ThomasPowers]

Hard or soft firebrick?  If it's hard it looks like a terrible gas hog and the extra fuel it will go though would pay for a better insulated forge *quickly*.

How do you plan to use it?  Hard to make suggestions on how to improve it for use if we don't know the use planned. Blacksmithing can be anything from doing delicate hair pins and flowers to welding up 20 pound pattern welding billets and improving the forge would be quite different for those examples.

[SeniorNugg3t]

It's hard brick. I can line it with Kaowool or refractory cement.

I'm mostly wanting to work with shaping round and flat rod for now. general work. in the future, learn forge welding, make some knives.  I have some split bricks for inserts to reduce volume as well.

Did the video work? I'm at work so I can't get hardly any videos to play.

[JHCC]

10 minutes ago, SeniorNugg3t said:

Did the video work? I'm at work so I can't get hardly any videos to play.

Worked for me.

And welcome aboard! If you haven't yet, please READ THIS FIRST!!!

[ThomasPowers]

First of all may I say that your construction looks very well done indeed; (I might be worried about expansion and contraction differences in the materials vs the heat they see). However that "style" is not very appropriate for a hobby forge.

Lining it with refractory cement which is seldom insulative does not help the basic problem---you need insulation.  A forge is a heat balance: heat in vs heat out.  The firebrick surround is basically just a waste. A nice 2" thick layer of kaowool will do very well indeed.  The shell around the kaowool isn't very important, I've used a tin from christmas popcorn as the lightest I've used and a section of Oxygen welding tank as the heaviest shell I've used.  It's the kaowool lining that is the heart of the forge. Covering it is mandatory to avoid health issues with the wool shedding with use. Have you read Wayne Coe's  site about propane forge building?

Commercial firebrick forges are designed for 24x7 heating and hard usage and are very expensive to run! (And even they are now often rebuilt with insulative refractories due to soaring energy costs.)

I would remove the firebrick and put some thin unplated sheet steel inside it conforming it to the straps already in place and line it with 2" of kaowool and put the appropriate covering material on the inner face of the kaowool and adjust the burner.  Put split firebrick on the floor on top of the kaowool to deal with abrasion in use.

Adjust the burner for proper length inside the forge and use the removed firebrick as front and back doors, not as efficient as insulative stuff but a lot better than nothing.  A lot of the heat transfer in a propane forge is infrared, "letting it all out" is very inefficient.

Can you tell us where you got that idea for a forge so we can warn off other new folks? For example there are a LOT of really bad youtube videos on building really bad/inefficient forges.  We generally get told of them when people come here because they don't work worth beans.  Often to the tune of "I've blown my budget making something that won't work" or even my least favorite: "I can't afford to build a forge correctly; so I built one that will cost many times more to run and it doesn't work".

(I'm at work in Mexico and cannot run videos at all.)

 

[SeniorNugg3t]

Thomas-

The idea was project driven. I'm working on building some cool heavy medieval wood/steel furniture and wanted to forge the straps and the hardware. My wife likes the industrial type tables and whatnot and there's just so much garbage out there with guys nailing a bunch of pallets and pipe together looking like a 7th grade shop project gone wrong and lacking quality craftsmanship. The firebrick was super cheap and picked up locally for under $25 and I got a bunch of it. So i went with it knowing it was going to absorb a lot of heat.

I think once I tune and set the burner properly, I'll get through the current projects I have going and then do like you said. Probably knock out the brick, plate it up, and throw some kaowool in there.  I went into this with both feet with minimal/no knowledge on the matter. Only real money spent was on the burner. the rest was pretty cheap. I'd still chalk it up as a win because drinking beer in the garage and cutting up firebricks and welding scrap steel together is still cheaper/better than hanging out at the bars and the information learned is priceless.

Thanks for your thoughts and honest input. 

 

[ThomasPowers]

No problem; I'm actually *happy* it was just a guess and not someone leading others down the primrose path.

What books you got on Medieval furniture?   (been a member of the SCA for going on 40 years this fall---of course one project I have yet to do is making some of the medieval, and roman, folding metal chairs...I need strikers or a powerhammer to do them.)

My Grandfather, 93 last month, served as a Marine in a garden spot known as Iwo Jima, Battle of...

[SeniorNugg3t]

I have no books, just some wild ideas and the internet lol.

Not a lot of the WWII vets left, just a handful. I shake their hands whenever I get a chance. Toughest men I've ever met.

And I'm originally from Hobbs,  lived just off Denver city highway.

[ThomasPowers]

OK one thing to keep in mind was that it was the massive overbuilt pieces that tended to stick around till modern times.  The pictures show a lot of lighter stuff that never made it to the museums. (And of course Hollywood goes for "crude"!)  Since they were often building using split rather than sawn lumber they could actually build lighter with the same or greater strength.

You might ask your local public library to ILL; the best way to look at books *before* buying them!

Constructing Medieval Furniture: Plans and Instructions with Historical Notes Paperback – December 1, 1996

by Daniel Diehl  

or

Medieval Furniture: Plans and Instructions for Historical Reproductions

Diehl, Daniel, Donnelly, Mark P.

Diehl has some issues; I corresponded with him about his method of reproducing an iron candlestand by welding together a number of pieces of decreasing size to get a taper vs forging one.  As I recall his comment in reply was "How many people have access to a forge and know how?" my reply was that "you could build a forge in your backyard pretty much for nothing and learn to hammer a taper in an hour and how many people had a welder and knew how to weld and how much and how long would  that take?"

One book I personally like is 

Masterpieces, Making Furniture from Paintings  by Ball, Richard and Campbell, Peter  as it teaches you how to look at paintings and use them to create the furniture show.  However it is NOT done using medieval methods.  It also shows extent examples of the sort of furniture you are trying to reproduce.  Not all medieval, though the surealist and cubist stuff was not to my taste...

[Mikey98118]

I see good and bad ideas in your forge; how much changes you may want to make, would be much clearer if you light it up and post a photo of how hot it gets as it is.

Before you run your forge...P-L-E-A-S-E  move your fuel hose away from the forge body; where it is, you're likely to have a propane-fueled fire in short order!!!

[Frosty]

Welcome aboard Nugg, glad to have you. Thank you for serving, much abliged. 

Not a bad job for just jumping in. Take a look through the gas forges section here and the most recent thread "Forges 101" for how we're building efficient gas forges currently. Hard fire brick is good for doing torch work on so you aren't cutting, burning and warping bench tops. Please don't tell me I don't have to tell you NOT to use an anvil for a bench to torch stuff on. PLEASE.

In general a outer insulating forge liner made of two layers of 1" 8lb. ceramic blanket refractory commonly called Kaowool. Rigidized with a fumed silica solution to encapsulate fibers and stiffen the blanket making it stronger and more durable.

A hard inner liner, AKA Flame Face of approx 1/2" layer of a 3,000 f. rated, water setting, castable , high alumina refractory. to provide flame contact resistant, mechanically durable and welding flux immune inner surface. A large flat floor like in your forge could probably stand maybe 3/4" hard refractory deck and a little extra kiln wash. (see below)

Lastly and recommended though not actually necessary, is a high zirconium content kiln wash. This provides a nearly chemically inert surface even at welding temperatures. and is an efficient IR re-radiating material so more thermal energy you're paying for in propane is radiated back into the forge to be absorbed by your work.  ITC-100 is a name you'll see almost everywhere for washing propane forges but it's expensive and there are better products. Matrikote and Plistex being two.

A couple of us have been brain storming home brew kiln washes and refractory liners but I think those will be a while yet.

Wayne Coe breaks up store quantities of forge building materials into sizes a person needs for small forges and he'll help you decide what you need. 

You're forge issues are really pretty minor for a complete NUGG to the craft. It needs some serious tweeking but I give you a well done.

Frosty The Lucky.

[SeniorNugg3t]

So I put in some work this weekend. Had the forge running for quite a while yesterday bending up some 1/8" mild steel straps. I did back up the burner a bit. I need to tweak the burner some more I guess. I was getting a lot of huffing once the forge was glowing. Upping the gas caused the loss of flame at the flare nozzle and was causing ignition at the floor. turning it down very much caused back-flame: really touchy. 

The refractory on the floor didn't last very long- 3rd use, maybe 6hrs total time. I used Meeco's Red Devil 611 (3000*) refractory to bond the bricks, round the corners, and a thin layer on the floor. The floor refractory bubbled and cracked off.  After construction I had let it all set about a week, then fired it up to a low heat and let it run a while before cranking it up.

The first time I really cranked it up I had yellow-white steel within minutes with steel placed in the hot spot on the floor and yesterday I could only get to a medium orange with a glowing forge and about 25% fuel remaining in the tank. kinda sucked and required a lot more effort with the hammer.

So, I'm not up for breaking out all the brick just yet... but I may have to.  Just wondering why I had yellow steel with the current setup and now I'm getting orange. A lot of variables I know, but just kind of talking things out...

Just trying to finish this project before i overhaul my forge.

 

[Frosty]

Red Devil is mortar, NOT a flame face refractory it can't do the job you're asking of it. You see that now. Yes?

Your burner was probably huffing because of one or two probable reasons: 1, exhaust fro the forge being sucked into the burner intakes. Or 2,  (I'm leaning towards this one a little.) The burner nozzle and refractory around it are getting hot enough to cause it to back fire. (burn IN the burner tube)

MORE Red Devil? If you like bigger bubbles I guess.

Plistex will work but you still have a fire brick liner and that WILL get regular doses of HIGH temps, at or above their rating. The thermal cycling is also very fast which kills common soft fire brick in two or three cycles. The K 26 insulating bricks are a different matter and might do it for you. One of our guys uses it in his seldom used forge but they're still fragile and get replaced pretty regularly. 

Keep at it, stubborn is a good thing when you're trying to make STEEL do your bidding. Honest, I like your set up with a couple tweaks I'd be happy using it.

Frosty The Lucky.

[SeniorNugg3t]

HAHA thanks Frosty.

https://www.amazon.com/gp/product/B002OU2Y62/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1

I thought this stuff would suffice. I have a good bit left lol! 

Eventually I'm going with the ceramic wool insulator and hard refractory liner as suggested.

[Frosty]

Yeah, we all make mistakes and mistaking a mortar for a flame face is a common one. Plistex will keep it together a little longer and won't bubble unless you stick a straw in the can and blow. 

Please feel free to give me a shout if you have questions any time. 

Frosty The Lucky.

[SeniorNugg3t]

Thanks, much appreciated.

[Frosty]

You're welcome, it's my pleasure.

Frosty The Lucky.

[Hans Richter]

On 20-4-2018 at 4:38 PM, Mikey98118 said:

P-L-E-A-S-E  move your fuel hose away from the forge body; where it is, you're likely to have a propane-fueled fire in short order!!!

Welcome SN, a nice proper forge. After my idea a bit to open, and I'm 'beg' you to, to remove the hose from the exhaust.

[SeniorNugg3t]

The picture with the hose... 

The forge had not even been fired yet and hose was placed on the cart to keep from running over the regulator when pushing it into the corner. When the forge is hot the hose is well clear and safe. When it's running the tank is taken off the back of the cart and placed as far away as the hose will allow.

[Mikey98118]

Good.

[SeniorNugg3t]

So I found what i think is a good deal on some IFB and rigidizer on eBay...  also some K-Bond.

Are these good deals?

https://www.ebay.com/itm/201581718286

https://www.ebay.com/itm/263583477883

I think I'm going to keep the hard brick floor i have, cover it with some refractory, and knock out the hard walls and roof brick and replace with with 2 layers of 1" HTZ and button up the outside with sheet metal.

Is the K-bond going to work going over the IFB as a hard liner?

Do I need to do the whole thing, or just the walls and floor?

I was thinking of pressing a hard split brick that I already have into the side of the IFB  where the flame reflects off the floor. shouldn't be too much of an issue since I'll have an IFB liner and it should help my liner live a while longer.  

[Irondragon Forge ClayWorks]

You might want to contact Wayne, for small propane forge supplies and he will help you out.

https://www.iforgeiron.com/profile/6890-waynecoeartistblacksmith/

[Hans Richter]

Hi SN, please find below a assembly of all the refractory I use to work with. All of them have their advantages and disadvantages. From left to the right.

·         Plaster of Paris,  use it to make pouring moulds (lost wax) for my foundry or add it to the mortar for quicker stiffness because of the exothermic reaction (you have to work quiet fast)

·         Blanket Superwool (NO KO-wool because of an-organic fibres and less change of sintered fibres and future cancer) till I find (here in Europe) a good rigidizer I only use it for sealing leaks and small openings or cover it with mortar.

·         Soft bricks (low density) which I use for surfaces are not exposed to mechanical stress and not as a direct flame face

·         Ceramic beads for filling gaps on the flame face and to attach future superwool lining to a hardening/kiln/raku oven

·         Ceramic pads how are excellent surfaces and reflectors to flame faces -I have very good experiences with them in de gas forges and both of the furnaces.

·         Mesh enforced Superwool pads which are good backups and insulators behind the bead pads and also as insulators not exposed to the flame face

·         Aluminium Silica mortar to connect the bricks and fill some gaps or line/cover future Superwool structures

·         Kanthal-wire (heat resistant nickel alloy) to connect/make pads (superwool/ceramic beads)

·         Heat resistant sealant to seal small joints or gaps

·         Hard chamotte/fireclay bricks (high density) for body/base of furnace or gas forge as a flame face and ‘heat keeper’ (soak up a lot of energy) use them also as stone moulds for bronze casting

·         Hard fireclay/kaolin brick (high density) as direct flame face and resistant to mechanical stress which I use as possible for all the forge/furnace cambers.

 

Last but not least a picture of one of the 4 hybrid forced air burners I use for the forges and furnaces. They work as normal venturi burners at normal circumstances (without pressured air injection) 1750°F at 15psi propane pressure and after pressured air injection up to 2200°F at 25psi. Need this temperature to forge weld and melting bronze. Burners are made from 1in Inconel tube. However there are not so famous as Frosty’s legendary T-burner or one of Mikey's but their miniature copycats of the burners I know and build from the oil crackers in all the petrochemical plants I worked for several years.

 

Gents, the hunt is open shoot on it, and comment (very welcome).  

Cheers, Hans

B.t.w. Got many of the stuff from here

https://www.stork.com/en/cooperheat-equipment-shop

[SeniorNugg3t]

7 hours ago, Hans Richter said:

Aluminium Silica mortar to connect the bricks and fill some gaps or line/cover future Superwool structures

So an alumina-silica mortar can be used to cover fire blanket?

 

[Frosty]

3 hours ago, SeniorNugg3t said:

So an alumina-silica mortar can be used to cover fire blanket?

 

No. Mortar is intended to glue things together NOT survive as the flame face in a forge. It isn't that kind of refractory, just because it says it's good to 3,000 f. doesn't mean directly in a 3,000 f. fire. It means it won't fail to keep the brick, tiles, etc. in place in a 3,000 f. furnace but it has the brick, etc. to shield it. Propane fire is extremely chemically active it can be a nasty thing.

Just contact Wayne and order up some Kastolite 30. He'll even help you figure out how much you need and his prices are reasonable. Why guess?

Frosty The Lucky.