Latticino

Don't have anything to add to the rural farmhouse stories as I'm a suburban fellow (though I do live in the snow belt). 

However, as regards your gas forge design, a bunch of the folks in my local blacksmith group built gas forges that were "D" shaped, with the flat side of the D facing down.  This flat side was indeed made of high temperature INSULATING bricks, not hard fire brick which will be a huge heat sink.  If you must use hard brick for the floor, I would recommend going with splits (that are 1/2 the standard thickness) with the same wall thickness of insulation used for the walls underneath.  Needless to say these insulating bricks are almost as prone to being eaten away by flux as insulating glass fiber, so some type of protection for that surface is recommended (thin kiln shelf, bubble alumina coating, cast Mizzou liner, high alumina split bricks...).  The forges that were built used single side firing blown burners with small squirrel cage blowers from Graingers or the like, and I believe worked quite well. 

One nice aspect to the design was the ability to remove the entire top section of the forge body to allow replacement of the floor with inexpensive and easily available insulating bricks.  Looked pretty similar to the floor of Frosty's forge shown in recent photos on this site.

Saw Tom Latine forge one up quickly in a recent class at Touchstone and then use it to split down a number of hammer handles from log stock.  Worked extremely well.

You are joking regarding the magnesium burner flares, right?  Might want to check the flash point on magnesium first.  Even though the flare is cooled by the combustion mixture going through it while running there is always a chance you might shut off your burner while the forge is still at elevated temperature.  Since it is naturally aspirated that forge temperature will certainly heat up the flare.

Sounds good, but have a couple of notes.  First, at the velocities we are talking about I'm not sure that turbulence inside the mixing chamber is an altogether bad thing.  I see this turbulence serving two functions: first more thoroughly mixing the air and propane, and second potentially reducing the friction effect of the pipe walls to flow (Note that laminar flow is not always your friend as far as friction in piping goes, and no, I'm not going to go through all the calculations to figure the correct Reynolds number to validate this at this point, just going with my gut).  Of course it will probably not be a big deal if you want to bore out the weld seam on the pipe, it could work to make the flow more uniform and symmetrical.  Just seems like added work to me, but would be interesting to have a side by side comparison.

Second, you may find that a threaded fit for the flare is a better idea.  There is going to be a lot of thermal expansion and contraction at that point as you cycle your forge.  A slip fit, like you are suggesting, may not hold up without some kind of further mechanical method of joining.  Typically I try to keep the far end of my flare just inside the first 1/2" or so of the forge insulation, with a small annular step protecting the edge of the flare.

Third, I'll let Frosty make a final decision here, as it is his burner design, but as far as I know it shouldn't make a great deal of difference if the mixing portion of the burner is a bit longer than specified.  There should be a minimum length for adequate mixing and "flow straightening", but I don't see how an extra inch would effect the burner operation unless the induced flow from the ventauri doesn't have enough static pressure to overcome the extra pipe friction in the mixing chamber.

Looks more like a compressor than a blower to me. If coils are copper may not hold up to forging temperatures. Will be an interesting experiment. 

I use a short, light Kevlar glove on my left hand.  Works a treat and is much more heat proof than leather. Strongly recommended. 

Probably major overkill, but you can source single wall SS kitchen exhaust duct from numerous manufacturers.  Here is one at $42 (US) for a flanged 2' section:

https://www.floaire.com/catalog/ShowPartDetail.asp?catid=371&CalledFrom=C

I used a, safely, cut up helium tank from a balloon animal kit for one of my gas forges and a Harbor Freight compressed air tank (I think it was the 11 gal model, and I got it very cheap because the gage was broken off...) for another.  IMHO, unless you plan on leaving your forge outdoors in the weather (and then you will have plenty of other issues to deal with regarding the insulation), there is no real need to go with a stainless liner.  In fact if you are willing to coat the outside of the unit with furnace cement, and live with a little cracking, you could probably get by with a forge made of chicken wire around the 2" of frax insulation.  The shell is really just there to support the insulation and burner head, and there are a lot of ways to skin that cat.

On the other hand a stainless flare for your burner is a very good idea, unless you are casting the burner flare out of refractory (Mizzo works great for these).  With the chamber length you are looking at a ribbon burner might be a good option, but then a more advanced burner design might be in order.  No detraction on the Zoeller or T-burner designs, but they may not be optimized for the backpressure from the small ports required for the ribbon burner.

One of the banes of pattern welded steel, especially for a new maker, is inclusions.  Even experts can get these at times.  Needless to say it is a shame to have an inclusion in a knife or sword, but to have one in a gun barrel...  That sounds like a recipe for disaster.

Smelting steel from ore can have similar issues.  As a machinist you have been spoiled by modern steels and large equipment.  With your skills a more approachable goal might be to look into stock removal for your weapon making.  I think one of the experienced knife makers on that Forged in Fire show resorted to stock removal to make his weapon when faced with a sword configuration he was not used to. 

Sword making is significantly more difficult than knife making.  I applaud your enthusiasm, but your timeline is pretty ambitious.  In addition to the perils of forging up a pattern welded blank the size you need for a sword, you need to deal with forging long tapers, accurate bevels, a fuller or two (not required, but I'm sure with your aspirations you will want them as well), grinding or draw filing the bevels and then properly heat treating without warp, corkscrew or sabering.  That doesn't even include all the design work that is required to have a sword (with reasonable weight, tapers, weight distribution, pommel size, center of percussion...) instead of a sword like object as your goal.  Your press will certainly help, but until you learn how to use it effectively it will just be a tool for screwing things up faster.  Pressing one billet while heating the other sure is an efficient way to make pattern welded billets, but I didn't get the idea you were going into production...

That being said, I don't see anything wrong with a forge interior that is 10" long by 8" diameter.  As long as you are willing to "waste" a certain amount of fuel while you attack the learning curve, and put in enough burner to get it to welding heat (that you will need for pattern welded blades) you should be fine.  Strongly recommend you get Jim Hirusiclas (sp?) books and study them.

Hard to tell from your photo, but is the eye a complete cylinder?  If not the force of using the tool will work that wood loose in time.  I would probably term this a tomahawk based on the eye shape, but that is just nit picking.

The shape you have achieved it pretty good for a first effort, good job spreading the edge laterally.

You probably have not done any heat treating as the girder used is most likely not high carbon steel.  Edge retention will be limited due to this, though it certainly matches some of the period hawks that were used as trade items here in the states.  Better tools had hardened steel pieces forge welded to the cutting edge to act as bits.

Been wondering about this also.  With the numerous blades that have shown up with cracks on the show I would have expected these expert blade smiths to at least torch temper the spines.  Based on the typical requirement for both chopping and slicing capacity I'd probably temper fairly aggressively.  I think that is just as exciting to watch ( especially if they could capture the color change and have the expert commentators talk about why this is critical) as seeing yet another crossection reduced in the press or power hammer.  It does appear like the smiths are often quenching their blades in the last 10 minutes of their allotted forging time.  You would think leaving that 5-10 minutes to either torch temper or tong temper would be prudent.

Of course what I would really like to see is demos of austempering, marquenching and Cryogenic hardening, along with detailed analysis and descriptions, but can see how that might not be as interesting to the general public.

Forging looks great.  Hope you left enough meat in there to make it through heat treat successfully.  Chef's knives on my bucket list for sure.  Will look forward to seeing this one completed.

Can see why they are thrilled with this.  Lovely work.

Sidewall exhaust fans, set up high in the peak of your shop, are the bomb for venting the shop.  They are best for high volume of air at low static pressure (basically the opposite of what is needed for a forge blower).  Get one with a back draft damper/louver if possible to keep out the cold in the winter.  I now like the Greenheck SBE line (belt drive, steel prop), but there are plenty of others out there.  To get the recommended 10 air changes per hour in a 10' high shop of the size you mentioned you only need 800 CFM.  That is a 2' square fan with a 1/4 HP motor.  I think I originally got mine from WW Graingers.  Remember to have somewhere for the air to enter the shop as well...

If you ever plan on moving/lifting anything substantial, you may want to consider bulking up your framing in one section of the shop where you could hang a cheap electric or chain hoist .  Sure wish I had something like that in my shop.

RR Track (2'length at least) set vertical with the "end" surfaced flat tied onto a post firmly mounted into the ground.  Search this site for rail road track anvil info (best I've seen for general use is here: http://www.iforgeiron.com/topic/42290-another-rail-road-iron-anvil/ , but you can certainly get away without the extra work making a horn).

Suggest that you take a beginner class or two first to find out if you have the bug for blacksmithing, rather than build a forge.  Getting some of the fundamentals down from a competent teacher is orders of magnitude better than trying to reinvent the wheel (though it does appear that you have been doing some good research online as you were aware of the depth of your fire being an important part of forge design).  There are a bunch of other fine nuances for constructing a coal forge (method for introducing combustion air - including flow rate, orientation and configuration, vent stacks, clinker breakers and ash dump), but you can certainly get by on a shoestring with a blow dryer and capped steel pipe with small holes drilled in it placed in a shallow trench in the ground if need be.  If it were me I would try to experience using some coal forges that have been well constructed before putting any significant effort into building one, but each to his own.

This is a very dangerous operating point.  I have seen similar burners operating properly and working very well, but perhaps not by the same manufacturer.  I would contact the manufacturer and get a replacement rather than futzing with it further.

From the photos it appears that the ventauri effect to entrain air at the gas mixer is not working properly.  I am more familiar with blown burners than atmospheric type, but in my experience this is usually related to orifice size, gas pressure and/or orifice location in the mixing assembly.  It does look like there is a set screw in the side of the burner to adjust the nozzle location, but you should get direction from the manufacturer for the proper setting. They can be a bit tricky (and if the orifice is obstructed with any flash from drilling the behavior of the ventauri can certainly suffer).

Also in looking at your photo it appears that the nozzle assembly is not set inline with the overall burner.  Was it dropped at some point or damaged in transit?  For most naturally aspirated burners it is very important to have the nozzle perfectly centered and aligned to operate properly.

Since you went to the expensive of buying a commercial burner I would go directly to the manufacturer for resolution.

Do you really classify a 3 lb. hammer as a sledge, or was that a typo?  I use a 4.5 lb. rounding hand hammer on my 128 lb. Peter Wright regularly without any apparent bad effect (admittedly it may not be as efficient as it would be on a heavier anvil and I'm always careful to work over the center mass when using a full swing).  I've also used a 16 lb. sledge with a striker, carefully, on the same anvil and so far avoided any incident (never over the horn or heel though).

He means in your search term.  If you search beginner projects correctly you will find a lot of info here.

Lovely little utility knife, forged from pretty unforgiving steel.  Like everything about this one, proportions, construction, fit and finish, handle design, forged finish...  Only thing wrong here is I didn't make it myself

Be prepared for curmudgeons to come down on you a bit for spamming the same questions on multiple places on the board without even bothering to do any of your own basic research on this site and in other areas where this info is readily available.

A lot of these questions have been asked and answered before.  You should try cruising thru the site and reading some more so you have a better basis for asking your questions.

Weight is a more typical method for evaluating anvil size.  Does the anvil you are looking at have a number on it (typical for Fishers, this will indicate the weight range)?  Put yours on a scale and ask again.  Generally speaking though it looks in good condition (but rebound test would certainly be helpful) and should be adequate for knives, small tools and nails (some forge knives on much smaller anvils, even upturned 12 lb sledge heads).

Did a softbrick forge just like you have pictured for my first construction.  It lasted through only 3 firings, but that was probably because I used older softbrick that may not have been rated for the elevated temperatures (I'm not completely certain that any softbrick is available that is rated for over 2,300 deg F).  It started melting opposite the burner flare.  Softbrick also has a bit more thermal mass than the insulation blanket, so will take longer to run up to heat, but will hold that heat a little better.  As far as I know, softbrick is also prone to damage from contact with hot flux, though not as much as the glass blanket.

If you are a scientist it is pretty easy to calculate the relative heat flux out the sides of your forge with a variety of insulating methods/materials.  All you need to know is the U value for the material, the dimensions of the forge and the heating capacity of the burner.  To get the actual heating characteristic is a bit more complicated due to door openings and flue losses, but the relative proportion between two insulators can be addressed without too much trouble.

Monolithic refractory castings are pretty strong, when cast properly and not subject to  extreme thermal cycling.  As I mentioned before the refractory is a lousy insulator, and thickness matters a lot.  There are also castable insulation materials, but they don't expand and contract the same as the refractory typically.That is why I recommended the intervening layer of glass fiber if you go that route.  You would also be able to use a cheaper castable insulation.

IF I were making an industrial forge for major production of pattern welded billets I would look into getting a section of high alumina precast tubing for an inner liner.  Then cast a larger ring out of insulating castable with a 3" gap on the interior of this new ring from the outside of the precast tubing.  I would pack the interstitial space with high temperature blanket and go to town.  The only difficulty would be to make a burner port in the precast, but that could be drilled out with either a diamond hole cutter or the old silicon carbide slurry and rotating steel tube method.  Something like that should last for years if properly used.

Otherwise realize that a forge interior is also a consumable and run with it.  Small cracks in your inner liner are not a bid deal provided molten flux doesn't find a way to enter same.

Yes it can, depending on the thickness of the material.  Even though the castable refractory is not a good insulator, on thicker sections it is possible to have a significant difference between the temperature at the interior of the material and on the outer walls.  Depending on the material, the thickness the configuration of the casting and the heating/cooling rate some pretty significant stresses can be evident.  Check with the material supplier for recommended firing/cooling rates.

Please be aware that most high alumina castable refractory (that is resistant to flux) is very dense and does not work well as an insulator.  So you will certainly need a  good insulating layer behind the refractory if you want to have any level of efficiency in firing your forge.  As an interior liner, like used by DanielC it should work well.

It is also somewhat subject to thermal shock , which it will experience given rapid thermal cycling.  This propensity to cracking under thermal stress gets worse the thicker the layer of refractory you install.  Note also that the coefficents of thermal expansion between the castable refractory and insulation tend to vary, so a layer of high temperature glass fiber insulation between the two is a good idea (unless your insulation is the glass fiber blanket...).  I have in the past added stainless steel needles to the refractory mix to help with this, though any exposed to the surface burn out and it is a real bear to mix up the refractory with those needles.  As far as I know these high temperature refractories were designed for forges, kilns and furnaces that operate continuously for long periods of time and users slowly heat them up and cool them down.