Category: Ed’s Editorial

  This article IS NOT intended to be all encompassing, it is primer, focusing on the differences between gas forges used my Bladesmtihs, and those used by General Blacksmtihs, with some “Do” and “Don’ts”, and safety thrown in for good measure!

As one who started my career as a Blacksmith, I agree that there is a world of difference between Blacksmithing and Bladesmithings, AND the equipment used for each.   The way/method that a Blacksmith’s forge heats is generally not a factor, because of the material/steel types utilized…… short of a forge “burning” the material/steel, there’s not much consideration as to how a Blacksmith’s forge heats.

Now, it’s a totally different story with Bladesmithing.   The materials/steels that Bladesmiths forge are usually VERY heat sensitive, and can be easily degraded with improper heating.   Evenness of heating can also make the difference between a successful or a failed outcome, particularly with Damascus/laminated steels.

So, those things being taken into consideration, the how’s and whys of a Blacksmithing forge are far less important than those of a Bladesmithing forge.

So, what should those seeking a Bladesmithing forge look for?  Based on my experiences, here goes….

1. Round design period.  Even if the burner is not placed in the optimal location(s)/position(s), a round forge is always a better choice for Bladesmithing because there are far few “hot spots” than in any “square” design.   
2. Burner(s):  A SINGLE blown burner, of proper size is by far the least complicated, easiest to use/operate, and most versatile of any forge burner(s).

**What should you look for/build in a blown burner??

-Black iron pipe

-A blower SPECIFICALLY DESIGNED/BUILT FOR FORGE APPLICATIONS.  (NO “squirrel cage” blowers, because they they are design to operate where NO BACK PRESSURE is present, and WILL burn out at some point…usually sooner than later. ALWAYS PURCHASE A BLOWER THAT IS DESIGNED/BUILT FOR A FORGE APPLICATION.  Personally, I buy mine from Blacksmiths Depot online.

-Sizing:  It always better to err on the side of a burner and/or blower being too large….. You can always “dial it down” as required, but if a burner and/or blower are too small, and you open everything up to its max…..and still don’t get the heat level you need…… you’re only option is to buy/build a bigger burner and/or blower. So again…its better to have a burner/blower that is too large, versus one that is too small.

-Where the fuel enters the burner.  The further away from the ignition point, the better the fuel & air mix…. and if there is an angle built into the burner (such as a 90 degree elbow) all the better, provided the fuel inlet is positioned very close the end the blower is attached to.

-A propane needle valve at the fuel inlet which allows far more control than a typical ball valve.  (use a ball valve at/near the fuel source.  Ball valves are either FULLY OPEN OR FULLY CLOSED….. DO NOT try to use them for anything in between!! I always place a ball valve at the propane source….if a tank, then right after the regulator.  If you have a large outside tank, place the ball valve where the propane comes through the wall, etc, and into your shop.

NOTE:  Can you use venture or multiple burners??  SURE!!  But by doing so you inherit many potential issues/problems that do not occur with a single blown burner, I simply don’t understand why anyone would want to.  I have given up trying to help those who insist on using multiple burners, especially the venture type in a square forge design… my thought pattern with this is….. Some people are always trying to ice skate uphill. Do yourself a favor, and build a single blown type burner!  It will run trouble free for YEARS, and you can spend your time forging, versus messing around, trying to get venture burners to operate correctly.

Here’s an exert from a recent forum thread, where I was attempting to explain to an individual about venturi burners:

“I’m not going to attempt to answer the question about where to put the burners  (multiple venturi burners), simply because getting multiple venturi burners to work well/correctly, in the same forge is nearly impossible. To explain, I’ll concentrate on a two burner setup here…… when fed off the same fuel supply, one burner will always get more fuel than the other, meaning one burner will burn hotter than the other, and all the things that go along with that occur. I’ve seen people waste literally months and months of their time goofing/trying to adjust multi venturi burner forges, trying to adjust them……and they never can. Those who tell me they have a multi venturi burner forges that are “adjusted just fine”, are ones I don’t even bother trying to help, because they either have no clue, are are simply in denial. The ONLY time I would recommend a venturi burner, is for a single burner application, and then for someone who will never required “welding heat”, and/or who needs a forge that either requires no power, or must be portable. So how does one make a multi burner venturi setup work correctly? The only way I have ever seen it accomplished is to have completely separate/independent fuel systems to each burner, then each burner is adjust as if it were the only burner. Everybody has this fantasy that using a “T” to supply a single fuel line to two burners means they must be getting equal fuel…..and it’s just not true. The line to one burner might be a bit longer or shorter then the other, the ID might vary, or any of a hundred other things….but two venturi burners, running off the same fuel line never get the same amount of fuel.

I have no idea why so many beginners gravitate towards venturi burners….they are far more complicated, far more finicky to work with and adjust, and consume far more fuel than any blown style burner. Maybe it’s back to the “lemmings” jumping off a cliff?”

3.  Refractory/Linings:  Basically you have two types to choose, Blanket/ceramic fiber, or castable.   There are others, but cost and availability usually put them out of reach for the average person.   Each refractory has its pro and cons, and each heats in a different manner.   Most believe that refractories are simply “reflectors”…..not so.  There is also a common belief that “more is better”, particularly when it comes to the blanket/ceramic fiber refractories…. which is also a fallacy.

Castable:   Very durable and long lasting.  It is intended to absorb a given amount of  heat, then start reflecting….the amount of heat absorbed/reflected differs for each variety…in general, those castable refractories with lower temp ratings will absorb more heat before reflecting, and tend to look heat quicker.   Those with higher temp ratings absorb less heat before they start refelecting, and tend to “hold” the heat longer.     Most varieties of castable work best in a layer of at least 3″. My personal favorite castable refractory is Cast-O-Lite 3000.

The issues with castable refractories are:

-VERY specific mixing ratios must be observed for product to perform as advertised.

-MUST be allow to cure NATURALLY to be durable.  “Firing” to force cure it GREATLY REDUCES THE REFRACTORY’S LIFESPAN.

-Significant amount of time required to heat a forge using this material….typically 45min-2 hours.

The Pros:

-The best durability of any forge lining material.

-Once heated, you can turn down the fuel/psi and the forge will maintain its heat

-Temp does not drop significantly when a large piece of steel/billet is inserted

-Does not give off dust/fiber during use like Blanket/ceramic fiber does.

-Overall forge will last for years, versus weeks of months Blanket/ceramic fiber….especially if flux is used.

Blanket/Ceramic Fiber: This material is also engineered to absorb a given amount of heat before it starts reflecting.  How much and how fast are dependent on the type/variety.  For the purpose of this information, I will ONLY CONSIDER 1” THICK X #8 DENSITY Blanket/Ceramic Fiber.   This is the place where I’ll lose some of you.  For anyone who is/intends to use 2” of more of #8 Ceramic Fiber for a forge….. You are wasting your money and costing yourself extra fuel every time you use the forge.

I’ve done the tests, using the exact same forge body, burner, etc.   1” of #8 density ceramic fiber reaches temp quicker, on less fuel pressure, and maintains that heat WHILE WORKING IN THE FORGE  at a lower fuel consumption than 2” of the same material…..weather that’s a single 2” layer….or 2, 1” layers stacked.

Next, Blanket/Ceramic Fiber SHOULD have some type of “coating” to keep the ceramic fibers from flying around and getting sucked into your lungs.   The best coating that I have ever found is ITC-100.   It’s expensive, but a pint will do SEVERAL coatings in a large sized forge is reduced properly.

VERY little of this product is necessary to gain the maximum benefit.  MORE IS NOT BETTER!!!  Use too much, and your just wasting the product, and in many cases, reducing its effectiveness.   How?  A couple of tablespoons in a paint/mixing cup…..add water and keep stirring until you get the consistency of latex paint (NO THICKER).  Spritz the inside of the forge (already lined with Blanket/Ceramic Fiber) with water/spray bottle.   Using a cheap paint brush, simply paint the coating onto the interior of the forge/lining.   One done as with all refractory products…. It must be allowed to cure naturally!   This is so important, that I feel it necessary to explain further… Many, because of impatience want to “fire” the forge to a given point, then shut it down, and let cool, then repeat.  THE ONLY THING BEING DONE IS A FURTHER WEAKENING/LIFE SPAN SHORTENING OF THE REFRACTORY……..simple as that.

    Now that I’ve beaten that dead horse some more, just how can you “expedite” curing the refractory??  AT MOST, place a single “heat lamp” bulb, or a 100 watt incandescent light bulb inside the forge, and LEAVE IT ALONE!!  Depending on where you live/the environment, it could be from a couple of week, to a couple of months for the refractory to cure.  One novel approach that a student of mine did….a couple days after “pouring” his new forge….he placed it atop a wood stove in his shop, that basically burned 24/7…. And within 2 weeks his forge was nicely cured, and ready to fire.

Even with a lengthy curing time for a castable refractory forge, care must still be taken on the initial “firing“….. I like to bring the forge to about 500F, then shut down and let cool overnight…..next day I will take it to 1000F, then shut down, and allow to cool COMPLETELY.  Next firing, it “let it go” time.  Usually a new castable refractory forge will get to around 1500-1700F and stall….meaning it won’t get hotter…for a while.  That “while” will entail a lot of steam and maybe even drops of water as the last remaining moisture is forced out.  Once the steaming and weeping end, the forge temp will start to climb again, and they treat it as normal…go to work, and have fun!!

SAFETY:

   This is the part that everyone hates, but I’m going to lay it out plain as day for you….  YOU BUILD, SETUP, AND USE A PROPANE FORGE AT YOUR OWN RISK!!  I have seen so many people do really dumb things over the years, it’s ceased to surprise me.  Here are some tips that will make things as safe as possible…

-NEVER PLACE/USE A FORGE CLOSER THAN 6 FEET TO ANY FLAMMABLES!  THAT MEANS WALLS, DOORS, FLOORS, AND SOMETHING MOST NEVER CONSIDER CEILINGS!  This goes double for things that can melt….. These forges are heat throwing monsters, and I have seen items as far away as 8 feet from the front opening of a forge melt!

You also have to keep distance and safety in mind when building….

DO NOT build a cart for your forge, with a propane tank sitting on the bottom of the cart…..when I said AT LEAST 6 FEET…. And means your propane source too!  Also, electrical wires, and/or anything else that can melt should be kept as far from the forge as possible, or at the very least, heat shielded.  OK…ONE MORE thing…..hoses and fuel lines…. MAKE SURE THEY ARE RATE FOR GAS/PROPANE!!  There is a reason that they make PROPANE hose…..because if you try to use other hose, such as air hose, fuel hose, etc….. Propane will break down/eat up the hose from the inside out…..and if you forge is running when it lets go….You and your shop will be a smoking hole in the ground!!

Next, let’s talk about propane.  Propane is heavier than air. That means if a leak occurs, it will naturally “pool” at the lowest point(s) on a shop floor, and if a spark or other ignition source reaches it….not good.  So, how do we protect ourselves??  First, we regularly (I do it weekly) inspect ALL propane lines, pipes, tanks, hoses, regulators, valves, and any connections visually, to ensure they are good and not damaged in any way.  I also go over EVERY connection with a spray bottle of soapy water….you see even the tiniest bubble(s)…you have a leak….FIX IT!!

One final rule for all forges with a blower type burner….. THE BLOWER IS ALWAYS THE FIRST THING TURNED ON…..AND IT IS THAT LAST THING TURNED OFF.  Follow that rule and you will eliminate 90% of possible accidents.

I could go on and on forever with various scenarios of do’s and don’ts for propane forges, and never cover it all.    A propane forge is nothing more than a controlled explosion.  Keep that in mind at all times, and your mind will be in the right place.  Don’t HOB KNOB anything when it comes to a forge….your life is literally at stake if you do.

(My current welding forge, after removing the forms and before allowing it to cure (this one took almost 2 months to cure before it’s first firing)

But once cured and in use……..

Good Luck!!

Ed Caffrey, ABS Mastersmith

“The Montana Bladesmith” 

For a long time I have watched as more and more 2 x 72″ grinders on the market utilize Gas Spring Cylinders (https://www.mcmaster.com/#spring-cylinders/=1byb3fm) for belt tension.  I’ve tried it too, and in the beginning, had durability issue….the cylinder rod seal would fail within weeks or days of me putting one of the grinder.  I finally figured out that I could make them last by using a “boot” zip tied on, to protect the rod/seal from all the grinder debris floating around.   But that’s a different story… the whole reason for this post is to expose something that I find very interesting.  These cylinders are NOT the “end all” that many make them out to be….particularly when it comes to belt grinder tensioning.    I have/use/like the KMG grinders.  I have changed mine to direct drive, and love it’s rock solid/heavy build quality.  I tried using one of the Gas Spring Cylinders on it, and found that when used on this particular grinder, Gas Springs seem to cause more issues than they solve.  A few grinding session after installing the Gas Spring Cylinder on the KMG, I notice that I was getting serious belt chatter on both 50 and 120 grit belts.  I tried adjusting the mounting locations and positions of the Gas Spring Cylinder, but nothing helped.  When using a flat/glass face platen, the belt chatter was so bad it made grinding nearly impossible….no matter what brand, backing, or type grit of 50 or 120 grit belt I used.

I spent a small fortune on different poundage rated Gas Spring Cylinders from 20lb, all the way to 90lb, all with the same, or additional issues. depending on the poundage rating…….

Out of frustration, I removed the Gas Spring Cylinder, and reinstall the coil spring mount, and the coil spring….. NO MORE BELT CHATTER!!!   I pondered this for a while, and can only come up with the following……  A Gas Spring Cylinder is built to apply a specific poundage of force.  I believe that the pressure applied to the belt when grinding caused addition tension on the belt before it reached the drive wheel…..and a slight amount of slack after the drive wheel.  The constant tension of the Gas Spring Cylinder is what caused this.   On the other side of the coin, a typical coil spring provides for a “variable” amount of tension, based on the amount of “drag” I cause when applying pressure during grinding.   Preventing the situation, or part of the belt having more tension than the other, and in turn, eliminating the belt chatter!  Since returning to the simple coil spring for belt tension, the infuriating belt chatter has been eliminated!

OK, What’s the take away?   1st….. just because something is “cool” doesn’t mean it works well.  2nd….. the latest and greatest, just might not be.  And finally……if you’re having issues with belt chatter on a grinder…… it MIGHT just be the TYPE of tension mechanism!  🙂

During this past week, I have fielded several phone calls & emails, most dealing with an individual telling me they wanted to purchase a forge, and asking my advice.  In ALL cases the individuals first consideration was to find the cheapest forge they could, which is understandable, but it’s also DANGEROUS when that is the main consideration.  Several of the emails sent me a link to a “new” outfit that is selling forges.   Not having heard of them, I followed the link to their site.  OMG!!  Are you kidding me?!?!  Besides the fact that these forges are VERY poorly designed, they had copper tubing and a needle valve affixed directly to the exterior of the forge body!  If you have even a fraction of knowledge that propane ignites at around 900F, and that doesn’t scare the poop outta you, then you need to look something else besides forging to do….. you’ll likely live a lot longer!

In another email, an individual asked me what I used to etch damascus, and told me that he was using Muriatic acid MIXED with Clorox Bleach!   I asked him why, and who’d told him to do that.  His response was….. “I saw it on YouTube”.     Again…. OMG!!  This is a sure way to kill yourself!  DON’T DO IT!!!!

FOR HEAVEN’S SAKE!  IF YOU DON’T KNOW OF WHAT YOU’RE DEALING WITH, DON’T DO IT UNTIL YOU GET ADVICE FROM SOMEONE WITH EXPERIENCE…. OR AT LEAST SOMEONE WITH A FEW BRAIN CELLS!

Mark my words…… we are going to start hearing about home/shop/garage explosions, and/or people dying from doing stupid things like these!   I’ve already been made aware of 2 incidents where somebody watched Forged in Fire, and decided “I can do that”…… and burned their houses to the ground!

I love it when a plan comes together!   This is a “slice” off the billet I produced in the upcoming video “Canister Welded Damascus”   The video was taken pre-heat treat, at a 220 grit finish.  It’s gona look killer when finished out to 1200 grit!   Look for the video to be available in the near future on the sale page.  And look for this blade, and others from the same steel at the Blade Show in Atlanta, GA, June 1-2, 2018!

Tim and I have been filming a COMPLETE video on Canister or “Can” Welded Damascus.  This will be as complete a video as we can offer…. from the type and size of “can” to use, to what goes inside, as well as tips and “tricks” to help you be successful.  Here’s a short clip of a “slice” that I sawed off the finished billet…..  This piece is fully annealed….so the high carbon steel have a “frosty” look.  Once heat treated, those areas will be very dark/black.     Look for the complete video to be available on KnifeMakerTraining soon.  (Tim has a LOT of editing to do on this one, so it might be a couple weeks) 🙂

Today Tim and I put in a full day of filming.  Tim had a great idea of “5 Minutes with the Master”….. a series of videos on who I am, about the ABS, and what I do.  I’ve never been one to toot my own horn, and had Tim not suggested it, would have never thought to do it.  But, he made me realize that there are a lot of folks out there who have no idea who I am, my experience level, or what I do.   Once again….. Tim has proven himself to be the brains of this outfit! 🙂

We also started the first in a series of creating damascus videos.  So look for those as Tim gets them edited and ready.  We got so wrapped up today, that we didn’t get to start on “Basic Bladesmithing”  but he’ll be back in the morning!   I’m having a blast doing this stuff! 🙂

Since my December surgery, I’m feeling great, and have just about fully recovered!  I am now taking reservations for One-on-One Bladesmithing/Knifemaking classes.  I offer classes/instruction from basic beginner classes, to advanced classes in Damascus, Liner Lock Folders, and just about any area of Knifemaking.   There is no set schedule for classes. One of the best thing about teaching One-on-One is that I schedule classes as requested by students.  Dates fill up quickly, so if you’re considering a class in 2018, contact me with your desired dates, and I match them up with my schedule.  If there are no conflicts, I will schedule you in.

For more information and prices, visit my Classes webpage:   http://www.caffreyknives.net/classes.html

Students must be 21 years of age, with exceptions being made on a case by case basis.   Class fees are PER INDIVIDUAL, and each student is responsible for their own travel, lodging, meals, and safety equipment.   As of today, I am scheduling classes for June 2018 and beyond.  April and May are reserved for Blade Show preparation.

Over the past week I have been slowly firing the new welding forge… starting out below 1000F several times, shutting it down, and allowing it to cool. Day by day I inched up the temps to 1200F, 1400F, then 1600F… letting it cool down fully after each firing. Today I decided that, for better or worse, I would see what it would do. Any time you build a new forge, that differs as much as this one did from my previous welding forge, there is always some doubt about how it will perform… those thoughts are now long gone! 

After starting the forge and letting it idle for about an hour, I inched the temp upward a bit at a time, and, at about 1950F, the steam started rolling, water was dripping off the front and back openings, and out of the burner holder. I just about shut it all down… JUST ABOUT… but took a chance and kept going. The temp stalled for a while right around 2100F, but I suspect it was due to all the steaming/dripping going on. The forge ran, holding at around 2100F for about an hour. As the steam dwindled, the temp started rising again, and before I knew it, the temp was 2430F!

After a sigh of relief, now knowing that this forge is going to reach the level of heat I was hoping for, I tweaked the fuel and the blower a bit, and it just kept climbing. I honestly do not know where “top end” is on this forge… my pyrometer tops out at 2499F… and there have been times when I check the temp readout and nothing but a row of “EEEE” shows… telling me the forge temp has topped 2500F!

And this was WITHOUT any coatings on the interior! I’m going to pull the forge off the table this week, and give a coat of ITC-100, and that should make it even better! 

The forge actually got to 2490F, and I figured I’d better not press my luck. So I dialed it back a bit, and used it to forge down some 410SS that, in the future, will become laminated with Mosaic.

So, now you know everything about how I built this type of welding forge and burner. If it works for me, there’s no reason it shouldn’t work for you too!

Thought I would add to this thread and show you what I use for a burner in my welding forge. Before we get to that, I just want to mention something that I feel is VERY important with any burner you use in a forge… KEEP IT SIMPLE! I’ve spent countless hours trying to help folks with forge burner problems, and I’ve come to fully believe… The more you overtake the plumbing, the easier it is to stop up the drain. The vast majority of problems I’ve assisted with/solved concerning forge burners can all be directly related to over complicated burner designs. Just keep it straight forward and simple… and your life will be much nicer.

I choose to use a very simple, single burner with a blower on my welding forge. Easy to build, very few things to go wrong, and it just plain works.

It all starts with choosing the correct blower for the application. While I know that many folks use “squirrel cage” blowers, otherwise known as Shaded Pole Blowers, that are very inexpensive, and easy to find, I personally think that is one of the least desirable blowers a person can choose. Squirrel Cage/Shaded Pole Blowers are NOT designed to function with ANY amount of back pressure… something that is always present in a forge burner application. Here’s what happens: As back pressure increases, air flow decreases, and causes the motor to heat up, and burn out the windings. Don’t get me wrong, some folks who use their forges very little, have gotten away with using this type of blower for years, but for those who do any kind of higher volume or prolonged usage of their forge(s), they can be a real pain. I know, because I did just that… used Shaded Pole Blowers. They worked fine, as long as I didn’t run the forge much, but as I got into longer and longer days at the forge, blowers started burning out. At the time I simply didn’t know any better, so I just kept replacing them… and kept burning them out.

Finally I broke down and purchased a blower that is specifically designed for forges. At the time (over a dozen years ago) I believe I paid $125 for this one.

It cranks out 164 CFM, and has been going strong for all these years. If you’re going to use a blower on a forge, I highly recommend this one/type.

Here’s a pic of the entire burner I use in my welding forge:

From the blower to the forge, the parts are:
-164 CFM electric blower, wired into a ceiling fan speed controller (DO NOT use a typical light dimmer, it will cause the motor winding to burn out… you’ve been warned!)
-Pipe Flange with 2″ threaded fitting
-2″ X 12″ piece of blade iron pipe, threaded both ends
-2″ X 1 1/2″ 90 degree elbow (this is a very important part of the burner… the reduction from 2″ to 1 1/2″ aids greatly in the fuel/air mixing, and increases velocity at the burner end for better control and high temps)

-1 1/2″ X 18″ black iron pipe (this is the pipe that goes into the forge and is the “burner”)

Propane is delivered through a common rubber propane hose, controlled with a propane needle valve (there is also a ball/shut-off valve located at the propane regulator). I far prefer a needle valve to a ball valve at this location. Its far more controllable, and makes fine adjustments MUCH easier. The 2″ pipe has been drilled and tapped to accept the 1/4″ pipe nipple. The nut you see next to the burner pipe is to “snug” the pipe nipple in place. I DO NOT USE ANY TYPE OF ORIFICE IN THE PIPE NIPPLE. I tried several differ sizes of orifice, and found that with the needle valve, they were totally unnecessary, and made the forge much more difficult to “tune”.

After a bit of experimenting with this burner, I installed 3″ concentric pipes in the burner end… I found that it quiets the roar of the burner nicely, and it gives me a better flame pattern, with a wider adjustability than without the concentric pipes.

Finally, the burner holder is an important part of the equation too. You want something solid and heavy gauge, that will be able to withstand the high/long endurance heat. It need to be welded solidly to the forge body, and be of the proper I.D. to “fit” the burner you’re using. In my case I used a piece of schedule 80 pipe, and using a boring bar, enlarged the size to about .030″ larger than the O.D. of my burner pipe size. This allows for expansion of the burner pipe, but isn’t so oversized that it allows flames to come out the burner holder. I drilled and tapped three 1/2-13 holes approx 120 degrees apart, and use 1/2-13 bolts to hold the burner in place.

The new forge has been curing for a couple of weeks now. I’m guessing that in about another week it might be cured enough to do some test firings and see how things are going to work. The current plan is that once the castable refractory is cured enough, give it a good cleaning with a brass brush, blow it out, and apply ITC-100.

Once I get it ready, I’ll add to this thread as things move along.

With the forge curing nicely, I figured I’d better get busy and build the lid. I cut off a 3″ tall section of the same diameter pipe that I used for the forge body… split it, then filled in the sides/gaps with 1/4″ plywood to make it match the outside diameter of the forge. Laid the form on a piece of plywood, and used nails to ensure everything stayed put. I decided to build the lid just the reverse of the forge… putting Kawool on the inside, and making the rest out of castable.

The pieces of bent rebar will be handles for the lid… inset into the castable.

Next, I mixed up some castable to a very soupy consistency, and basically soaked the Kawool in it. Then I laid the Kawool in the form, and mixed up a thicker batch of castable.

Then it was just a matter of filling the form with castable, and putting the rebar in place.

I got the castable way more wet then I wanted… but I guess “it is what it is”. Now it’s just a matter of curing time before I can do anything else. Once I get it in place and fired, I’ll update the thread with how it works out.