Latticino

Sweet, nice score.

I'm hardly an expert, so take this for what it is worth:  You can work "divots" into both sides of the stock by using the anvil horn under the stock while you are hammering with the peen side of the hammer.  This greatly increases the effectiveness of each blow.  Flatten thereafter, as you have been doing, using the flat portion of the anvil, but keep your steel hotter (at least orange, yellow if possible) so it moves faster.  Also make sure the steel is heated "all the way through".  With thicker stock you can end up with only surface heating, and your blows won't penetrate deeply.

Working tool steel is a compromise between decarb and being able to move the metal.  Long heats at high temperatures will cause decarb (bad), but if it takes too long at the red-orange heat you run into similar issues.  It does take an awful long time to hand hammer down that size tool steel stock (I turned a similar size spring into a long, socketed, spear head and it was a bunch of work, though on reflection it may have only been 3/8" thick).  Still think of all the exercise you are getting...

This is why the big boys have those power hammers or hydraulic presses.

Check out Brian Brazeals videos on tapering to see other techniques for reducing metal using other sides of the hammer and the edges of the anvil.  Some of those techniques may also be helpful.

Sheesh, hope you have a power hammer or a striker with some serious stamina.

Took a class concurrently with Steve Ash at Touchstone.  He is an excellent smith and a good instinctive teacher.  Saw some forge welded axes he made and they looked quite good.  Don't think you can go wrong there.

Welcome to the site.

Please do more research on bladesmithing on this site.  You will find that while spikes are great for some things, including testing out blade shape and learning forging technique, they aren't really good steel for making knives.  Not enough carbon to harden effectively with conventional treatments.  Not to mention the potentially questionable aspect of their sourcing, though if you are getting them from flea markets you are probably OK.

If you are really interested in bladesmithing I strongly recommend that you take a class in same from an accomplished smith, or at least get Jim Hrisoulas (http://www.sharpeningsupplies.com/The-Complete-Bladesmith-Forging-Your-Way-to-Perfection-P150.aspx?gclid=COrI747d_skCFQovaQodEywBNw ) and Steve Sells books and study them.  There is a lot on the internet that will send you in the wrong direction.  The forging side of making knives is only the tip of the iceberg.  Filing, grinding, heat treatment, steel selection, handles and sheaths are also in your future.

But to answer your question, if you have 6" of steel left after making the handle section of the knife you should easily be able to forge it out to an 8" blade (depending on the crossection of the material before and after).  Forging is all about moving a volume of steel from one configuration to another.  Basic geometry calculations can tell you what is possible, though you will lose some material to scaling.

Another outside the box option might be a vertical 4 x 106 belt sander typically used for glassworking (check Covington), depending on what your plan of use is.  They can sometimes be sourced used from glass shops that are closing for very attractive prices.  They don't have the massive motors that the metalworking ones do, but I have one and have gotten some good use out of it.  They can also be used wet, so that is a big advantage.

Very impressive for one week of forging, even with an experienced instructor helping one-on-one.  You must have been working morning, noon and night.

I'd jump on the Soderfors immediately if it was a good price.  Looks to be all the anvil that anyone would need starting out, and maybe forever if you don't do large architectural work.  Love that German double horn style, and it is in great shape, at least visually.  Try a rebound check if you can for the face.  That one looks almost too nice to use.  Do yourself a favor, if you get it, and work on your hammer accuracy for a while on the rail anvil.  It would be a shame for an errant blow to chip an edge there.

Just think what you will be able to do when you start making your tools out of recognizable high carbon tool steel.

What mix did you use to insulate the inside of your soup can?  Unless high temperature castable insulation of some sort be careful what you mount the forge on and how close you set your burner to the forge port.

How long does the compressor run at night?  If a single time, or widely separated, could just be stored air temperature dropping and losing just enough pressure to startup unit.  Have you checked for valve and fitting leaks at your indoor storage tank as well?

Might want to see if you can increase the deadband in your compressor controls so it can drop a reasonable percentage before kicking on.  Another remediation option would be to put a timeclock on the power to the compressor, though if you wanted to work off hours you might want to add a HOA switch for override as well.

Completely understand.  I was replying to Frosty on this regarding his custom "fibrous brick" project.  Please note that the rating for the fiber board product is 1400 deg. C, approximately the same as the blanket often used for a low mass forge insulating barrier.  I still strongly recommend an inner protective coating as well as a burner block and/or flame "strike plate" (for the wall opposite the flame) made of materials that will resist the 3,000+ deg. F flame temperature.  I typically use Mizzou for this.

I have posted elsewhere that I am definitely in favor of a multi layer forge lining (Kastolite or equal interior and wrapping of refractory blanket) that you suggested.  I also have used an inner lining of high density refractory at times (inside the Kastolite), but only for equipment that will not thermal cycle often, or rapidly, as the two castables have markedly different thermal expansion ratios and one of the two will inevitably crack during the cycle if it is too rapid.  I always wanted to experiment with putting a layer of blanket in between the two to see how that worked, but haven't had a chance to do so to date.

On ‎12‎/‎8‎/‎2015‎ ‎3‎:‎06‎:‎39‎, Frosty said:

A proposed experiment is to make a form and rigidize Kaowool into a brick size and shape. Properly washed Kaowool is pretty indifferent to thermal cycling so long as it's not exceeding vitrification temps and the wash is the direct heat shield.

I'm sure you are aware that Kaowool, or a similar high temperature glass fiber material, is also available in board form.  It is fairly expensive relative to the blanket, but rather than casting it yourself you might want to look into using that.  Board available up to 2" thickness from this manufacturer: http://www.morganthermalceramics.com/products/refractory-ceramic-fibre-rcf/board-products.  Not as "structural" as brick, though I suppose you could cut out 2" thick rectangular sections and stack them similarly to your brick design.  I'd still coat them with a rigidizer of some sort.

I would use Mizzou for that type of burner.  It is rated for 3,000 deg. F.

Mizzou is a high density, high temperature castable with fair resistance to molten glass (flux).  Refractory castables with higher percentages of alumina and/or zirconia have better flux resistance. It has very little insulating value (close to that of concrete).  As you noted, it is a good choice for forge liners, if you are looking for a high thermal mass forge (and plan on backing it with some kind of high temperature insulating material), and ribbon burners.  It is more economical than the equivalent high alumina refractory castables and in my experience a bit less prone to thermal shock.  It also has a coarser surface finish than the high alumina castables, which can be an issue with ribbon burner ports.  Additional info here: http://supplies.foundryservice.com/item/castable-refractories/dense-castables/mizzou

Kastolite 3000 is a castable insulation which can be used for a forge liner as well without  specific requirement for backing insulation. It is still higher mass and less insulating value than refractory blanket insulation, so you will need more thickness to get an equivalent insulating lining.  As far as I know, Kastolite is not very resistant to flux, so some kind of inner protection, at least at the forge base, may be required.  A composite lining of an inner wall of 2-3" Kastolite wrapped with an inch of blanket, and a forge floor of bubble alumina, Mizzou, or Greencast 97 might be the best of both worlds, though it will certainly heat more slowly than a blanket insulated forge with a thin refractory liner.  Additional info here:  http://supplies.foundryservice.com/item/castable-refractories/insulating-castables/kaolite-3000-kast-olite-30-li

Glad to help.  For what it is worth, I used Giberson burner heads on blown, low pressure, natural gas burner assemblies for 10+ years.  They are quiet and supply a nice soft, hot flame.  Have to be careful regarding thermal shock, but that is the case for any type of refractory.

1. 8 hours ago, Mikey98118 said:

   after some consideration it seems to me that a mixing tube that is tapered, could be the naturally aspirated burner fan's answer to fan-blown ribbon burners, if they get too uppity about them you may have to complete your experiments, just to keep the competition going :-)

   The classic Ransome industrial NA burner has a tapered mixing chamber, as described.  These are used extensively in the glass and ceramics world for firing furnaces and kilns.  One of the best ways to use same is with a Giberson style cast high alumina refractory burner nozzle.  These are round, or rectangular in cross-section and have multiple small openings for the mixture to exit the burner (remind you of anything?).  You can check them out on this site:  http://www.joppaglass.com/burner/mini_square.html.  Note that he even has a small forge design to go along with his burner/burner tip assembly.

16 hours ago, stan said:

The type of blade a typical bathroom fan  uses can`t handle static pressure ie so  they are not designed to be ducted so you would have to keep the duct section short for it to work .A squirrel cage blade fan are designed to be ducted .

Actually typical bathroom exhaust fans are designed to be ducted, just not with a whole lot of static pressure.  Typical bathroom exhaust fans run in the 50-140 CFM range and between 0.1 and 0.25 inches Water Gage of static pressure.  This pressure is fine for the typical backdraft damper and 20' of 6" diameter duct that is run from a toilet.

However, though a good bathroom exhaust fan is rated well for the high humidity bath exhaust it is not at all well suited for the heat, ash and sparks that might arise in a solid fuel forge exhaust stack.  Many bath fans have plastic components, including impellers.  I would never recommend using a bathroom cabinet fan for forge exhaust.  You might be able to use one as a forge air source, but there are many better options available.

I have a "low pressure" natural gas forced air forge in my shop which works quite well.  I am using an industrial burner with high quality mixer, ventauri chamber for expansion, high pressure blower, and zero pressure regulator.  I've built several pieces of equipment with this kind of burner assembly, and it works just fine, but might not be the easiest system to configure (I got mine for free from a glass studio that was being upgraded - everything was in the dumpster!).  Forced air systems are a lot easier to use as far as dealing with backpressure of forge configurations as well as varying the proportion of the gas air mixture to change the forge atmosphere.  There are safety considerations though, and your local codes may require either a gas shutoff interlock with UV sensors for flame proofing and/or airflow sensors to ensure the blower is running.  Without these I would not leave a blown system unattended.

I have seen sketches for home built NG burners with forced air.  They are essentially the same as propane/forced air units with larger gas orifices and gas feed connections.  

As Tim states it is not really feasible to use low pressure natural gas in a naturally aspirated burner for a forge.  The pressure isn't sufficient to create the velocity needed to induce the right amount of air.  Blown burners don't need this velocity, but you will be surprised at the gas pipe diameter needed to move the quantities of gas required for forging in a reasonable size enclosure. 

These also work great with ribbon or Giberson style burner heads which give you a much quieter and more distributed flame.

As usual our local curmudgeons are trying to gently steer you along in a safer and more practical direction.

Casting metal is very dangerous.  Get some hands on assistance and training from someone who has actually done it successfully for a couple of years (and still has all their parts intact).  Training by watching YouTube does not qualify.

As far as crucibles go, how are you going to cast a crucible if you don't already have a crucible to heat the metal up in?  Kind of horse before the cart there.  Not to mention, that as Thomas said, non-metallic crucibles are a better choice.  Crucibles are a consumable in a foundry in any case, so a cheaper, time tested alternative is a better choice.  Suggest you Google search graphite crucibles for info on suppliers and crucible types.

As I mentioned in another post on this forum the same thickness of high temperature glass fiber blanket is around 10 times better insulating material than a plaster/sand mix from what I could find regarding these materials.  Even though there are certainly some losses due to radiation out the open door and convection of the heated combustion byproduct gasses, this is a rather significant difference.  This is not even taking into account the thermal mass of the plaster/sand mix which will take a lot of time to heat up every time you fire the forge up.

As Vaughn correctly states, using this material for a gas forge liner is a false economy, unless you get free fuel...

I'm in process of building a quick paint can forge to use as a demo for my blacksmithing group this weekend.  I plan to use a scaled down Frosty T burner (1/2" dia. burner tube with a 0.23 MIG tip).  This forge will be insulated with Kaowool and will have both front and back door openings.  If successful I will post results, but I fully expect it to get up to forging temperatures easily.

Amazing result for a first effort.  Love the activity in the Hamon. 

A coil spring?  Seriously?  Did you forge weld it to make up the required billet width?  I could see this from a leaf spring, but the only car coil springs I've seen were 3/4" dia. max and would be a real chore to spread out this far and keep enough thickness for the spine.

What was your quench media?  How did you accomplish tempering?

I'm sure some of the experts will have suggestions as regards your grinding and polishing, particularly as regards the tip geometry, but all in all I would call this a major success. 

How does she cut?

Sorry for all the questions, but this is exciting work.

I don't have a tremendous amount of experience building solid fuel forges.  In my experience of using same they don't need a lot in terms of "enclosures", just something to consolidate the fuel in a location where the forced air can be directed to burn it as required (not to mention drain away the ash produced).  I would certainly experiment, but believe that you are overthinking your forge design, and possibly combining it with flue design (which is a whole different kettle of worms).  Might want to try building a successful design before you set out to reinvent the wheel.

1 hour ago, Micah Burgin said:

 if you look at his steel crucible, it's reached yellow, and my aluminum casting expirience (Which is not vast, but I'm pretty well-versed) has shown that to get aluminum to flow

 

(BTW, I think I'm going to do a test on the insulating properties of the stuff. Any recommendations on how? I'm thinking a calorimeter and trying to measure it's specific heat capacity but that's tricky because of the water involved....)

Please remember that digital pictures and video don't give anything like accurate colors for heated steel.  If you look carefully, or even experiment yourself, you will notice that the steel being forged in most amateur videos looks like it is much hotter than required (often white hot).  This is due to the camera sensing elements, not the actual heat of the material. 

As this is only the basin for holding solid fuel, insulating characteristics are not necessarily critical as regards potential for forging, just for keeping the body of your forge from burning the surroundings and the rest of your assembly (including the PVC, whose vapors on burning are nasty).

Insulating properties for materials can be calculated for known material thickness, enclosure geometry and interior and exterior temperatures.  Of course losses from various types of heat sources must also be taken into account (i.e. radiant losses from doors and convective heat losses from transfer of products of combustion).  Probably the best way to test materials would be using electric heating coils (where an enclosure can be fully sealed).  I'll bet ASTM has a standard for this (ASTM C177 or C518).

Please note that the thermal conductivities of some of the products you have been discussing are as follows:

Plaster/sand mix:  0.71 W/(m deg K)  per the Engineer's Toolbox (which I have found to be rather accurate),

Insulating fiber blanket:  0.07 W/(m deg K) per manufacturers data.

Note that the latter is 10 times better insulator at a more elevated temperature

Mixing it with sand will certainly help with it's refractory properties, but I doubt greatly it does anything for it's insulating capabilities.  Two things to remember from that DIY video.  First, there is no indication of how much fuel needs to get dumped into the melting furnace, so efficiency (which is pretty directly related to insulating capacity) is not spelled out.  The other is that aluminum melts at around 1,250 deg. F and forging temperatures can reach twice that.  I'd be really careful to put some kind of non-flammable and preferably insulating material between this proposed enclosure and any table support (unless that table is itself quite heat resistant).  Of course your bricks will help with this, but be aware that normal bricks and concrete block are not rated for this kind of temperature either. 

It might be prudent to actually build one of these before recommending a design to all and sundry. 

I'd say this material would be fine for the basin of a solid fuel forge.  After all, folks use raw clay mixed with a variety of additives (including sand) for that as well.  If it burns thru you can just break it out and replace it cheaply.  Not sure how this mix will resist flux, of course, but that may not be a big concern for you.

Finally, here is some additional information that may help you in your cheap refractory formula search.  Admittedly it isn't on You Tube, but Anvilfire has some very reputable contributors, and this one appears to have actual forge building experience: 

Good luck

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