side blast trouble

[lupiphile]

After having been "raised up" on a bottom blast forge, I, having, more time than money, decided to build a side blast forge , ala blacksmiths journal, mark aspery/CBA ect... And I'm having considerable trouble managing the thing. It's been my principal forge for about six months now and I can't say I've gotten much better at removing clinkers, or managing two irons in the fire. I, of course feel fairly stupid for not just building a bottom blast , with a bought firepot, but , alas sheer cussedness prevents me from getting rid of the thing.Its clearly my lack of experience that seems to be causing such woes but I have little else to go on. My coal is, in part, comprised of an upsetting amount of fines, that just seem to fill up the duck's nest within about an hour of fire management, this also just helps to muck everything up with removing the clinker and keeping the work clean.I also find it incredibly difficult to keep from pushing the ash/fines bed into the fire accidently, when trying to feed the fire. I do enjoy the concentrated heat zone, but have yet to tease out enough redeeming qualities to out weigh all the negatives associated with my ineptitude. I'm sure some of you old timers can set me straight. Well any advise would be greatly appreciated. Thankyou much, matt

[HWooldridge]

Fines are best worked into a wet paste before adding to a fire because it will coke better and not fall into the fire as you have experienced. My coal is mostly fines and came from Oklahoma; it is also pretty clinkery so I have to stop about every 30-45 minutes to pull a clinker (that's in a bottom blast pot). I let it cool briefly for about 1-2 minutes and fish it out with a small 1/4" poker with a slightly hooked end. This allows you to poke down through a hole in the coke mass and pull the piece(s) out.

[lupiphile]

Thanks for the advise. My coal tends to coke thoroughly (think Impenetrable bastille) around the edges,without much liquid intervention, but as I break it up to feed my fire, well thats when the trouble starts. As for the clinker, It just always breaks into a million insidious pieces, no matter how long I let it cool for. The aforementioned wall of coke, of course, does not help much, in the retrieval process. At some point I might try replacing the ash bed with old foundry sand, or the like, but the prospect of digging out all hundred pounds of ash and fines, not to mention getting foundry sand isn't much of an enticing prospect. Maybe some of you british folks could offer some insight, I hear side blasts are still very much the cat's meow in the old country. Thank you much, Matt

[John B]

Hi Lupiphile, that's difficult to sort out without seeing the coal you are using, or other details like depth of forge under the tue hole, amount of air blast going through tue and how you control it, how you put your workpieces into the fire etc.

I have only come across similar problems with one lot of coal I used, which may have been similar in constituency to what you use, and although I managed to forge well enough with it, I changed from that fuel to something that worked better for me, and i did not need to sprinkle the fire as much with this coal as I did on other coals.

Having said that, if you are finding the fuel cokes and forms a nice impenetrable shell, I would tend not to break this covering shell up, but try to feed the fire from the supply of fuel from in front of the cavity you are working through, this in effect gives a small furnace that you can look into and observe what is happening to your metal ie when it starts sweating etc.

This method gave little clinker, and that seemed to be in smallish pieces rather than one large piece or granules.

As for the clinker, it usually breaks into small pieces if you are working and disturbing it when heating your metal, try to disturb the fire as little as possible when placing your workpiece in the fire.

I don't think the ash/foundry sand would make much difference, one of the reasons we use sand to fill the base of the hearth is its cheaper than filling it with forging fuel, and usually when we have inadequate amounts of ash available when initiallising an new set up. It is not unknown for a new forge to be filled with fuel for the first time, shut down and left for the night, and come back into the forge the next day, and the whole hearth is a glowing mass as the heat and fire spreads through the new fuel, the ash/ sand contains and limits the amount of fire spread, without having to douse all around regularly whilst working.

I dont't know if this helps or not, please try and report back, and Good luck with it.

[lupiphile]

Ah, thank you much. Its sort of a slow/ sick day around the shop,a perfect day for forge remediation. As for dimensions, the tueyre sits about 3" down from level to the sides, and the base of my "duck's nest" is about another 3" down from that. I had always been taught to settle pieces into the top of the fire, thusly always ensuring a good bed of coke to alleviate and oxidation problems.It did cross my mind that maybe this was making things harder on myself, though old habits die hard, and Ive never had much luck with that furnace style fire.It always ends up a little too oxidizing, and I've always have a hard time both feeding it and getting my metal in and out of it without collapsing the shell. I'm often working odd shaped/large pieces. As for disturbing the clinker , that makes a lot of sense. I do find I often have to stick my poker right down in front of the tuyre to keep the air flowing freely. This I know disturbs the clinker but most of the time I'm more concerned with getting one more heat.Like I said before,I know It's my habits mostly , but I'm not sure which ones are bad and which are ok. Thank you for giving me something to go on.As for the foundry sand, I just thought it would be advantageous to have a substrate thats easily delineated from the fuel so as to not be continually pushing ash and other undesirables into the fire. Thanks again, Matt

[John B]

Hi Matt, 3" under the tue is possibly a little shallow, 4" plus would probably be better, I run about 5"plus

If you feed the fuel in from the top of the hearth, you shouldn't be feeding in ash or sand, just clean out the fire area regularly, I generally have an area like a pot about 10" around the tue end this is the working part, the size of the hearth is irrelavent really as it is only a place to stockpile your fuel, I have a small 16" square forge that I can do most things in, I just need to add fuel more often.(But I don't have to carry much fuel if I have to pack it to demonstrate at shows etc)

I tend to think its a fuel problem as I've just dug out some of the old coal that sounds similar to what you are using, and it was OK for about an hour or so, I then had trouble with it "granulating", I could still use the fire, but it was very dirty, I haven't pulled the clinker yet, but I don't expect much

[ironwolfforgeca]

I have built 4 side blast forges like what Mark A has done he is at most of are meetings. one thing I did was to put in fire brick @ an angle on sides & on bottom to make a fire box in the clay i use in the forge work well and keeps coke or coal cleaner working side blast forge takes sometime to get use to it TO ! though I will take ti over bottom blast easier to clean out the clinker :)

[lupiphile]

Thanks again for all of the advise. John, After reading your response I did in fact deepen my "ducks nest" by about an inch.I'll have to see if that helps, as that after doing that I when home and promptly passed into a coma-like state for about 14 hours. Good old strep throat to ring in spring with a bang. Everything you wrote makes a bunch of sense given my conditions and habits.I believe I'll try to source more intact coal.I do live right at the cusp of coal country(eastern pennsylvania ) But I got this coal from the most frequently recommended place on the local blacksmith's radar screen. Also at 212 dollars a ton its hard to beat. Mr. Wolf, I had already done that and like you said It does indeed help with the cleaning/ and fire management a bit. Thanks for all of your timely responses, Matt

[hdvoyager319]

I am Paul R.. I have always used the traditional bottom draft forge. I have several small forges and a large stationary forge. the coal I have been using was removed from several house basements. I have several tons of soft ball size and larger chunk coal. The clinkers formed in the forge require the forge to be cleaned out every 2 hours. This forge doesn't have a clinker breaker, just a grate.  I then researched the Side Draft Forge where the clinker are formed below the air inlet.

 I am in the process of building a Side Blast Forge. The Hearth is 24" sq., 9" deep. I basically am following Mark A. design. I wanted each component of the forge to be separable. The forge stand is made from 1" sq. tubing with removable legs. The Water Tank was reduced in size to be easily removable: 9"w x 24"l x 18" h. The tuyere is per Mark A's design except it is connected to the Water Tank thru 1" dia. hoses, top and bottom.  The air is supplied using an electric blower.

Currently,I am building a Super Sucker Side Draft Hood and will be using a 10"x 25'  grain elevator auger tube as the chimney.

Problem: The forge has been fired up twice to test its function. Both times, the air supply plugged up at the end of the tuyere. By disconnecting the air supply, I could run a rod down the air tube to clear out what was deposited in the tube. When I looked down the tube, the end was black with the plugging material. After pushing the rod thru, I had a view of red hot coals. Then the fire roared to life up to welding heat. Am I the only one to have the air supply plugged up and need to push a rod thru to remove the material that is plugging the air supply?

Set-up information: The bottom of the Hearth is covered with fire brick and then "fill lime" is used to fill the Hearth and make the coal's nest. The bottom of the water cooled tuyere is resting on the firebrick. There is about 1" of fill lime over the firebrick which makes the air hole about 1-1/2" above the fill lime. The fire was started with charcoal, then a little bituminous coal and the forging was done with anthracite coal. since I am running without the chimney, the clean burning anthracite solved the smoke problem.

I will add pictures of the forge when it is back together.

After 4 hours of forging, the top 3/4 of the water tank was hot and steaming but the bottom 1/4 was still with cold water. Since my cut down water tank holds about 10 gal. (15 gal. is recommended) a method was devised to cool the water using the natural rising of hot water ( coffee percolator effect) tp pump the water up and then over a screen arched high over the top of the tank. 

After having water in the system for several weeks, the inside of the tank got quite rusty.  I have a drain facet on the bottom of the tank. The water was emptied into a old beer keg after a day's forging.. A sump pump will be placed in the keg and used to pump the water back into the forge when the forge is to be used.

Welding the tank and tuyere with a flux  core wire welder was quite difficult to make the seams water tight. The flux core weld is at best, rough and may have some porosity.  The seepage leaks were located and then the tank was re-welded to plug the leaks. All welded seams were welded on both sides. Welding the inside of the tuyere was  difficult with the wire welder. A stick welder would have done a better job as it could have reached in easier to weld the inside where the pipe was cut out to make the taper. 

After the 2-1/2" air tube pie shaped cut outs were welded shut, the end was plugged and tested for water leaks. The 5" tube was also welded and tested for leaks. After the two tubes were welded in position, the assembly was tested for leaks. After welding the tuyere, several weeks later, cracks surfaced in two large, thick welds. The crack was "V" ground out and the crack filled with new weld. 

Have any of you made a Side Draft Forge and hood?  What problems did you run into? And how did you fix these problems?

[hdvoyager319]

After a days forging in my old bottom draft forge, I pull the fire and am amazed at the size of the clinker that comes out. 

For the next fire, all the old coke and coal from the previous fire are run thru a hardware cloth with a 3/8" sq. mesh. 

The fire is started with a charcoal base, then the coke from the previous fire, then raw coal is added around the fire.  The large chunk coal is placed around the sides of the fire to make the fire deeper without using more coal. As the chuck coal heats, it becomes greasy in appearance. A "Coal Hammer" makes quick work to break up the chunk coal into small pieces.

Another trick to increase the heat in the fire, is to place a piece of thin steel plate over the fire. The steel will reflect the heat down onto the fire. Placing a flat piece of large chunk coal works the same way to reflect heat back into the fire. Now, the project steel will heat a little faster. The steel over the fire also spreads the heat out to be able to heat a longer piece than would be possible without the steel sheet over the fire.

[Mikeyn]

Quote

Both times, the air supply plugged up at the end of the tuyere.

I had a problem with the same thing three times now, to the point where i`ve been redesigning it, this time i am going to try to put the clay a little further forward , proud of the pipe end.. by around half an inch or a little less, I am also increasing the depth of the fire pot in the thinking it will allow any molten crud to drop down below the tuyere pipe, also, my problem seemed to of come from the back side of the fire pot, the bit where the tuyere pipe came in, being too slanted, this seemed to help build up clinker around the top of the pipe and helped to melt / plug up the air pipe...so in making that back side flatter i am hoping it will help drop that material into the bottom of the pot rather than collecting around the tuyere..  fingers crossed...

[Irondragon Forge ClayWorks]

On 9/21/2019 at 7:15 PM, hdvoyager319 said:

I am Paul R..

Welcome to IFI... Have you read this yet? READ THIS FIRST  It is full of tips to help you get the best out of the forum.

[hdvoyager319]

My forge is based on the article, "Building the Side Draft Forge" written by Mark Aspery. This is the basic design of my forge. I made several changes to the forge to make it capable of being broken down into components not weighing over 50#. The water cooled Tuyere follows the dimensions in the article however the Tuyere is connected to the separate water tank via upper and bottom hoses. The hot water rises up the Tuyeres top pipe to enter the top of the tank and the cool water flows out the bottom water tank  hose into the bottom of the Tuyere to circulate the water in the Tuyere.

The front portion of the Tuyere protrudes 8" into the Hearth. To use less coal, fire bricks were placed on either side of the protruding Tuyere which left about the last 2" of the Tuyere exposed to the heat of the fire. Other fire bricks were used to fill the space in the 2' square 9" deep Hearth. Since the Tuyere is water cooled, there was zero evidence of the fire heating or burning the exposed end of the Tuyere. 

??Mikeyn, is your Tuyere water cooled or is it a bare pipe extending thru a bed of insulating clay?

 I failed to determine what was blocking the air pipe, I just pushed a rod thru the pipe to clear it. The blockage was solid black when viewed thru the opened rear of the air tube. When the blockage was pushed out with no difficulty, I assumed it was ashes and possibly some fill lime from the Duck's Nest.

Every time steel bar stock was placed in the fire zone, the coal was pushed out the other side, requiring the coal to be raked back into the fire zone. Since the bottom of the Tuyere is buried in the fill lime, the air tube hole is only a little over an inch above the fill lime. After the fire was established, the coal used was Anthracite "Nut Coal" purchased from Tractor Supply. The Nut coal is in walnut size chunks with very little fines or dust. However, the Nut coal burns with a considerable flame (which eats any smoke) and creates a bright yellow/white  heat when the full air blast is used.

After 4 hours burn time, the fire was pulled to extinguish it. There were two small 2" dia. clinkers pulled out of the bottom of the Duck's Nest plus ashes, coke, and unburnt coal all mixed with a little fill lime. 

I wrote to Mark Aspery and received a response suggesting that raking the coal back into the fire could also cause fill lime and ashes to be raked into the air tube and cause its blockage.

I have a theory: Since the anthracite coal is extremely hot, is possible that some of the coal and fill lime could be pushed into the air pipe during raking (as Mark suggested), the coal could quickly burn out and then with the cooling air supply hitting it, cool to a mass? 

When I get the forge back together, the Tuyere will be raised 4-5  inches above the bottom of the Hearth. Sand will be used and the fill lime removed. The Tuyere air pipe will be changed to add a "T" section with the back side of the "T" giving access to clean out the air pipe.  Then, I will carefully inspect any air blockage to determine what it is. Also, is the blockage inside the air pipe or is it clustered ash outside the pipes opening.

PS: I live in Scotch Grove, Iowa which is between Cedar Rapids and Dubuque. So if any of the blacksmiths with a Side Blast Forge who lives within a 100 mile radiusI, I  could possibly schedule a visit to review their Smithy to see how they have solved this and any other problem peculiar to the Side Draft Forge design.

[Irondragon Forge ClayWorks]

18 hours ago, hdvoyager319 said:

I live in Scotch Grove, Iowa

We won't remember this once leaving this post, hence the suggestion to edit your profile to show location.

[hdvoyager319]

Surfing the web, I found an article by Lea Sauder titled "Forging and Using a Wrought Iron Tuyere" This article covered in depth using a clay covered Tuyere, and how to make one. I believe that Lea's article will solve your Tuyere problems.

[Glenn]

First suggestion would be to raise the tuyere off the firebrick floor. This will give the clinker a place to form without causing a problem with the incoming air.

 

[hdvoyager319]

Thank you. I found Lee Sauder's article "Forging and Using a Wrought Iron Tuyere". He used wood ashes wet and tamped to make the Duck's Nest (I used Fill Lime). He also tilted the tuyere down. Do you have any ides of how much of a down angle I should use? Should the water cooled Tuyere be packed in clay or ashes in addition to being water cooled? How high would you recommend lifting the Tuyere's center above the bottom of the Duck's Nest? Is a fire brick necessary under the Tuyere? When I pulled the fire, the brick was glowing quite red. The Tuyere was laying on the fire brick.

My Hearth is 24" square by 9" high. How far should the Tuyere extend into the Hearth? I am thinking about making a 16" or 18" square by 9" deep Hearth to cut down the amount of coal needed to fill the large Hearth.

I started the fire with charcoal then soft coal and topped the fire with Anthracite coal. The Anthracite coal was used for the rest of the test run. With the Guillotine closed, there is enough air leakage to keep the Anthracite coal burning. Also, the fire didn't creep out like the bottom blast forge does which requires continuous control watering.

How strong should the air blast be? With the 1725 rpm 1/3hp motor connected 1-1 with the blower, the air flow would be adequate for a bottom blast tuyere. The pulley diameter is adjustable so it isn't any problem to increase the air flow by 50%.

In the diagram you sent, are the sides of the Hearth lined with fire brick or clay?

I have been reading everything on the Side Blast Forge that Google posts. 

The cooling of the tuyere using hoses connected to the water tank worked well. However, I am building a wire mesh "A" frame over the tank. the rising heated hot water (coffee percolator principle) should lift the water above the tank to trickle down over the 1/4" sq mesh Hardware cloth.  Some 1900's tractors and gas engines used this method to cool the water.

I have been using a bottom blast permanent style forge for the last 20 years. Depending on coal quality, the clinker problem can be a show stopper requiring clean out at short intervals. That is why I decided to make the Side Blast Forge with a Super Sucker Hood and 10" dia x 20' chimney. The tube is from a grain auger loader that was wrecked. Also, no part should weigh over 50# so this old man can move the forge piece by piece.

For a chimney Top Hat, I intend on sealing  the chimney with a flat plate that is balanced similar to the tractor balanced exhaust cap. It will be held open by pulling a cable down and locking it in the open position.

I am in new territory with this forge. I appreciate any suggestions or corrective actions to eliminate potential problems.

thank you and any others for help.

[hdvoyager319]

Removing coal fines: I have a hardware mesh sieve that is 18" square with 6" high sides. My coal is sifted thru the sieve before being used. When I come back the next day, there is a lot of fine ash mixed with the coke and unburnt coal. Again, everything is sifted to remove the fines, ie: anything that will pass thru 3/8" square hardware cloth mesh has been used to fill in soft spots in my driveway..

Tractor Supply sells Anthracite Nut size coal. This coal has been washed to remove the fines. My soft Blacksmiths coal supply is about 5-10% dust and fines. I will try making a dust and fines and mold them into brickets. I have a load of coal removed from a basement. There are a lot of coal brickets mixed in the coal. So far, the coal brickets work as well as the coal chunks.

[Glenn]

Down angle on the tuyere should be enough NOT to trap air in the water system.  No reason to try to cool the water, all you need to do is keep the water level up so the system does not run dry or allow air into the tuyere.

Try putting a house brick under the tuyere. If you need more turn it on its side.  You simply want to create a catch basin for the clinker.  Higher is not a problem as the depth below will collect clinker, ash, etc and fill in. This will insulate the bottom of the forge from the fire.

The size of the fire depends on what is being heated. Small material only requires a small fire where larger material requires a larger fire. Use bricks to form the sides as needed.  

Fuel does not make a fire hot, air makes a fire hot. How much air do you need? How hot does the fire need to be.  You can be surprised how little air is needed sometimes.  Get a good fire going and then cut back on the air until you get the heat you need.  Anthracite coal requires some constant air (a little bit) to keep going. You have to play with it and dial it in.

When you screen the fines out of the coal save them. Put them into a 5 gallon bucket and pour in water. They will want to float until they get wet. When you need coal, reach your hand in and scoop out a handful of wet coal mud and place it on the fire. 

How much water?

Breeze or coal dust. Just add the damp material to the edge of the fire and let it coke up.

[pnut]

6 hours ago, Glenn said:

Down angle on the tuyere should be enough NOT to trap air in the water system.  No reason to try to cool the water, 

The heat from the tuyere will cause a temperature differential that will make the water circulate. Hot water rises as the cooler water sinks circulating the water and supplying cooler water to the water jacket. A lava lamp illustrates the principal well.

Pnut

Edited September 25, 2019 by pnut

[hdvoyager319]

After several hours of my first test firing, the top hose was too hot to touch and the bottom hose was still cool. The top water in the tank was steaming. If the water boils then I will add a wire mesh cooling "A" Frame over the tank. This cooling method was used in sone gas engines and tractors in the early 1900's . Yes, the water was circulating nicely. The water will rise to enter the screen by using then coffee percolator principle.

[hdvoyager319]

My forge building progress: Today the chimney portion inside the building was completed. It took two of us, a come-a-long and several ropes to lift the chimney bottom two  sections into position. The connection joint is made by cutting a piece of the tubing into a 6" high piece with a 2" wide strip removed so the chimney section can be squeezed to be stuffed into the top of the chimney section. The section is then welded to the top end of the tube section to make the male joint. The Female section is made by making 8 each, 4" long slits in  the bottom end of the tube. The tabs are pounded out. The two chimney sections are checked for a proper mating. A 3" wide clamping collar was made to go around the tubing joint.

Since the Side Blast Forge is water cooled and winter is approaching I had two choices. a, fetch 10 gallons of water for the forging session and then drain the water when thru forging. b, go to used antifreeze. I opted for the used antifreeze that I got from the local car dealer.  The antifreeze should not cause the steel tank and tuyere to rust. Antifreeze conducts heat a little better than water. ??Has any blacksmith used antifreeze to cool their Side Blast Forge?? If so, what is your evaluation of using antifreeze in stead of water? Is there any surprise problems associated with using antifreeze as a coolant?

Are we having fun yet?

Paul

[pnut]

6 minutes ago, hdvoyager319 said:

Is there any surprise problems associated with using antifreeze as a coolant?

Dead critters, unless you get the non toxic anti freeze.

Pnut

[hdvoyager319]

Great!!! now the coon that have holes in the shop dirt floor may pass on to the next world without passing "GO"!

[pnut]

Check the tank daily for floaters. 

Pnut