My forge will not get hot enough

[Ferguson]

I have been struggling with slitting and drifting, and the consensus is that I need to get the steel hotter. So I went back and very carefully tuned my Reil burner, using the recommended Tweco 14T tip. The most I can get out of it is orange color, not even yellow.

I went ahead and set up a web page with more information and photos, so take a look.

My forge

Suggestions would be appreciated.

Richard

[pkrankow]

So you are using the .035 tip?

Are you closing off the back and closing down the front to reduce your radiant losses? You can use a piece of scrap wool or a couple of firebricks. The firebricks take time to heat up.

Also is there a way to eliminate that large cap? Swage or forge the end of the pipe down and tap it maybe? That is disturbing your airflow significantly.

[Ferguson]

Right, using the 14T 0.035 tip.

I see what you mean, the large brass cap could be disrupting airflow, although the cap is back an inch or so from the end of the tip, and well into the wide part of the bell adaptor. Let me think about that one. I am not sure that this is the "smoking gun" that would explain my problems, however.

I do use firebrick front and back, although I am not sure how much I should close them off. I have to have enough of an opening to let the air out without creating too much back pressure.

I wonder if at my elevation, 5800 feet, 263 cubic inches is too much for a single Reil burner.

Richard

[Dave Hammer]

What are you using for a forge floor? If it is refractory, take it out and replace it with kaowool (for a test).

If you get the heat you want after that, the floor is not heating up, taking too much to heat up, or you are not waiting for it to heat up.

Two other things.... If you haven't coated your ceramic blanket (with something like ITC-100), you should. It helps. The second is.... are you using hard or soft firebrick on the ends. Hard firebrick will work, but it absorbes tremendous amounts of heat and takes a long time. If you use soft firebrick, it does not rob your forge of heat nearly as much.

[yllowcreak]

First make sure you have no wool in the way of the flame as it can cause fluterring of the flame. Next thing to check is the depth of the nozzle into the wool as you might have to move it in or out to develope the best flame characteristics. Seal off the back of the forge totally. The opening in the front of the forge will handle all the exhaust. What I have always found is the forge design is what determines the heat of the forge. Once you have a good flame characteristics (neutral), that only leaves the forge. More than likely, the front of forge will need to be reduced as well, sealing the top down as heat rises. Fire bricks, wool, even metal will work.

[MLMartin]

you may be dumping to much gas into the forge, if to much gas is pumped into the forge then you will have long fire tungs coming from the front and back of the forge and the fire in the forge will be burning in a dull yellow instead of a deep blue. many people think that the more gas that is shot forth the hotter the forge will get, this is wrong. you have to get the air and gas mixture just right for the burner to put out the most heat. how about trying a .23 mig tip instead of the .35, the smaller tip will create a higher pressure and limit the gas down a bit. a small tip / orifice may help to shoot the gas out in a better stream and mix the gas better with the air
good luck

[yllowcreak]

Also, forgot to add...a reil burner is good for 250 cu inches, not 350.

[Ferguson]

Lots of good comments, let me try to address them.

The floor is refractory, but buried in the refractory is lightweight fire brick, for better insulation. I really don't want to rip the refractory out, I don't have any to replace it.

The firebricks at the end are the soft lightweight type, so not a big thermal mass. I ran the forge for a long time today at high pressure, so I think that the thermal mass had plenty of time to heat up.

I have heard people talk about ITC-100, but I have never seen it, where can I get it? I understand that it is kind of a slurry that I would brush on. I have heard the claim that it increases efficiency 30%, that sounds like a lot.

I think that I set the end of the burner flush with the kaowool. I have the stainless nozzle on it, so I suspect that I could stick it into the chamber a bit further and get away with it.

I can try closing the forge up more with firebricks.

I am thinking that the mixture may be too rich, which might explain the loose and poorly defined flame front. I would have to cut back to .030 or .025, but would have to special order the 14T tips, like I did the .035 tips.

Thanks,
Richard

[Bob S]

You're probably closer than you think. It seems to me that every forge and every burner is a little different. Even if they are made the same they all need a little fine tuning. I would close off the back and part of the front. I think I would start cutting a little off the burner pipe.... maybe 1/2" to 1" at a time and give that a test. That's what I did and it worked.

Bob

[pkrankow]

Do not project the flare into the chamber!!! It should be about 1/4 inch into the outside of your refractory, and the refractory should continue the flare.

Don't worry about the shape of the tip, get regular cylindrical tips, the losses from a less good shape are not very large, and you have bigger problems right now.

Anvilfire.com sells ITC-100

You can choke your exhaust openings down to a total of 1 square inch or less without worrying. Difficult to light it that way, but once it is lit it will stay lit. You can also light it then immediately close the firebrick in on the opening. Your dragon breath will travel farther though.

Phil

[Dave Hammer]

One more thing you might consider trying... Put a good needle valve on the top of your burner so you can manage the volume of propane, rather than the pressure. I use a 0-60 PSI regulator cranked all the way down, and manage the amount of propane with the needle valve. I use Alcon needle valves.

You wouldn't need ITC-100 to get a yellow heat, it's just better if your forge has it. Also, pull the burner back out a bit. The tip of the flare should be back at least 3/4 of an inch from the chamber.

[reefera4m]

Lots of good comments, let me try to address them.

The floor is refractory, but buried in the refractory is lightweight fire brick, for better insulation. I really don't want to rip the refractory out, I don't have any to replace it.

The firebricks at the end are the soft lightweight type, so not a big thermal mass. I ran the forge for a long time today at high pressure, so I think that the thermal mass had plenty of time to heat up.

I have heard people talk about ITC-100, but I have never seen it, where can I get it? I understand that it is kind of a slurry that I would brush on. I have heard the claim that it increases efficiency 30%, that sounds like a lot.

I think that I set the end of the burner flush with the kaowool. I have the stainless nozzle on it, so I suspect that I could stick it into the chamber a bit further and get away with it.

I can try closing the forge up more with firebricks.

I am thinking that the mixture may be too rich, which might explain the loose and poorly defined flame front. I would have to cut back to .030 or .025, but would have to special order the 14T tips, like I did the .035 tips.

Thanks,
Richard

ITC-100 is a refractory clay that you thin with water and spray or brush on. I coated my ceramic wool with furnace cement (to protect the wool) and then coated the cement with several brushed on layers of ITC-100 (available at most large pottery supply stores). ITC-100 reflects heat back into the forge increasing both the maximum temperature possible and decreasing the time it takes to get to temp. I saw a thread on another forum where Ed Caffrey, aka The Montana Bladesmith, said he saw an increase in top temperature of 500 - 700 degrees. I didn't get that much with my 'venturi' forge but it does get hot enough to weld with.

I also have incorporated removeable rear covers for my forge - they seem to help quite a bit as well. One cover has a slit it it just big enoug for a blade to fit through. When I'm working on smaller blades I just stuff some ceramic wool in the slit.

[ArtWerkz]

Check out Chile Forge, I have their Tabasco. I am at sea level running about 5-6 psi with one of their super burners and that baby gets hot.

[Rich Hale]

I expect to get ripped for this responce but that is not a first for me:

I never thoiught it was a good idea for someone with no forging experience to attempt to build a gas forge. (if you have a lot of experience don't read this)

Experience will allow someone to make the fine adjust ments to a gasser much easier as you should have learned what a forge does, what colors look like to you as an individual and how a metal you are familiar with works when hot.

If you have developed a way to slit and drift pieces in the past with a known metal heated to proper temps you can know now if your forge is getting hot enough of not.

One of the biggest mistakes I see with folks new to smithing is not developing skills, muscle memoryan moves that prevent loss of heat when forgeing.

If you have al ot of hours forging you will build these skills. If you have not done basics then this may be an issue of heat lost while you move pice from forge to anvil. Poor fitting tongs that cause part of that delay, cold anvil sucking the heat out of the piece. Failure to be fully prepared to use tops tools quickly and accureatly or any number of things.

I feel that using colors according to pics is a poor way to judge heat of metals. We see things differently. I may call bright red something you see as yellow, etc.

If, you are new to this work see ifyoiu can get to visit an experienced smith and see what they do and how they do it. Then you need to attend workshops, classes etc.

If you have not spent alot of time on basics then it is time to do this. As the bps return use them as study gides print some out and learn how to forge from them.

If you have all the skills aperson could ever desire to attain then remember that others that read this may benifit from what I just shared. and do not be offended.

And have fun!

[Countryforge]

I have the same problem with my forge not getting hot enough. Since reading the suggestions I have tried all possible changes, form using an .035 to a.045 tip. Changing to add kaowool to the forge and reducing forge size. No luck. One question though. On the end of the burner should there be a space between the pipe and the flare? My flared piece is tight fit as some I have seen have a space??? I also am using a Zoller side arm and z burner configuration. Should this burner be increased to a One inch rather than 3/4 inch size.

[Ferguson]

No, I am not offended. I never claimed to be very knowledgeable about blacksmithing. My work is in metal, but my expertise is more in sheet metal, especially copper. If you want to see my work, http://www.fergusonscupture.com Yes, I have taken a blacksmithing class, and attended a couple of blacksmithing conferences, but blacksmithing is not something I do every week or even every month.

There are no shortage of those who say that building a forge is not that big a deal. I hear people talk about getting a white heat from a propane forge. I have never even gotten close to that with this forge.

From my standpoint, I was just disappointed that after reading everything that I could find, then following all the recommendations, experimenting with the burner in free air and tuning it there, my forge did not seem to get much hotter. I have spent a day or two working on the forge in the last week or so, so it is not for lack of effort. It does run better at low propane pressure, so that is an improvement. My blacksmithing friends tell me that I am close, but from my standpoint, I am running low on ideas. I do plan to try smaller MIG tips, probably .030 and .025, maybe that will help. It is unclear to me if my 5800 ft elevation is part of the problem, my guess is that it plays a role.

I am sure that a store bought forge would work better. I need a forge that I can pick up and put on the shelf when I am not using it. I am usually pretty good at figuring things out. I can wear my artist hat or my mechanical engineering hat, usually one or the other will give me what I need. I tend to prefer to build my own tools anyway. But I also know that commercial tools generally work better.

I think that if the ITC-100 and the smaller MIG tips do not help, I will rebuild the forge to include two Reil burners, or perhaps one larger burner.

So for those readers thinking about building their own forge, perhaps this thread will give you some idea of the downsides of doing that. You might be better off buying a propane forge for $500 or so, presumably getting good results out of the box.

It is on my list to visit one of the local gurus and see how he would slit and drift a hammer, that might also help

[Fe-Wood]

I'm surprised nobody mentioned this yet and I may be off my rocker. The fitting before your orifice (pipe cap) is really big! It may be causing enough turbulence that it interrupts air flow. This will cause it to run rich and possibly not heat up enough. Looking at your picture, it looks like your tip is way in the mixing/intake bell too also reducing intake air...

[reefera4m]

No, I am not offended. I never claimed to be very knowledgeable about blacksmithing. My work is in metal, but my expertise is more in sheet metal, especially copper. If you want to see my work, http://www.fergusonscupture.com Yes, I have taken a blacksmithing class, and attended a couple of blacksmithing conferences, but blacksmithing is not something I do every week or even every month.

There are no shortage of those who say that building a forge is not that big a deal. I hear people talk about getting a white heat from a propane forge. I have never even gotten close to that with this forge.

From my standpoint, I was just disappointed that after reading everything that I could find, then following all the recommendations, experimenting with the burner in free air and tuning it there, my forge did not seem to get much hotter. I have spent a day or two working on the forge in the last week or so, so it is not for lack of effort. It does run better at low propane pressure, so that is an improvement. My blacksmithing friends tell me that I am close, but from my standpoint, I am running low on ideas. I do plan to try smaller MIG tips, probably .030 and .025, maybe that will help. It is unclear to me if my 5800 ft elevation is part of the problem, my guess is that it plays a role.

I am sure that a store bought forge would work better. I need a forge that I can pick up and put on the shelf when I am not using it. I am usually pretty good at figuring things out. I can wear my artist hat or my mechanical engineering hat, usually one or the other will give me what I need. I tend to prefer to build my own tools anyway. But I also know that commercial tools generally work better.

I think that if the ITC-100 and the smaller MIG tips do not help, I will rebuild the forge to include two Reil burners, or perhaps one larger burner.

So for those readers thinking about building their own forge, perhaps this thread will give you some idea of the downsides of doing that. You might be better off buying a propane forge for $500 or so, presumably getting good results out of the box.

It is on my list to visit one of the local gurus and see how he would slit and drift a hammer, that might also help

I know you're discouraged but don't give up! When I first built my '$20 Forge capable of welding heat' one burner did not work - at all! I played around with it for several days then discovered that when I tapped the threads for the MIG nozzle into the propane feed line (3/8" steel plug) I use a standard tap and that MIG nozzle had metric threads. This caused a leak with prevented the nozzle from generating enough pressure. When I fixed the problem - voila! Forging Heat! Then I experimented with a couple of coatings, furnace cement and ITC-100 - again voila! Welding Heat! My $20 forge was now a $25 dollar forge (and the 2nd one cost $30 - I ran out of some scrap). I could build 10 of these forges @ $50 for the cost of 1 $500 commercial forge. Even if only half of them worked for forging and only 1 in ten got to welding heat I'm still way ahead! Step back, take a deep breath and think about the problem - sometimes it the simple things that make a BIG difference.

[reefera4m]

One other observation. Your forge is a lot larger than mine (and maybe larger that it needs to be). Riel burners are very inexpensive to make wo you might try adding a second burner. I'd put the second one on the opposite side and space the apart a couple of inches if possible. That will distribute the heat more evenly as well as increase the heating potential.

[Ferguson]

Do you know what the threads are on those MIG tips? I should have known they were metric. I just screwed them in to snug, knowing that the threads were wrong.

I just ordered ITC-100, that should help.

I also spoke to Chile Forge, they mentioned that for customers at higher elevations, they recommend their two burner forge, not their one burner forge. This makes some sense to me.

Richard

I know you're discouraged but don't give up! When I first built my '$20 Forge capable of welding heat' one burner did not work - at all! I played around with it for several days then discovered that when I tapped the threads for the MIG nozzle into the propane feed line (3/8" steel plug) I use a standard tap and that MIG nozzle had metric threads. This caused a leak with prevented the nozzle from generating enough pressure. When I fixed the problem - voila! Forging Heat! Then I experimented with a couple of coatings, furnace cement and ITC-100 - again voila! Welding Heat! My $20 forge was now a $25 dollar forge (and the 2nd one cost $30 - I ran out of some scrap). I could build 10 of these forges @ $50 for the cost of 1 $500 commercial forge. Even if only half of them worked for forging and only 1 in ten got to welding heat I'm still way ahead! Step back, take a deep breath and think about the problem - sometimes it the simple things that make a BIG difference.

[pkrankow]

Threads are typically 1/4-28. Most inexpensive tap kits do not have this size. Take a tip and go buy the tap, it'll set you back $5 or so with the correct # drill at the big box store.

Phil

[Ferguson]

I went out and found my thread gauge, and it appeared to be 24 threads per inch, not the standard coarse thread, 1/4 - 20, or fine, 1/4 - 28. I will try to find a 1/4 - 24 tap.

If that does not work, it must be metric.

Thanks.

Richard

[Ferguson]

I went out and found my thread gauge, and it appeared to be 24 threads per inch, not the standard coarse thread, 1/4 - 20, or fine, 1/4 - 28. I will try to find a 1/4 - 24 tap. But when I looked in my Enco catalog, that was a 'special', $12 each, I doubt my local store has one. Maybe it is 12-24.

If that does not work, it must be metric.

Thanks.

Richard

[Mainely,Bob]

Richard,

If you are planning to make a trip out to get the tap I`d suggest taking the tip with you and going to a well stocked local fastener supply house that you can find thru the phone book.
Any good fastener shop can measure the threads(both SAE and metric) and then provide both the tap and the correct size tap drill.
While it may not be as cheap as Enco it`s alot better deal when you factor in the frustration of guessing and then receiving the wrong tap.
My closest fastener guy is a little over an hour away(Portland ME.)so I combine errands and maybe a little pleasure.Like going out to lunch with my wife down in the Old Port. :)

[Ferguson]

I visited the best hardware store that I know of, about 15 minutes from my house. They have a large fastener selection. We were unable to find a compatible nut. The pitch is 24 threads per inch; that is what I measured, and they confirmed it. We tried metric sizes, as well as #12-24. Nothing fit. I measured the OD of the threads with a digital caliper, and came up with 0.230 inches, a little less than 1/4 inch. The manager of the fastener department said that it had to be a special thread, and I am inclined to agree with him. He said that anything 1/4-24 was probably pre world war II, but that the railroads still used it because they have some lights that were made that way.

I may order a special tap, size 1/4-24, knowing that it will be a little large. It may not work too well, but maybe better than the 1/4-20 that I tapped the hole for the first time. (For quarter inch, the standard threads are UNF 1/4-28, and UNC 1/4-20.)

Richard