localsmith

Nice burner but that burner is going to scale up work quickly. That flame is very hard. To clarify, there's purple at the end of your flame envelope (first pic) and that flame is straight blue. I don't know why Mikey and Frosty are saying that the flame is too reducing or fuel rich.

Lot's of good information Mikey. I have tried sanding drums but the glue did not hold up even when they were used in a low speed cordless drill. They were really inexpensive ones which explains why they did not hold up for me. In regards to forge efficiency, do you happen to know at what point (when using your style of burner) maximum efficiency is obtained in regards to psi and the time it takes to heat stock up in a given forge? I was thinking about it and was curious if a forge using your style of burner running at 4psi (with no exhaust flame/unburnt gas) to heat a piece of 3/4" Round would use less or more gas compared to the same Mikey burner running in the same forge heating up the same 3/4" Round stock but using a psi of 8 (with no exhaust flame/unburnt gas) to obtain the same heat. From what I know and have experienced, at 4psi the stock would take significantly longer to heat up and bring up to critical temperature or a low forging heat. On the other hand,the same burner running at at 8psi would take significantly less time to bring up the same 3/4" Round stock to critical temperature or a low forging heat. But I'm not sure if a faster heating cycle is more efficient vs a slower heating cycle. I've been curious and trying to figure out if the burner running a higher psi would be less efficient because its pushing heat into, and out of, the forge at a faster rate. I couldn't find much information regarding optimal psi or stock reheat times when doing google searches on furnaces and optimizing furnace performance. I found some information that pertained to boilers and a few studies have been conducted that purportedly show that high speed burners when used in a boiler that runs off of gas are more effect and use less gas because they lose less heat to the surrounding boiler environment because they are able to pump out more heat and convert water to steam very quickly.

I thought low psi was a good thing because I had the opportunity to ask a German smith about his forge and he told me he won't run it any higher than 4psi using a 0.035" contact tip in a 3/4" burner because he believes he loses too much heat to the atmosphere with a higher psi. I also live 1 hour away from the local propane supplier so it becomes a multi hour affair to get propane which is why I was looking into increasing my forges efficiency.

Frosty I really appreciate your post along with Mikeys. I have learned a TON from both of you and both of your recent posts have made me think more about what I'm looking for in a forge and why. In regards to why low fuel consumption is important to me, my first forge was a gas hog and I didn't know it until I designed a better burner. It required a psi of 12 just to reach forge welding heat on 1/2" X 1" flat stock. My current burner allows me to hit forge welding heat at 8psi which is a big improvement using the same sized orifice with the same sized stock. For me fuel consumption and efficiency is extremely important because gas can be expensive and its in my experience that a forge that is more efficient burns hotter. If I can get a tank of propane to last 3X longer due to engineering improvements I'm all for it. I've had burners that were so inefficient that they used 3X as much fuel as my current burner yet did not produce as hot of a forge interior. I considered designing a forge that was based off of the reverbative design that's out there but I don't like the fact that the front and back have to be closed up most of the time. I feel like the more I learn about burner design and forge design the hotter and more efficient I can make a forge. I'm always learning new things as I did not know that friction within the forge was a big deal. I figured that a smaller forge might reach the point of diminishing returns because I theorized that the smaller/shorter forge could possibly lose heat to the environment quicker since there is less total heat within the forge at any given moment which means there could potentially be more heat loss per minute compared to a larger forge. As an anecdote I read about your idea of using a polished stainless steel forge interior to potentially increase the IR heat being reflected within the forge and thought it was an interesting idea.

That makes a lot of sense Frosty. I noticed that the smaller forge does not heat up very evenly. Is there a point of diminishing returns in regards to how small you could build a forge in relation to the size stock you place in it with the sole purpose to lower fuel consumption? As an example, lets say someone builds a forge only for forging hammers that was 3"X3"X7"L which comes out a whopping 63" SQ. Inches. Would the 3"X3"X7" forge use around 1/10 as much fuel as a forge that was 8"X8"X10"L (640 SQ. Inches) to bring a piece of 1 1/2" Dia. X 5" SQ. Stock up to the same temperature forging heat all other forge design considerations being equal (such as 2" Kaowool and same thickness castable in both forges)? I assumed (potentially falsely) that a larger forge could contain, store, and distribute more heat (compared to a smaller forge) to any given size stock placed into it because of it's larger mass. I thought that this was one of the reasons why Ron Reil suggested a minimum forge size when it comes to forge welding but I could be mistaken.

I acknowledge that you and frosty are experts in the field and I have learned a TON from both of you and am very thankful for the educational content you both have provided on here. I thought that most heat loss was from the size stock you put in the forge? I was running a forge that was 4X4X14" long with a 3/4" T burner and it seemed like overkill so I switched it over to a forge that is 6X6X12 and the larger forge seems to only consume slightly more fuel than the smaller forge. Do you think it could have been because the 3/4" burner was overkill for the smaller forge? The insulation is the same in both forges using castable over 2" Kaowool.

I never understood the recommendations for smaller forges. A larger forge will only use slightly more fuel compared to a smaller forge in my experience. I had a small forge I got rid of because it was using practically the same amount of fuel as a forge I had that was twice its size.

I apologize Thomas and Frosty I'm so used to only thinking about bringing steel up to critical for hardening when it comes to heat treating and forges.

When most blacksmiths refer to heat treating in the context of talking about how well a specific burner performs in a forge they are more than likely referring to the hardening & tempering process. Just stating how well a certain forge works for heat treating is not, "sloppy", in the context of talking about a forge. What else could I have been referring to in regards to a ribbon burner in a forge, cryogenic treatment?

This is good enough for me! I always thought the main advantage of a ribbon burner was that you could spread out your hot spot to as wide as you want it to be. I have seen videos of people running ribbon burners and it appears to me (although I could easily be wrong), that all of the tiny flames that come out of each hole in a ribbon burner consolidate back into one larger flame that is the shape of the ribbon burner. Ribbon burners for me seems like it would be ideal for heat treating longer stuff since you could spread out the hot spot out to match the entire length of the forge.

Humorous :D. I see your point. I just think that it's interesting that nobody has posted any hard numbers showing that a ribbon burner is more efficient than any of the other burners out there. I don't have a ribbon burner so can't test for efficiency but one could weigh a tank of propane before a set period of forge operation using a ribbon burner and then do the same thing the following day using any other burner and the burner that used less gas would be considered by most, to be more efficient. The main advantage that I see in a ribbon burner is that you get a wider/longer hot spot, which is useful for certain things but could end up using more gas (needs to be tested).

I haven't seen any evidence that supports the idea that a ribbon burner is more efficient than a venturi burner.

I've only tested my own. I've never used a commercial ribbon but I'm sure they would work much better than the ribbon burner that I made. The nature of the design of a ribbon burner is to push high velocity low pressure flames through each hole in the burner block (the small outlet holes in a ribbon burner produce high velocity flames with low pressure). The thing that I see with most ribbon burners is that each flame combines to form one large flame at the front of the burner block. To me, the main advantage of a ribbon burner is you get a much better heat spread. I don't see them as being any more efficient than a well turned NA burner. They seem ideal for heat treating and forging long stock.

I don't personally believe that a ribbon burner is more efficient than any other burner design. 5PSI is a lot of gas when it's coming out of a 1/4" orifice. Each of the holes in a ribbon burner creates a high speed flame that ejects from each hole and ends up creating a wider hot spot. Based on what I've seen, a well tuned venturi burner is going to be significantly more efficient than a ribbon burner and it does not require electricity or blowers. Ribbon Burners are typically used in larger forges that are going to consume significant more gas regardless. I've tested a few naturally aspirated ribbon burners and all that they end up doing is focusing the flames wherever the holes are facing. You don't get any vortex or good swirling action because the flames move out of the holes at a very high speed. It's similar to trying to create a swirling action inside of a cylinder using a hose with no head on it vs a hose with a shower head attached to it. Those small fast flames move quickly but lack momentum so they end up creating a very focused hot spot within a forge which is probably a reason why most ribbon burners are quite large (to create a larger hot spot within the forge).

Whatever you do, stay away from inverter welders unless it's from a made in the USA brand. All the cheap inverter welders are junk and have a very limited lifespan.