Latticino

Currently work as a professional HVAC design engineer (means I'm certified to stamp construction drawings), for a small consulting firm, working primarily on health care facilities. Several former jobs, but the most notable was around 10 years as a self-employed glass blower (still hesitate to call what I did art rather than craft, so won't use the glass artist title). Blacksmithing only a hobby at this point.

Nice punches. Suggest you photo them with a recognizable object to give a clear sense of scale.

Fantastic project. Always intrigued by timepieces

Very glad you got rid of the quick release fitting on the gas train. You would be much better served with use of a true piping union fitting if you need to be able to take a joint apart for service. I don't believe that typical compressed air quick releases are rated for gas service.

That's a home built unit? Fantastic design and build quality.

Singing= high speed exhaust flow=effective fume capture and disposal=good design Note: colder outdoor temperatures will improve the chimney effect for correctly designed vents as well.

Thermonuclear, seriously? Are you that close to White Sands so you can collect atomic testing debris and use it to power a reactor?

You beat me to the punch on that design for a spike hawk. I had planned on doing something similar, but with a bit of a change in the "behind the eye" area. Hopefully I'll get one done and will be able to post it. Consider use of a slot punch to make the original hole in the spike to minimize the loss of material. I think you still may have to upset it some to add mass to the eye. Great effort for an early forge weld. Did you get the Damascus billet elsewhere?

Excellent concept, similar to one I've used with a three layer glass furnace construction. Just be careful to seal all glass fiber as well since it will break down at that temp to small fiberswhich become airborne.

If it doesn't, it should (otherwise it is just a big fume collector that conveniently dumps right at head height). Just that the collector attachment to the stack for the metal hood should be variable so it can be balanced to favor inlet at the sidedraft hood. Not sure what kind of fan you have wholly interior to the chimney. Most motors I'm aware of don't like that kind of heat. I'd try adjusting your sidewall inlet closer to the fire and possibly making it smaller. A small local opening will suck in fumes at a high velocity and pull the flame towards it, once the stack is drawing properly. They typically aren't self starting though. ON the other hand you shouldn't need the typical lit bundle of newsprint to start the draw provided the fan actually works. I assume you have tested that it is pulling exhaust?

In my opinion a side draft hood should always be as close to the coals as possible. A good design feature is also an inclined "cinder shelf" to catch same before they enter chimney. Velocities in a well designed stack can easily entrain cinders and ash which can coat your stack or start a fire. With a properly sized and installed fan, your setup should be effective. Rain cap is a little obstructive, but fan could take care of that if done correctly. Can't tell type or stack configuration from the photos though. Does ceramic liner go all the way up, or is brick fascia the stack/chimney? Are there more than one opening into said chimney? If so the upper one should probably be closed down a bit. This design should be able to be tuned to work well even without a fan. I don't see anywhere to put a fan in this design. Where is it?

SReynolds: Here are some laws of physics for you: Unless you have a mechanical assist (fan) for your hood exhaust duct in the horizontal, the horizontal run only contributes duct friction to the passage of that exhaust. Duct friction slows down the passage of forge exhaust fumes in your exhaust and reduces the impact of the "chimney effect" forces that drive the exhaust in the vent. The fume exhaust speed is directly proportional to the amount of fumes that are captured at the face of the hood, so slower velocity in the stack means less combustion products capture. Empirical testing has determined that 90 degree elbows can be modeled as equivalent lengths of straight duct for the purposes of determining the duct friction in your system. A good rule of thumb for a long radius R/D greater than or equal to 1.5), round duct elbow is that it is equal to approximately 10' of straight duct length. Gored and short radius elbows are worse (see ACCA Friction rate reference charts). Duct friction is your enemy for effective venting of a forge hood. The chimney effect only gives limited force to pull the fumes from a hood. The more resistance to that force you have, the less effective your hood will be. It is highly recommended to reduce the horizontal runs, abrupt changes in diameter and offset elbows in your stack. Another thing that can lead to duct friction is rough duct interiors (i.e. flexible duct). Try to duct with smooth, hard duct surfaces whenever possible. Joey Van Der Steeg is a talented smith, but that does not make him a good hood designer. In the latest videos I've seen, his shop appears to be quite tall and pretty large. He may not have significant concerns about hood capture efficiency. I also haven't seen any illustration of the entire duct run from his overhead hood. In one video I saw he had a (what appears to be overly small) flex duct connected to the top of his hood with a very nominal horizontal run, that appeared to turn up afterwards. It is possible that this duct connects to a fume exhaust fan just upstream. I haven't seen a video which covers this completely, perhaps you can tell us which specific video he has that illustrates his exhaust ducting and indicates how well it works. Actually I just viewed one of his videos where he discusses his quite large overhead hood (October 29, 2011). He specifically mentions that he didn't design it, that it does not always capture well because the duct leading from it is too small, and that he will be adding a fan for improved mechanical exhaust! OF course you can design a suboptimal stack if you add mechanical exhaust. Bottom line is that horizontal runs are not helpful, other than to relocate the building penetration, as required. Provided you have a sufficient diameter exhaust duct, and you have enough vertical exhaust run to use barometric pressure to drive the exhaust (or use a vent fan), some horizontal ducting is certainly acceptable, but should be minimized. How much horizontal run and/or duct elbows are reasonable depends on a lot of factors. These include the outdoor temperature your vertical stack experiences, the relative size of your hood, the height and diameter of your vertical stack and the characteristics of your exhaust fan, if any.

Love the work, as usual, but I'm particularly attracted to the "simpler" blades. There is just something about the elegance of proportion and attention to fine detail that appeals to me. To my mind it is sometimes more difficult to execute a clean, well designed knife without a lot of ornamentation and still keep the same level of aesthetic interest. You really nailed it with these. While I would be thrilled to own any of JPH's blades I would have a great deal of trouble passing by the single edged knife with the dark wood handle (photo #4) if I walked past it on a sales table.

Had no idea that NPS pipe thread existed, so that does sound like a good work around for the various compression and/or set screw type systems I've seen for properly positioning the gas nozzle in a NA burner. Of course, if you are threading the outside of a pipe yourself, and tapping a carrier cross-member, you could always have just used standard taps and dies of the correct diameter I guess, but I've never tried to do that. As always, thanks for the tip. I've not been commenting on this thread as it has gone past my skill level in constructing of NA burners some time ago. Will have to make up a mini-ejector burner when I can source a lurelock orifice though. Need a mini travel forge for hammer-ins.

Theory sounds good, but you need to get some practical experience. Frosty alluded to the fact that most of us like to have at least a slightly reducing atmosphere inside the forge to attempt to limit the scaling up of the stock during the heating process when it appears to be most vulnerable to same. To get that reducing atmosphere you need less than perfect stoichiometric combustion. The high velocities of gas needed to entrain the air for the mixture are an issue, but with a well tuned NA burner design you can achieve anything from close-to-perfect combustion to a mixture where some of the combustion takes place in the chamber and even at the doorway to the forge, just by adjusting the choke and gas regulator. I still find it easier to do with a blown burner, but that is just where I have more experience. In any event the key issue is that perfect combustion is not always preferable.

Well that sure is a large chamber. Still not sure what you plan on heating in such a huge enclosure, but follow your dream in any case. Hope you aren't planning on using that current door system as the only way to get stock in and out of the forge. When it is swung open you are not only going to lose a tremendous amount of heat, it will be radiating right at your hands as you attempt to pull your stock out of the forge. I expect you are planning on making a smaller opening in that door and only swinging it open very rarely, if at all. You do know that you will need a port in the chamber for combustion byproducts to exit, right? Have you ever actually done any smithing in a gas forge? Before spending a lot of time constructing your own it might be prudent to find a shop that will let you rent time or get lessons so you can see how more conventional systems work. It is great that you are trying an innovative design, but there is also something to be said for iterative evolution of design leading to more refinement. I assume you are open to constructive criticism, otherwise you wouldn't be posting your progress. Oh, and I agree with the other posters regarding the relatively small disparity between NA and blown burner BTUH output. I feel that all things being equal blown burners a bit easier to construct and tune, but that may just be because I have more experience with them. I've heard a lot of folks discuss use of internal baffles for their forges, but never seen one successfully used. Theoretically it does appear promising, I just haven't seen a practical installation. Part of the problem is going to be the turn down ratio for the ribbon burner. Pine ridge indicates that they recommend running them "full out".

Even with side draft hood you need a significant vertical rise in your stack to drive the chimney effect. If you end the vertical rise above your roof line (as is typically required by code) and use either a low loss stack cap or weather retention annular termination wind direction shouldn't be a huge factor. It is only when you have the termination pointing horizontally in the direction of the wind that I would be concerned.

Don't completely agree with that one. I've made a couple of pretty cool hammers out of wrought iron with high carbon forge welded faces. I also plan on doing San Mai and forged axes using wrought and high carbon bits in the future. The stuff I have, from some wrought bridge bolts, is a bit refined to show great structure, but I just picked up some different wrought at SOFA and have high hopes. They certainly are a bit tough to forge weld together though. For what it is worth I'd rather not try to forge weld 52100 to wrought again.

Just as a small update. I was lucky enough to run into Andrew at SOFA this year (purely by accident). Purchased one of his Czech/Hofi style cross peen hammers. Really enjoy using it. A great hammer and becoming my go-to general forging hammer in that weight range. Look him up.

I have worked in furnaces designed by Charley in the past and used some of his concepts for the configuration of my glass furnace I built back in the late 80's. It ran flawlessly for over 10 years. He wasn't making multiport burners at the time (so I used a Giberson burner tip), but I have always respected his design and engineering chops. You most likely won't go wrong in buying one of his burners and following his guidelines for chamber size. I'm glad to see that he is still in business. All bets are off if you just use the general size of the burner block though, as number and size of ports, as well as baffle design, has a large influence. We still are gently suggesting that your forging chamber is rather large for a small shop. Of course it is small for a glory hole or glass furnace (which is where both Mr. Correll and I have the bulk of our experience. As regards your question on the fiber blanket installation, I have used two methods to date. If the blanket is put in in layers, and the density is correct, slight compression will hold it in place until rigidized. You are planning on using a rigidizer prior to your refractory coating I hope. This rigidizer can be applied to the surface of each layer as installed. The other method is to lightly dampen the blanket and accordion pleat it around the chamber curve. The advantage to that method is that it both forms a natural arch and can provide a nice thick lining, rather than using multiple layers of thinner material. I would still use rigidizer.

You need to allow for the reduction in length that the insulation at the ends makes (24-6=18). Then you need to add in door openings, of some sort.

Word to the wise: sarcasm aimed at those trying to help you will likely get you ignored by folks who could save you a lot of grief. Incidentally I get approximately 2,770 cu inches, assuming you are going to line the ends with fiber blanket as well. If you factor in some openings in those ends, also assuming that you are planning on having doors that fit over those openings instead of inside same. Including those openings, assuming they will be around 6" diameter x 3" long, you have closer to a total interior volume of 2,940 cubic inches. In any event a rather huge forge for an individual. As Frosty noted if you are going to run at forge welding temperatures you will likely use up a lot of propane. Unless you have a power hammer or a good striking team you will be hard pressed to hammer a length of stock heated to an 18" length. Stoichiometric calculations are all well and good, but those calculations should be taking into account the required airflow at the heating rate you need, not the blower static pressure, per se. Of course if you have done the static pressure loss calculations for the required airflow for perfect combustion at the heating rate you have determined (presumably from the combination of radiant, conductive and convective losses from the forge interior, and factored in the losses due to exhaust of heated combustion products, not to mention choosing the correct skin friction value for the assumed airflow characteristics in your shop) you should be fine, as that will set the characteristic system curve for you to coordinate with your blower's fan curve. By the way, what loss coefficient did you project for the custom forced air ribbon burner? Any idea about the optimal multi port opening quantity and sizes to coordinate with the anticipated flame velocity for the variety of heating rates you are going to want for your forge? Frosty has done empirical tests that worked for designing his ribbon burner. Unless you get lucky, just winging it won't work. Of course you could do the computational fluid dynamics calculations for the fuel air mixture, but if you miss something it is going to be a lot of effort for an unexpected result. And you are going to build your own blower as well. I'm really impressed that you have been able to anticipate the external static pressure it will put out at the airflows you are expecting. I'm pretty sure industrial blower manufacturer's have to empirically test their new designs to ensure they meet the required fan curves (check out the AMCA standard testing for example). Perhaps you would be better off sourcing a used blower from the same type of place you got the high temperature insulation and refractory for only $10. Hey, I once picked up a high pressure blower from a liquidator for $25, but that was quite some time ago. In my limited experience of building forced air gas fired burners 25" WG is more than should be required, unless you plan on including a lot of equivalent duct length and a control valve or two.

I'd get as hot as possible at the 100 deg/hr rate recommended in your oven, then candle it slowly in the forge. As long as it isn't load bearing, or restrained from expansion and contraction I've been petty successful with that. Remember to vent the oven periodically to allow the moisture out. You will be surprised at the amount of vapor driven off and the temperatures it still is produced at. I know I was. I used to use my annealer to fire Mizzou. If you know someone with a temperature controlled kiln, that will work well also. Recently preheated a Mizzou ribbon burner in my heat treat oven.

Fond memories of listening to him singing seafaring songs when I was a youth. He had a marvelous voice.

I'm going to stick with simple answers, as subtle ones don't seem to get through: You are probably not anywhere near ready for forging swords, or even making them by stock removal. Make a couple of dozen knives first, starting with 4" blades and working up to 12" blades. When you can do that successfully, then start to think about swords. When you are ready, take a class in sword smithing from a teacher who knows what they are doing. Expensive, but will likely cost less than getting completely setup yourself and going through all the trial and error necessary. You are lucky that there are teachers out there these days. For my interpretation of what you are looking for I would suggest 1084 or 5160 for your work. These are relatively easy and forgiving steels to work with. Unless you are really excited about smithing, and remain that way after getting burned, cut and bone tired from forging and the extensive grinding and filing needed to make a decent blade, you should probably look into either commissioning an actual sword smith to make your dream sword, or do better research to see if one can be purchased that will suit. Places like Cult of Athena sell a wide variety of replicas at cheap prices. Note that if no one has made your dream style in the thousands of years that swords have been forged there might be a good reason (like it is only practical in fiction).