timgunn1962

As long as you are able to change the jet size to tune it, yes the burner will work or can be made to work. Most likely quite well if you tune it well. However, this is true of almost any NA burner and it does not look as if it will actually perform any better than most of the much simpler burner designs out there. The jet looks to have a step-change in section, rather than a smooth transition from large to small diameter. This suggests to me that you are not familiar with the fundamental principles that apply to NA burners. There is a very good reason to maximize the discharge coefficient of the gas jet, namely to maximize the kinetic energy of the gas. I am pretty sure the reason most of the better homebuild designs use MIG tips is because of their smooth transition into the minor diameter. The MIG tips are designed to smoothly feed wire, but the shape is coincidentally very good for feeding gas. If a smooth transition can achieve a discharge coefficient of 0.8 and a square-edge gives about 0.64, the smooth transition gives 25% higher velocity and 56% more kinetic energy. It's effectively the KE that draws in the air. Although you have included a 1:12 machined bore, it is usually the expansion section after the Venturi throat in the commercial designs. In fact, there is no Venturi throat to speak of, so there is no Venturi. Many (most?) of the homebuild burner designs dispense with a Venturi because, although it can make a significant difference to performance, it's difficult to make one without machining facilities. Your design seems to require the machining facilities but does not make use of a Venturi. It looks like a minor change would make the gas jet location axially adjustable: a no-brainer since you mention that you are unsure where it should be. Unless it's a college project or similar, it would seem much cheaper and easier just to cough up the 65-ish quid (including VAT and delivery) for a 3/4" Amal atmospheric injector. The Amal-style flame retention cup should work fine if you are intending to run the burner outside the forge. For use in a forging or welding forge, it is wholly unnecessary. It can also get expensive if the plan is to use materials for the cup that will stand up to welding temperatures. I use retention cups in dedicated HT forges which run very rich and with flame temperatures around 800 degC (1472 degF) or a little less. In forging or welding forges, I just use straight pipe and an Amal injector. The exhaust area of the forge seems very small with just the round opening(s?). I think you'd probably need the small door(s?) open to run at all. The vertical burner aimed at the centre of the forge floor seems to me to be about the worst arrangement commonly seen: prone to chimneying on shutdown and with a high probability of the flame hitting the metal before combustion is complete, Oxidizing the workpiece.

As Latticino says, the PID controller is a controller. You don't specify what it is that you wish to control, so it seems likely that you are just using it as a pyrometer (temperature display)? It's not a problem to do this, but you may need to trawl through a lot of setup parameters to make it do what you want. If it is "just" a temperature readout you want, an ebay search for "DM6801A" will bring up a handheld type K pyrometer that gives very few opportunities to get things wrong and costs under ten bucks delivered (though you'll also need a 9V battery). It takes a type K input and reads temperature in either DegC or DegF (there's a button to toggle between them). If you really want a permanent thermocouple, the 8-gauge one with ceramic sheath is a pretty good option for the reasons Latticino mentions. It is worth noting that type K thermocouples are particularly prone to "drift" when used at temperatures above about 1000 degC (1832 degF) and it would be a mistake to assume that a permanently-installed Type K will remain accurate for very long at typical forging or welding forge temperatures. Things are not nearly so bad at typical Heat-Treating temperatures The SYL2342 controller has relay outputs. If you are looking to control the temperature of a forge using a HI-Lo burner arrangement, it would be a good choice. The Hi stage solenoid valve would be powered through the output relay. It will not directly trigger an SSR though. For use with an SSR, you'd want the SYL2352 instead, which has a 12VDC pulse output intended to drive an SSR. SSRs are usually used where short cycle times are required and tend to be better suited to electric heating than to gas-fired systems. If you are not controlling anything, you will not need the SSR. The learning curve for controllers tends to be steep and mistakes can get expensive. I've been lucky enough to make most of my mistakes at my employers expense. My personal preference for forges is for a long hand-held thermocouple which can be inserted while the forge is adjusted and then removed while the forge is in use. This allows the temperature to be measured at different places in the forge. Unless specifically designed to provide a very even temperature throughout, most forges have quite large temperature variations throughout the chamber. Color can be a good indicator of the even-ness, or otherwise, of chamber temperature but it's nice to be able to put numbers to it. Examples of forges designed for even heating are dedicated Heat-Treating forges and vertical welding forges intended for welding billets of pattern-welded steel. Both of these examples are fairly specific to bladesmithing, though there may be other applications I am unaware of. Given that we are in the HT sub-forum, it seems fair to assume that the OP is either intending to run a forge designed for Heat Treating or is intending to use a general-purpose forge for HT. In my experience, once the burner is adjusted there tends to be little temperature change at any given location unless a further burner adjustment is made so I usually take the thermocouple out when forging but keep it in when Heat-Treating. My preferred thermocouple is an Omega KHXL-14U-RSC-24. This is a 1/4" diameter Mineral-Insulated handheld thermocouple assembly, 24" long below the handle, with a culy cable terminating in a miniature plug which fits almost all type K pyrometers (including the DM6801A and TM902C). The junction is Ungrounded and the sheath material is Omega's proprietary "Super Omegaclad XL", rated for use to 1335 degC, 2440 degF. The upper end of the range is good for checking that forge temperatures are adequate for welding high-Carbon steels. TBH, most of the time I actually use otherwise similar thermocouple assemblies with type 310 stainless steel sheaths because I can buy these much cheaper from the supplier we use at work with no shipping costs. They don't last nearly as well at the higher temperatures though. Apart from the drift issue, the main reason I don't like permanently-installed thermocouples in forges is that they are fragile and, to give useful information, need to be positioned where the workpiece will be positioned. This makes breakage pretty much inevitable for someone of my limited skill. Omega have a lot of information on their site about temperature measurement and control and it's worth a look. A good starting point is http://www.omega.co.uk/prodinfo/thermocouples.html I used to carry a printed copy of the Labfacility Temperature Control Handbook back when the world was young. Everything you could want to know about temperature control in one slim volume. The .PDF can be found at http://www.controlsdrivesautomation.com/orgfiles/ZORGF000011/IPE/Enhanced companies/labfacility/Temperature Handbook.pdf I use the DM6801A pyrometers myself now, having previously used TM902Cs, also from ebay. The TM902C only reads in DegC so there's even less chance of operator error and I tend to think in degC so don't miss the degF reading. I was quite happy with them intil last year when I had a batch of ten of the TM902C handheld pyrometers that were fine up to 800 degC (1472 degF), but had increasing errors once above that temperature. They didn't look quite like the 30 or so "good" TM902Cs I'd had previously, but the visual difference was not enough to show in an ebay photo and I decided it was safest to use something else. I have access to a calibrator at work and always check any personal instruments with it. That's how I found the bad ones. All the earlier ("good") TM902C units were as accurate as big-name units costing much more and the half-dozen or so DM6801A units I've tested so far have been similarly accurate.

I poured 1 litre of Rigidizer into a measuring jug, stuck it on the kitchen scales, noted the weight, poured out the rigidizer, weighed the measuring jug again and subtracted the weight of the jug. I like simple and low-tech, it minimizes my chances of screwing up.

You'll need more speed. Much more speed. The hydraulics look to be the 10,000 PSI/ 700 Bar stuff that gets used for jacks and small workshop presses where small size, light weight and general portability are needed: occasional tool use only. You'll need a pump, cylinder, control system, tank and plumbing that will provide the force and speed required for forging and that are suitable for continuous use: the sort of stuff that runs 24/7/52 in in industry. Max pressure of this will most likely be in the 140-300 Bar range (2000-4500 PSI), so the cylinder will be much bigger than the one currently on the press. There's a world of difference between a tool that cycles to full pressure a few times a day at most and one that cycles to full pressure a few times a minute. The frame of a forge press will usually be much heavier and much more rigid. Welded joints seem to be the norm, probably because bolted joints under cyclic loading tend to start moving quite quickly. Welding brings all sorts of new and interesting variables into the design and the pragmatic approach is usually to make things as big and heavy as possible to try to compensate for the (usual) builders inability to do all the design calculations and stuff that would be done by a full industrial design team prior to going into production. You can be pretty confident that the workshop press has been designed, with stress calculations, to have the absolute minimum weight consistent with not failing in the anticipated (workshop) use. The minimum weight because steel costs money and shipping weight costs money. Not failing in use is important because killing or maiming users also costs money, lots of it. The upshot is that it's probably best to view the press as essentially unmodifiable.

The cordless angle grinders, even the good ones, have very much less power than the corded ones. It is most noticeable as slowing of the machine under load. Bear in mind that most of the cordless angle grinders have no-load speeds substantially below those of the corded versions to begin with, and you are looking at having to make significant allowances for the fact that you are using a cordless tool. Realistically, for the tasks you mention, a cordless angle grinder should be fine, though "wire brushing" covers a lot of things and many of them don't fall into the "light work" range. I have an 18V, 4 1/2" Makita angle grinder and if a truck ran over it tomorrow, I'd buy a replacement by the weekend. It is good with thin cutting disks, reasonable with flap disks and a bit meh with grinding disks. I have not tried it with a wire brush yet.

Was that in the forge, or out of it?

End grain timbers do seem to work well. I routed a pocket into an end-grain base for my anvil to sit in and cut a piece of Fabreeka Fabcel 25 psi anti-vibration mat to fit. The difference it makes to the noise level is astonishing. The Fabcel is pricy (mine was a freebie) so if I was doing it again, I'd probably clingfilm the bottom of the anvil to stop it sticking and bed it on low modulus silicone. It seems to me that the contact area is important, allowing the initial sound wave to travel on into the base, rather than getting reflected back into the anvil and bouncing around to produce the ring. A wire cup brush on an angle grinder will do a great job of cleaning it up, with the caveat that it can be the most dangerous tool you'll ever use. Once it's clean, a dusting with chalk or similar will usually help to show up any markings there may be. Don't be surprised if there aren't any though. What are you using for a forge? If you are intending to build a gasser on this side of the pond, I can wholeheartedly recommend basing your burner on an Amal Atmospheric Injector.

Yes and Yes. Caveats: there are hydrophobic and hydrophilic versions of fumed Silica. You need a hydrophilic type. I think Cab-O-Sil M5 is probably the most widely-recognized product. When I last bought some of the commercial rigidizer, I measured it's density for when I got around to making a homebrew version. I got a density of 1109 grams/litre. I don't think it's critical at all, but it gives a starting point. At 1109 g/l, it suggests that there is a little over 100g of fumed silica per litre of water: about 2 Oz/pint. Checking out prices for the West System 406 over here, it looks like it would cost as much to homebrew using the West stuff as it would to buy the commercial rigidizer, so I'd suggest checking out generic fumed silica products.

It looks like a burner design I've seen somewhere before. Did you follow a set of "known good" instructions? If so, did you use the same size jet as in the instructions? Photos in daylight are about the least helpful at showing what is going on in terms of combustion because they don't show the Dragon's Breath. Is there a lot of it? What color is it? The most usual problem beginners make with NA burners, in my (admittedly somewhat limited) experience, is using too big a gas jet. This results in an excessively fuel-rich mixture and a lot of, usually yellowish, Dragons Breath. If it's an easy thing to do, going down a size on the gas jet has a very good chance of improving matters. If you can get a wide-angle photo across the mouth of the forge at night, it'll usually give the guys who know about such things the best chance of diagnosing the problem.

Too much gas, not enough air. Try a .023" MIG tip and see if it gets hot enough to do what you need it to do.

There's certainly a neat broaching oil that works pretty well and it doesn't take a lot of it to work well on the standard oiling system. I'd always assumed it wasn't a soluble oil, though that could just be because I've always used it neat. Having worked under the steel erectors on various sites, there's certainly not enough oil around to give an advanced warning of that hot razor-edged top-hat slug before it hits you. In most cases, I'd have thought judiciously-located blue roll and duct tape could minimize the risk of contaminating anything nearby. There's a solid paste that works well. The Hougen/Rotabroach version is called Slick-Stik. I've not tried that one but have had good results with "Exact" cutting paste, which I'm pretty sure came from Screwfix though they are not listing it now. It's still available through Amazon. It also works well as a general drilling and tapping paste IME, so is probably very similar to the stuff you already have. I've used tallow-based cutting compounds for drilling, tapping, etc in the past and found them pretty good. I've used straight tallow for thread cutting on pipe and conduit with handheld diestocks, but have never tried it for drilling as far as I can recall. Unless there's a vegan involved, straight tallow might be worth a try if the blue roll and duct tape aren't viable and you feel a lubricant is needed.

There are some major deviations from what I would regard as normal practice when it comes to home-made forge burners. The inlet pipe Mikey mentions is unhelpful. I think the designs that use something similar tend to do so primarily as a means to clamp the gas tube in place. Yours appears to have the gas pipe located in the reduced section where it cannot be clamped by that inlet pipe and where it offers the greatest possible restriction to airflow without actually providing any of the Venturi effect the majority of NA burner designs strive for. You also seem to be running without a regulator, which strikes me as extremely unwise. I get the strong impression you do not understand the basic principles and that your lack of understanding goes way beyond anything that could realistically be dealt with in a forum post. For many people, the required understanding comes through observing what happens when things are changed during operation. To reach this stage, it is helpful to have something that is reasonably functional as a starting point. I would strongly advise that you find a design that is proven to work in your application and build (and operate) a burner EXACTLY to that design.

The issue sounds like your Air:Fuel ratio. Your "not enough air" sounds like it's the most likely thing, though much more information is needed for a proper diagnosis. Photos would certainly help, including pics of the burner and a wide shot of the forge in operation. Ideally, there will be a wide shot in the dark across the mouth of the forge to show the Dragons Breath clearly. Bear in mind that "not enough air" is pretty much the same as "too much gas". Depending on your burner design, a smaller gas jet might be a quick and easy fix. When it comes to gas jetting, many people seem to assume that more must be better. In reality, it's a little more complicated than that.

Can you get smaller gas jets for the forge? You mention that you get "tremendous dragons breath" above 12 PSI. This suggests that your Air:Fuel ratio is too fuel-rich. A Neutral flame gives the hottest flame temperature and a very rich flame is quite a bit cooler. Since there does not seem to be any way to adjust the air intake and they seem to be Naturally-Aspirated burners, using a smaller gas jet should lean off the mixture and raise the flame temperature. Although the flame will be hotter, there will be less of it at any given gas pressure due to the smaller gas jet, so the forge may not get any hotter overall. However, if you then increase the gas pressure, you should be able to get the gas flow back up to where it was with the bigger jet and see higher forge temperatures. I'd initially try for a 10% reduction in jet diameter and see how it goes. Going too small will give an Oxidizing forge atmosphere and you'll just produce a mass of scale. You still want some DB, which is a good indicator of a reducing forge atmosphere, Just not too much. With a gas jet 90% of the diameter, you'd have 81% of the area and would need one and a half times the gas pressure to get the same flow as before: (100%/81%)squared = 1.524. I don't imagine you'll have a gauge that'll read to that degree of precision, so 1.5 is good enough.

Run on variable speed, fans follow the "fan laws", perhaps unsurprisingly. On a fixed system (one where there is no adjustable throttling): Flow varies with the speed. Pressure varies with the square of the speed. Power absorbed varies with the cube of the speed. It may also be worth mentioning that flow through a fixed jet varies as the square root of the pressure difference across it, at least for the sort of pressures we tend to get involved with. It stops being true when the speed through the jet reaches the local speed of sound (choked flow), which usually happens somewhere in the region of 30 PSI for Propane. I've seen posts in the past where the poster seems to have assumed that halving the pressure halves the flow. This tends not to be the case in reality.

The first thing to understand about fans is that you will very rarely get the information you want about them unless you are paying top dollar. It's the curve you want to be looking at. The CFM value quoted is almost always the flow at Zero pressure differential. Where quoted, the static pressure is the pressure against a closed discharge (zero flow). You need to know what happens between these 2 points. I think I'd be looking at radial blowers, rather than axial fans, since they generally have higher static pressures and lower headline flowrates. http://media.digikey.com/pdf/Data Sheets/Sunon PDFs/Maglev Catalog.pdf seems to have some actual curves. Axial fans are near the front and the radial blowers are near the back. I have no idea what the prices are like.

On the face of it, the Voltage *should* make no difference. However, when the current available is limited, which it normally is by the circuit rating, the maximum power available on the lower Voltage is reduced. This makes the time for the oven to reach temperature longer and results in more power being used over the cycle. The difference in power cost-per-blade between 110V and 220V is usually pretty small in the real world: unless you fit a power meter to measure it specifically, you are unlikely to notice it. The difference does get larger when higher temperatures are involved. If you are looking to HT some of the Stainless Steels that need temperatures well over 2000 degF, then 220V is most likely the way to go. If you are going to be working mostly with Carbon steels at around 1500 degF, it's much less of an issue. It really boils down to how big and how hot you need to go (big and/or hot calls for 220V), and what power supply you have available. I have a 3 kW, 230V, homebuilt HT oven with a chamber 7" wide, 6" high and 28" long. At the hour mark on full power, it reaches 2041 degF. Once it reaches the temperature setpoint, it cycles power on and off to maintain the set temperature. At Carbon steel temperatures, the "on" part of the cycle is between 20% and 30%. It is considerably more for Stainless temperatures. If we assume that a Heat-Treat cycle takes full power (3 kW) for an hour to reach temperature, half power for an hour to hold temperature and then switches off, that's 4.5 kWhr per HT cycle. If we then throw in an arbitrary 25 cents/kWhr to get a ballpark cost, that's $1.13 per HT cycle. My oven is big and, even though it's on 230V, probably represents a worst case scenario. I don't know what you pay for power: you'll need to check your bill for the price per kWhr, but I'd expect it to be lower. For most makers, the energy cost for HT is likely to be insignificant compared to the cost of grinding belts.

The last commercial colloidal silica rigidizer I used had a density of about 1100 grams/litre. I've not yet tried making my own with fumed silica but I took the density measurement with a view to doing so.

By my reckoning, that's around 2700 cu.in. To be honest, it's so far out the normal range for homebuilt blacksmithing forges that many of the normal rules of thumb won't apply, if only because the surface area: volume ratio will be significantly different. It may be a 2:1 linear scaleup of a "normal" forge, which would give 4 times the area and 8 times the volume. On the other thread (Firebrick Forge Questions), you say "it works great", so it seems fair to assume that whatever you have, it does what you need it to do. For most "normal" applications though, the general consensus would be that three half-inch burners will probably not suffice. As you are apparently in an industrial environment, there may be lots of things you've not told us (high-pressure-air-fed burners, for example) that move the goalposts. Some pictures would be helpful.

To be fair to the guys who have viewed the thread, for most, there's probably not really much information that can usefully be imparted given the contents of the Original Post. You are describing a build that is some way from any of the "usual" designs and you are using a proprietary burner (or two) in it. There are a lot of unspecified variables in there and it's a pretty safe bet that nobody else on here has direct experience of a setup similar to yours. There is perhaps some very general information that could be given, but that's already on the forum and you have presumably either read it and chosen to ignore it or not read it. In either event, adding to the amount of information you are going to ignore is not a particularly constructive use of anyone's time. Being as how I'm a sad, lonely old git with a lousy cold that's keeping me out of the workshop, I've actually got nothing better to do and may as well give it a go. However, it's probably going to mostly be a cranky RTFM. The exact type of brick makes a huge difference. Some are very prone to breaking up with temperature cycling, others less so. If you have one that is prone to cracking up, the thinner bricks will see steeper temperature gradients and this is likely to exacerbate the problem. Whether or not the furnace cement will help much is quite likely to depend on the type of bricks. The Original Post included links to specifications for 2 very different materials, each with what appear to be pretty good descriptions of their intended applications. The details for the castable cement seem to refer to "large voids or cracks" and mention a slab 1 1/4" thick. This would seem to suggest that it is not intended as a thin paint-on coating. It may work really well, but most folk probably use something developed for the purpose. As far as I can tell, the Atlas 30k burners are designed to run the Atlas forge, which seems to have a 2.5" diameter, 11" long chamber. I make that about 54 cu.in. You are looking to run a forge with nearly 5 times that volume on one, or maybe 2, of these burners. There is an oft-quoted rule-of-thumb that welding temperature needs 450 Btu/hr per cubic inch of chamber. For your 263 cu in chamber, that would suggest 118k Btu/hr is needed; about 4 of the 30K burners? Though I'm not personally convinced by the 450 BTU/cu.in figure, it may well be pretty close for general blacksmithing. There are a number of variables to consider, not least the material to be welded. For bladesmithing, I've built forges that easily achieve welding temperature at something under 300 BTU/cu.in. For bladesmithing though, with around 0.8-1% Carbon steel, the temperature needed is likely to be significantly lower than for mild/wrought and the workpiece access opening for bladesmithing can be smaller than for scrollwork or similar. You've said you won't be welding, so the lower temperature will reduce the BTU requirement considerably. I think my inclination, in your position, would be to try to keep the internal dimensions of the firebrick structure pretty close to the Zoellerforge dimensions and maybe try to back up the bricks with additional loose insulation if possible: something cheap and readily available like Perlite or Vermiculite. I'd certainly give it a try without any cement first, since it keeps it easy to modify if you just have the bricks. Once you've got it working to some degree, you'll have a better feel for what needs to be done to make it work better/well enough. Pictures will help a lot, as Glenn says. Don't forget the wide shot(s). All too often there's a tight shot of a forge chamber that's not performing as it should with nothing to show how the burners are set up.

The OP goes on to point out that he's a newbie, but the thread title is "My first Heat Treat Forge Build". This suggests to me that the intended purpose of the forge might be Heat-Treating blades, rather than forging to shape. Outdoor Gater, is this the case, or have I misunderstood? In my limited experience, HT has a very different set of requirements to forging, let alone welding, and a HT forge is likely to look very different to a more conventional forge.

If you are primarily looking to Heat-Treat tool steel, many of the "normal" difficulties might just go away. The difficult thing tends to be getting a combination of flux-resistance, resistance to physical damage and adequate insulation at the high temperatures needed for welding (2300 degF plus). Often, a composite structure is used to provide the overall combination of properties needed: a kiln-shelf floor, resistant to flux and physical damage, over Kaowool blanket for insulation, for example. Your temperatures are likely to be much lower (Austenitizing temperature is around 1500 degF for most Carbon steels) and flux will likely not be involved. If you are not going to be heaving big, heavy lumps of hot stuff into and out of the forge every minute or two, there is likely to be less need for resistance to physical damage. Plistix over rigidized blanket may well be perfectly adequate for your application. I have actually used unrigidized, uncoated Kaowool in forges without any major issues. The health hazard is not to be ignored, but trying to be realistic I use a forge relatively infrequently and the measures I take to avoid the risk of inhaling Carbon Monoxide also contribute towards reducing the risk of inhaling ceramic fibres. As potential risks to my future health go, Ceramic Fibre seems to be a very long way down the list. To be honest, the biggest difficulty I think you'll face is getting the temperature low enough and even enough with a chokeless burner. You have said you'll be using tool steel, but that covers a range of alloys. Many of them need to be held at Austenitizing temperature for several minutes and this is usually the difficult bit.

"Zircon" usually refers to Zirconium Silicate, rather than Zirconium Oxide.

First thoughts throw up 2 questions: Why so big? Where in the UK are you? I'd really suggest you sit down with a pencil and paper and make a couple of lists. One with the "must haves" and the other with the "would likes". Aim to keep the must-haves to the stuff you realistically expect to be doing within 3 months. Be realistic and include the sizes in the lists. Also be honest about welding; if it can go in the "would likes", it makes building for the "must haves" a whole lot easier (and cheaper). Come back with the must-have list. Forget any ideas you might have about building the ultimate forge first-time. Whatever you might know about forges now, you'll know a lot more with 3 or 6 months experience under your belt and will be in a much better position to decide what you need to build in order to do the job(s) you want your forge to do (be aware that the jobs you want it to do may well have changed by then, too). Castable within fibre is certainly a good way to go for some things. Be aware that the drying schedule for castable can be pretty difficult to accommodate in many places over here if you work in an unheated shed, particularly coming into winter. Not all burners are able to provide the turndown for low-firing the castable either. As you are in the UK, I'd urge you to at least consider a burner based on an Amal Atmospheric Injector if you have not already decided.

I think Wolverhampton seems more likely than Southampton: Wolverhampton is in the Black Country which is/was an area well-known for its iron industry. Wolverhampton is about 20 miles from Ironbridge. Pigot's listed 2 anvil makers there in 1828-9. http://www.gracesguide.co.uk/1828-29_Pigot's_Directory:_Wolverhampton