timgunn1962

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About timgunn1962

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  • Birthday 03/15/1962

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  1. 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.
  2. 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.
  3. Was that in the forge, or out of it?
  4. 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.
  5. 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.
  6. 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.
  7. 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.
  8. 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.
  9. 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.
  10. 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.
  11. 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.
  12. 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.
  13. 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.
  14. 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.
  15. 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.