jsurgeson

Yeah there must be, unfortunately most of the companies and industry that uses refractory materials are the other side of the country. But I am sure I will come right. B)

Makes sense, however priced a 50mm one yesterday and found that they cost more than a complete type k tc with leads and fittings. Going to have to find another supplier or a cheaper solution. I am also going to try pulling the tc back into the tube in the wall, and see if thats does the trick.

SS tube, great idea thanks, even if it destructs after a while probably still cheaper than buying purpose made. Thanks for suggestions guys

Do you know if protection tubes are designed for the turbulence issue or to protect it from damage, both?

Kinda of what I thought, just did not think that flame/air movement would cause the tc input to vary that much. I think I need to rig it so i can put a meter in the box to see if the tc output is actually changing as much as that. And a shield as you suggest might be a answer, do you know if commercial tc's are shielded from the turbulence or not?

The tc is brand new and as I said out of the forge with torch flame applied directly to the tc the reading is correct and stable well over 850 deg C

I know this is partly a electronic design issue but I am sure that there are many here that are knowledgeable or have experience with regards digital temp indicators or controllers on forges. I have built a type k temp indicator for my 2 burner blown forge, here is the thing, when the forges get up to 600+ deg C the reading starts to jump around 600 - 1200 erratically different values. I thought this was a electronic issue however when I turned the burners and blower off, the reading immediately stabilized and slowly started to drop as it cooled. I assume from that, that it is not the electronics or the tc. Also when I tested outside of the forge, using a gas torch to apply heat directly to the tc, it remained stable all the way up to 800 odd degrees, the hottest i could get it with this little torch. What do you guys think?

Well it sure burns great, and appears to support what you say about "more" air and not "less" Do you have any other images/details of the "side blast ceramic ribben burner" I dont have a needle valve on my gas, which also makes it hard to tune.

Thanks guys, that should keep me going for a while :D

Thanks kcrucible, I need to play a bit now and see what happens. Going forward i might just re-plumb the burners with 1 1/2" straight through and get proper gate valves for finer control. I cant find any plans for blown burners like there are for atmospheric (reil, mod side arm etc etc), any links you know of?

Agree with you, it has nothing to do with lining. Hmmm don't think so, that blower chucks out plenty air, and yes it does blow out any flame put near it, even on 90% choke. My previous post when I said "removed the mig tip, pulled the 6mm pipe which held the tip back to about where the air is injected and vooma!" I meant that it was now working almost perfect barring the few questions I just asked. So I have to say that the guys were pretty much on the nail for what the problem was. I need to learn how to adjust my mix correctly, it might be that due to the design of my burners i am not getting a "proper mix" and as a result am battling to adjust without killing the flame. Also why I cant increase it above 2psi, this I suppose could be as a result of what you say not too sure. 1. Will increasing pipework from 1" to 2" from start to finish increase volume? 2. Would I then take a 2" pipe all the way into chamber? 3. How much air do you need to work with?

Yeah well it was as you said, removed the mig tip, pulled the 6mm pipe which held the tip back to about where the air is injected and vooma! Questions? 1. The gas oriface is now 6mm, too large? 2. Gas pressure at below 2 psi, hardly registers on gauge, if I raise, flame out. 3. Flame at burner blue, lots of orange dragons at rear and front, is this correct? 4. Is there a correct (or best) start up procedure for 2 x blown burners? had a lot of problems starting. 5. Is there a right and wrong position/order/distance between the forced air in/ gas in? This is what i currently have, position of gas in is B, any advice on position and orifice size?

No thank you, the very detailed info is more than helpful. It makes sense to check with supplier as you suggest, either way it is not the best but \ unfortunately will have to do. Sorry i misunderstood Grants post, I think he has possibly hit the nail on the head when he asked the question "any orifices" I think also the fact that I have the tip in the throat of the burner does not help as well. Strange posted images of the burner a few days ago and none commented on that? I will remove the mig tips tomorrow and try without..good one guys, thanks :D

No there are no openings, I built this as a blown burner not as a atmospheric type. Except on initial ignition with low air pressure when you get a belch of soft flame, I cant get any flame to exit no matter how I adjust the gas/air.

The heavy brick are kiln bricks so must be insulate, in any case i have used them on their own just stacked together in one layer no cast-able and after 15 mins it is at 980 deg C, you can still put you hand on the outside, just very warm. So yeah they are insulative, and combined with castable furnace cement, i assume even better, not so? The high tech light weight high temp board is very expensive here, as is any of the wools. Brick and cement although not ideal, was the most cost effective way. Are you saying that I can not achieve a working solution using brick and cast-able?

It is a South African product called "Verokast 1300" It is not solid castable, it has heavy furnace bricks for insulation encased in cast-able. The 1300 denotes its temp rating and is designed specifically for furnace use, so i have to assume it is insulating. No only about 5psi

It does not look like it but my plates are as you describe. If I close the air completely the burners is fairly unstable, the flames burns at least 4 inches from the end of the burner tube.

Posted a few days ago my new blown forge, added the blower with adjustable air gates. As you can see below although the burners run stable, however they do not appear to burn right. The images below are after 30 min's, and as you can see it it still no where near even forging temp net alone welding temp. I ran from 15kpa (2.2psi) to 30kpa (4.4psi) with little difference. The air gates are almost closed, probably only 3mm open, any more and flame out. I am using 0.6mm (0.02") tips. There is obviously something very wrong with this design as my 2 burner (reil style) made out of stacked loose fire brick got to temp in 15 min. 1. Is internal vol too big (1028 cubic inch) for 2 x 1" burners? 2. Is thick cast-able liner absorbing all the heat? 3. How to tune these forced air burners.

0.6 cubic feet / 17.1 liter (22cm x 45cm) Correct, I think 0 - 1300 degC is its operational band. I am a knife maker so need accuracy for hardening. yes the length was for adjust-ability, probably more so that I am fairly new to blacksmithing and all things forge related. I had quite a few problems tuning my atmospheric burners, and in fact never got the one to burn quite right or the same as the other, so thought i should leave myself some slack. You are right though it does take up a lot of floor space and in hindsight should have had it at an angle to reduce.

Thought I would share my second attempt at a gas forge. My first attempt was a crude pile of fire brick and even cruder atmospheric burners. Although the forge worked well it was not efficient I did not have much control over the temperature or the way the burners burnt. With my second one I constructed it from an old steel water heater tank. The lining is firebrick (thats why so thick) covered with 1300 degC castable cement. I also decided to scrap the atmospheric burners and try blown burners. The position of the burner tip is fully adjustable and although not shown, each burner forced air inlet will have a fully adjustable gate to control air flow. The blown air will come from a squirrel cage air blower. If you are wondering what the green arm is on top the forge, it is a swing arm to hold my digital temperature indicator. I have built up a 7 segment display which will display the temp in degC from a type K thermocouple. The thermocouple position is between the two burners.

Well I personally like to avoid "cans of worms" as the resulting dissusions are more often that not pointless. And I should have been a bit more careful and qualified my original question properly. This was in no way a call to "control, restrict, force" the naming of blades, shapes or anything else. I was looking for advice with regards website "knife image gallery categories", and was looking for the most "generally accepted, commonly used, broad based" categories names for listing "different knife types" and the best way to determine what knife should go into what category. So let me ask again, with care! Can anyone give me there personal preference with regards how they categorize their own knives for inclusion under website gallery categories. For example, what do you regard as "utility" is it only chef/kitchen/eating or does it include general campsite blades like machete, axe etc. "Hunters" does it include "Bird & Trout" or do you put them under "Field & Dress" etc etc Please again this is not a call to a debate on what is right and what is wrong, I just wanted to hear other knife makers personal opinion's and how they determine this so that I can learn from them. Regards Jeff

Hmmm, I can kinda see how I may have asked "how long a piece of string is" And in hindsight, and due to the lack of response, I suppose it is either an unanswerable question, or maybe no ones ever given it much thought. Will have to ponder this a while Thanks anyway

Yeah saw that thanks, however what I am really looking for is a little more than just "blade shape" classification, and more along the lines of a detailed classification of what makes a hunter a hunter, and what makes a dagger and dagger, as well as the then multitude of "blade shapes" that would then fall under each category, for example: Hunter -> Clip Point / Drop Pointer / Skinner / Bird & Trout etc Tactical -> Utility -> Camp -> Along with spec of what makes each of those fall into each category I am amazed to see that the national & international bladesmith/knife type associations do not make any recommendations/specification as to what would make a Bowie a Bowie or any other for that matter.

Hi All Is there such a thing as a naming convention with regards blade shapes? for example "bird & trout" "drop point" ext etc If so, where would I find details on this convention, with regards shape => name? Regards Jeff

Hi Wim Cheers, I would certainly like to be kept posted of events etc, dont know if and when I can attend, things are rather tight of late. But I would really like to try. Jeff