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?

I just finished building a new forge for knife making. It’s long and narrow. I made a manifold that branched off into two 1 inch burners that came into the forge from the side. Well, after futzing with it for a few days, I could not make it work. So I decided to go radical and make a side blast ceramic ribben burner for the forge. I could not be happier with the results. Forty minutes after a cold start I had a pool of metal in the forge.

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?

From the pics you posted, I take an opposite opinion from most of the responders thus far. It has nothing to do with the refractory lining.

Agree with you, it has nothing to do with lining.

And, you have too little air being forced through the burners not too much.

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.

By the time you adjust your gas to get a stable flame for the amount of air you are blowing in, you are not putting in enough fuel and you get very ‘soft’ flames. Just not enough heat for that volume of forge.

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, not at all, I just wasn't sure the nature of your castable. As I was trying to illustrate, there's a huge difference in performance possible, and outlined one method to turn non-insulative castable into highly-insulative castable yourself... no need to buy it.

The point still stands though, that you may want to ask your supplier for the insulation specs on the cement and compare to the two I listed. If it's edging toward the first, then it is going to take a lot more heat than the latter.

But if you're confident that energy loss isn't the problem, then you can move on to other things. Since you suggested the idea yourself I thought I'd give you some things to consider/research.

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.

Miscommunication here I think. He means anything that would restrict the gas flow, like a mig tip.

My 1" atmospheric pipe burner uses a .045 tip, just for reference. .02 is way too small for that (and apparently isn't needed at all for blown burners anyway... no point in accellerating the gas to draw in air, etc.) This could be the problem... I think .02 tips are in the 1/2" burner range and heat-class. Sounds like you may just be able to pull the tip out and try it there.

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

Do you have some sort of orifice on the gas? With blown you don't need any. When it's running as shown, is there dragons breath out the front? Like actual flame at the door.

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.

That's not a good assumption. many people combine a solid refractable over wool, etc. For use in furnaces just means that it can take the heat. The fact that it contains "heavy furnace bricks" makes me think that that it's not especially insulative. Heavy bricks mean a lack of air pockets that give insulative firebricks their qualities.

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?

What castable? Is it insulating? Is it backed by wool? Do you have ITC-100 on the face?

Firebrick has better insulation value than insulating cast-able from what I've read. Backing the cast-able with wool would have slowed down the loss too.

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.

Have you tried going up to 10 psi?

No only about 5psi

I suspect you still have way too much air. Are you able to cut the air back to where you have a lot of "dragon breath" coming out the front?You could make new throttle plates like this:

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