My forge build.....WIP......it's going to take a while!

jaxxas

Well-Known Member
Gas is done usable and I fired up the forge! Not sure I what I learned though?

I fired up the forge and it seemed to run fairly normal but it only got to about 1950 F or so and started having issues. I'm thinking propane issues. My tanks started icing up on the bottom. The feel like they are somewhat less than half full. I think I need to start weighing them. Maybe need to scale up the number of tanks? They never iced up before in my test runs, but the total propane volume is now definitely less than it was.

This video really doesn't show much, it was before I started having issues.



It seems to be mostly controllable, I could adjust the blower over a wide range. It almost seems as if I could run the forge with the damper always closed, I don't know. Seems for any given PSIG and needle valve opening that I could dial down the blower until I got some dragons breath and then ease the blower back up until the dragons breath subsided. I assume that somewhere around that adjustment I'm achieving the right balance of fuel to air?

The new needle valve seems to have a very large adjustment range. Hard to say how much of an opening I was using but at the end it was opened only about a single turn.

The picture below is kinda interesting. I haven't noticed these hot spots before, though not to say it didn't happen similarly every time I ramped up the forge. My shop is lit up pretty bright light BTW. This is probably at about 1950 F or so....?

 

KenH

Well-Known Member
In the photo it really looks like the front is closed up too much (that is the front?). Boy is that thing glowing red, looks HOT. The TC says around 1950F? In the video the two brick don't look as close together as the photo above. I wonder if there is a tad too much air space between the burner tube and insulation allowing heat to come to the shell around the burner tube? Perhaps this is made worse by the front bricks being so close together? I don't have a clue, I've never had my front closed up that much. Seems like I did have two brick with perhaps 3 or 4" between them. Normally I only use one brick closing off one 1/2 of front.

What is PSIG is the propane at regulator? 2 to 3 psig?

I do hope Ed will chime in on that red glow on the shell - it just don't look to me like it's going to last all that long glowing red. Remember, I'm still learning about forges and hoping Ed and others will chime in on this.
 

jaxxas

Well-Known Member
Yes the front! In the video the bricks are opened up to position where I had fired it up. I closed them a bit later to see if it helped bring the temps up. It definitely brings the temps down in the shop. I can leave them opened up if it matters.

The PSIG was about 6 PSIG. I messed with the regulator at about 1950 F, I think it was giving all it could due to the tanks icing up. I turned the regulator all the way up and then opened up the needle valve some more and it wasn't getting hotter and the PSIG gauge actually read about 4 PSIG at that moment.

Yes the TC was reading about 1950 F for that picture. Not sure what to think about the hot spots. I was pretty happy with the kao-wool installation, but un-happy with the refractory coating on the sides and the top. But it seems obvious I have an insulation problem?


Maybe I should test my TC? Maybe my pressure gauge? I can doubt anything at this stage.
 

KenH

Well-Known Member
With no orifice/jet in use, only the 1/4" nipple I'd expect more along the lines of 2 psig or so, maybe 3 psig.

gotta run - supper
 

jaxxas

Well-Known Member
FYI, I weighed my propane tanks they are definitely all but empty. 69 lbs full, supposedly 33.5 lbs empty and they are weighing in at 37 lbs!

I tested my TC, at least on the low end, it pretty much agrees with my kitchen thermometer in ice water within a couple of degrees.
 
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KenH

Well-Known Member
When tanks frost up it's really hard to tell about tuning the forge. AND a tank will frost up as it gets low worse than when full. With the 20 lb tanks I used at start were just plain hard to use because of frosting up after they got half empty. Switch to a full tank
 

jaxxas

Well-Known Member
When tanks frost up it's really hard to tell about tuning the forge. AND a tank will frost up as it gets low worse than when full. With the 20 lb tanks I used at start were just plain hard to use because of frosting up after they got half empty. Switch to a full tank


Totally agree! And I can but that doesn't really address the long term forge issues of the hot spots!? I'm a bit befuddled about the semi-long term of my forge....


ymmv
 

jaxxas

Well-Known Member
Well thinking it over it seems that the problem might be the rear plug, leaves little escape for the hot gases, forcing it into all the nooks and crannies?
 

KenH

Well-Known Member
Looking at the photo showing all the red spots it's like WOW!!! That sucker is HOT!! but the TC is saying only 1950F or so. From what I see the red spots are a small one around the TC pipe, a tad larger red spot around the burner pipe, and a really big hot spot around the front opening. That red around the front opening really looks like there is flame getting trapped between the fire brick and forge causing the metal shell to glow red hot. The front could almost seem like it's too much propane making too large a dragon's breath, too much flame trying to come out the front and getting trapped between fire brick and forge. Running way too rich might well give those same results because it's too rich it wouldn't be super hot, but the escaping flame could be burning hot. There's a bit of air spare around the TC nipple and the burner tube both that could cause a really rich flame to burn hot around the pipe like that. Understand, I'm grasping at straws here.

Try again, light the forge then turn the psig down to around 2 psig, adjusting the airflow for good burning. Allow maybe 1/4" crack between firebrick in rear - wait, do you have an opening without removing the plug? The front slide one of those firebrick all the way to side only allowing one brick to close off half of forge opening and see what happens.

Boy I wish Ed or somebody would chime in here and give us some real guidance {g}
 

C. Killgore

Well-Known Member
I’m certainly no Ed. I would just say that I normally run my blown forges between 1-2 psi then adjust gas only at needle valve. Only time I get up to 5psi+ is if I’m welding in the big forge to get it to up to heat quicker.

You never want to seal that thing up. It really needs to breathe. Give it some space to breathe and dial down down psi to 2 or so as Ken mentioned. Getting the right ratio of air/gas takes some tinkering. What you were saying about adjusting air seems right to me. Leaving my psi low, if I want a little heat, I open up needle valve a little and then adjust air to appropriate sound and dragons breath.

I will reiterate that it’s very hard to diagnose if you are low on propane. It will start dying down slowly once your tanks begin to freeze up.
 

KenH

Well-Known Member
Thank you for chiming in with your advice - sounds like you're confirming lots of what I've told Joe before, lower pressure, low propane in tank, open up forge so it can breathe a bit better. Yep.

Got anything to say about all those hotspots? Do you think some of it could be what I mentioned above about having way too rich a mixture?
 

C. Killgore

Well-Known Member
Well in the video (where the door is a little more open), I can't really tell if it's glowing around the burner entry point. I would expect some glowing around the top front firebrick door with it setup as-is. That area is in direct line-of-fire of the flames. Might also get some glowing in the front if the fire has room to squeeze in between the firebricks and the front of the forge.

The bottom picture definitely looks like it's all sealed up with very few places for heat to escape. I could see where a too-rich mixture might have flames going places they normally wouldn't go... but at the same time I would think it would still be fine if there was a big enough door opening. Something to consider as well though. I would hope the issues would go away once he lets it breathe a bit.

I am no forge expert. I use mine fairly frequently but haven't had many issues to diagnose.
 

jaxxas

Well-Known Member
I think you are both correct about it needing to breath.

I've got bigger issues with this forge currently. I fired it up today going for low pressure with only about a half brick blocking the front. I started at about 6 psig to light the forge and once it got to about 500 F I turned the psig down to 4. I had the blower damper closed and the control at 50% or so and the needle valve about 3 turns open. The temps crawled up to about 950 F or so and pretty much stalled. I played with the needle valve and blower settings and coaxed it slowly up to about 1100 F. But it wasn't going higher without more gas,

Then I noticed a warm vinyl smell in the air and I saw a big problem and I took this picture.



It's melting my lights! Even the far set of lights have bow in them.

I never had any issues like this with my old venturi forge. Maybe the blower is the wrong way to go in a small fairly enclosed shop?
 

KenH

Well-Known Member
Bummer on the lights, I've never even considered running my forge inside the shop - my ceiling is only 8ft so wouldn't even consider it. I roll it outside anytime I wish to run the forge, even for a quick test. Interesting the venturi forge didn't have any problems with excessive heat build up inside. You think those lights hot too hot yesterday when the forge was glowing with hotspots?

With the pressure down in the 2 to 4 psig range, you might need to open the needle valve up even more - didn't you say it has several turns? 3 turns is less than half open? Of course low flow thru needle valve can be offset with higher psig to force the same amount of propane thru the valve.

I know you've got issues with HOA and need the forge close to the treadle hammer and anvil so moving forge outside would be hard - maybe outside while testing? For inside work perhaps build a metal hood over forge to collect heat and vent outside? If the garage is that small, you might wish to be concerned about CO build up from forge also. For sure have a CO detector mounted inside garage.
 

jaxxas

Well-Known Member
Yeah, I was probably foolish to even consider running it in my shop. I actually have great ventilation across the ceiling of my shop even with garage door cracked open even a small amount as the squirrel cage blower is mount up high and it pulls almost directly from the rather large opening at the top of the garage door. I'm kinda surprised at the heat build up.

No I'm pretty sure it wasn't totally due to yesterdays high heat episode. I think it accumulated more over all the firings and I've had it up higher than the 1950 F yesterday in earlier firings. I think it's totally due to the blower pushing out all that hot air. In previous firings I thought I had got a smell of something (besides the forge) a time or two getting hot, and though I checked all around the forge at those times I just failed to look up I guess. The farther light with the slight bow is actually nearer to the rear of the forge which is plugged currently so it likely bowed from my earlier firings when the rear was unplugged.

I definitely think that yesterday's high heat episode is directly attributable to the rear of the forge being plugged, well that and me pumping lots of gas into it. In earlier firings the forge had no issues getting up to heat though I never got to mess with the blower control and a 'better' gas needle valve during those firings.

During today's firing I actually had turned the PSIG down to about 3 at one point and had the needle valve all the way open in an attempt to bring the heat up. The needle valve has like a total of 15 turns!

It seems pretty obvious to me the blowert pumps way more heat into the shop than a venturi does. I mean a venturi only sucks air right? Not a totally valid comparison but I could mostly stand in front of my old venturi forge, not so with the blower.

I could manage to test it out back but I'm not sure about using in my shop at this point. My shop is a little over 400 sq ft. And the garage door takes up probably about half of the ceiling sq ft in the up position. A hood and ventilator would be hard to fit in. It would definitely require a major re-design of the whole shop.

I'm not sure what do yet. I definitely want to forge. Is it even possible to use a venturi type burner in my forge design?

My spring weather is rapidly evaporating, another month or so it will be too hot to forge inside or out. That bottle of tequila is looking pretty good right about now!
 

C. Killgore

Well-Known Member
I will say, on my first blown forge when I was learning the ropes... I had a tendency to keep turning up the PSI to try and get more heat but the problem wasn't the PSI but my air/gas mixture. I just wasn't sure exactly what I was looking for at that point. So, for a long time I ran it around 10 psi but I couldn't get within 2 feet of the opening without searing off some eyebrows. That thing was pumping out a ton of heat. I have 10 foot ceiling in my shop and run my forge right at the edge of the garage door opening (I always run my forges with the garage door open and a door across the shop open). The garage door (directly above the forge when opened) has some plastic bubble insulation and the only time I ever had that plastic start to melt was early on running that thing full bore. I'm not sure if you have any type of orifice for the propane coming in? Both of mine are just 1/4" pipe through a needle valve.

Nowadays, I cut the forges way back and couldn't imagine them being much different than a similar size venturi.

After a while, I realized I could cut the psi way back and even the needle valve. Part of the problem I had was that my blower was a lot more than I needed. It had a metal damper with a wing nut so you could move it across the opening to adjust airflow. I usually ran it barely cracked or even completely shut even at some fairly high pressures. Eventually, I had it completely shut *and* tightened down the wing nut. This got a bit more seal and let me lower the gas and run it at lower temperatures. I much prefer an air gate valve nowadays as it gives you more fine-tune adjustment.

Is it possible that you're having to turn up the pressure because you can't turn down the air enough?

Also, not sure if you're still running on fumes but if your bottles are almost empty it will take them very little time to ice up. I got as far away from smaller bottles as I could as it was a big source of frustration for me (especially since my local place charged me the price for filling a full bottle no matter how much propane was left in it).
 

jaxxas

Well-Known Member
Hello Killgore, thanks for replying!

I obviously don't know what I'm doing but I hope I'm learning.

First off I did change out the propane tanks this morning before testing, 2 full 40 pounders. The tanks are manifolded to act as a single 80 pounder. If I had my druthers there would be a 500 pound tank in my back yard! And my ceilings are unfortunately only 8 ft tall as well. I'm not using an orifice, just a straight 1/4" nipple injecting right between the blower and the first elbow. Also at this point I'm pretty sure the rear forge plug is not a good idea.

I too think I have way more blower than I need. At first I didn't have any blower control. For some reason my original blower control died before I ever got to test it out. So at that point I was running high gas pressure to try to match the blower output (at least I think that is what I was trying for!). And the forge had zero issues getting up to temp, just little control. So I had to wait for a new blower control unit. Not sure how to quantify the blower speed but it dramatically slows down when you dial down the control. You can almost see the individual fins when it's dialed all the way down. Today when I was testing the forge at about 4 PSIG (and even 3 PSIG for a bit) I had the blower damper totally closed and the speed control at about 25-30 percent. I played with it quite a bit but at about 25% or a bit lower the temps would rapidly drop off. I also played with the full range of the needle valve. And the temps were mostly stalling out or at best slowly climbing. So I guess I don't really know if I still have too much air pressure but I don't think so!?

Wow your propane place sounds like a bit of a rip off. If I smile nice and keep up the pleasant banter the lady at my propane usually rounds it down to the nearest pound!
 

jaxxas

Well-Known Member
Ok, took me a couple of days but I've decided on how I'm moving forward. I talked to my neighbor the fireman a couple of doors down and he pretty much thinks I'm nuts with this forge. I think I'm lucky I didn't burn the house down. So I looked around and decided to go back to a venturi forge.

After looking around a lot and talking to a couple of forge makers I decided on an Atlas. While I really like their Graham Forge I was a bit leery of the blower system I inquired about the venturi setup for the Graham but they really don't recommend it using a venturi. So I went with their Firestorm forge.


I understand it's not perfect and it may take some work, that's Ok! I'm good with work, I just want to get back to playing with a forge. And buying a forge get's me back into the game before my forging window expires. I spent the last 6 weeks or so building a forge and I think I (we) probably built one heck of a forge but it's just too much for my shop. For now it has been disassembled and is resting in the storage shed out back.

New forge is due to arrive Tuesday!
 

C. Killgore

Well-Known Member
Whatever gets you forging! Not an ideal design for blades since the burners are pointing straight at your work but it will do the job.

I understand your concern. It was hard to advise further when I’m not there standing in front of the thing.

Most people in the safety line of business think we’re nuts. You should have seen the look on the face of the propane guy when I showed him what I intended to run on the 500 gallon tank he was installing. I had to fight with him and read the fire codes myself before he agreed to hook it up. The downside to renting a tank... they have more say in what you can hook the thing up to. Lots of savings on propane and now I have a heated shop as well tho. Only about $10/mo rent.
 
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