Larger Moya???

No bubbles busted. I have one of those quiet vacuums in the house. Different tools to fit different applications.

Pete

 

Blowers with involute curved vanes are supposed to be the quietest most efficient blowers, while straight vanes are the noisiest, least efficient but easiest to fabricate. I think there are differences between a unit built to suck rather than blow but not enough to stop you using a vacuum pump as a blower.

 

I like a straight burner tube. Put the fuel tube on an ell and weld the ell through a hole in the side of the burner tube. Mine is a brake line held on to the ell with a flare nut so I can remove it with a foot long socket but realize not it lasts and that was not necessary.

 

Whats really odd with your Late arrival, it's very similar to what I have in my Minds eye ... Hell the furnace is very similar to My current build ... getting an A20 out of a 10 inch bore furnace would be a struggle every time I'm running A16 in a 10 inch any chance you could get a picture of his lifting tongs with something for size reference

Thanks in advance

V/r Ht1

 

OK enough about blowers... Lets talk safety

1) all the blacksmiths recommend installing a normally closed solenoid in the Propane supply so if you loose power Propane is immediately cut off. this is inexpensive, reliable, simple and I Know how to do it... so We will see that in the eventual build

2) BUT loss of power is not the only reason to loose air what if the Blower just eats it's self, or the intake gets blocked, (I have done this with a pants leg)
does anyone have a good idea on a air flow sensor that would also shut off the Propane. and enough patience to explain it to me. so I can include it in the Build


Thanks in advance

V/r HT1

 

Inside I guess it's nice to avoid large flames but an outdoor furnace it seems you can shut off the propane if you didn't take a potty break. The more controls the more aggravation.

I reloaded my fuel tank with mostly gasoline last night and this morning when it hit the needle valve I remembered it has lower viscosity. Nice pretty big flame roaring four feet out the top of the furnace. So I turned the valve down a bit.

 

Look in the nicest way I can be, Knowing I have a 50 Minute melt... ( the new furnace wont have that problem,) I go inside and watch the furnace from the comfort of my air conditioned house. to avoid collapsing on what are already 80% humidity 100 Degree days, so a loss of air safety device seems prudent.
I have a thought I think I can implement, But I think there should be an easier way since house furnaces already have these sort of safety devices

V/r HT1

 

It's called a sail switch
https://www.ebay.com/bhp/sail-switch
Wire it inline with the solenoid and when the blower is off the valve will be closed.
But, that means the propane won't come on until the blower is running. If you need the propane on first, put a momentary switch in parallel with the sail switch. You hold the switch on, light the burner, turn on the blower, release the momentary switch.

 

I'll take some pics next time I'm there with steel rules for scale:

I think the current lining bore is 1/2" to 1" larger than the drawing and we are using A25's for both aluminium and bronze. It can be a struggle to get the crucible out, there's a lot of slag buildup in the bore over the years so there is only one wider position the gripper will fit. It's the same style of gripper mentioned in the crucible tongs thread so I'm linking those photos, it's made from 1/2 square hollow steel if that helps for scale. I've recently built a new gripper with 1/2" square bar and 5/32" x 1.5" flat bar, it has a couple of thin stainless discs with 1/2" thick zircon wool sandwiched in between. If the crucible falls against the walls somehow due to the plinth having crud on it there are two custom 16" long tongs/pliers with wide jaws that can straighten the crucible back up into position or even lift the full crucible out in a pinch, but this is with a mechanically stronger Morgan brand silicon carbide crucible, not sure a clay graphite would work or crumble. The only issue I had making this style gripper is ensuring enough gap between the gripper handle and the hinged top arm for a gloved hand to fit when you are in a hurry.

This gripper shields from the heat very well as the heat shield sits maybe an inch or two into the bore at most, I think you have good control over lifting the crucible and the latch won't shut unless you have the gripper positioned right. That said I can understand why it makes other people cringe, maybe a lifting loop and electric hoist would make it safer. I have only lifted a tired old silicon carbide A25 of aluminium so far with no issues (10 times).

That furnace drawing I included is from the first owner's website so the bore could be a bit wider these days, now that I think about it.

 

I'm very sure that you will find that furnace bore over 10 inchs an A25 is 8.26 add an inch for the square tube lifting tongs, and you only have 3/4 of an inch clearance since I intend to make an IFB furnace rubbing the sides with tools is a NOGO so I gotta go Bigger Ive intended all along to go with 15 inch, though I dont think i will need it running Propane, but I have not solidified anything but my blower choose

Thanks for the input

V/r HT1

 

There's no reason to run such a tight bore, I think it was a case of jamming the biggest crucible into the bore that would fit. I made the mistake of making a propane furnace design and trying to run it on kerosene/diesel/oil. I think an oil fired furnace will run fine on propane but in my experience running a propane furnace on oil works poorly, there just needs to be more time for the oil to burn fully and that means more volume and slower airflow.

 

It's been hot as hell out west so I prefer to light up about an hr before sunset. I only suit up 5 mins before the pour. Doing multiple melts back to back sucks for me. With the added heat from a big kiln going at the same time, it's an exercise in timing. The kiln takes way longer to hit 1700 than it does to melt a pot of metal. The last thing I need is to melt faster or hotter.

Drink lots of water this time of year guys. Sweating is a good thing, If you stop sweating, that's a bad sign, get cooled down immediately!

 

Here in Florida the Humidity makes it so Much worse. I returned From a Year In Iraq in 08 in Sept. I went from 130 to 80 and I felt Like I was going to die it was like living in a Sauna day in and day out I labored to Breath for about a month and really did not properly acclimatize for 2 months. Never overlook the Humidity it's a killer

V/r HT1

 

Hmmm, I don't live in Florida or south Texas but not by mistake.

 

When it's 98 outside with 90% humidity, it's every bit as hot as 105 with a 20mph oklahoma wind blasting you like a hair dryer on high! I'm not sure which is worse; they both suck! In florida, I'm okay with it in shorts and a T shirt, but if I'm in uniform, OMFG is it miserable. When I did time in Iraq, Turkey, Saudi, Morrocco (you know all the fine places in the world to visit) I was able to tolerate the heat pretty well as long as I was covered and could find shade. When it's humid, it sucks EVERYWHERE! I did time on the flightline in Vegas one summer... It was so hot we would keep tools in a bucket of water so we could use them. I'm thinking the mountains in NC might be the solution. About 4000feet, the weather is pretty nice most of the year.

 

When we were at the North Rim recently, one of the park rangers warned of the danger of hiking into the Canyon with heat being at or above 100 F.
My wife and I hiked down over 2,000 ft, and while the climb back out was rigorous, the temperature was no problem because the humidity was probably no more than 30%.
My wife and I are use to 95F and 90 + percent humidity, so the Canyon felt like it had air conditioning running while we were in it, even at noon in the direct sunlight.

The dry weather does tend to dry you out, and it takes a lot more water than you may imagine during such a hike.

.

 

LOL, that is what I told my wife I needed (oxygen) when we started back up the 2,000 ft climb.
I was gasping for about 5 minutes, but was able to maintain a nice pace after that, and we climbed out in less time that we took decending (3 hours in, less than 3 hours out).
It was the second day at the rim, and so we had one day to acclimate.
I generally don't notice much altitude problems. Generally just some headaches the first day or two.
Anything under 12,500 ft is no problem as far as oxygen (for me). I have not tried to go above that.

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