Non-Chemical Melting into final product

[Paige]

I looked at Paragon's small furnace which says it gets up to 2350 F. It's about $500.

The small hand held units are about $1500.

My question is on the pour.

How much time will you have to pour from a Paragon funrnace into a mold before the gold begins to harden? I would expect temperatures dropping very fast when you open the door, use tongs to grab the crucible, and then start pouring into a mold that you have perhaps hand heated.

I guess you could put a graphite mold into the furnace with your gold and then you'd be pouring into a really hot mold.

I am just really puzzled how to make it work right.

Thank you for your patience.

Paige

 

[AuMINIMayhem]

I have that same kiln.. takes about 45 min to an hour to get up to temp.. yes you are correct the temp drops extremely fast as soon you open the door and takes a while to get back up to temp.

have you read any of my misadventures on the other thread? (http://goldrefiningforum.com/phpBB3/viewtopic.php?t=378).. just a couple things to note when using this partuicular kiln..

A) the inside tiles like to melt over 2000f whenever certain substances touch them (ie: sodium nitrate, borax, etc.. even the graphite crucible or molds will start to melt the tiles.. the tiles are replaceable (haven't done it yet) for the paragon Q11A, the one I have, it's about $26 per side to replace if they melt..

B) there appears to be a piece of metal metween each of the tiles (looks like a thin grout line).. be VERY careful, it is energized (or grounded.. whatever)! if your kiln melts down like mine did, do not do either of the following two things..

#1 Do not reach into the kiln with tongs that are conductive (which you know they are) and hold onto the door at the same time, YOU WILL GET SHOCKED! It's not a bad shock..it didn't mess me up, but it was alarming because of the "what if?" factor..

#2 Do not let the tongs touch anything on the the inside AND the door.. you will get a good spark and possibly tack weld your tongs to the door, mine did not get tack welded but came damn close, did leave a bit of a melted spot in the metal handle..

Also remember (something I discovered the hard way) graphite crucibles and molds ARE conductive! :shock: Treat them the same way you would any surface on the inside of the kiln..

Keep these things in mind and you'll do fine.. also, make sure you get a pair of welding gloves... :wink:

 

[AuMINIMayhem]

ps... trying to get my digital camera up and running.. if so, I'll post pics of what the inside of my kiln looks like.. it'll be good for a laugh, at any rate. :lol: :lol:



UPDATE:
OOOH OOOOH!! I just literally got my camera to work somehow (it's been on the fritz for months now..)

Without further ado.. The Paragon Q11A post "3 Milet Island" meltdown.. temperature achieved: approx. 2100f before panic set in and I shut off the oven.. This is what happens when you have too much material in too small of a mold at too high a temperature.. :shock: :lol:

Nice, huh? :lol: :lol:

 

[darkelf2x1]

what exactly caused the damage, because you could be able to continue to use that kiln...

had something like that happen to my kiln but it still was ok and now ive added some additions to fix it ( a fired clay silica mixture that was ground into a fine 100>= mesh particles which was then laid down to cover the hole and the floor to cover the borax that i couldnt remove)

 

[AuMINIMayhem]

oh thank god.. I'm not the only one that's had this happen.. yes, it does still work, but at the moment I have no more crucibles or cupels, so now's the best time to just fix'er up anyways.. more for safety than anything.. see those grooves between the tiles?.. that will carry a charge. be careful if you're still using yours like this (read my previous posts about that)..

yeah it was borax and/or sodium nitrate, not sure which was most responsible..

At any rate, I called Paragon and am getting replacement tiles for the inside.. not too bad a price (not going to replace the door surface or the sides, just the roof and the floor, should be around 60 bucks after shipping ($26 for replacement floor and $26 for ceiling, not sure about shipping..) The roof melted from my crucible (which was about an inch from the roof) I believe in that instance it was just the Sodium Nitrate and the fact that there was so little room between the mouth of the crucible and the ceiling of the kiln.. when I opened it at around 2100f, the entire crucible was engulfed in this ghostly almost plasma like bright yellow flame.. the only things inside the crucible were as follows:
sodium nitrate, borax (20 mule team), #70 silica and the precipitates from my electro-cell (flux in a 3-1 ratio to the precips).. the crucible itself was destroyed after a couple firings (3 maybe?).. it was extremely brittle and full of glass droplets when I cooled everything off, it was as though the contents soaked straight through the graphite at high temps..

 

[darkelf2x1]

your refering to the heating element, right?

- - - - -

i overloaded a damaged crucible which burst and released a stream of molten gold and slag into the kiln

 

[AuMINIMayhem]

nope... if you look closely there is a division between each tile, not the coils on the sides and the back but on all interior surfaces.. hang on a sec.. let me post a pic.

 

[AuMINIMayhem]

ok.. here we go.. the red lines indicate where there is something, perhaps a metal plate or whatnot, that is either grounded or "hot" (electrically speaking).. if you touch one of these lines and it has been exposed due to a meltdown such as mine and you touch the door handle or body you will get a startling tingling sensation :shock: also, if you touch the red lines with your tongs at the same time the tongs are in contact with the door or the handle you will get an arc and your unit will shut down for a bit (is there some sort of "safety" that resets itself after a bit?.. sometimes it'll conk out on me and I'll have to leave it off for a bit, then I'll be able to turn it back on, but only after the temp dips below 1000f or maybe even cooler..)

now this is a best guestimate of mine as this didn't happen until after the meltdown, but it could possibly be that the tiles themselves are either grounded or "hot" with current.. either way, it didn't happen until after the big melt.. I had tried refiring some stuff and I noticed if I reached in with the tongs (and no gloves on.. duhhh, stupid mistake) I would get shocked if I was holding onto the door latch at the same time.. I also tried to shut the door and hold the tongs in there a bit to warm them prior to grabbing my crucible, that's when it arced as it touched that aluminum (?) door latch at that point..

 

[Paige]

So, how much time to you have to pour?

Paige

 

[lazersteve]

Mayhem,

You've definitely have one hell of a mess on your hands.

Here's a few things I notice looking at the pictures:

1: The majority of your 'product' appears to be on the bottom of the kiln.
Q: Did you try to 'extract' any of the embedded material out of the bottom tiles? Save these tiles as they likely contain your precious metals.

2. The door tiles appear to have some sort of vaporized substance condensed on the near the center area. This may be precious metals as well.

3. The arcing/shocking you are experiencing could be due to the precious metals which have 'soaked' into the tiles, making a semiconductor of sorts.
Uplug the kiln and do some continuity and resistance checks with a good digital multimeter to determine which parts are conductive. Measure from the various tiles to the metal frame and note your resistance readings in ohms. Also check the resistance across the surface of the various tiles to determine which ones have become conductors. These tiles are probably where the precious metals are embedded now and will need to be replaced with new 'nonconductive' ones. To the best of my knowledge the tiles should be excellent electrical insulators and conduct nearly no current when properly functioning. SOme of the tiles that appear in good shape may have become conductive as well. You can confirm the correct resistance of the tiles when you get your new ones. I think you'll find thay are insulators not conductors.

As I've already stated, DON'T toss out any tiles that exhibit any abnormal resistance readings, these are likely canidates to have absorded the precious metals you've lost.

Steve

 

[goldsilverpro]

Excellent analysis, Steve. I think you're right on the money.

 

[AuMINIMayhem]

That's why YOU ARE THE MAN, STEVE!

You know, I never even came remotely close to considering that possibility.. Ok, will do for sure. I was just going to chuck the tiles.. I figured it was just over-spilled borax and/or sodium nitrate or even the glass particles I put in.. This is why I love this forum, sometimes it takes someone else looking at a problem to come up with an alternate solution. You guys are the best!

BTW, Steve, the package I sent you came back today.. wooops.. :shock: it'd help if I put your address on it, wouldn't it?.. (you guys must think I'm a total screw-up :lol: :lol: :lol: I swear, I'm not.. just one of those "so preoccupied he tends to forget stuff" types.. :wink: ) Anyways, package going back out Monday AM ..

Thanks again!
Derek

 

[AuMINIMayhem]

So, how much time to you have to pour?

Paige

30 seconds max..provided you are at least around 2000f.. have EVERYTHING ready and in place.. don't let yourself get rushed though.. that's when people get hurt. I screw up a lot but I always take a deep breath and move in a very smooth and purposeful way when messing with pouring molten metal..in fact sometimes if it's a weird angle, I'll do a couple of "dry runs" while everything is cold so that I know where everything is and if anything is going to be in the way or trip me or anything flammable might be nearby.. and ALWAYS have at least a gallon pitcher (not a milk jug) of water around in case you drop some on something flammable or you burn yourself.. I say not a milk jug because you want to be able to pour it fast not the glug glug glug of something with a small opening..

and lastly.. and probably most importantly.. keep in mind, anything this hot doesn't just make a little blister, it will burn straight to the bone if given the chance.. I've seen it happen (not to me, surprisingly), that's what gave me such a healthy respect for the heat you're dealing with..

 

[Paige]

Thank you AUMinimayhem.

Paige

 

[catfish]

Hi Paige:

If you are interested in buying a Paragon Kiln (oven), you may want to check the following site. “Sheffield-pottery.com”. They sell the Q-11-Akiln for $345.00. That is where I bought mine about 18 months ago and have been very happy with it. They are still the same price. I have melted lots of gold in it with out any problems.

You also ask about pouring time. This is a problem with any oven. You just have to have all your molds close to the oven and be ready to pour when you take the cupel or melting dish or etc. out of the oven. It takes about 45 minutes to reach max temperature of ~2300 degrees F. I have found out, even though gold melts around 1064C or about 1948 F, you have to let it get to about 2200 before you can pour it into a mold.

There are many advantages to an oven over a torch. You can run several batches at the same time. You don’t take a chance and loose your gold. It doesn’t take near as much flux. I have my oven in my shop and can run it any time or type of weather.

Disadvantages:

The torch will get hotter faster and also reach higher temps. With a torch, you can gather your gold beads and make one button. This can be done in an oven, but not easy. The costs of a torch, with Mapp gas is less capital outlay initially, but after buying map gas every time you turn around or you wind up getting a professional rig for about the same price as an oven.

No! I don’t own stock in Paragon ovens, but I am really satisfied with mine.

Catfish

 

[catfish]

Already posted.
Catfish

 

[goldsilverpro]

You guys with these ovens should look into trying fire assaying. It's the cheapest and most accurate way of finding out what your scrap is really really worth. It will work on most every type of scrap, with very little preparation.

Besides the oven, the big item is a .0001 gram scale. They aren't cheap, but lots of used ones are available. Action Mining (I think) sold a cheapo fire assaying setup that, instead of needing a scale for weighing, you simply measured the diameter of the final gold bead and found it's fairly accurate weight on a chart, which they provided.

You need assay crucibles (I prefer 20-30 gram size) and cupels (I like the composite 1-1/2" or 1-3/4" ones). You need a small cast iron cone mold and some tongs at least 18" long. You need some leather welder's gloves and some pure lead foil. There are several fairly inexpensive chemicals to buy, including a small quantity of nitric acid. A couple of small porcelain crucibles and a hotplate. And a few other small things, like a small ball peen hammer and some tweezers.

If several people got interested in this, one person could buy bags of the chemicals, at a much lower price, and all could share the costs.

Assaying can be learned in a day, or two.

 

[Paige]

Many thanks, Catfish. It sounds like Sheffield Pottery and I will be doing business.

Paige

 

[jimdoc]

Action mining sells a dvd that shows you how to do it,
I got it bundled in the deal when I got the catalytic
converter dvd. Seeing it done on the dvd is much better
than reading it, if you don't have somebody that could
teach you locally.