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Anon
01-31-2006, 01:09 AM
This isn't exactly about foundry burners, but at least it's about flammable things.

I have a small, refillable (and also quite expensive) butane torch. I was using it to do a small brazing job (actually the first time I've tried brazing . . .) and it wouldn't burn right. It would sputter increasingly the longer it was on, finally going out about the time my workpiece reached brazing temperature. It also became increasingly hard to relight, requiring matches and eventually burning wads of paper to get it going, instead of its built-in piezo. I finally got the brazing job done, but it took far longer than it should have.

It seems to be burning with an oxidizing flame (I taped up the air vents and the flame stabilized a bit . . . clearly it gets some of its air from a hidden vent somewhere . . . ), which is another way of saying that it's not getting enough fuel, even with the fuel valve wide open. Could there be a clog somewhere? If so, how do I fix it?

No, it isn't out of fuel. I refilled it, and that seemed to help for a few seconds, but then it started doing it again.

This is an intermittent problem . . . it's done this to me before, and after I set it aside for a few months, it started working again. As of now (when I've finished all my brazing, of course) it seems to work fine. Any suggestions as to what's wrong with it, and how to fix it, would be greatly appreciated.

Adam Ziegler
01-31-2006, 02:16 AM
I am only familiar with butane cigar and pipe lighters. Sometimes those get air locks. Also, some fuels aren't as clean and can clog up the works. For an air lock... hold the flame valve open, while you are filling it from the fill valve. Sometimes that will help get rid of the lock.

Tim
01-31-2006, 04:24 AM
Sputtering sounds like you're holding it upside-down, letting liquid into the valve.

I'm not unfamiliar with this, having used handheld propane torches in such orientations, not to mention I once had my 20 pound tank icing up good, so I turned it on its side, letting liquid through the regulator, eventually resulting in sputtering at the monster burner as it spurted liquid! :lol:

But liquid results in a rich, not lean, flame. Liquid doesn't pull as much air as a gas jet does, and in addition, the liquid has a lot more fuel in it, hence, rich.

Tim

Daggoth
01-31-2006, 04:32 AM
Kinda sounds like a problem with the valve since it is intermittent. A seal getting out of alignment ever so often. Just a guess.

Anon
01-31-2006, 08:07 PM
No, I wasn't holding it upside down--I've done that before, though, and it actually seems to improve the burn, which would go along with my theory that it's too lean.

I'll try the air lock thing . . . okay, that didn't help.

The fuel is advertised as "triple-filtered" and "non-clogging," but that doesn't mean it actually is non-clogging.

If it's a valve problem, how should I fix it?

Techno
01-31-2006, 10:31 PM
I doubt this one but some butane refills need to be right side up instead of upside down. If you have it bass ackwards it refills with gas instead of liquid.
Its almost empty.

Anon
02-01-2006, 12:11 AM
Actually, the way this one is designed (the fill spout is on the bottom) it has to be upside-down for the liquid to fill. That's the position in which the fuel canister is above the torch.

I finally took the whole thing apart (a drastic measure, as I know how hard these things can be to re-assemble correctly) and after several long, tedious, frustrating, and slightly dangerous hours of fiddling, I found the problem. First of all, the design is terrible. The "variable" fuel switch is really just an on/off valve--sliding it farther does absolutely nothing. This is the first major problem--how am I supposed to adjust the flame for a neutral burn without a variable valve? This would be okay if it burned fine on that single setting . . . but, as luck would have it, it doesn't.

The second major problem was the fact that the fuel line had no sealant of any kind on one end (it wasn't even a tight fit, and onto a smooth nipple at that), and, as a result, leaked badly. I found this one out the hard way . . . when air intake is restricted and the gas velocity lowered, it burns inside the nozzle instead of the end, igniting this leaking gas, and very nearly taking my hand with it. Luckily, it wasn't such a big leak that I couldn't blow it out.

The third major problem is that the valve isn't only non-adjustable, the gas pressure on the other end varies widely according to how much liquid butane is in the fuel tank. Since, due to the leak, the torch uses butane several times faster than it should, the level in this tank varies quite dramatically with usage.

The fourth problem is that there is no way to check the fuel level in the tank without completely disassembling the torch. This makes the other three problems very hard to diagnose.

The fifth problem was with the piezo unit . . . it had a large and completely useless internal spark gap, enclosed in a plastic tube to keep it from igniting the leaking fuel line. When I re-routed a few wires to bridge this gap, the strength of the sparks increased significantly.

I sealed up the leaky fuel line, removed the internal spark gap, struggled to get everything back in place, and filled the fuel tank. This time, I got it full--the directions on the torch say to fill for 10 seconds, which is what I'd been doing up to this point . . . I filled for a full minute. And now--you guessed it--it runs rich.

For a $1.00 Wal-Mart cigar lighter, this level of quality might be reasonable, but for a twenty-buck torch, this is ridiculous. For those of you that might buy torches like this in the future, stay away from the WL Lenk LPT-200 . . . it's complete junk for the price. These torches, in general, are very handy to have, but not when they're this badly built.

If anybody has any suggestions on homebrew improvements to that valve, let me know . . . it's directly on the fuel tank, though, so modifying it would be a major undertaking.

Adam Ziegler
02-01-2006, 01:12 AM
For a $1.00 Wal-Mart cigar lighter, this level of quality might be reasonable, but for a twenty-buck torch, this is ridiculous. For those of you that might buy torches like this in the future, stay away from the WL Lenk LPT-200 . . . it's complete junk for the price. These torches, in general, are very handy to have, but not when they're this badly built.

A good butane pipe lighter starts at $50... The lighters that sputter out, and die after a few months of cost about $20!! :D For about $30 you can get a MAPP Oxy Combo torch at some hardware stores. The tanks are the same size as a plumbers propane tank. It can braze weld and cut...

Anon
02-01-2006, 01:50 AM
Eh . . . I have a $10 propane torch, that fits normal propane cylinders and works just fine. The problem is, it's a little bit overkill for electrical soldering. Besides, my parents won't let me use it inside.

I like that little torch, when it works right. The disappointment for me was finding out that the innards were no higher quality, nor better assembled, than the fireplace lighters you can buy for $1.00 each at Wal-Mart. Really, you could narrow the jet a bit, point it down a tube, and you'd have the same thing that I spent twenty bucks on. I was expecting something that didn't leak gas, at least.

I know about the MAPP gas setup--do you know how long the fuel tanks last? My oxy torch hardly uses any fuel, so I can afford $7.00 a tank for fuel (oxygen is a different matter . . . ), but I suspect this will use a bit more.

Edit: I was thinking about the MAPP gas torch--not the MAPP/oxy torch, which I already have. I paid closer to $50 for it . . . and oxy is a rip-off, so I was looking for something that heats faster and better than a propane torch, without requiring oxy.

On a different note, I've been experimenting with quick-heat resistance soldering, like the "Cold Heat" units that sell for an exorbitant price at Radio Shack. So far, all I've managed to do is make a lot of smoke and mess--my transformers are all too small to heat up to soldering temp (half an amp at 9 VDC), and my 6V 5Ah lead-acid is way too powerful. It reaches welding heat almost instantly, albeit over a very small area, and fries my alligator clips (not to mention my fingers . . . ) Obviously, it's impossible to solder like that--the solder overheats too quickly. Besides, it's bad for the battery. A few resistors wouldn't hurt, but I'm going to look around for a better power supply sometime--I don't want to run this off batteries. Does anyone know how "they" manage to keep the AA batteries in the commercial version from dying in about half a minute, while keeping the tip hot? My estimate now is that it will take several amps at 6V, which isn't much soldering time.

Adam Ziegler
02-01-2006, 02:05 AM
Those cold heat units are a waste of money. The tips (whatever funky alloy it is) are super brittle, and break easy. (Keep it away from your FETs too!!) For soldering, what wrong with a plain old soldering iron?

Anon
02-01-2006, 02:34 AM
They're probably just graphite . . . which is what I'm using for my experimentation. I've broken a few, but since they're just bits of pencil lead, I don't really care.

If I had any MOSFETs to keep it away from, I would, since right now it scorches everything around it. That design is deadly to sensitive circuits with closely-spaced pins, since the electrical circuit travels through the solder.

I don't like conventional resistance designs--the irons are too slow and can't heat a large enough area, and the guns are bulky and awkward. My torch is great for bigger electrical work/small structural soldering and brazing, but it's not for circuit boards. And, of course, my big torch is relegated to large jobs only.

Tim
02-01-2006, 04:18 AM
I don't like conventional resistance designs--the irons are too slow and can't heat a large enough area, and the guns are bulky and awkward. My torch is great for bigger electrical work/small structural soldering and brazing, but it's not for circuit boards. And, of course, my big torch is relegated to large jobs only.

My soldering gun works fine...maybe you need to work on your hand-eye coordination 8)

Torch is good for chunky bits (without one, I would've never assembled my induction heater capacitor bank, with its 1/4" copper tubing), but you've got to be very careful around plastic...(and yes, some of the capacitors on that bank have melted corners :roll:).

FYI, torches are a *great* way to strip circuit boards of ICs, assuming you are going to trash the board!

Tim

T-Gold
02-01-2006, 05:50 PM
Wear a charcoal filter respirator when stripping boards with a torch... BTDT. :) MAPP torches don't eat fuel very fast, but the oxy-MAPP torches eat oxy bottles rather quickly for my taste. I think I only ever bought one bottle of oxy for that torch before I sold it/traded it...

Anon
02-01-2006, 08:44 PM
Rather quickly? It costs about $20 an hour in oxygen to run . . . which forced me to buy an arc welder and relegate the torch to detail work only . . . which it performs flawlessly for the price. Even an expensive MIG/TIG setup would have trouble with welding 24ga. steel. And you can do a lot of this type of stuff in an hour. For structure-type welding, though, it's way too expensive.

Do the MAPP cylinders last longer than propane assuming the same rate of consumption? I probably won't buy the torch any time soon, but I've had my eye on it for a while.

Soldering guns are bad for detail work. I have no problem using them to attach 16ga. leads to something-or-other, but they're a bit hard to use when removing a single component from a circuit board without damaging the others--especially as small as circuit board electrics are nowadays. I have to use it, though, because my iron is awful. The tips refuse to stay tinned, and it will barely melt solder on a good day. Besides, it takes a long time to heat up--and the stand that came with it won't hold it up.

Tim
02-01-2006, 11:39 PM
The tips refuse to stay tinned, and it will barely melt solder on a good day. Besides, it takes a long time to heat up--and the stand that came with it won't hold it up.

Get a 9 or 10 dollar iron from RadioShank... works fine when I need an iron (not often :P ). If you leave it plugged in without use, the tip overheats and once the iron plating eats through, the copper core will disappear over a few weeks.

Tip cleaner and good tip care practices keep it from gunking up. If you've let it go to pot, use a file or sandpaper to shine it up.

Tim

Anon
02-02-2006, 12:46 AM
I have the Wal-Mart version. It's considerably cheaper in both price and quality. The tips aren't even slightly ferrous--when they were new, they looked galvanized. (The instructions came with a warning to coat the threads of the tips in carbon to prevent sticking in the gun--ostensibly, due to thermal expansion. One of the tips did get stuck, and it was hard as heck to get out--somehow, I have a sneaking suspicion that it soldered itself in.)

The tips never tinned right in the first place, and it wasn't from overheating. The iron heats so slowly that the tip tends to oxidize before it comes up to melting temp--I suppose I could file all the impurities off and tin them with a torch, but it wouldn't last long. Even when I manage to get them tinned, the coating doesn't last--and I have to keep it warmed up to use it, because of the long heating time. I'm sure if I spent the extra money on a decent iron, it would work, because I've used them before . . . but money isn't something I have a lot of.

On a different note, my instant-heat soldering device is coming along well. I found a 18VDC 1.7A printer power supply (it's amazing what I can find in my closet, if I look hard enough) and it, unlike the power cube I was using earlier, has plenty of power. Actually, it has too much--I need to hunt for a suitable resistor. Using a graphite pencil lead, it reaches mid-orange heat in about half a second, and white heat in about seven seconds. It also has an annoying tendency to strike an arc--so much so that I had to get a welding lens. With a bit of practice and a very sparing touch as far as heat is concerned, it can be used quite effectively to solder. It's no good for brazing, because it doesn't heat enough area (mostly, only the electrode gets hot) and the borax tends to stick to the electrode and break the circuit. It would be pretty good as a tiny arc-cutter, if I had a lens light enough to see what I'm doing, yet dark enough that the arc didn't blind me.

Is there a better way to electrically and physically connect graphite electrodes to wire than the alligator clip I've been using? It has to tolerate heat . . .

The electrodes burn up pretty fast--that would be reduced if I could keep it from striking arcs all the time. Even so, tips are a "consumable" with this type of device.

Tim
02-02-2006, 08:22 PM
Hmm, well Wal-Mart is quite obvious...

RadioShack isn't exactly quality either, but it's better than the nothing you describe.

What you need for the "cold heat" thing is to recognize that it heats through contact resistance. Voltage is low and current is relatively high. Since volume is low, power is low, as with welding. (When welding, you don't melt the whole damn chunk of steel, that would take a mess of heat -- just a corner of it.)

At 18V, arcing and generally overheating is definetly going to be a problem.

To hold the lead, use a collet type grip. Make it out of brass or copper. You could drill a hole the exact size of the graphite lead then saw the block in half, through the hole, and add two clamp screws on either side. You can probably tighten it too far and crush the lead, so don't tighten it too much.

Tim

Anon
02-16-2006, 01:12 AM
Well, the only reason I'm using the 18V power supply is because it's what I had. I tried some other scrapped power cubes, but they don't have enough amperage. I'm too cheap to burn a bunch of D-cells in the R&D stage, and my 6V lead-acids have far too much amperage--probably about thirty amps, overheating even worse and arcing just as badly. Besides, that high draw is bad for the batteries.

The collet idea is a good one--I'll make that when I have extra time some day, since I've already welded a few alligator clips shut while messing around with arcs.

One thing I find interesting, since I've never before welded DC, is that when it's set up as an arc-lamp or arc-furnace, with two carbon electrodes, it's completely silent. I'm used to the sputtering and popping from my AC welder, and the silent, steady arc is a lot nicer. It can melt a few grams of solder from about a quarter inch away, but it's not terribly useful as an arc furnace. As a light, it might be, since it's bright enough to see easily through a #11 lens. As a soldering tool, it works well with practice and a sparing touch. The irritating thing to me is that the non-tinned graphite tip conducts heat poorly into the joint, requiring a bit of a knack to get a good bond.

Tim
02-16-2006, 01:28 AM
I recently was puttering around with my induction heater and discovered what a joy a 100VDC arc is. I was testing with a 50 ohm wirewound resistor and the connection came loose: after checking that I manged not to fry the circuit, I realized I was simply arcing with a resistive ballast. :)

Tim

einstein
06-02-2006, 04:57 AM
I thought those coldheat guns use an oscillator to drive a transformer- giving you say 10mV at like 20A, with the end result ending up sort of like an induction furnace or arc welder with a resistor between the electrodes.

at least the oscillator drive wouldn't kill batteries overly fast- with the volage across the tip is so low, that the total wattage is low, making the batteries not die instantly.

20920474
07-11-2006, 01:31 AM
ya, I got one of those cold heat things for my B-day, what a piece of shit!! you have to buy solder that is so thin that you have a hard time seeing it! :P
Basiclly the manufacturer of the cold heat thing is going way overkill o safety, I guess they think were are going to give a iron for some little kid to play with!

einstein
07-15-2006, 04:28 AM
yeah, the coldheat irons are worthless. I'd take my 15watt pencil for PCB work, and my 100 watt gun for heavy wiring.

as for mapp gas torches, I use them at work to solder plumbing. the gas cylendars give 1-2 hours run time in most torches (mapp/air), and are running around $7 at the local hardware store. the company I'm with buys them in bulk for closer to $4/tank.

I'd only use a mapp/oxy if you need heat close to oxyactelyne in a small package. the oxygen tanks on one of my coworker's mapp/oxy that he uses to braze refrigerant lines on air conditioners only give ~20 minutes runtime, and cost a good $10/bottle. for the cost, it'd be cheaper with an Oxyacetalyne torch.

Belmakar
07-22-2006, 01:19 AM
Do the MAPP cylinders last longer than propane assuming the same rate of consumption? I probably won't buy the torch any time soon, but I've had my eye on it for a while.




Yes. they burn about 200 C hotter and so you use less to do more. as well you can use MAPP in many propane torches in place of propane for a almost brazing hot flame. in fact have used MAPP gas in a plumbing torch to braze.


in terms of the volume of gas in the cylinder the MAPP is denser and lasts a little longer then the propane in terms of the volume ex-pendant as opposed to work done. so the answer is really it depends on what you are using it for. it wont last shorter then the propane in any case.