Back to Ganoksin | FAQ | Contact

Smiths little torch & oxygen concentrator

Thanks to everyone that responded so far. It is much appreciated.

Thank you Rob.

Thank you royjohn

Hi Rob and others who have been using oxygen concentrators,

Can your 5 LPM concentrators run a casting torch, like a Harris, for melting 4 to 6 oz. of sterling for centrifugal casting? Do they run constantly or do they have holding tanks? Do these machines have regulators or do you just plug in, switch on and solder away once the hose is primed with oxygen? Does it matter if you’re using a Smith mini torch, a Hoke or a Meco midget torch and does it matter what tips you’re using? Also, has anyone tried using a “Y” splitter and running two torches simultaneously?
Has anyone done platinum soldering with a 5 LPM concentrator and has anyone bought the #500140 EX-5 machine from Rio Grande? If yes, what is the warranty on the refurbished machine they sell? I understand that they don’t provide a manual. Maybe that’s to prevent the illegal resale of the machine as medical device.
Thanks for your help. Swapping oxygen tanks at the welding supply shop is becoming problematic since I don’t own a truck and they won’t permit transport of oxygen Y tanks in enclosed cars. Also, the delivery fees for exchanging tanks are outrageously expensive.

Lots of questions. I will tell you what I can and some of what I can’t do, for how do I know what I can’t do until I try it.

Gas: 1 lb propane camp stove cylinder. I buy them from Lowes, but have a couple that can be refilled. They all work the same.

O2: Currently from a 5 lpm O2 generator unit, but I have had the same experience from a 10 lpm unit.

Regulators: Non-adjustable on the propane cylinder only. The O2 generator can’t be regulated nor do I have any dea what the output pressure is, it just works.

Torch: Meco Midget and Little Torch on Y connections with a flashback arrestor on both the propane and O2 Y. I have never run both at the same time as I have no reason to.

Work: I regulary solder large 4 - 18 gauge pieces of silver, copper, brass and gold wire end to end, side to side and just about any other way that they can be soldered. I have not tried platinum.

Melting: I can easily melt 50 - 60 gram silver and gold melts to cast into ingots and probably any other shape that I wanted to cast. I can’t easily melt copper and brass. The extra 200 degrees is beyond this system.

Rio Machine: No idea, looks very expensive and you can put your own together easily. I originally looked into it and the shipping alone was awful. Warranties are probably more trouble than they are worth.

That’s about it. Most of what you have asked can be answered by a search of the archives, but here it is again. Good luck…Rob

I forgot to add:

Hose: Go to Tin Man Technologies for the lightest hose that you can find.

Tips: Go to Paige Tools for Meco, Liitle Torch and Hoke tips. They make a world of difference from the standard tips that you get with a torch.

God luck…Rob

I use a regulator on my 1 lb propane tank because that’s what I had from my prior setup (with an acetylene tank and an O2 tank) before switching to propane and concentrator oxygen. I checked a couple of sites and the DeVilbiss concentrator is 8.5 psi, while the Invacare is 5.5 psi. I think another one I read about a while ago was 15 psi. I think what matters most is the flow rate in this application. You can adjust that on the concentrator to match the pressure on your propane tank (if you have a regulator).

Take a look at the acetylene tips for your torch…they look the same as the Paige tips, and I am using some of them with propane on my Hoke, no problems. -royjohn


Please tell me more about the Paige tips? How does it make a difference? Thank you!

The tips that came with my Meco were standard single orfice and sometimes difficult to use tips. I did some research into tip design and ran across Paige Tools. This was a number of years ago. At the time they were developing a series of multi orfice tips specifically for propane that would fit the Meco torch that I had. I ordered them and they worked great. Paige has since developed tips for the Little Torch and Hoke torches, some of which are interchangable with Meco using an adapter. I had trouble with one tip that turned out to be the way that I was using, actually abusing, it. They sent me a new one for free. I haven’t visited their website lately to see what they are doing, but they will sometimes share on ganoksin, especially if someone asks the kind of question that you are asking. Please know that I am nothing more to them than a satisfied customer. I was also very unhappy with the standard welding shop hose set that came with my torch. It was very long and stiff. It drove the torch sometimes rather than my hand. Again, after a lot of research, I found the hose that I now have and purchased it from Tin Man Technologies. I am sure that others sell it or a similar hose. It is light, flexible and very easy to use. In the end, after buying a meco torch outfit that included the torch, tips, hoses, regulators, check valves and flashback arrestors, all I currently use are the torch body and flashback arrestors. Everything else sits in a box on a shelf in my shop having been either replaced or just not needed in my current torch setup. Down the road I would really like to try using NG. It requires that I either buy an entirely different torch that will work at street pressure or install a NG concentrator…Rob

Thank you for the additional information. I’ll take a look at the Paige tips.

Rob - a meco midget works just fine with street pressure natural gas. The hoke also works according to Emily Ruffin. I now have a concentrator so that i can run 2 torches for class. I used one at street pressure for at least 14 years. The only drawback is that you can’t make a flash back arrestor work at street pressure. and I agree with you about the Paige tips - a huge difference in usability. I’m also a fan of the lightweight hoses from tinmantech.
judy hoch

Judy…Thanks, I will give it a try. I have all the fittings, just need to do it…Rob

i have a question regardingthe non-gauge single stage regulator for 1lb disposable propane bottles.

i normally screw the top full open to use, and full closed to shut down

now…i am wondering…does the amount of turns on the regulator screw top affect the output pressure of the propane bottle…?

also, as the propane is used up, does the output pressure from the bottle…increase?

just curious…


Can you tell me more about the spark arrestor vs. regulator?

Julie…I am sorry, I didn’t see this. As far as I know, the valve is either on or off. The only thing that might happen, if you partially open the valve, is that the flow might change. The pressure regulation is fixed. Suppliers who follow this conversation might be able to give a better answer…Rob

They are different devices with two different purposes. The regulator regulates the pressure of a gas to a set point, the spark arrestor prevents a flame front from moving through it. Do some online research and you should be able to answer your questions in a lot more detail…Rob

An flame arrestor will close if an explosive pulse propagate through the line and thus stop a flame/explosion from going into the bottle.
It is either closed or open.

A regulator “just” regulates what pressure and or flow is going into the line from the source.
It may not stop an explosion/flame from entering the source.
Much more complicated than an arrestor.

Normal. Procedure is to open the combustible tank 1/2 to one turn.
Oxygen tanks should be opened completely.
The reasons are in the case of a hose leak that catches on fire you can rapidly close the valve on the tank feeding the flame.
The oxygen valve is made different in as much as it has 2 sealing surfaces so has to prevent leakage by the stem due to the much higher pressure. They are called back seating valves.


1 Like

I have a 5 liter per min and its plenty. I have 2 that I bought off of facbook classified for 200 dollars. I love them they are super easy to use and a lot better than running out of Oxy all the time with my old tanks.