http://tinyurl.com/5ux3kl
http://tinyurl.com/5wg4e8

can anyone tell me where to find valves like the ones on these?

I'm interested in DIYing a soldering torch similar to these. In the jewelry class I took in high school they had torches that were almost exactly like the one in the first link, and those valves took over 2 full turns of the knob to go from off to full-on, with no irregular jumps like on cheapo home depot needle valves.

They would probably need to be NPT threads for this. The ones in the links are obviously custom made because they're built into the torch handle/body, and I havn't found any other than that. It would also be best if the adjustment is by an actual knob, not a T-handle or something like a lot of valves seem to have.

The rest of the body I think could be built with modified plumbing fittings. I don't know what the inside of that Little Torch looks like, but at the end of the line, the fuel and air/oxygen come out together through the little hole at the end of the tip, so I think the key is just getting them thoroughly mixed before getting there. I think this could be done by having gas and air come out through lots of little holes after the valve into a common mixing chamber, which would then go to the burning tip. It won't be small and perfectly ergonamic, but that's what your paying for by buying their product.


What do you guys think? Mostly I just need help finding some possible valves to use and how much I can expect to spend for good ones.

Thanks for any help
-Jon

*cringes*

No, the gasses do NOT mix before they come out at the tip! That would rapidly melt your torch, and probably cause an explosion.

Look at images of gas welding torches. They are exactly the same thing, but bigger. Also, welding torches might be a good source for those valves.

alright well it is very feasible that im wrong on that one... I don't know much about them which is why i asked before trying to throw such a thing together. how exactly do they work inside then? i just can't see any way that they could be kept separate and then precisely mixed AT the tip. i have looked at quite a few pictures, such as this one...
http://tinyurl.com/67nxsf
... and some of those tips appear, atleast to me, to be insanely thin... like 20 ga. hypodermic needle thin. i just can't see any possible way that fuel/air mixing goes on after the tip instead of before.

http://tinyurl.com/67cwsq
found that site in the middle of writing my reply... i have no way to back up its credability, and im not even entirely sure im understanding the diagrams correctly, but if i am then they fully back up my assumption of mixing before the tip.

o and btw, my goal here is to obtain the needed valves to build a product (the soldering torch), not buy a more expensive product (a welding torch) to take the parts off of in order to build the desired product. I could buy a hell of a soldering torch ready-to-use for the money i'd spend buying a welding torch to take apart in an attempt to remove the valves and install them in a nigger-rigged torch made from plumbing fittings.

a friend of mine's dad owns a "Piping Alloys" warehouse that stocks tons of different stainless parts.. everything from stuff you'd find in the hardware store to parts used in plumbing sterile medical equipment, and I'd think a suitable valve exists somewhere in that spectrum so im gonna check it out. If I find something that works it'll be great because he'd give it to me at their wholesale cost, so i'll see what I find.

Have you tried looking on McMaster-Carr (http://www.mcmaster.com/)?

What kind of stuff are you going to be using it to solder? & what kind of fuel are you going to be using? I remember reading once that jewelry-smiths(?) use H2 torches, is this true or do they use a variety of different fuels?

& incase you're not aware, you don't need to use tinyurl anymore b/c the new bbs can handle long urls, see (http://images.google.com/imgres?imgurl=http://sweethaven02.com/ConstructTech/Welding01/fig0503.gif&imgrefurl=http://www.sweethaven.com/sweethaven/BldgConst/Welding/lessonmain.asp%3FlesNum%3D5%26modNum%3D1&usg=__X72MC4fucobwrgfQmludG4h1_Hk=&h=300&w=458&sz=18&hl=en&start=16&tbnid=yzqg71jCi4W5kM:&tbnh=84&tbnw=128&prev=/images%3Fq%3Dwelding%2Btorch%2Btip%26gbv%3D2%26hl% 3Den)

Check a hobby shop. You might be able to use parts from model airplane engines.

http://sweethaven02.com/ConstructTech/Welding01/fig0503.gif

That is a good illustration of what's going on. I stand (somewhat) corrected. The gasses still don't mix until the thin nozzle area, and thinking back on what I wrote (at 2 am last night, no less), it is the pressure of the gas flow that keeps the flame from coming back into the handle.

I'm pretty sure there are also flashback arresters somewhere along the line. Like I said, the gas welding stuff is identical to a jewelry torch, just bigger.

And, by the way, how hot do you need it? If you are just soldering, you don't even need oxygen. Plumber's torches just use propane, no oxygen tank. A propane flame can get reasonably hot.

emag, what's the html for doing links like that? like if I want to embed this link,
https://www.aalborg.com/images/products_overview/VT-PTFE%20METERING%20VALVE.jpg
and have it read "PTFE precision needle valve" in the post, how would I code that?


I'm planning on using it mostly for soldering silver and brass plate, band, wire, etc... jewelry type stuff.

I guess I'd like to be able to get a large 3000+ degree F flame. I have no intention of using oxygen with any fuel; DIYing a torch has enough risk... getting pure oxygen in the game would be asking to blow my head off.

Some jewelry torches use H2, but the ones we had in class used natural gas and compressed air. If my house had an exposed natural gas pipe in the garage I would hook into it with a Tee to use it, but that's not the case so propane it is. I'm planning to use a 20 lb BBQ grill tank and compressed air.

Sentinal that's what I was thinking, about the pressure of the gas keeping the burn from crawling back into the body of the torch. I agree flash arrestors are probably in-line. If I was trying to do this with oxy/acetylene (outa the question), they'd be a must. I think it MIGHT be ok to do propane/compressed air without them, but i'll probably try and integrate a simple one in.


McMaster-Carr has a sweet variety of valves that look like good options for what I'd need, but am I reading the prices correctly? the cheapest "flow control needle valve w/knurled knob" (what I need) I can find is $21... Brass body with 1/8" NPT, Cv factor of 0.25, pressure rated to 2000 PSI. This is overkill, to say the least.

I'll look around at model plane engine parts... a google image search of "precision needle valve" turns up quite a few images of model plane engines, so it sounds like a good possibility.

any other possible items that i could salvage or get for cheap on ebay etc that would have valves like this?

Carburetors have them, but I'm not sure how precise they are, or whether they are easily adapted for using with tubing.

EDIT: If you had access to a lathe...you could make one.

Carburetors have them, but I'm not sure how precise they are, or whether they are easily adapted for using with tubing.

EDIT: If you had access to a lathe...you could make one.

yaa i've had lots of little needs for unusual parts/items lately continuously nagging me for some time to buy one... if you read my post about them, i have a delta midi-lathe that i got as a gift 1 or 2 years ago, and in hind-sight i could kick myself for not asking for a metal one instead.

question... would there be any problem with using a torch made for oxy/acetylene with propane/compressed air? or if that isn't acceptable what about MAPP/compressed air? i found this listing for replacement hoses for oxy/acet torches,
http://tinyurl.com/6oebf9
and there's a note saying that you cannot use it with propane. is there any reason concerning the rest of the components that would not allow me to use it (as long as i used different hoses)?

I'm asking because I'd be more ok with buying a torch that can do both, because I could use it as a good piece of equipment with propane/compressed air or MAPP/compressed air, and then when I had the money I would buy the cylinders to have the full spectrum of welding/brazing/soldering available.

I found some needle valves from RC plane engines, but can't find enough info on their pressure/chemical/heat tolerance to feel good about buying them to DIY something like this. and if the brass/SS ones are 20-30 bucks a piece, i might as well just buy a setup professionally put together

input?

from: http://www.artmetal.com/blog/rob_sigafoos/2008/05/mapp_gas_acetylene_propylene_propane

Thanks for the comments, folks. Here is what I know (per my gas distributor and the Victor welding pamphlet) about MAPP vs. acetylene vs. other gasses. Acetylene seems to be unique in the hoses, torches, fittings, regulators, etc. required. My understanding is that MAPP, propylene, propane, and natural gas can all use the same fittings, acetylene uses different hoses, torches, fittings and regulators.
I switched to MAPP from acetylene since I use a rosebud quite a bit and don't want to worry about rate of depletion of the tank, manifolding tanks together, and the general hazard of acetylene.
Rich and Jaybird- I would love to go to propane from my 1000 gal tank I use for my forge, but I don't have a clue as to how to hook it up. I have 20 pounds coming into my shop. I guess I would have to get a larger regulator and bump up the pressure a bit? Otherwise, can I just tap into the line directly, or do I have to jump through other hoops?
-Rob
As for the needle valves, I'll give you a couple of hints:
*the gas flow will keep almost all of the torch cool. You could touch everything but the nozzle with your bare hands.
*No gas that you'll be working with will significantly corrode plastic or metal valves (hydrogen might make some metals brittle, but that's it).
*The pressures you will be working with are probably okay. The fuel gas will always be very low (even gas-cutting plate steel only calls for 7 psi of acetylene), and the oxygen will be maybe a dozen or so psi MAX for jewelry work.

can anyone estimage the cost of filling a 40 CF oxygen bottle and 10 CF acetylene bottle at a gas supply center?

i'm starting to consider just up and buying a full welding/cutting combination outfit. I'd buy my own tanks, not lease them, because I wouldn't use it enough in a short span of time for leasing to be economical (and I cant stand "paying rent" on things).

anyone know?

emag, what's the html for doing links like that? like if I want to embed this link,
https://www.aalborg.com/images/products_overview/VT-PTFE%20METERING%20VALVE.jpg
and have it read "PTFE precision needle valve" in the post, how would I code that?
For links, you highlight the text you want to embed the link in and then click this button (http://i35.tinypic.com/231vzt.png) and then paste the link into the popup window (http://i34.tinypic.com/w0s18i.png).

Or you could just type it in as this (http://i34.tinypic.com/2mhs8pk.png)

Thanks a lot emag, I hadn't even realized that you could change the message editor to include all these nifty functions :) I thought everyone just knew the formatting for smilies and embedding links and stuff :rolleyes: I'm sure plenty of regulars here do, but I've never been great with computer code so this is handy :D

can anyone understand these price rates (https://weldingsupply.securesites.com/cgi-bin/einstein.pl?Next::1:UNDEF:OR:terms::PH)

i guess its for refills/tank swaps, but the prices make no sense with the volumes. look at the rates for acetylene

i dont get it

thanks again emag

^$$$$ xyz/CF = cost per xyz cubic feet of said gas(ie. $20 5/cf would be $20 for 5 cubic feet of said gas)

i really don't think that can be. if that's the case, acetylene would be $22 for 10CF, $13 for 40CF, $18 for 80CF, $49 for 145CF, and $51 for 397CF. So between a 10CF and an 80CF bottle, you would be paying $4 less for 8 times as much acetylene.


Whatever the case on all that, over the last few weeks I've scrounged up all the parts of a light/medium duty oxygas welding/cutting outfit for very cheap, so I'm pretty excited and no longer need to try and build one myself :).

I bought both bottles in 40CF on ebay. The acetylene was $80 and the oxygen was $90. I'm going to get them filled hopefully the day after Christmas, as they ship empty (obvious to some folks here but probably not all, cause knowing the USPS one would probly get ruptured and blow up a post office). I've only gotten a quote from a company called Praxair so far on filling cost, and they want $43 for acet. and $26 for the oxygen. I'm going to call a few others and see if that's as good as I'll get, but either way it'll probably take me atleast a year to go through the oxygen, and atleast 2 yrs to go through the acetylene.

If you buy tanks like I did isntead of leasing them, you're almost guarenteed to not have to directly pay to get them pressure tested again when the previous one is expired. Basically every gas supply place takes ur empty tanks and gives you full ones, which sucks cause you are giving away ur nice freshly painted tanks, but apparently it's just how it is. In x-change, by law they are not allowed to swap you full tanks that are due for pressure testing... they gotta be current. so when they bring out ur full tank, check the date and if you think you might not use it up before the expiration date, ask em for a more current one.



QUESTION:

how much pressure is gas-line teflon tape OK for? on the roll it says something like
use for pipes carrying propane, butane, kerosene, naphtha, etc etc, natural gas (pressure not exceeding 100 PSIG)
and I don't know if this means only that pressure for natural gas, or for anything... acetylene in this case. read below for why I'm wondering.

.....The oxygen regulators for these seem to be pretty universal in how they hook to the tank, using a "CGA-540" valve. Acetylene ones though have CGA 200, 300, 510, 520, and maybe even one or two more. My regulator was a cga-200, which is for the smallest tank you can get (10CF), and the 40CF tank i bought needed a cga-520. I knew this was the case and just didnt want to deal with having such a tiny tank and refilling it so often. They sell adaptors to make it fit, but they are expensive and not a good long term soln and they make ur regulator stick way out from the tank stem. So I adapted it by just getting the inlet nipple and stem for the cga-520 part, which is supposed to thread into the regulator body with 1/4" NPT, but my regulator body accepts some kinda weird UNF thread (you can get a visual of these in this link (http://www.westernenterprises.com/enterprises/cga_fittings.php)). So I had to cut off my cga-200 attachment, cut 1/4" NPT threads on the end of it, and then attach that to the cga-520 nipple with a 1/4" NPT coupler. I used the yellow teflon tape in there because the threads I cut were not perfect, so I didn't fully trust their ability to seal like brass is supposed to. pain in the ass and it looks kinda bust, but its way sturdier than using an adaptor would be. I'll post pics when its set up tanks full etc

I've read plenty about how doing this on the oxygen line is very bad and dangerous, and I would definately agree with that and have no intention of fucking with that at all. But I can't find much at all about doing it on the acetylene. If this proves to be bad/dangerous (i will figure out if it is with the utmost caution), I can redo it, or just buy the correct regulator (i stole this one off the home depot floor model anyway lol :D )



thanks for the help along the way in this thread, and for any thoughts on this teflon tape thing.

I've read plenty about how doing this on the oxygen line is very bad and dangerous, What exactly are you talking about? Modifying the high pressure/tank side of the regulator? Why exactly do they say it's bad, what are the potential risks?


Where are you at now w/ all of this? Did you get your tanks filled? Are your camera's batteries charged? ;)