<Posted from OT/YAK new member>

Hi, I’m a new member and I’m trying to teach myself oxy-acetylene welding. So stay at a safe distance. I apologize for a long-winded first entry. In my area the available instruction seems to be “welding schools” – both expensive and vastly beyond my goals of light, modest projects. I don’t want to weld professionally. I don’t have access to 220 volts. I’m trying to approach this methodically.

I bought several videos on welding, including one on safety procedures. I read everything I can find on welding I purchased a small portable welding kit (Victor Firepower), arranged a workspace and recently began “practicing”.

My practice setup: pieces of 1/8” thick ( some a little thinner) steel plate perhaps 1.5” by 3”. Oxy and Acet at 4 pounds working pressure. The set came with a #2 tip, and my initial trials were with that. I set acetylene flame to where smoke nearly disappears, then added oxy until acet flame just enters inner blue cone.

Just running beads I seem to be a little hot. Difficult to get a puddle that isn’t sparking too much (my assessment). Occaisional popping. I tried adjusting flame down initially but the torched warmed up a bit and I thought tip starvation might be occurring- my new policy is never adjust flame down, but move to a smaller tip.

Ok – bought a smaller tip. (#1). This took six weeks before the local welding store could get the right one for the Victor torch I have.

Yesterday I was practicing and after a torch pop there was a flame burning where the tip screws to the torch and also where the tip itself enters threaded fitting. A yellow, rich looking flame – my guess - but I’d say the fuel was leaking and not the oxy.

It went out immediately when I shut the torch valves, but it freaked me enough to shut down the system and end the session.

First I realize that the seal at the tip threads is NOT checked by typical leak tests (soapy water or pressure drop). Leaks cannot be found beyond the closed torch valves.

The word is never use a wrench on the tip or the o-rings may be damaged( I didn’t ) – but I can’t say for sure if it wasn’t tight enough or the wrong size.

Specific Questions:

How dangerous was this situation?

Does a fire in the tip damage the o-rings?

Is there a way to check for leaks at the tip/torch fitting?

I have flashback arrestors on the torch handle, but my thought is that any type of leak anywhere in the system is absolutely unacceptable!

I need to know if the tip or operator error was the cause for this problem.

General Questions: I would like to get to the point where I can practice in relative confidence that I’m not going to blow up the building.

AM I INSANE to do this? Thanks for any thoughts!

It's good you read over lots of information before starting up the system. But you pose good questions that are not usually answered in the literature.

You are correct to stop using the equipment until you are entirely sure what is happening and why. And how to fix it, and be confident with your setup.

Yes, Victor has O-rings on the part that threads onto the torch body. (Not all brands do)

Check them, but they should not have been damaged by the flame: you reacted quickly and they can take some heat/flame.

These two O-rings are two different sizes. Make sure you have an extra before trying to pull them off.

You should be able to visually inspect with good light and not have to take them off. It is cracks in older O-rings that we are usually looking for.

A good hand-tightening of that fitting to the torch body is all that is usually needed: the flats on the torch tip are so that you can unloosen them if hard to do later.

Notice that the torch body, torch tip end and the part of the torch tip that screws to the torch body are different colors.

The torch body is brass, as is the torch tip part that screws to it. The tip itself is copper, a deeper "gold" type color. This part screws directly into that brass part with no O-rings at all. This part (the copper tip) needs to be well-tightened into the brass tip part.

You CAN test for leaks this far down the system.

Use the same soapy water.

Open the oxygen at the torch valve.

With a gloved hand, put your finger over the torch tip.

Spray the soapy water and look for large bubble to form.

Really, when you are checking for leaks...it is obvious that it is not the little froth bubbles from mixed soap and water.

Just checking with the oxygen should be enough, since the oxygen and the fuel are mixed earlier in the torch. But you can check separately with the fuel for reassurance.

If a leak does show, you can gently use two wrenches to tighten the fitting. If it happens to be the one with the O-rings, do it gently. Shouldn't need more than hand tightening, firmly, on the one with the O-rings.

It is a good idea to do this type of leak testing on torch tip parts when assembling for oxyfuel cutting, too. 

Tip size to metal thickness
A #0 or #1 is what I use for ~1/8" thick.

Number 2 can be used, but as you noticed, it is gets the puddle quite hot and there are sparks.

The sparks mean you are rapidly oxidizing the metal. #2 is too much for the 1/8"

I'm sorry that it took so long for your supplier to get you a #1! Surprising too that your kit did not come with a range of tip sizes. Anyway, I would find a supplier that can service you better...or use a company over the net or phone. Next day.

Look under Groups on ArtMetal and there is a Welding group in which I just posted some reference material on oxy-fuel.

I'd be happy to talk you through it on the phone if you have any questions. It is easiest to do this with a experienced person at your side. I also have got a video tape of actual welding demo with torch, flame adjustment, filler rod, how and how not to...done during an actual technical class/ could send. Not commercial; it is real life one. Email me w/ contact info if you wish. Vrock@mhtc.net 

Success to you!

VRocK

I tested the number 1 tip as you suggested, and it definitely leaks at the nozzle/torch fitting. A simple and effective test, and I'm surprised I haven't seen it before- it worked great. Actually, unless I really hand tightened the fitting down hard, I could actually hear the leak when I covered the tip opening.

It is a brand new nozzle/tip and I haven't used a wrench on it (yet), I supposed there is a possibility it is somehow incompatible. The o-rings appear undamaged as far as I can see.

This nozzle/tip business is a bit hazy to me. I see tips being sold separately from nozzles for a few dollars but this tip/nozzle cost me around 60 dollars at my local welding supplier.

Can tips be freely used on other nozzle fittings? Could I transfer the number 1 tip to the nozzle that hasn't give me any trouble (currently with a number 2 tip) with leaks?

Well, glad that the problem was isolated that easily! Check over everything before using it even if it is new. Assemblers at the "factory" might not even know what they are handling!

Yes, those fittings at the torch handle can be used with different tip sizes (of the same brand, and these are Victor ones we are refering to here). I would dedicate this torch-to-tip fitting to one actual tip, though. These are brass fittings. And although the O-ring fitting is designed for frequent loosening/tightening, that copper tip to brass fitting is not.

Why the two pieces? Is because of the different materials used. Some brands have a one-piece that is all copper.

I found an online supplier and ordered a number 0 tip which arrived in three days and cost me half as much. I checked all three tips for leaks and the number one(the problem tip) leaked worse than ever – even when I applied a gentle wrenching.

I had second thoughts on swapping out the tips. The thing leaked brand new out of the box, so I took it back. I am curious what tool you would recommend for coaxing that soft looking copper tip out of the brass fitting.

My understanding is a leaky tip is prone to popping, and a popping, leaky tip is pretty much certain to start burning where it shouldn’t. It has the smell of inevitability. But know I know how to check the tip for leaks. Thanks Valerie!

More on copper. I have tip cleaners and the Victor chart. Is the cleaning a fairly delicate operation? Seems easy to grind that soft copper , slowly enlarging the tip opening. Are there ways to tell when a tip is worn out/ beyond repair? If bent can they be straightened?

Hey there! Here are some more postings to your questions: 

You can use an adjustable wrench to lightly tighten the brass part to the torch body if it is necessary. Most often, hand tightening that fitting is all that is needed.

You are talking of the copper tip to the brass fitting. Hand tighten. And then use a vise grip on the copper tip to hold it and to do the tightening. And gently hold the brass part with pliers. Vise grips would never be used on fittings designed to be used with wrenches. But this particular fitting does need a "nudge" to tighten it.

Tip cleaners: you should not need to use a tip cleaner yet. Not unless you submerge the tip in metal or get a speck of metal from a spark into the tip.

Choose a wire from the tip cleaning set and go straight in and straight out of the hole (orifice or tip opening). It should fit easily, don't force. I usually have the oxygen on slightly when I clean it so it blows any dislodged material out. No, you never see the stuff blown out.

Correct assumption: it you ream the cleaner in and out it will actually remove material and make the tip opening larger. It gets a tapered hole, larger at the open end. And that makes for more popping.

If the tip gets bent (dropping it), I consider it to be non-repairable.

If a tip keeps popping even though you have cleaned it and checked all the other things that may cause popping, then I consider it worn out. But you can enlarge the opening to a larger size...If you want.

If it is your own gear, it should last indefinitely.

In my shop, where there may be several classes of beginners in there per semester, there is more wear of course. And although students are shown and taught and supervised, the equipment experiences more wear.

When there is only one operator, (as with an automobile), and that operator is the owner, it lasts longer.

That said, our equipment rarely ever wears out becoming non repairable. Of 25 sets of regulators, we may have one regulator that needs replacement per year maximum. And that is because of the needle "creeping" slightly.

Never do we have to replace torch bodies. And only because we keep a good stockroom do I change tips out from a booth. A lot of popping, easier to replace tip than have student keep trying to clean one that has been used a lot. 

 Popping (backfire) and leaky tip do go together. But there are more things that cause the backfire.

P.S. I love the Capt Kirk snapshot!! VRock

I bought Victor’s little “Tote” portable gas welding kit to teach myself welding with, in part because it was marketed toward first time welders. I’m beginning to think the marketing dept at Victor should stay in closer touch with the technical dept.

After my brand new leak-free welding tip leaked (sort of like expecting bread to be fresh if the package has a “fresh” sticker on it ) I thought I’d better not leave much else to chance, so I started checking some other things.

First, the kit comes with a 10 cubic foot acetylene bottle with a #2 tip. The packaging claims you can weld up to 1/8” steel with this tip. What they don’t mention is you better not use that tip with supplied bottle or a flashback is quite likely.

The withdrawal limits using the 1/7 rule for a 10 CuFt bottle is 1.4 cubic feet per hour. The Victor chart for flow on a number two tip on 1/8” steel is between 5 and 10 cubic feet per hour! Even a size 0 tip exceeds the 1/7 rule slightly. I thought I might be missing something so I called Victor.

Turns out all my calculations were correct, the number 2 tip should only be used for extremely short bursts (the only tip supplied with the kit) , and a number 0 tip for only 10 minutes max. Or expect regulator damage and flashback (this is from the tech at Victor).

COOL! This is like a FLASHBACK KIT :)!

Can anyone recommend a minimum bottle capacity that I might be able to use and still transport fairly easily?

I'm wondering what's the best way to determine if a fuel or oxygen tank is too low to draw from. I understand it's best not to let bottles become entirely empty which may allow reverse flow of the opposite gas into the empty bottle. The number I've seen is 20 psi - don't let pressure drop below this. I've also seen that the only reliable way to judge the acetylene level is to weigh the bottle. I've also heard that this doesn't work with oxygen because it is lighter than air. Well, if it's lighter than air The bottle should actually become heavier with use!

My partner has a set of bottles I believe are 70 cubic footers, I will have to ask him tomorrow to be sure, that work nicely. We use them for spares because they are easily handled. On my truck I have a 120 for acetylene and a 140 for oxygen. In the shop I think it is a 300 for acetylene and a 240 for oxygen. All of these are coming off the top of my head so don't quote me.

As for when to change the bottles out. I normally run 40 psi oxygen to my torch and 10 psi acetylene. When acetylene gets low the torch will go out, but you can see the flame shrinking as well. I believe you aren't supposed to run an acetylene bottle below 50 psi or you start pulling the acetone. On oxygen I call it quits when the flame starts to feather and I have to readjust my torch. Keep in mind this is when cutting and when it gets low there is no point in trying to go on with it.