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  #1  
Old 09-19-2013, 12:08 PM
cederholm cederholm is offline
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Default Sheet metal welding - poping question

Hi all,

I'm new here and new to metal shaping. I'm trying to learn how to gas weld sheet metal and I'm making progress. One problem I have often is that as soon as the metal is getting close to making a puddle it "pops" sending sparks everywhere.

Any insight as to what I'm doing wrong?

Thank you,
Carl
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Old 09-19-2013, 01:31 PM
weldtoride weldtoride is offline
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Carl, welcome to the forum.

You are not alone in your experience, just about everyone has this problem when they start out.

We have a great search function here, and the "advanced search" works even better.

Here is an older thread on your problem, it was one of several that turned up with the search terms: sheet metal popping

http://allmetalshaping.com/showthrea...+metal+popping

This one turned up with search terms: torch popping

http://allmetalshaping.com/showthrea...=torch+popping

(O/A is short for OxyAcetylene)

Please don't misunderstand, by not directly answering your question I am not trying to be dismissive by any means. It's just that there are so many different conditions that cause torch popping, as you will read in the links above.

Hope this helps, and again, welcome.

Let us know what you discover, don't be afraid to ask more questions if the links don't help.
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Last edited by weldtoride; 09-19-2013 at 01:43 PM.
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Old 09-19-2013, 01:53 PM
cederholm cederholm is offline
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Mark, thank you for your input. I look forward to reading the threads you've posted.

~ Carl
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Old 09-19-2013, 02:43 PM
Ken Hosford Ken Hosford is offline
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Use a smaller tip with higher pressure , what is happening is the fuel is getting to ht inside the tip causing it to explode . I learned to gas weld at age 12? with a craftsmen torch with the smallest tip a #1 welding refrigerator,washer and dryer panels into 2 stroke expansion chambers . It was years later I learned about 0 and 00 tips I now have a Mico torch .
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Old 09-19-2013, 04:16 PM
David Gardiner David Gardiner is offline
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I take it as read that you are welding 19 or 20 gauge. You should only need about three pounds of pressure, you need the same pressure on both gauges to ensure you can get a neutral flame. I can't tell you the tip size because our sizes are different here in the UK. Set your flame in the following way and you will have a perfect flame every time.

Turn the acetylene on a little and light it, turn it up so that the smoke just disappears, introduced the oxygen slowly and turn it up slowly, watch the flame you will have a small cone near the tip and a feathery blue flame, keep increasing the oxygen until both flames are the same size and you will have a neutral flame which will be perfect for the tip you are using. If you find you are having to move along the weld joint very slowly increase your tip size, if you find you are blowing holes use a smaller tip.

Gas welding can give great results, I seldom use anything else.

This is a gas weld done by my employee James who I taught to weld...


I show some of this process in my youtube footage.
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Old 09-20-2013, 09:18 AM
cederholm cederholm is offline
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Ken, thank you for explaining what's happening. I find that knowing the cause can be as helpful as knowing the solution.

David, thank you for your input. Having read the links that Mark posted above I saw you gave the same set-up and adjustment information to someone else. At this stage of my learning I think it's the most valuable information I've read! I'm excited to put my newly found knowledge to use.

Thank you all,
Carl
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Old 09-20-2013, 11:23 AM
biffspagnuts biffspagnuts is offline
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Anytime you dip that inner cone into the weld puddle you are going to get that pop, so don't do that

Also not sure on your metal prep, torch set up, and so on but a few general tips for welding steel.

Grind down to bare metal with a sanding flap before welding. Any mill scale, rust, or galvanizing/paint is going to make problems.

Make sure you have enough pressure, too little pressure (or improper mixture) for the tip you are using can cause popping too.

I hold my torch like a pencil, and brace my forearm against something like the welding table for better control. Sometime wrapping the hose around my forearm to keep it out of the way

When I first started my flame was too cold, it was the right tip size and the flame mixture was right the pressure was a little low. This resulted in having to put the inner cone closer to keep the weld puddle liquid. And more importantly this also meant more accidentally dipping the cone into the puddle.

Good luck
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Old 09-20-2013, 03:54 PM
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Marty Comstock Marty Comstock is offline
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Too little VOLUME through a tip can cause popping. Not too little pressure. for the same volume, use a smaller tip, or open the valves some more. Keep the same pressure. Inside T joints are prone to this, changing angle and not staying in the corner so long helps. Sometimes, going with a bigger tip, more energy input gets you in and out faster, spending less time welding, meaning your tip is in the weld area not as long to get heated up.

Davids guide is spot on for adjusting your regulators to the tip. I use my largest tip, adjust neutral to it, and make volume adjustments as needed on my smaller tips.

I have welded rust to dirt and this technique always works for me.

Marty
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Old 09-21-2013, 06:13 AM
cederholm cederholm is offline
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I am so happy I found this forum, such great advice. Thanks all!

- Carl
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Old 09-23-2013, 03:03 PM
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G. Anderson G. Anderson is offline
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Default Popping

With a neutral flame the hottest portion (roughly 6400*F.) is 1/16" in FRONT of the neutral flame cone.
That (1/16" in front) is where you want to be with the weld puddle and filler rod.
Popping usually comes from not enough gas volume for the tip size and over heating of the welding tip.

Your Pal, Gary
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