TFS: Back Purging - How and Why
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- Опубликовано: 9 июн 2024
- Back purging is a process in welding where the back side or under side of a weld is shielded from the atmosphere during welding. In this episode, Justin the Fabricator will break it all down step by step and show you two different types of purging as well as a really cool metal explosion!
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In the last month I stumbled across your RUclips videos. A little background on me. I started welding in 1990 but in the old days if you didn’t go to tech or what some people say welding school employers wouldn’t even look at your application. So I did. Welded full time and went to school. In my welding career I have had the opportunity to do a lot of things. Full penetration welds that required ultrasound and x-ray inspection. I have done work for the gas and oil industry to welding stuff for drag specialties ( after market motorcycle parts) to working for featherlight trailers on their custom line, car haulers, NASCAR, even Horse trailers that cost more than a lot of houses. The point of this comment is your truly amazing and even as long as I have been welding I have learned from your videos and the new or young welders should watch you vids. If I didn’t live in Minnesota I would definitely take one off your classes for sure. Keep up the great work!!!
josh schow ,
Are you still welding? I’m an older guy and I’m interested in learning to weld. Do you have any suggestions on how to get started? School first or just try to learn on my own through trial and error? I don’t know anyone who welds so I’m on my own on this.
John Morales I am still welding. I put in about 60 hrs a week. Currently tig welding big stainless steel tanks. As far as learning to weld. School is the best start. Not sure if your looking to go in to the trade or weld stuff for yourself.
Settle down bro. Nobody cares.
One thing to keep in mind, is if you tack the tubing with sufficient heat to penetrate to the inside, you will contaminate the finished weld since no purging is available during assembly. On 316SS tubing (generally about 16ga.,) I would fusion weld a tack about the size of a pinhead, in about a dozen places....the more tacks the better...it keeps the tubing from creeping out of round during welding. Then, fusion weld (without rod) under 50% pulse after setting up the purge. Generally, rather than leave the exit hole for purging, I stick a small piece of steel wool in the exit hole to eliminate turbulence inside. Works beautifully, and you should see nothing but bright, shiny weld on the inside, with no spots where the tacks were. Heat shrinkage at the weld prevents suck back and provides a slightly raised weld inside and out. Takes a bit of practice, but makes pretty impressive,strong welds. Most of my work was in Lab equipment and prototype fabrication in Stainless and Titanium, where back purging was always an absolute MUST.
I build a lot of stainless headers and all of them are fusion welded. I was wondering why the welds do not become undercut when not using filler, thank you for explaining that. And yes, I always purge stainless. I start out at 10-20 CFH for a couple of minutes then drop it down to only 2-3 CFH when I start welding.
Once again .. I searched for am answer to a topic on which I was clueless and you answered it comprehensively beyond my expectation.
this early stuff is the reason i still love you dude.
dont change man.. great energy in your delivery brother.
I do pharmaceutical process piping and every single weld we do in a system is back purged. One tip for setting internal flow rate is to not go too high. You can create a ventrui effect and can actually suck in your weld causing concavity and in my field that means a failed weld due to cleanliness issues and is aesthetically not as pleasing if that matters. Also if you have a large OD tube and you're welding close to the inlet of your purge gas you can use an air tool exhaust muffler to break up the jet of purge gas and spread the flow out and push all the oxygen out.
Thank God, somebody knows what they're talking about. These YT stars are more like enthusiasts not truly experienced Welders/metal fabricator's. Sugaring or whatever else he calls it, is simply known as contamination. Shaking my head in disbelief 😂
Same here, in the company I was working before we were doing a lot of pharma and food-grade work and one way we sped up productivity was to fabricate out of stainless all the accessories we needed for every type of pipe and connection to the pieces we had to weld. Having a Purgeye oxygen sensor also helps a lot in bigger pipes. Usually, I start the back purge with loads of flow rate until the oxygen drops considerably and then I tone it down to avoid the root concavity as you said.
Key concepts for TIG, always nice to have a refresher from a reliable source.
I'm new to your channel and you do an amazing job of teaching this stuff. I've learned alot so far and i even find myself taking actual notes, not just viewing your videos. Thanks man, please keep the awsome videos coming!
Justin you make so much sense , a pleasure to watch and learn from you ! Many thanks
A really clear explanation with well prepared samples - great work and thanks.
i can't accept that he only has 53k subs ...is the public target for this subject of video too low? all his videos are 10/10 hes a awesome teacher and speaker, the video is greatly done , this is not some lame ass dude filming with shitty web cam in a dark room... this and the fab forums is my favorite channels and blv me i got around 600 channels subscriptions from news to games to cnc machinery etc.. please dont stop the doing these videos ever, there is nothing like this on the internet we need this knowledge.
you greatly inspired me to start to weld and become a welder for building rollcages and metal fabrication for automotive use... thats how i found your channel, this year im doing it thanks to you!
I appreciate your comment! The biggest reason for not having hundreds of thousands of views and subs is because the content is niche and the channel is not even 2 years old yet. It will continue to grow and as long as people are learning, I'll keep producing. Thanks for watching!
This was exactly the video I was looking for! Thanks for explaining everything! Subbed 😎👍🏼
I have never welded before and I saw some terms mentioned in a video and you covered everything here and what not to do as well. To be honest, I subbed just for the intro!
Great tip about the weep hole! Not only is it necessary when back purging but also when welding most any enclosed container. As you know, when you weld the air inside heats up causing it to expand. When this happens, as you get to the final sealing weld the pressure buildup from the heated air will do the same thing as in your video (maybe not as spectacularly though)
Thank you sir for this awesome series of fabrication tips
Just starting my own welding business and I’m knocking off the rust for tig. Great vid, I subbed, thanks I look forward to more content and lessons.
I gotta say, this is the first video purging was explained so well. Excellent idea to show everyone what happens when you do and do not weld correctly. I had a boss that would get mad and tell me that sugar forms because you're over heating the pipe and would say he's never purged a pipe in 15 years and has never had any problems with durability. (Lies). This video helped a lot, thanks!
Very good info, I've learned a lot. Thank you!
Thank you, I needed the refresher course.
I appreciate the effort you put into this video the solar flux is an interesting option for large parts where back gas dams are difficult to apply.
Thanks so much for the time you put into your videos, i hit the ground running when i started tig welding due to the knowledge i gained through your videos 👍
Awesome video! You’re very informative and anticipated the right questions! Great work! I’m subscribing.
Thank you so much!!! so many answered questions Your information is really gonna help with my stainless exhaust project... I respect the way you teach
amazing video, informative and straight to the point.
Great job. Learned a lot. Thanks
Just started doing welding for myself. This is one of many videos of yours. I have watched.
Thank you, very helpful
My bad hit the thumbs down that was not my intention. Thank you for the great video I learned a lot 👍
@Fabrication Series - I tried the Solar Flux & Heet, worked great. It immediately prevented oxidation on the inside of stainless tube. Very helpful, not something I would use for food or pharma components because it does leave a black enamel like coating, but good for just about everything else.
it seems right at home for automotive at least especially exhaust systems. but every other video I find they're still back purging lol
Thanks a million for such a great video !
Very precise valuable information
great video,...thanks from Portugal...
Awesome video very informative thank you learned alot
I do not do, nor intend to, do any automotive welding (especially at 71 yrs) - but I always learn something from every one of your videos! Techniques, procedures, task analysis and planning, reasons for doing something a certain way..... etc. Who knows, the wife may want me to weld up some stainless do-dad in the kitchen and I actually have a dual regulator on my argon tank.
Thanks for the professional videos :-)
Thanks for watching! Glad to know people are learning!
great explanation!
Hey bud! Your a very good teacher. Thank you for your time and effort. It counts. I've been watching welding and fab RUclips videos for years now. I sum what contribute my career in pipe welding, pressure vessels, and industrial boilers to Jody over at weldingtipsandtricks. But hands down your the best teacher out of all the RUclipsr welding and fab guys! Thanks man!
-Ben
Thanks, Ben. I actually don't do a lot of vids on welding because it's Jody's turf (so to speak haha). I'm not trying to step on toes. But they few that I have put out are a bit more specific about a topic that a lot of people write in and ask about. I'm sure I'll have more in the future and I'm glad people like them.
Thank you. Very nice quality tutorial
On SS tubing , lap joints and butt joints , I have experienced that it is much easier to weld/control the puddle when you BP ! (much easier and edges don't burn away!) It does make a difference, "sugaring" aside! Thank you for the vid Justin!!
Great Job, These videos Help a ton.
Very good video, thank you.
Happy new year from France my friend, great video as usual :-)
Happy New Year! Thanks for watching!
Great video, learnt lots and explained well 👍
Thanks for watching!
very well done! good theory, 👍
Great content very well edited
Great video
great info. thank you
Thanks for your knowledge 👍
great video. really professional, loved it
Thanks for watching!
Good video, nice presentation
Thanks for watching!
Great Video.
love your videos, a lot of what we learned here will reflect on our build on our channel!
Cool. Thanks for watching!
@@TheFabricatorSeries I'm going in for a stainless steel testg and an an aluminum test today at a company that maks custom gates and fences. I've never TIG welded aluminum or stainless but I have TIG welded mild steel in welding school. This was a great video to help m at least start my entry into TIG, which is where I want to specialize for the long run. THANK YOU FOR THIS VIDEO!
First great video about this problem i can say that.thanks
great vid thanks mate
dude, kick ass video, you explained that so great and kept my attention
Thank you.
very nice. finally someone explain to understand a person like me that no nothing! thank you. hugs from Mozambique
Thank you!
That solar flux is amazing.
hey dude you rock. cheerz from brazil
obrigado pela dica.. vlw mesmo parabéns pelo canal
there was an advertisement I had to listen to before I could watch your informative presentation and I thought I'd ask you about it. The topic was Lazar welding. So I thought I'd ask . Thanks
Am I the only one that saw the shark shadow at 7:47?! That’s awesome!
I use aluminum foil to wrap the pipe for back flow. Also in you don't have a dual reg. you can get a Y at the Welding house and small flow knob and use that. Really Nice Video on this. Must have taken a lot of editing.
Thanks! Your vieos are amazing! :)
Esta chingon este bato mis respetos
Thank you 🤙
great video very informative
Thanks for watching!
awsome video Thank you
Thanks for watching!
I welded low pressure SS pipe and plate with a flux cored wire process for years and one thing I really wish I tried while I was there was back purging the pipe. At my current job we're getting some of this wire per my suggestion and now I'll get to try it next time we need some SS welded.
Thanks dawg!
Thanks for the video, is it possible to use acetone to mix paste? I apologize for the automatic transfer.
Thanks!
what brand of purge plugs do you use @the fabrication series looking to buy some , and which do you prefer the silicone one or nylon ? thanks for the great video on back purging 💪
Excellent information as I have been wondering how to go about back purging. Still need to locate a dual flow regulator, as I don't have room for a second Argon tank.
Thanks!
Just do a quick online search but do avoid the cheap regulators that are around $100 or less. They aren't very good.
I was afraid of that. $100 being considered lower quality.
The problem is consistency. They will show something like 10 CFH, but the flow is either much less or much more that your argon goes away really fast. That's actually more expensive than buying a good regulator the first time.
Makes sense. Thx.b
Really good stuff. Thanks for the knowledge.
Thanks so much for sharing. I did some welding on stainless tubing today and it was awesome to see the inside weld.
Thanks again.
Hey can you come to Australia and teach here? You are the bomb man!
Cool video, nice presentation. Subscribed. :-)
We use to use 315/316 brushed or polished stainless steel plates/sheets, used for pharmaceutical/hospitality,
If we was welding two stainless steel plates/sheets, that was butted up side by side together,
We use to use a copper plate the length of the join, clamped to the back of where you was welding, which also protected air from getting into and around the back of the weld, giving you the same effect,
But we only did this for three reasons,
1 it would take a lot of pure Argon to fill a room,
2 by doing this would probably bankrupt your business,
3 you wouldn’t be able to go into an area that is full of Argon Gas, and if you tried it, you shouldn’t be welding, your weld might not need oxygen, but you do,
If it was a sealed tank or ventilation system, we would back purge it using the Argon Gas, making sure that the outlet is at the highest part of the vessel/tank, as Argon is heavy then air,
Using a lighter at the outlet port, if it’s a large vessel/tank etc. to check if there is Argon coming out, if the flame goes out, when you place it near the outlet, there’s only Argon gas inside it,
👍🏼
nice video man.
Thank you!
The huge rear green screen background footage format is next level compared to any white board... anywhere in 2021
Great video. thank you. I was going to start welding up my exhaust for my boat. it's a 5" stainless tube. and there will be saltwater in it. Would you back purge?
Maybe some notes on plugging irregular shaped parts for purging? Looking at doing a job that would involve that problem and I haven't dealt with any purging yet
Dude the technique required to not dip the tungsten when that blow out went down is masterful 👍
Thanks!
I was just explaining this to my nephew and why its so important to do when welding stainless steel
Very important step
This really is a wonderful video. Thanks for making these!
I wonder if there's any mileage in making a set of inlflatable toroidal balloon plugs? This may make them easier to push into/pull out of interior situations which are awkward and may reduce the amount of Ar required if they can be moved into closer proximities either side of a weld.
For the purging, it may help if one remembers that both Argon and Carbon Dioxide (if a mix is used) are heavier than 'air', so it may be a good idea to plan it so one is welding towards the bottom of the parts, rather than the top. May also help when planing how one is going to be introducing the purging gas.
Oh, standard treatment for methanol poisoning is ethanol - true! So, AFTER the use of the flux, and the welding, a beer can be medically recommended... ;-)
Now I see what took you so long, you put a huge amount of work into this video, and it's not filmed while doing a job for money. This was cool!
Anyone knows how the "back purging" called in russian, please?
Thank you! I
Hopefully someone will know the translation or term in Russian.
Just search for a bigger welding supply and go through their catalogue. In some place you will find purge hardware like plugs for pipe. Then just look how the called it ;)
just take some solar flux and pour in some vodka.
Excellent. Is there any issue if you get solar flux on the mating surfaces?
I was a pipe welder for the food industry and I can tell you that getting a correct purge weld is not as easy as it seems. It should be smooth and free of discoloration
Question. What would be the best way to get a smooth inner surface of the tube? Would I just grind it or is there an alternative method?
What about an exhaust for a Diesel engine? Would the ash and soot and diesel coat the weld enough o protect it from the elements that’ll corrode the weld?
Good info 😀
Thanks for watching!
Would you use solar flux on boost pipes and intakes. You mentioned it's glassy will any particles get carried into the motor. Do you rather recommend pushing?
nice vid
Thanks! I've been watching your work for years.
The Fabrication Series that's awesome...we will to do some kind of collab at some point.
That would be cool. I'm open to suggestions.
Justin. Great talent. Super quality on non standard jobs. One question or challenge. How do you or actually can you weld in an aluminium cylinder head port to add metal to the base of the port. . From the base of the valve to the intake gasket to reshape it into a D port? It is so small and you can't see what you are doing. Do you have a way of doing it?
Great info if your not sure can't find info on a metal grade run some test piece cut them and look at it
This might be a dumb question but if I were to weld two stainless tokens/plates together do I purge? And how do I go about it?
Would a stainless steel car exhaust need to be back purged? It’s not structural and I would be curious if the carbon from engine combustion would coat the inside of the weld and protect it after a short amount of run time?
Also is cleaning material before welding with brake cleaner instead of acetone acceptable? Being a mechanic I have tons of brake clean all the time but not a lot of acetone.
Good info and I nice Conan armbands
Hi,
Thanks for your video, it was very helpful, as I have not had a great deal of experience in Tig welding stainless steel tube etc.
I'm going to be back purging 75mm stainless steel tube on a job I will be doing in the next few days.
Just wondering if you would be able to assist me with a couple questions that I have. Much appreciated, and I sincerely appreciate your advice.
Just wondering what gas flow rate do you recommend for back purging over a approximate distance of 3 feet.
This weld piece has a number of outlets tacked in place and to be fully welded in position.
The thickness of the material is 2mm. What would be the ideal amperage settings for this weld procedure?
What about regular stainless exhaust? Do you back purge that? Or is that up to the customer? I've read about the Solar flux, do you present that as a option for the customer?
All good info, however I wish you would have touched more on your solar flux. Building non turbo headers, and can back purge, but if I can run solar flux on everything before tacking it all together, then I wont have to cut it all up to back purge.
What about nitrogen as purge? I’m an A/c tech and we purge the copper piping with nitrogen and it’s clean, it acts same way by removing atmosphere from inside.
Or is actual welding and stainless require argon?