Question: plug welding mini tub

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Hey guys,     I've been using this forum for technique and guidance since I bought my little Lincoln Handy Mig, but I usually don't post anything. I'm starting on my mini tub project this weekend and was just practicing on some 22 gauge (since that's the thickness of my new tubs I'm plug welding in). I posted a picture below, and wanted some opinions if my settings look right for the plug weld (firs time doing it). Any insight and guidance is appreciated!-Ken
Reply:Looks pretty good according to this page:http://www.mig-welding.co.uk/plug-weld.htm
Reply:Side note: I drilled the holes out to 1/4" and settings on the welder were Low-1 and wire speed of 4.5
Reply:Originally Posted by dbotosLooks pretty good according to this page:http://www.mig-welding.co.uk/plug-weld.htm
Reply:Any other input?
Reply:Can you explain what a mini tub is? I've welded on tub grinders, and helped tub out a car for larger tires, but I'm not familiar with the term mini tub.
Reply:Originally Posted by FireForge1Can you explain what a mini tub is? I've welded on tub grinders, and helped tub out a car for larger tires, but I'm not familiar with the term mini tub.
Reply:biggest mistake a beginner makes when doing plug welds is making the hole too small, then when welding it up wind up just closing the hole on top of the bottom plate, but not really fully penetrating the bottom layer much, making a weld that looks fully closed but a weak weld. best way to test your own method is to put 2 pieces together like this: II and then do a few plug welds on one end, then pull them apart, like this: V and keep pulling until it rips apart. where it tears will show you how good your weld is. it should tear a circle around the outer edge of the plug weld and tear off on either one side or the other adjacent to the weld, but it should not separate as 2 intact panels at any of the welds. you have to make sure that your initial arc is on the rear plate and that it remains there long enough to get penetration before jumping to the second layer with the hole. also if your amperage is too low you are more likely to just weld a cap on the hole rather than a properly penetrated plug weld. I'd say in testing  you should keep cranking it up until you start to get burn through, then back it off one notch and go from there, not enough amperage will kill plug welds while they may look ok to you from the outside. you really need to be sure your fully melting the rear plate inside the hole. also you really want the whole hole to be fully flat against the rear plate, the welds are not so strong when there is any gap. the best way I have found to get full flat engagement where clamping is difficult is to do one tack weld on the edge of the hole, then, when you hammer/dolly the spot it will close flat and flush and stay that way so you can then fully weld it closed.Last edited by turbocad6; 06-14-2013 at 02:05 AM.miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:When I did my quarter panels I got some plug weld pliers. Could turn the amps up and not worry about burn through. You probably couldn't use them on all of the plugs on a mini tu, but might help here and there
Reply:Originally Posted by turbocad6biggest mistake a beginner makes when doing plug welds is making the hole too small, then when welding it up wind up just closing the hole on top of the bottom plate, but not really fully penetrating the bottom layer much, making a weld that looks fully closed but a weak weld. best way to test your own method is to put 2 pieces together like this: II and then do a few plug welds on one end, then pull them apart, like this: V and keep pulling until it rips apart. where it tears will show you how good your weld is. it should tear a circle around the outer edge of the plug weld and tear off on either one side or the other adjacent to the weld, but it should not separate as 2 intact panels at any of the welds. you have to make sure that your initial arc is on the rear plate and that it remains there long enough to get penetration before jumping to the second layer with the hole. also if your amperage is too low you are more likely to just weld a cap on the hole rather than a properly penetrated plug weld. I'd say in testing  you should keep cranking it up until you start to get burn through, then back it off one notch and go from there, not enough amperage will kill plug welds while they may look ok to you from the outside. you really need to be sure your fully melting the rear plate inside the hole. also you really want the whole hole to be fully flat against the rear plate, the welds are not so strong when there is any gap. the best way I have found to get full flat engagement where clamping is difficult is to do one tack weld on the edge of the hole, then, when you hammer/dolly the spot it will close flat and flush and stay that way so you can then fully weld it closed.
Reply:test worked pretty well, I think Im getting plenty of penetration. The only thing I notice is that my welds have really big mounds built up, and I read they should be semi-flush. What could be causing that?
Reply:not enough heat, turn it up till you're just about  burning through, then back off just enough to not burn through... lots of times I run it too hot, enough that it would burn through, but then I just weld half of the plug, pause, then finish, either that or pulse it a bit, you want to be on the verge of burning through but just before actually burning through or you're going to have to do a lot of grinding and risk not getting full pen on each plug. when it's hot enough the weld can be totally flush and still have great fusion. if you have really good control you can actually plug weld with no holes even, just melt through the top layer enough to weld the 2 together but this takes a lot of control and experience and isn't foolproofLast edited by turbocad6; 06-18-2013 at 05:06 PM.miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:Originally Posted by FireForge1Can you explain what a mini tub is? I've welded on tub grinders, and helped tub out a car for larger tires, but I'm not familiar with the term mini tub.
Reply:OK Ill crank up the heat a bit and see what happens on some scrap.New question:  There is an area I have to weld that I cannot get my W clamp on, so what's the best way to clamp the two pieces together for the plug weld? The are has no exposed edges for me to get a clamp over, so Im not sure the best way to go about this. Thanks for the help!
Reply:Here's the area in yellowLast edited by schmen; 06-19-2013 at 07:38 AM.
Reply:you could use some cleco fasteners, or even a few screws temporarily... this is also a good spot to just push one spot down/up with a screwdriver and tack it, then after it's tacked hammer/dolly it flatter to weld. when using clecos or screws it may help to then use a backing to then fill these holes, a piece of flattened copper tubing can help there if you don't have anything else but most welding shops have a heaviercopper backing thing with a handle that can help fill holes without continuing to just spread the hole. we usually use screws to assemble but cleco's are cleaner and easier to re-position stuff if you wanted to pick some up, would def help with something like this although plain old self tappers will also work. the copper backing isn't 100% necissary but would make your life much easier as a novice, either that or pulse, pulse pulse, etc...Last edited by turbocad6; 06-19-2013 at 01:23 PM.miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:I use a few pieces of copper. I have a 15 pound slab thats 1 inch thick, and a few smaller ones. Even a screw driver I built up with silicon bronze to push the edges of metal together with. Copper makes weeks like this extremely easy. Turn your machine up as high as it goes, and still wont burn through with a copper backer. Just make sure to cool the copper off in water every few times.Sent from my Galaxy Nexus using Tapatalk 2Miller: 200dx, Bobcat 225, Passport, Powermax 45, Milwaukee: Dry Saw, MagDrill, grinders
Reply:I used all C-clamps everywhere when doing any sheet metal work.
Reply:Originally Posted by turbocad6you could use some cleco fasteners, or even a few screws temporarily... this is also a good spot to just push one spot down/up with a screwdriver and tack it, then after it's tacked hammer/dolly it flatter to weld. when using clecos or screws it may help to then use a backing to then fill these holes, a piece of flattened copper tubing can help there if you don't have anything else but most welding shops have a heaviercopper backing thing with a handle that can help fill holes without continuing to just spread the hole. we usually use screws to assemble but cleco's are cleaner and easier to re-position stuff if you wanted to pick some up, would def help with something like this although plain old self tappers will also work. the copper backing isn't 100% necissary but would make your life much easier as a novice, either that or pulse, pulse pulse, etc...
Reply:Originally Posted by VPTI used all C-clamps everywhere when doing any sheet metal work.
Reply:Ran into a snag tonight, took off my copper nozzle to clean the slag off the inside of it and when i tightened it back on i tightened too far. Now i cant get it off. As I turn it to the left to try to get it off I can feel that I'm spinning more than just the nozzle. Any suggestions?
Reply:If your Handy Mig has a Magnum 100 gun you are unthreading the diffuser from the gooseneck.There are two flats on the back end of the diffuser that may allow you to grip it to get the nozzle off once the diffuser is out of the gooseneck.
Reply:I cranked up the heat and I THINK I got good results. I can see better penetration on the back of the weld, but maybe you guys can tell me if its too hot or not hot enough?
Reply:The plug welds look good from here.For a bit more info on CLECOs check out this old thread.http://weldingweb.com/vbb/showthread.php...ighlight=CLECORogerOld, Tired, and GRUMPYSalesman will call, Batteries not included, Assembly is required, and FREE ADVICE IS WORTH EXACTLY WHAT YOU PAY FOR IT!Dial Arc 250HFThunderbolt 225 AC/DCAssorted A/O torches
Reply:ideally it should look about the same front and back or close to it, and neither should be very high at all, and there should be no voids or gaps. a really good weld is just about flush front and rear or close to flush, yet fully welded too. one way I get nice flush welds is to spiral out from the center, but hot and fast, start dead center at trigger, and then quickly spiral in the circle from the center out but don't hit the inner edge of the hole till around the third or forth swirl, and then have this swirl trace the outline of the hole at it's edge. time it right and you can get nice flush welds, but you're better off with a bit high welds that are really penetrated than you are with flush welds that are not fully penetrated, so it's safer to error towards too much deposit vs not enough fusion. each weld by itself is a very small weld but it still takes a lot of practice to get nice flat fully penetrated and filled spot welds consistently, and some areas may need more or less heat than others too depending on what's going together and where the joint is, and if a spot doesn't seem like it really got fully "in there" then no reason you couldn't just grind it down a bit, crank up the heat and burn a plug cap right over itLast edited by turbocad6; 06-25-2013 at 01:41 AM.miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....