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I just got a Miller 252 with a spool gun.I am a total new-b, but I am want to learn so I can fabricate my own truck aluminum flatbed. I have some experience setting up production TIG (fusion) welding process. The perimeter frame is designed with 6x2x.25in Al tubing. I bought some extra material to practice on. I am first practicing on small pieces and then I will build a weld table out fo the same material for more practice before starting on the flatbed. Since I made a big investment in welder, I am trying to do it all myself. But if I run into trouble, my fall-back plan is to get the main frame tacked up and let someone with more experience make the critical welds.My first question: When I am welding aluminum rect or sqr tubing, should I stop at the corners or try to continue welding around them? I attached a pic of what I'm working with - comments/advice is appreciated.-Brentpicture is here www.pbase.com/bajaroad/image/92396143Last edited by bajaroad; 02-01-2008 at 05:50 PM.Reason: picture not showing up
Reply:Hey Brent,Aluminum is another world, but a great one once you get the feel of working with alum. and is quite fast-paced compared to steel. Your best results will be obtained if you are constantly aware that aluminum has to be virtually germ-free as far as cleanliness. You will get excellent welds with a good SS brush(toothbrush size) and acetone just prior to welding, keeping in mind that a well-ventilated work area and nitrile gloves will limit any physical affects of acetone or any other chemicals.I do a lot of 1.5" sq. tube at work and I like to do what I call the "corner wrap" by continuing the weld just around each corner. Once you get around the corner, stop. Wire brush the following area and start again on the next side. It takes a bit of practice, but once you get the feel of it, it is quite easy. I like to maintain an almost vertical gun position and just use a slight 10deg. tilt and, of course, the "push" technique. We use strictly .035 5356 at work with 100% AR at 20cfh. I maintain a 3/8" stickout and never over 1/2". Keep your nozzle & wire tip clean.I'm sure others will provide techniques they have success with and you can do an evaluation of each suggestion. The secret is to practice as much as possible...it will come... Good Luck..... DennyComplete Welding/Machine/Fab. ShopMobile UnitFinally retired*Moderator*"A man's word is his honor...without honor there is nothing.""Words are like bullets.... Once they leave your muzzle, you cannot get them back."
Reply:Thanks Denny. I will give that technique a try. Fogive my ignorance, but what exactly is the stickout - is that the distance from the tip to the material? And how far should the wire stick out when starting?Do you cut your wire tip before each start. I notice it starts hard if I don't.I don't think the Post Flow on the Miller is working. I adjusted it to over 1 sec to be sure, and nothing. The preflow works. Am I missing something?When I weld the frame I will have to weld some seams vertical up (or down) and some upsidedown welds - any advice there?-Brent
Reply:Hey Brent,Stickout is the length of wire protruding from the tip. Try to keep a minimum of 3/8" & a max. of 1/2" and be sure to cut the wire every time after stopping. That will insure a good start. I like to use a tip that is .005 oversize, ie., .035 wire/.040 tip.You don't need a post flow for AL. MIG. As to vertical welding, your best and sound welds will be vertical up. Takes practice. Upsidedown welds are gonna be a headache. You kinda have to do short "stitch" welds to maintain a decent bead, and, of course, cut the wire after each stop. Keep cleaning as you progress. Hope that helps a bit.... just ask anything from those here to help you understand technique and we'll get you thru it so you can make it a good resulting project.... DennyComplete Welding/Machine/Fab. ShopMobile UnitFinally retired*Moderator*"A man's word is his honor...without honor there is nothing.""Words are like bullets.... Once they leave your muzzle, you cannot get them back."
Reply:I sectioned the tube I welded together and then beat it with a hammer until the weld broke. Does this look normal? Attached Images
Reply:No the weld is all full of porosity. And stack your dimes closer together or strait bead it. --Gol'
Reply:See if you can adjust your heat and run a nice smooth steady bead. Looks like you got enough on there.If you look at the broken piece, you can see how much root penetration you got on one side and not the other. You can also see where you got into the base metal and where you didn't.Steady and consistent.....David Real world weldin. When I grow up I want to be a tig weldor.
Reply:Stack of dimes with MIG doesn't provide as good penetration as straight bead.
Reply:Originally Posted by Go1lumNo the weld is all full of porosity. And stack your dimes closer together or strait bead it.
Reply:Try putting the cables for the gun over your shoulder. That will help with them pulling on the gun.Me!
Reply:wire brush it, wipe with acetone. then weld..
Reply:Originally Posted by bajaroadWhat would cause the porosity thru the weld if it looks OK on the surface?I wish I could say I meant to make a stack of dimes - more like an unsteady hand. The spool gun is a bit of a load. I'll work on it this weekend.Thanks for the feedback - Brent
Reply:Originally Posted by bajaroadI just got a Miller 252 with a spool gun.I am a total new-b, but I am want to learn so I can fabricate my own truck aluminum flatbed. I have some experience setting up production TIG (fusion) welding process. The perimeter frame is designed with 6x2x.25in Al tubing. I bought some extra material to practice on. I am first practicing on small pieces and then I will build a weld table out fo the same material for more practice before starting on the flatbed. Since I made a big investment in welder, I am trying to do it all myself. But if I run into trouble, my fall-back plan is to get the main frame tacked up and let someone with more experience make the critical welds.My first question: When I am welding aluminum rect or sqr tubing, should I stop at the corners or try to continue welding around them? I attached a pic of what I'm working with - comments/advice is appreciated.-Brentpicture is here www.pbase.com/bajaroad/image/92396143
Reply:On the post-flow issue, if you have a Spoolmatic spool gun, the gas valve is in the gun, mechanically operated by the trigger. Once you let go of the trigger, the gas flow stops, regardless of how the machine is set. The pre-flow feature should work though, it works on mine.I don't cut the wire before starting the weld, no time for that in production. If you end the weld with the torch in the right position for normal stick-out, the wire will be the right length for the next weld. If you're pulling the torch off the weld as you're letting go of the trigger, your wire will be too long for the next weld. Use your run-in speed adjustment to control how the wire touches down. A 50% run-in speed setting works good for me.On an inside corner, I will weld a little bit onto the next surface. On an outside corner, I weld up to the end and stop. I don't think there's a right or wrong way to do it though, so do whatever you like best.Last edited by DesertRider33; 02-02-2008 at 02:04 AM.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op |
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