Using Flux Core for floorpans?

[1973mach1]

What do you guys think about using Flux Core for floorpans? I just bought a Hobart 125 welder, it comes ready to do flux core so im hoping that will work OK for floor pans, but some people told me it burns through thin metal? I can get the gas hookup for 90 dollars from Sears and use solid wire and the bottle for probally another 100 but if flux core will work i'd rather put the money towards an air compressor. Do you guys think this was an OK choice welder for car work?

Thanks,
Jim

 

[RajunCajun]

Worked Fine for all my sheetmetal including full pans jus tmake sure you set it right and it will put down some very nice welds

 

[hdgapeach]

Get some scrap that is the same thickness as what you are intending to install in the car to practice on. This will let you get more confidence in your welding and give you good info as to what your heat range and wire speed should be. Have fun!

 

[1973mach1]

Thanks, What size flux core should I use for sheetmetal?

Thanks,
Jim

 

[1320stang]

Well, it should come with .035 flux core wire. That's what my Miller 130 came with. I use .023 solid wire with the gas for sheet metal. I agree, use some of the old pan or some similar sized scrap to practice on. And don't just practice right side up, clamp a couple pieces to a 2x4 that you run over a pair of jackstands and get on your creeper and practice welding it from below. Any shmoe can lay a good bead working from above in just a few minutes. Welding from other angles is a bit tougher and the practice will help you out.

There may be some better books out there, but I'd recommend getting HP books Welding book. You should be able to get it at Waldenbooks or Barnes & Noble for under $15.

 

[TurboDoctor]

Flux cored wire will work fine. The flux core is actually better for the beginer welder anyways. With the flux core you just need to make sure the welding surface is pretty clean, a good once over with a wire cup on a grinder is a good way to do that. You will proably be stiching in the panels so watching the puddles isnt that important in sheet metal work, but if you ever weld plate or something where you are really laying down a weld, with the flux core you have to watch your puddle carfully and make sure the flux is burining out to the top. If not you need to adjust speed and or your machine. Just something to keep in mind if you ever decide to do some fab work.

 

[1973mach1]

Thanks for the tip, I have some spare sheet metal to practice on. When welding in floor pans do I have to have a weld around the entire floorpan? Or do you just do a short weld every few inches?

Thanks,
Jim

 

[1320stang]

Well, one thing about stitch welding with flux core... Flux core is like arc welding, you'll need to clean the slag off the weld after you've made it if you are going to continue the weld, or else you'll contaminate the strength of the weld with slag inclusions. This is why I don't like using flux core on sheet metal, you stitch or spot weld, then you have to clean the spot you welded before you continue, which is a big pain if you are butt welding two pieces of sheet metal together using spot welds. You spend more time cleaning than you do welding, which I guess is good if you don't have a very long duty cycle.

 

[TurboDoctor]

Flux cored welding wire, and Welding electrodes use to different styles of flux. If you stitch weld your pans in using flux cored wired you dont need to stop and clean every time you pulse the trigger. The flux in the cored wire is just a small trace. If you are really laying down a bead on something thick, and stop and want to continue, You will need to clean the weld first. The more heat you apply in a specefic area will keep the flux pooling to the top of the weld and it will not burn away as fast. The flux in the wire makes such a small impact in the intergrity of the weld in a situtation like floor pans, it not really going to matter. But if it makes you feel better you can always just use a hand wire brush and once over the the weld. I have been a certified welder for over 3 years and have been welding for many more years before that. I do alot of stitch welding on hand rails and stair stringers and many other things with flux cored wire and I never clean the welds before laying down a weld on top of a weld or a second pass over , I have never had a Welding inspector Fail a weld on me yet. I always brush down the finish weld. Once you actually Start welding you will see that there is very little flux left on top of the weld after the fact. Not saying its not a good idea, or that you shouldnt, But I just dont see the need in it. Its all up to you though and how you feel about it really.

 

[1973mach1]

Flux cored welding wire, and Welding electrodes use to different styles of flux. If you stitch weld your pans in using flux cored wired you dont need to stop and clean every time you pulse the trigger. The flux in the cored wire is just a small trace. If you are really laying down a bead on something thick, and stop and want to continue, You will need to clean the weld first. The more heat you apply in a specefic area will keep the flux pooling to the top of the weld and it will not burn away as fast. The flux in the wire makes such a small impact in the intergrity of the weld in a situtation like floor pans, it not really going to matter. But if it makes you feel better you can always just use a hand wire brush and once over the the weld. I have been a certified welder for over 3 years and have been welding for many more years before that. I do alot of stitch welding on hand rails and stair stringers and many other things with flux cored wire and I never clean the welds before laying down a weld on top of a weld or a second pass over , I have never had a Welding inspector Fail a weld on me yet. I always brush down the finish weld. Once you actually Start welding you will see that there is very little flux left on top of the weld after the fact. Not saying its not a good idea, or that you shouldnt, But I just dont see the need in it. Its all up to you though and how you feel about it really.

Thanks for the reply, here's a stupid question, whats a stitch weld? Also what size flux would you recomend for floorpans? Hopefully my welder will be here this weekend and I can practice.

Thanks,
Jim

 

[TurboDoctor]

.035 is what I would use. You can get the flux core smaller, but you are most likely going to have to order it from a welding supply store, and its not cheap. When I say stich welding, im refering to just pulsing the trigger on the gun. Just one little tack at a time. You will need to lay in several "tacks" in one spot then move down a little and then back up or whatever. You have to move around when welding or the heat will try and warp your pans. You basically just "stich" it all together until you have one weld the length of the pan. You will get the hang off it fast and you will be able to work out a technique that works best for you. Its always different for everyone.