Originally Posted by MARTINSR
The cool thing is they aren't "proud". It doesn't pile up like the MIG. And yes even then, it grinds very easy, NOTHING like a MIG weld.
I agree with Brian on this one O/A welds grind very easily compared to a MIG. Also, a MIG will supply filler material whether or not you want it. You end up with much more build up to deal with. With O/A you only add filler material if/or when you need it. As Brian is teaching, the better you get the less filler rod you need and if you get to the point where you can fusion weld there is no build up.
The biggest challenge for me with fusion welding is you must have a perfect fit between the panels. As you heat the metal to fusing temperature the heated metal has no where to go as it expands so the molecules are compressed together. Once the metal is heated to the point that they melt together (fuse) and the panel begins to cool those panels contract and the piece shrinks. If this shrinkage is not controlled by planishing two things will happen.
First, the weld will try to contract and will suck the welded area in causing some ugly distortion.
Secondly as the already closely fitted panels are pulled together the areas that are not yet welded will be pulled into an overlapping position that is extremely hard to deal with.
I am not negative when it comes to O/A welding. I am, however, pointing out that O/A welding requires a good deal of skill, lots of practice and a good understanding of what the metal is doing and why. Planishing and working the metal as you weld is just as much a part of this skill as the use of the torch itself.
I have really enjoyed watching Brian working his roof. It brings back a lot of good memories as well as some good tips and tricks he is discovering. I am not, however interested in selling my MIG. I do not want to fire up my torch to weld this 46" door skin with limited access to the back side.
Originally Posted by 496CHEVY3100
Well my day has not ben to good ,I need to take the VW bug off the rack so I started putting air in one of the tires,my compressor cam on and Blew UP,
i mean rods in floor,then I backed the trailor in shop ,,no i didn't hit wall ,but when I started to raise the bed a seal blew in the hydraulic cylinder that tilts the bed ,so I still didn't get the car moved so I can get my 55 Chevy in the shop,
I guess the HF or HD Santa will have to drop by.
Wow! Not good. Hope Santa gets you what you need. Don't let that Chevy get wet.