Cleaning the slag from a previous weld should be pretty easy using a welding hammer and a wire brush. My experience welding was working as a steamfitter/rigger for about a year on a powerhouse job along the Hudson River (Roseton, NY)in the early 70s. Also took a course at a tech school. I do ok with a stick machine for thicker material, but resort to brazing (or silver-solder) with a "B" tank and acetylene for the thinner stuff. Less burn-through because of lower temps, neater joints, and just as strong if you use the correct rod. Some alloys even wick nicely into tight joints. I got my gear and materials cheap or free from my brother, who was selling high-tech welding supplies at the time.
Greg -----Original Message----- From: Mercedes [mailto:mercedes-boun...@okiebenz.com] On Behalf Of clay via Mercedes Sent: Sunday, June 14, 2015 1:20 PM To: Mercedes Discussion List Cc: clay Subject: [MBZ] Wut I dun Lernt frum Wulding this week It has been a week of dragging my butt outside in the heat and playing with the flux core welding gun. In that time I have gained some perspective on just how much work making a decent weld is. At first I was just banging about with the gun and burning through wire and sheet metal. It was really nasty, but I got a feel for the machine and the gun. Having the old brake rotor to play with allowed me to get comfortable that I could lay down a good bead, but it seemed only on a heavy bit of iron, not something thin, like what I need to know so I can repair the rusted and rotted out floors in the 300D. SO, zapping thick metal is eazy peezy and most any monkey can do that. I also found that flux core is not good to try to start and stop. It took me a bit to understand that the slag and cruft impedes a good weld, so you need to clean the prior muck before you go at it again. Getting it back to bare metal would let the new bead adhere and flow instead of spattering out pellet of micro death all over the world. Flux is great for outdoor work, which the car repair will be. No need to worry the wind is blowing my shielding gas away and the air flow also will make the toxic fumes move away from the work. That is a plus. The HF welding toy is very basic and binary. You have either BIG amp or small amp button and a spastic wire feed control. The little graphic under the hood tells you if you need BIG or small and what wire speed for what thickness of metal. It lies and is very optimistic when dealing with thin sheet metal. At least if you expect to be laying down a continuous bead. I could not keep from blowing through the metal and having bad welds at the 0.5 wire speed (0-9 range) the graphic depicts. I up the speed and it still blows out, but at least the wire feeds. The slow speed would not put out wire dependably. The solution to that was to not try to make a bead, but to just put a bunch or tacks all over the piece and then go back and put some more next to the last ones. Refer to cleaning the old slag above, and my attempts were more successful. That took a long time to figure out. It also stopped the blow outs, warpage and other troubles that build up of excess heat was causing. Go slowly with lots of stitches from quick little spots of heat. What I also garnered from this learning curve was that the really hefty copper welding heat sink could suck calories out of the work. I do not have enough hands to hold that and the gun, but it was eye opening. I am fairly certain all this information was provided by Grant a week ago, but seeing it with ones own eyes drives it home. Much of my practice metal has been dead computer cases. It had a plethora of coatings, and even some of the metal I picked up at the scrap store had a film. For a very good end product, you need a VERY clean work surface. Initially, the wire wheel and grinder elbow grease I applied was not enough to really give me a clean, bare surface. I thought it looked bare, but it was not. SHINY metal is a clean, bare surface. No shine, not clean, no good welds will come. All the youtube videos and written explanations did not get that to sink in. Seeing it in action was the key. The current steep learning curve involves welding sheet metal to a thicker L bit. The heavy L is rather solid and flat. The body panels I need to tack it and weld to are not so flat. Gaps and uneven contact are not making for a good weld. I am still on the learning bench, not in actual car process. The sheet metal is 18 gauge, the L is 1/8 to 3/16. clay 2002 s430 - Victor, a Stately & well tailored chap 1974 450sl - Frosch - Two tone green 1976 300D - Blei Vanst - it looks silvery 1972 220D - Gump - She was green, simple and ran 1995 E300D - Gave her life to save me against a Dame in a SUV POS 1987 SDL - Beware Nigerian Scammers _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
