Authored by Wes Vann, last revised onApril 12, 1997
PLEASE NOTE; Any time working with welders wear the correct weldinggoggles for eye protection. The goggles for gas welding are not the sameas those required for arc welding!
Any gas cylinder should be handled with care. Even a scuba tank withcompressed air can kill if the valve stem gets broken.
Base Material; This refers to the two metal objects that you aregoing to attach.
Flux; Depending on what is being done, flux is basically an acidthat cleans the base material and helps remove impurities.
Soldering; When soldering, a metal (solder) that is a combinationof tin and lead is melted into the joint of the two base metals. Soldercomes in different percentages of tin and lead. When soldering, the basemetal is heated up to the point where it melts the solder. A flux or "tinningacid" is required.
Brazing; This is similar to soldering in that the added materialis not the same as the base material. A flux is required.
Welding; When welding, the added material is normally the same typeas the base material, with the same melting point. Not all types of weldingrequire flux.
It's said that a good weld looks like a stack of quarters that hasfallen over. Here is a scan of one of my welds done with the MIG welder(a fairly good weld). This is on a bumper hitch and the metal is 1/8"thick.
These are the good old Oxy/Acetylene welders. There are two cylindersrequired. One is pure oxygen and the other is acetylene. Don't confuse"pure oxygen" with the air that we are breathing. As an example,a scuba tank has compressed air and not "pure" oxygen. The oxygendoesn't by it's self burn, but is required for complete combustion. Theacetylene is the fuel that burns.
With an oxy/acetylene welder it is possible to braze or weld. It'salso possible to get a cutting tip (cutting torch) to make quick cuts.(the photo above shows the cutting torch)
Brazing is where the metal that is to be attached is heated up anda brazing rod is fed in. It's similar to soldering in that the base metalisn't melted, only the brazing rod. A flux has to be added when brazingand it is sometimes a coating on the rod. When done brazing, the flux leavesa glass left-over that has to be removed.
When welding, the base material is melted and the rod is fed intothe molten puddle.
When using a cutting torch, once the metal has melted, a lever ispulled and additional oxygen is fed in. This caused the melted area tobe both blown out and oxidized.
One of the problems with gas welding is the amount of heat that goesinto the material. That is why that it's not reasonable to use it for repairingbody panels. When heated excessively, the thin metal warps.
Arc Welders; I normally refer to these as stick welders. There isa grounding cable, from the welder, that is clamped on the object to bewelded. The other cable from the welder goes to the handle that grips thewelding rod. When welding, the rod is held close to the metal and thereis an arc that flows from the tip of the rod to the metal. The materialof the rod is transferred to the base metal and the weld is built up.
Wire Welders & Mig Welders;
These work great for body panel replacement. A wire welder has aspool of wire within the welders cabinet. This wire runs through the cableand out the welders tip. When welding, the wire is fed at a speed thatshould match how fast it is deposited on the base material. A "Mig"welder is a wire welder with a gas feed at the welding tip. The gas formsan area of gas where the welding occurs. As a result, the welding isn'texposed to "air" while welding. There are various gas mixturesused (I have had good luck with argon/co2).
TIG and HeliArc Welders; This set-up uses a tungsten tip at the weldingarc. There is also a gas feed to create the atmosphere that the weldingoccurs in. In Heliarc welding, the gas is helium. The tungsten tip is slowlyconsumed and a rod has to be added as you go.