By Talmage Ekanger
“The difference between an amateur weld and a professional weld is a 6-amp grinder!” Jake said as he started to “correct” a sloppy weld. Jake didn’t have any formal training; he just knew the basics of welding, and I didn’t.
Whenever I needed metal stuck together, he was more than happy to help me for the sheer pleasure of watching the sparks fly. Thanks to his price, for years Jake was my go-to guy for welding. Maybe the quality may not have been top notch, and a grinder was required afterward to make the weld visually pleasing … but at least nothing fell apart.
Fast forward 20 years.
I now have a welder of my own and thoroughly enjoy sticking metal together every bit as much as Jake did. I also lack formal training, but I did recently learn that Jake’s statement was all true– just not for the reasons he thought. Here are the basics of welding — what all amateurs should know.
The Basics of Welding
Start with a Clean Surface
Welding is a lot like painting, results are dictated driven by preparation. In order to get a good weld, the surface must be free of oil and debris.
An angle grinder provides this by removing the outside layer of oil, paint or other contaminant and exposing the nice clean steel underneath. Particularly when welding with light-duty welders on thicker steel, penetration can be greatly enhanced by preparing the weld with a V-groove between the pieces of steel being welded … another great use for an angle grinder. In both cases, the angle-grinder can be the difference between an amateur or professional weld.
Whether a DIY project is created from new steel or old, all steel needs to be prepped before welding. I’ve probably welded as much or more on used steel than new steel. Fixing broken items almost always includes welding to previously finished and used steel.
In addition, I build a lot of projects out of reclaimed steel (old bed frames are a favorite source of steel for me). Either way, used steel is usually painted to prevent rust, unless the bare steel has become a rusted relic itself, and all paint and rust should be removed before welding.
Avoid Welding Through Paint
Welding through paint seems like it should be possible. It would seem that the high temperature of welding should make quick work of burning away the paint, allowing the weld to take hold. However, the fumes and chemicals released in the process of welding painted metal not only harm the welder but are toxic to the weld itself.
The released gasses and chemicals mix with the metal, compromising the strength of the weld. It may hold for a while, but it won’t last forever. For a good weld, all paint should be removed within one-quarter inch of the weld site.
Tips for Rust
If reclaimed metal is not painted, it is likely rusty. Welding to rusty metal is both ineffective and miserable in its own way. Rust, also known as iron oxide or FE2O3, is an excellent preventer of welds, the primary reason being chemistry.
When iron oxide is heated, it releases one of its extra oxygen atoms to react with something else. When welding, that something else is the steel you may be attempting to weld, and the result is that the metal will get burned rather than melted and welded. In addition, the air pockets that develop in heavily-rusted metal also provide a certain amount of insulation against good weld penetration. In either case, welds across rusty metal tend to not hold well.
Still, rusty metal provides a better incentive to prep before welding. Iron oxide, while cancerous on trucks, does have its uses. It is a key colorant in some paints, and it is also an excellent catalyst used in Thermite. Thermite, a mixture of iron oxide and aluminum powder, is a military grade incendiary substance used for breaching armor plating. In the domestic world, thermite can be used for welding … if you are trying to weld two railroad ties end to end. The heat generated is absolutely phenomenal and barely controllable.
It is probably no surprise that rust doesn’t weld well. To the contrary, welding to rusty metal looks a great deal like fireworks (another domestic item in which rust is an ingredient), blasting molten sparks in every direction at a rate exponentially greater than standard welding. While impossible to prove, the sparks that appear to travel at random, actually have a unique homing ability to locate the one path down my collar or into my boot and up against my skin, where they brand me as a speckle-belly. Typically, this results in new and unconventional dance techniques usually only seen in a garage. While I suspect welding was involved in the development of both disco and break dancing, as with those trends, eventually the novelty of being branded wears off, and I’ve learned to prep the metal first.
New steel is much more fun to work with. It looks nice, with an even dull grey-black oily finish that’s consistent and even over the whole surface. It makes a much nicer raw material for a DIY project than reclaimed steel. However, that dull-grey finish is not the color of steel. It is paint of a sort, applied as a rust preventative. While the coating is generally thin, it offers the same problems with welds that other types of paint does. Therefore, for a good weld, the paint should be removed with a grinder before welding.
These basics of welding should help most beginners (and those that need a refresher course). At the end of the day, my buddy was right, the difference between a professional and an amateur weld is a 6 amp grinder … and the pros will use it first!
Talmage Ekanger is a husband, father of three, writer, and attorney-turned-information-technology-supervisor. A native South Dakotan, he’s grateful for the chance to raise his family in the land of the free and the home of the brave.