Taking proper preparations beforehand is what ensures a good weld. No matter the type of metals used in welding, one thing’s for sure – the parent metal needs to be prepared thoroughly before the welding session for the process to be accurate and effective. Any foreign materials in the welding area translate to imperfections.
You should not weld on concrete as it may introduce impurities to your weld. A workbench is a must for welding. You can try laying down a metal sheet and welding on that.
Bottom line is, welding directly on concrete is a bad idea. But, which surfaces are good for welding? You might ask. Well, we will talk about all that in the rest of this article. We will also provide 7 tips on how to properly prepare your welding materials for a fine weld as well. So, keep on reading.
Why You Should Not Weld On Concrete?
While welding is an integral part of the manufacturing process, you can’t weld on everything. Welding on concrete is doable. But not really recommended.
As the moisture in the concrete comes in contact with the heat, it turns to steam. The arc slowly builds up the steam, and finally, the mist blows out the bits of the concrete.
In other words, welding on concrete can cause an explosion. That’s why it’s stated in the Arc Welding Safety guideline not to weld on concrete surfaces.
However, some people try to make the best use of this situation by using concrete epoxy to raise the footing. As a thin layer of concrete on top of the footing doesn’t have enough strength, they tend to use epoxy.
You’ll have to epoxy your threads into the concrete, and the threads need to be stainless. Otherwise, once the water fills the holes, it can rust your bolts out. Nonetheless, you should try this solution only when no other options are available to you.
Best Surfaces To Weld On
Any good welder knows that the surface is a vital part of the welding process. To ensure the best outcome, you need a quality surface to work on. Here are some of the best surfaces to weld on.
Carbon Steel: Professional welders mostly prefer working on carbon steel surfaces. It’s an ally metal. The main difference between regular steel and carbon steel is the carbon content. While it has some similarities with traditional stainless steel, carbon steel is chemically different in composition.
Cast Iron: Cast iron is relatively high on the list of desirable surfaces to weld on as well. It’s all thanks to their durability and strength that many welders prefer working on cast iron tables.
Stainless Steel: You may be familiar with stainless steel. It’s one of the ideal welding surfaces. It’s easy to work with. And, you won’t have to worry about the cleanup process as it’s pretty straightforward.
Aluminum: Aluminum is a desirable material to weld on. While some aren’t satisfied with aluminum’s level of heat conductivity, this light material is elementary to work on. However, note that aluminum is prone to corrosion if kept in contact with other metals plus water.
7 Tips Preparing Your Welding Surface
It’s not just a matter of where you weld, preparing the welding surface itself is important too. The type of your welding process will define your prepping session. For example, TIG welding aluminum needs an impurity-free parent metal for a strong weld.
On the other hand, MIG welding steel has no such strict criteria. So, prep your welds depending on the type of your welding and welding material.
- Sand Paper
A common way to prep the metal for welding for both MIG and TIG welding steel is to use sandpaper. It’s very inexpensive.
However, sandpapers can’t permanently remove all of the coatings and can be pretty time-consuming. Make sure to use the right kind of sandpaper for the welding application and the parent metal not to damage the metal or leave behind any residue.
- Angle Grinder with Flap Disc
If you want to move on to a more efficient cleaning process, you can always go for the angle grinder. Whether it be to prep steel for TIG or MIG welding, using an angle grinder with a flap disc works great for both. The process is quite simple as well.
Once you’ve removed the top coating with a flap disc, you simply have to wipe it down with Acetone, and voila! The surface is ready for a strong weld.
It’s an excellent technique for heavy welding on parts prone to contamination because of their exposure to the elements. Note that the flap disc can be pretty hardcore, so try not to use it on thin sheet metal.
- Abrasive Blasting
If the parent metal is too rusty to be cleaned with sandpaper or with a grinder, your best bet will be to blast it. However, simply blasting it will not make the metal ready to be welded. You’ll still need to give it a quick wipe down with Acetone to remove any chemical impurities.
A downside to abrasive blasting is that it can sometimes trap bits of other metals, causing the parent metal to rust. That’s why I never use this method to prep aluminum for welding, as aluminum is sensitive to impurities.
- Wire Brush
Similar to sandpaper, the wire brush is another good way to remove any slag, mill scale, or other impurities from a metal. However, the wire brush is the best when it comes to any thick contaminants. It’ll especially come in handy when you have to brush off the flux after you’re done welding.
Keep in mind that different types of metal will need other specific brushes. For example, you’ll need a steel brush to clean up aluminum before welding.
- Chop Saw
When the angle grinder doesn’t cut it, you’ll have to bring in the big guns, as in the chop saw. If you don’t mind a messy cutting process, a chop saw is something you may want to look at. They’re portable and are the best for cutting metal that’s approximately three to four inches thick. When using a chop saw, it’s a good idea to switch to a thinner blade as the metal gets thicker.
- Oxy-Fuel Cutting
Can’t cut through something? Try oxy-fuel cutting. No matter the thickness, the oxy-fuel cutting system can make short work of it. It’s a highly versatile and practical cutting tool. With a cleaner cut than the chop saw, the oxy-fuel cutter is a sign of a big-time welder.
However, you need to be careful when using an oxy-fuel cutter. While it may be a very efficient tool, it’s equally dangerous as well.
- Plasma Cutter
Another big gun of the welding industry is the plasma cutter. The plasma cutter is the bread and breakfast of a welder who has to make frequent cuts of thick metal. It is simply the best way to cut metal before moving on to welding.
While it has quite a high upfront price, the plasma cutter will save you tons on preheating time and the additional cost of cutting fuel. Plasma cutters also offer fast and clean cuts with notably small kerf, making them the best choice for any welder who wants to save time and money on material costs.
Final Words
Fortune favors the prepared. This adage holds true even in the welding industry. No matter the type of your cut, you’ll need to prepare the metal to get the best result.
On that note, we hope that our tips on how to weld on concrete could be of help to you. Keep in mind that the type of tool you’ll use will depend on the metal and your welding application. Be safe and always handle welding equipment with caution!
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