Acetone For Welding, Clean the Oil and Grease on 3 Metals

By Ben Norton / May 1, 2019
Acetone For Welding Title Image

The 3 metals I cover in this article are mild or low carbon steel, stainless steel and aluminum.

I tell you about the effective use of acetone for welding – along with the why, the what and the how to use acetone on metal you plan to weld.

When you are MIG or TIG welding clean metal is crucial for a good weld. You can get away with dirtier metal when stick or flux core welding. But to get the best quality weld, your metal has to be clean. Oil and grease are metal surface contaminants that affect your weld. Acetone can remove them.

As a Home or Hobby Workshop Welder Acetone for Welding helps you;

    1. Degrease your Steel, Stainless Steel and Aluminum quickly and easily
    2. Acetone evaporates rapidly and leaves no chemical residue to affect the quality of your later weld.
    3. It is easy to source, and simple to use.

Why Use Acetone for Welding Preparation?

Acetone is a heavy duty degreaser. It does its job by efficiently cleaning the oil and grease from your metal’s surface.

  • Acetone disperses quickly and doesn’t affect the metal. No chemicals or other impurities are left on the metal to affect your weld. So leaving a clean surface for you to weld on.
  • And it is relative low cost to buy.
  • What more could you ask for?

Cleaning Mild Steel for Welding With Acetone

Newly Purchased Mild Steel or Low Carbon Steel

Generally, the surface contaminant on fresh mild or low carbon steel tends to be a mill scale covering.

Surface mill scale is the result of the manufacture of hot rolled steel.

Light mill scale is best tackled with a grinder complete with a grinding disc or a flap disc. Once mill scale is removed from where you want to weld, there is no need to wipe down with acetone. You are free to go ahead and weld with your welder.

Used Mild Steel

But when you plan to repair steel that has seen some use, you may well have a layer of oil and rust to deal with. Tackle the oil and or grease with acetone first. (method to use below). Next grind off the rust and mill scale with your disc of choice.

Then you are free to start welding.

Heavy mill scale on your mild steel is a different matter to deal with. Take a look at the article I have here to learn the methods of dealing with heavy mill scale.

Acetone Wipes on Metal For Welding

Acetone Wipes on Metal For Welding

Cleaning Stainless Steel for Welding With Acetone

Fresh Stainless Steel

Stainless steel fresh from the factory may look shiny and good to go.

Weld on that and your MIG or TIG welder will be stuttering.

Leaving you wondering what on earth is going on with your weld.

Unexplained porosity in your MIG or TIG weld?

Think back to whether you cleaned your stainless steel before you started to weld.

There is bound to be a layer of oil on the stainless applied by the manufacturer in an attempt to keep it fresh looking.

Even if the stainless steel looks great, it is a good idea to wipe down your welding surface with acetone to get off the factory oil.

Then take your grinder and flap disc (one designed for using on stainless steel) to your stainless steel.

You may be shocked and surprised at how well the metal looks and comes up afterwards.

Stainless Steel for Welding Repair

Dirt on the surface of your stainless steel takes away its appealing shine. That may well prompt pre weld grinding to clean your stainless steel.

But hold on.

Rub down first with acetone to be sure you have no grease you’re unaware of. Even handling your stainless steel can transfer natural oils from your hands. And affect your weld. Then follow up with some pre-weld grinding.

Before Welding Clean Aluminum With Acetone

New Aluminum

Factory fresh aluminum usually has a light oil covering. This is applied to keep to a minimum aluminum oxide build up on the surface of the metal. Bare aluminum left in contact with air naturally reacts and a layer of aluminum oxide is the result.

Which is a disaster for you to MIG or TIG weld through. Aluminum oxide is a weld contaminant, known to cause porosity in your weld.

Wipe down your weld surface with acetone to remove the oil. Then grind down with a flap disc rated for working on aluminum. This will get rid of the aluminum oxide.

Aluminum for Weld Repair

Aluminum is used in so many specialist applications. You will come across aluminum in hand rails through to food containers and vessels. All likely to have a layer of oil on them. Even if it is only oil from human hands.

The same as for fresh aluminum. Use acetone to wipe off any oil, then grind off the aluminum oxide with a specialist flap disc prior to welding.

Use Acetone on your Filler Metal Rods

It is not always obvious that the aluminum stainless steel metal filler rods for TIG welding have a layer of oil on them too.

Acetone Wiping Metal Filler Rod

Acetone Wiping Metal Filler Rod

Give them a wipe with some acetone on a rag and you may be surprised at the junk that comes off.

Acetone Wipe Dirt From Filler Rod

Acetone Wipe Dirt From Filler Rod

A Bit About Acetone In Welding

  • Acetone is great for removing dirt and grease.
  • It is relatively cheap.
  • It is highly flammable.
  • Acetone produces fumes.

How to Use Acetone On Metal Before Welding

  1. First of all it’s a good idea to wear solvent proof rubber gloves. Acetone is drying on the skin and can cause skin irritation.

My two preferred rubber gloves are: (Click on the Links to View the Price on Amazon)

a. ThxToms Heavy Duty Latex Gloves. They resist solvents and acids.

b. A cheaper set of gloves are 3M 9001 Nitrile solvent resistant gloves.

Both will protect your hands nicely.

  1. Make sure your workshop is well ventilated. Open the door or a window to get a nice breeze through. And think about wearing a face mask if you are particularly sensitive to fumes.
  2. Take a lint free cloth or rag, pour some acetone onto the rag. I quite like the Nabob shop rags. They are 100% cotton and lint free. So no lint left on your weld to catch fire later. They are great for these types of tasks and plenty of other welders like them as well.
  3. Wipe and rub down your metal with the acetone soaked rag. The acetone will evaporate from the metal after a couple of minutes.
  4. Put more acetone on the rag. Repeat to make sure all the oil or grease is removed.
  5. Close up the tin of acetone and remove it and the rags from your weld area. Do this before you start grinding or welding on your metal. As grinding produces plenty of sparks. And then there is the spatter from your welding arc.

Frequently asked Questions On Using Acetone for Welding Metals

Can I use Nail Polish Remover? It is Acetone isn’t it?

No, unfortunately not completely. Got nail polish to remove? Then to ahead. Metal to clean for welding? Then no.

Nail polish remover has skin and nail moisturizers added. Use nail polish remover to remove grease from metal and all those moisturizers will leave an oily residue, ruining your weld.

Is Acetone Dangerous to Me as a Welder?

Acetone is considered to be low toxic, and doesn’t cause cancer. However, the fumes may make you feel dizzy and heady.

Always use acetone in a well ventilated area. And use a half face mask or respirator, one with a charcoal cartridge if you’d prefer not to breath in the fumes.

Acetone causes mild skin irritation, for example, dry skin, and, skin that is likely to peel with a lot of exposure. The use of gloves resistant to solvents is a good idea, if you’re doing a lot of metal cleaning before welding.

Best not to splash in your eyes as it can cause moderate to severe eye irritation.

Is Acetone Dangerous to Weld with?

Although flammable, acetone evaporates within a couple of minutes. There isn’t an issue if you start welding once it has evaporated.

If it is still wet you’ll get a small pop as it combusts.

Cleaning inside a tank or vessel where there is lack of ventilation?

Then you might get a quick flash of flame as the acetone vaporizes.

But remember I said that acetone is flammable.

  • Keep the tin or container closed and away from the weld area. It is surprising just how far sparks and spatter can travel.
  • Don’t do your welding over acetone spilt on the floor. Wipe it up first.
  • Remove the rags used to wipe down your weld metal. Take them well away from where you are welding. The acetone on the rags won’t evaporate as quickly and the rags will go up if a spark catches them.
  • Best to keep the acetone tin elsewhere. Even an empty tin catching a stray spark can ignite.
  • And a little known fact, acetone is sensitive to pulse welding machines. Keep well away. You don’t want your tin of acetone going bang, sending shards of metal in all directions.
  • Lastly don’t use acetone on hot metal. Hot metal can ignite it.

Sourcing your Acetone for Your Welding Metal

Pure 100% Acetone is available from Lowes, Walmart, your local farm supplies and Amazon.

For example this 1 gallon tin by Mohawk Acetone is available. If you live in parts of the country where is difficult to source acetone, ordering from Amazon is an option.

Acetone welding wipes are another option. When you have a light covering of oil to wipe off your metal and don’t want to go to the trouble of getting a whole tin of acetone. These acetone wipes are then quite convenient to have in your tool box.

Blue Demon Ace Wipes is in a box of twenty individually sealed sachets. Each sachet contains a single acetone wipe.

These wipes are designed for those who weld. Each wipe removes grease and oil from your base metal and metal filler rods.

Have a large project to clean and weld? Then these wipes are no substitute for a tin of acetone, which of course would be a lot cheaper.

Last Words

I hope you found my post “Acetone For Welding, Clean the Oil and Grease on 3 Metals” useful. Whether you are MIG, TIG welding or even stick or flux core welding clean off any oil first. Whether it is on fresh stainless steel or aluminum or on mild steel for repair acetone will get that grease off before you weld.