Introduction: Rust Removal Using Multiple Approaches

About: I am a Design Engineer who enjoys challenges and finding new uses/abilities for the things around us.

I made it at TechShop!

During a recent excursion to a local metal/scrap yard, I found a pair of steel gear/flywheels which looked like they could be re-purposed into 'something'. With my recent experience at TechshopRDU with sandblasting and powdercoating, I figured this would be an excellent opportunity to gain some experience with prepping metal, so they came home with me. Please note that doing prepwork at home prior to coming to TechShop will allow you to use the equipment and your time more efficiently.

The problem: What is a low cost, safe, AND effective method of removing rust?
Solution: Try multiple approaches! I used three and rated them on 1-5 scale in terms of effectiveness.

Before we get further into the instructable, I want to mention that I am entering project into the Hurricane Lasers Contest.  If I win, I would like to continue this project by making parts necessary to turn it into a wall clock. Also, I am entering this into the Fix & Improve It contest because having these skills/knowledge will let you fix and improve any metal you find in a junk yard!

Something to prep [rusty steel gears are good :) ]
1 apron (or clothing you don't mine getting dirty, long sleeves with chemicals, short sleeves with power tools)

Rust Removal
- via Chemical/Mechanical approach (Step 1)
1+ gal White Distilled Vinegar {this depends on the size of your part and the amount of rust}
Container large enough for parts being prepared
Steel wire brush
1 pair chemical-resistant gloves
1 pair goggles
Respirator or dust mask (look for N95 NIOSH rating)

- via Mechanical approach [wire brush] (Step 2)
Respirator or dust mask (look for N95 NIOSH rating)
Steel wire brush
Steel wire brush (with bit for drills)
Power drill (adjustable handles REALLY help out when there is a lot of rust to remove)

- via Mechanical approach [Sandblasting/glass bead] (Step 3)
1 Sandblasting cabinet with power and air
Respirator or dust mask (look for N95 NIOSH rating)
Media (glass bead, aluminum oxide, walnut shells, etc.)

You may need some or all of these materials depending on which method you use to remove the rust.

Safety First:
Using chemicals, power tools, and other equipment requires knowledge and personal protection equipment (PPE) to decrease the risk of injury. If you decide to use this instructable of a guide, I am not responsible for any accidents/injuries that may occur. Be smart, plan ahead and wear your safety gear!

Now, on to get prepped!

Step 1: Step 1 - Vinegar

Time Required: 1 Hour to 2 Days
Effectiveness: 2 out of 5

Special Notes:
My first attempt at removing the rust is more in the chemical realm than the upcoming steps. There are various products out there that will strip rust and do so MUCH more effectively; however, I had read that vinegar can be an effective remover and wanted to try it. 
Vinegar can be an effective chemical for preparing the part for future mechanical means of removing the rust; however, I wouldn't rely on it solely. Plus it makes your parts smell pickled so this may not be the best fluid.

Materials needed:
1 gal or more White Distilled Vinegar
1 Container large enough for parts being prepared
1 Steel wire brush
1 pair chemical resistant gloves
1 pair goggles
1 apron/not so nice clothing

Step 1A - Prepare yourself by putting on your gloves, apron, and goggles, this process can get messy!
Step 1B - Place your part in the container in an area that is ok to leave if for a few days. Make sure the area you're working in is well ventilated.
Step 1C - Pour the vinegar slowly all over the part, be sure to completely coat the part and keep as much in the container as possible.
Step 1D - Wait! It will take hours or days for the vinegar to effectively remove the rust. Keep checking on it and add more to increase the concentration.
Step 1E - While wearing your protective gear, use the wire brush to scrap off rust. Be sure to turn the part over and repeat the steps.

Maybe try something a little more abrasive? On to Step 2!

Step 2: Step 2 - Wire Brush With Power!

Time Required: 15 minutes to Several hours
Effectiveness: 3.5 out of 5 (your arms will be tired!)

I would recommend this method only if you have patience and the ability to hold a drill for extended period of time; however, it seemed very effective.

1 pair goggles/safety glasses
Respirator or dust mask (look for N95 NIOSH rating)
1 apron (or clothing you don't mine getting dirty)
1 Steel wire brush (with bit for drills)
Newspapers or something to protect your work surface

Step 2A - Put on your safety goggles/glasses and protective clothing.
Step 2B - Place your part on newspapers or something to aid in collecting/disposing of the rust.
Step 2C - Install the wire brush into the chuck of your power drill. Be sure the chuck is tight on the brush bit.
Step 2D - Turn on the drill and begin brushing in the center and work outwards, be careful with the brush as it will want to 'pull' or 'push' in certain directions. Find what is most comfortable and safe and take your time. At some points, reversing the direction of rotation of the drill may help.

You may have to repeat certain areas multiple times to get the tighter corners in the part. I think it took about three rounds per side for my part to get it really clean.

Looking better, but we may need to step it up a notch. On to Step 3!

Step 3: Step 3 - Mechanical Approach (sandblasting/glass Bead)

Time Required: 15 minutes to 1 hour
Effectiveness: 5 out of 5

The final approach used was by far the most effective; however, requires equipment that may not be readily available to most people.

Sandblasting cabinet
Media (glass bead, alumina oxide, walnut shell, etc.)
Respirator or dust mask (look for N95 NIOSH rating)

Special Notes:
Prior to opening the blast chamber, it is recommended that a respirator/dust mask is used. You don't want to inhale the media which becomes a finer dust the more it is used.

Also, be sure to find out what media is being used and DO NOT MIX media. Glass bead and Aluminum oxide do a great job of getting to the bare metal quickly and may have an 'etching' effect while walnut shell is often preferred to get paint off of metal while doing minimal damage to the bare metal.

Step 3A - Review the condition of your equipment by checking the following items, If this is at TechShop, let an employee know if there are any issues prior to starting:
Light - Is there adequate light inside the blasting chamber?
  -> Shop lights or a new bulb may be necessary.
Dust Collection Vacuum - Are the hoses attached and in good condition, Does the vacuum turn on?
  -> Tighten hoses and empty vacuum container if more than 1/2 full [or less than 1/2 empty :) ]
Chamber Window Covering - Can you see through the protective cover?
  -> This may need to be replaced.
Protective Gloves - Are the gloves installed and free of holes/significant wear?
  -> Gloves may need to be replaced if too much wear.
Compressed Air - Is there adequate (90 PSI) supply air?
  -> Less air pressure may work, but the process is easier with higher pressure
Foot Pedal - Is the air securely connected to the pedal and gun?
  -> Tighten all fittings and verify hoses are free from punctures/wear
Media Blaster - Is the tip of the gun no greater than ~1/4" diameter?
  -> If the diameter is too large, it will take longer to remove material
Media - This can be tested with use, does the media effectively remove material? (i.e. is it coarse?)
  -> If the media has a lot of hours on it, it will be a finer powder and take longer to remove material. Consider adding 'fresh' media and DO NOT MIX types! Non-homogeneous mixtures may wear down the media quicker which equates to more $$$ spent on media.

Step 3B - Ensure the dust collection vacuum is turned off and place the part in the cabinet. Verify the blasting chamber is completely sealed.
Step 3C - Turn on the light and dust collection vacuum; then, using the cabinet gloves, move the part to the center (most accessible) part of the cabinet.
Step 3D - Depending on the weight of the part, it may be necessary to hold it with one hand while blasting with the other. Begin blasting by holding the media blaster gun and stepping on the foot pedal to shoot air and media.
Step 3E - Go over all of the surfaces at least once, take breaks to examine the part and find areas that haven't seen enough media.
Step 3F - Once all areas have seen blasting, allow the vacuum to remove the dust in the chamber air for ~30 seconds to a minute. Put on the respirator and check the part out. It may be necessary to repeat using the cabinet to get the smaller areas.

Once all of the rust is removed, it will be necessary to get the residual media off of the part. This can be done with compressed air, water, or the combination of both. If the next step will be to powdercoat the part, you can use air+water, then place it in a pre-heated oven to evaporate any remaining droplets...why give rust another chance to reform after you've worked this hard to take it off?!

Fix & Improve It Contest

Participated in the
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Hurricane Lasers Contest

Participated in the
Hurricane Lasers Contest