How to Polish a Keg


WARNING: It is understood that any of the information listed below is for educational purposes only, and that the reader is responsible for any injury that may occur as a result of carrying out these procedures.  We strongly recommend that all safety precautions be observed, and that all equipment is used as recommended by the manufacturer.  Do not drink alcoholic beverages while operating power tools. Proceed at your own risk.

Polished Keg Before and After

[Sweet, sweet polished keg on the left inspires epic brewing sessions.  Boring, lifeless keg
on the right will get the job done- probably.]


1. Angle grinder. Word of advice: Consider purchasing a 4 ½ inch grinder like the Chicago Electric Power Tools 4-1/2" Heavy Duty Angle Grinderinstead of the 4 incher I use, otherwise you’ll end up needing to purchase an adjustable spanner wrench for an additional $5-$10.  That said, I use a 4" Angle Grinder built by a brand called Chicago. I picked up my angle grinder for about $30, and I've used the heck out of it and it still works great, especially for the price.
Chicago Electric Power Tools Angle Grinder

2. Back-Up Pad for use with your angle grinder.  I recommend the 4 ½ inch Quick Change Back-Up Pad from Gator; just make sure you get the right size pad for your particular grinder.  This pad works well with a 4 or 4 ½ inch angle grinder.  I originally bought a DeWalt brand 4 ½ Backer pad at Home Depot, but I found that there was no way of tightening the backer pad onto the angle grinder, which made polishing more or less impossible. Lowe's ended up saving the day, which is where I also purchased my finishing dics. 

Gator Quick Change Back-Up Pad

3. Finishing discs. I recommend two different types of finishing discs from a company called Gator. Both discs are 4 ½ inches and designed to fit the Back-Up Pad, but one is labeled ‘Fine’ (it's navy blue in color and is used for finishing and blending) while the other is labeled ‘Polishing’ (it's white in color and is for buffing and polishing). Each package comes with two discs so you'll end up with two fine discs and two polishing discs. You can buy these at Lowe’s, ACE, Do-It-Best Stores, and True Value, to name a few.
Gator Finishing Disks
4. Adjustable spanner wrench.  Sometimes called an adjustable face spanner wrench, this tool is necessary to tighten your back-up pad onto your angle grinder.  The spanner wrench I bought was from a company called "Forney" and sells for about $5-$10.  Yes, your angle grinder will come with a pin-type wrench for tightening, but it may not be the correct size needed to tighten your back-up pad onto your grinder.  For some reason there are many different tools that require different sizes of pin-type wrenches, but the manufacturer doesn’t think it necessary to include that particular sized wrench with the tool. However, with an adjustable spanner wrench, you never need to worry about not having the right sized wrench again!  I purchased mine at my local Lowry/DoItBest store, but you could also pick one up online from Sears for about $5.
Adjustable Spanner Wrench Closed
Adjustable Spanner Wrench Open
[Notice how adjustably adjustable the adjustable spanner wrench is.]
5. Metal polish compound.  I recommend two different types of polishing compound from a company called Mibro. The polish compounds are labeled from 1 – 6, but you will only need # 2 and # 5, both of which are intended for use on steel.  # 2 is used first to clean and buff out minor knicks and scratches, and # 5 is used second to produce a high gloss finish. You may be able to purchase these buffing/polishing compounds from Lowe's. (If you don't have any luck at Lowe's, you may be able to order the buffing compounds online from Orchard Supply Hardware.) If you want to read more about the different types of compounds and their recommended application, check out the Mibro's website by clicking here.
Mibro Metal Polishing Compound
6. Paint thinner.  You will use this initially to clean off the surface of the keg.
7. Rags.  For use with the paint thinner.
8. Scrapper.  This may be used to remove any stickers or labels on the keg.
9. Two pieces of lumber.  These will be used to hold the keg in place while you’re polishing. 2x4s will work, just make sure the size is sufficient to prevent the keg from rolling around.
10. Safety glasses.  You don’t want chunks of polish flying into your eyes.
Safety Glasses
11. Gloves.  I use thick gardening gloves, but when working with an angle grinder it is wise to use some sort of hand protection.
12. Work clothes/ work shoes. You may end up staining your clothes with little bits of black polish that fly off your angle grinder as you’re working, so it’s a good idea to throw on some old work clothes.  I also recommend wearing shoes for protection in case you drop the grinder on your foot as you’re working.  
13. And, a keg...

NOTE: If the keg being polished has already been cut open for use as a keggle or otherwise, cover any openings so that no polishing chemicals find their way into the inside of your keg.  Also, this process may take 1 – 3 hours depending on the quality of work being done, but it will move along faster once you establish your technique.

TIP: When polishing, little black clumps of spent polish will fly off of your angle grinder and can make a little mess right around your work area.  So, if possible, polish your keg outside over a surface you don't mind getting dirty or place a drop cloth or throw-away sheet/paper down under your work area in order to avoid those little black clumps of polish from sticking to the surface of your floor. You can sweep the clumps up afterwards, but they often smear a bit on the floor's surface when you do. 

1. Scrape off any stickers or labels from the keg with a scrapper.

2. Clean the surface of the keg with a rag and paint thinner removing any paint or adhesive.

Paint Thinner on Beer Keg

3. Place keg on a clean surface, securing it between two pieces of lumber on either side of the keg to help prevent the keg for rolling while you’re polishing.  If you are working outside on a dirt or grass surface, place a towel or sheet under the keg to prevent dirt from getting on the surface of the keg as you work.

Prevent Keg From Rolling

[Placing two pieces of lumber on either side of the keg helps prevent the keg from rolling.]

4. I removed the safety guard from the angle grinder for convenience in this project because I was working with polishing discs and not blades, and because more surface area is covered without the guard on. But this is a personal choice, so proceed with caution.  I would NOT recommend removing the safety guard on an angle grinder if working with any type of blade.

5. Attach Back-Up Pad and a FINE finishing disc onto an angle grinder. Tighten with an adjustable spanner wrench.

6. Apply Mibro’s metal polish compound # 2 onto a FINE finishing disc from Gator.  You can do this by turning the angle grinder on and allowing the compound to coat the finishing disc as the disc spins. Remember to always wear safety glasses and gloves when working with an angle grinder.

Gator FINE Finishing Disc Beer Keg

7. Begin polishing the keg with the angle grinder, focusing on any minor scratches or marks.  You will notice that as your FINE finishing disc comes in contact with the keg, a layer of polish compound will become visible on the keg.  Apply this layer of polish compound to a section of the keg and polish this area until you notice the compound residue is no longer visible, and you are left with a dull gloss.  You will need to apply additional polish compound to the finishing disc as you move on to another section of the keg.  During this process, you will most likely use up two FINE discs, and about ½ of the # 2 polish compound.   Keep in mind that any small scratches you wish to be removed should be done during this step because you will only be polishing during the next and final step. You may choose to cover the entire keg more than once.  By the way, as you wear down your finishing disc, your back-up pad may come in contact with the keg leaving dark gray streaks behind. This may be a sign that you need to replace your finishing disc. 

8. After you are satisfied with the level of polish you have achieved, making sure that you have evenly covered all parts of the keg you wish to polish (excluding the very top of the keg which will either be cut away if you are making a keggle, or is already cut away), replace the FINE disc with the POLISH disc from Gator and apply Mibro’s metal polish compound # 5 onto the POLISH disc. The polish compound itself looks like a piece of sidewalk chalk (see below).

Mibro Polishing Compound #5

Again, you can turn on the grinder and apply the polish compound directly to the polishing disc.  Begin polishing.  As before, you will notice that as your polishing disc comes in contact with the keg, a layer of polish compound will become visible on the keg.  Apply this layer of polish compound to a section of the keg and polish this area until you notice the compound residue is no longer visible, and you are left with a high gloss.  Continue to polish until you have evenly covered all parts of the keg you wish to polish (with the exception of the very top where the keg stem is) and you are satisfied with the level of gloss. 

9. Rub a clean, dry cloth over the entire surface of the keg removing any polishing compound residue.  

10. Unplug your grinder, appreciate your work, and reward yourself with a homebrew or two- you've earned it. 



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