Masking



Masking is a tedious but required part of powder coating.  There are some parts that you will come across that will need some areas masked off.  I will explain several different methods and materials to help you do do that. This will be Masking Part I. Don't forget to check out Masking Part II and the Wall-Mounted High Temp Tape Dispenser.

 

When powder coating,  it is important to mask off certain areas of certain things.  Powder coating is a thicker coating than most paints and if you don't mask certain areas, things might not go back together when your done.  You can also use masking techniques to make designs, logos, and words on the things you are powder coating for a different look.  Masking techniques and supplies are not all standardized, sometimes you have to get creative to mask off certain items.  Again, this will be one of several articles on masking so I will cover the basics of masking here.

powder coat tape masking
This alternator case is masked with Polyester Powder Coating Tape.  This tape can withstand 400 degrees without degrading.

 

Cleaning and Degreasing before Powder Coating



cleaning parts powder coatingLets talk about the first step of the powder coating process. The very first thing to do is thoroughly clean and degrease your item. Even if it is brand new, it should be cleaned.After cleaning your part, check out this article for the following steps: "How to Prep for Powder Coating". The first thing you need to do is figure out what its made out of. Steel, aluminum, etc. Some metals like aluminum are very sensitive to certain cleaners and it can cause can corrosion and damage on a microscopic level. I will explain the steps I use to clean below.

Alternatives to Sand Blasting



removing rust before powder coatingWhen powder coating, media blasting (sand blasting) is one of the best preparation methods possible.  It cleans, de-rusts, and it leaves behind a texture that makes powder coating stick like nothing else. Read this Media Blasting article to realize the full benefits. But for the stubborn people out there (I was one of them) who don't own a big air compressor or sandblaster and don't want to invest in them, I will go over some alternatives to sandblasting. Note: The alternatives are slower and do not achieve the same durability in the powder coating finish as media blasting.

Stripping Powder Coat



stripping removing powder coatLets talk about how to remove powder coat. Why would you want to strip powder coat from a part? As you start powder coating, you are going to make some errors. It doesn't always come out like you expected. If that happens, it is nice to be able to remove the powder coating so you can try again. There are several ways to remove powder coat. You an remove powder coating with a chemical stripper, media blasting, or a burn-off oven.



Chemical Powder Coating Stripper

Benco B17 

By far the easiest way to strip powder coat is chemically, and Benco B17 is by far the best powder coat stripper. B17 will remove most powder coatings in less than 20 minutes. It is also great at removing paint and just about any other coating. It has a high concentration of methylene chloride which is what removes powder coat. To use the stripper, you simply dip the part in and wait. Check on it every 5 to 10 minutes and pull it out when you see the powder coating is falling off. From there you can rinse the part in water mixed with TSP (tri-sodium phosphate). TSP will neutralize all of the B17 chemical, but you also need another TSP dipping tank if you go that route. The water/TSP will rinse off and neutralize most of the B17 stripper, but to ensure that you have removed all of the stripper, a quick bake in the oven will evaporate any traces left over.  Once the part is completely dried, it won't be pretty.  The part will develop surface rust after the stripping process but this is easily removed by media blasting (to learn more about media blasting, check out the Media Blasting article).

benco b17 stripper on metal
After Stripping with Benco B17

For longer or awkward parts that won't fit in a powder coat stripping container, a rag soaked in B17 can be used to wrap around sections of the part.  Keep the rag stored in an airtight container when not in use and you can reuse it. All safety gear mentioned below must be used while handling the B17.



Benco B17 can be ordered from Benco in 5 gallon, 35 gallon, and 55 gallon quantities. You can also order B17 in a 1 gallon quantity here, however due to the dangerous nature of this chemical, shipping is very expensive. It is more economical to buy directly from Benco.

The downsides to using Benco B17:
  • Its dangerous
  • Its expensive
  • It smells terrible
  • It will burn your skin on contact
  • It slows down in cold weather (you must heat up part before submerging in colder areas).
  • Its just an all around nasty chemical

However, remember the upsides:
  • It works faster and lasts longer than just about any powder coat stripper on the market.  See video below.




 

Safely Storing Powder Coat Stripper



B17 and other powder coating strippers must be stored in an HDPE container with a lid. I suggest a container that is as big as your oven (if you are using a household oven or smaller). Since you cannot powder coat things larger than your oven, there is no reason to have a stripping tank larger than your oven. If you do have a large oven, I suggest a stripping tank that accommodates your biggest, most-frequently coated item. Example: If you often coat 22" rims, make sure you get a drum that is at least 23"+ in diameter. If you are powder coating motorcycle frames, get a tank that can fit at least have the frame in at a time. For the people powder coating smaller items, most of the time you can get away with the container that the B17 comes in. If you need to strip something that will not fit inside of the stripping container, you can soak some rags in B17, and lay them or wrap them around the part. This will work, it is just more labor intensive and takes longer.


powder coaitng supplies


These Eagle Overpack Drums are perfect for B17 use and are the same tanks a lot of professional powder coating shops use. They have a sealing lid which you is highly desirable. It will contain the smell and will stop the evaporation of the chemical. They are a little pricey, but you only have to buy it once and they are the absolute best way to store a dangerous chemical like B17.

Here you can see a very professional powder coat stripping area using 2 95-gallon Eagle Overpack Drum, one for the B17 stripper and one is used as a rinsing tank.  Also take note of the safety equipment such as the ventilation fan, chemical gloves, and chemical apron.  This is a good idea of the safety precautions that need to be taken when dealing with B17 in a shop.


These drums come in a couple different sizes so you will need to decide which one is right for you. Keep in mind the inside dimensions of your average home oven are about: 23" wide x 19" deep x 15" tall.


The 30 gallon drum matches a household oven almost perfectly. It has a diameter of 16" and is 27" tall. This is a great powder coat stripping drum for the home powder coater doing small parts.

benco b17 storage




The 65 gallon drum is perfect for wheels. It has a 31" diameter so it can all types of wheels and because it is 33" tall, it can fit at least 2 wheels at a time.

Benco B17 Powder coat stripper storage container


The 95 Gallon Drum is for the serious powder coater.  This drum will fit 4 wheels at one time which is sure to up your efficiency. 31" diameter x 41" tall.

Benco B17 Powder coat stripper storage container


Chains can be used to lower and raise large parts into the drum. For smaller parts, a dipping basket can be used.
benco b17 dipping basket



 Safe Handling

Benco B17 is a very effective but very dangerous powder coat stripper.  It can burn your skin on contact. Do not go near this chemical without gloves and eye protection.  I recommend the following.

Elbow Length Multi-Layer Glove
Full Face Respirator
Heavy Duty Apron
 
benco b17 respiratorbenco b17 powder coat stripper glovesbenco b17 power coat stripper apron




If you use the B17, remember to be careful. It is a serious stripper. Avoid actions that it will cause it to splash or spill. If you have small kids or animals that go in your work space, I don't recommend it. Be sure to read all of the safety warnings on the Benco website.



Alternative Powder Coat Stripping Methods

 

Powder Strip by Express Chem

 

Benco B17 is not the only powder coat stripper on the market.  There are others that work well, not as well as B17, but the trade-off is that they are more pleasant to use.  Powder Strip PS-1L is another powder coat stripper that I  have used with good results.  It is not quite as fast as Benco B17 and sometimes there will be some stubborn powder coat stuck in a crevice that does not get removed, but the smell is much better and it does not burn skin immediately on contact.  PS-1L is by no-means safe to handle carelessly, but if you do ever happen to slip up and get drop of it on your skin, you will have time to get to a sink and wash it off before it burns and leaves scars.  I can be around it with just a respirator and not smell a thing.  There are several strippers of different strength strippers from Powder Strip and you can request some samples to choose which one you want to use. Keep in mind that the stronger stripper, PS-2L, will burn skin on contact.  The average price for Powder Strip is $150 for a 5 gallon drum or $625-$695 for a 55 gallon drum.  


Paint Stripper


powder coat stripper
While Benco B17 is commonly referred to as the best powder coating stripper, it is really meant for a powder coater that will use it frequently. If you powder coat a couple of times a year and need a every-once-in-awhile powder coat stripper, a more common paint stripper, sometimes called Aircraft stripper, can be used. These come in aerosol which are basically a one-time use can, or gels which can be lathered on. These aren't extremely effective at removing powder coat, but with enough time and multiple applications, they can work. One important consideration, unless the product contains methylene chloride, it will hardly touch the powder coat.

It is best to wrap a part in saran wrap or a garbage bag after the product is applied as it will slow down evaporation. After waiting 30 minutes, unwrap the part, scrape off as much powder coat as you can. Repeat this process until all of the powder coat is removed. Chemical safe gloves, safetey googles, and a respirator is highly recommended when using these products.


Sandblasting


Another method to strip powder coat is media blasting aka sandblasting. This will take a very long time even for smaller parts. It takes about 30 seconds per square inch to strip powder coating this way. If you have a sandblasting cabinet and don't want to invest in the B17, then this method is basically the only other way. You can see how long it takes me to blast off very small areas in the video below. The first part is powder coated, ignore the second part as it is just spray paint.






Burn-Off Oven

The burn-off oven method of stripping powder coat is not really for the DIY'er or small shop at all. It involves an oven that can heat parts up to 1000 degrees to actually burn the powder coating off. I don't recommend this because at those temperatures, you are affecting the heat treating of steel and annealing aluminum. Also the ovens are very specialized, not something you can do with your home oven.


powder coating burn off oven

Powder Coating: Perfect for Car Restorations



I am going to take a break on explaining the types of tools needed for powder coating and discuss powder coating from a car restoration standpoint.  I am in the middle of a car restoration myself. My car is a Mitsubishi 3000GT VR-4. I learned to powder coat for this car and powder coating will play a major role in making this car look new and keep it that way for many years.  Because powder coating comes in so many colors, shades and textures, it can match basically any finish possible.  Even if you have a 60's era muscle car and would like a completely concourse restoration, powder coating can be used to match those original finishes.

black 99 Mitsbubishi 3000gt vr4

Media Blasting Part II - Setting up a Sandblast Cabinet

I explained the different types of blasters (pressure pot and siphon) and blasting in a blast cabinet, outside, or in a dedicated blasting room in the previous topic: Media Blasting. This article will talk about setting up your media blasting cabinet to be as efficient as possible.

Given that most people reading this are probably DIY powder coaters doing this in their garage, I will say that a sandblasting cabinet is the best setup. Your media is constantly recycled and the mess is contained inside of your blast cabinet.


powder coating in garage

Media Blasting



sandblasted alternator coverMedia blasting also known as Sandblasting is a great preparation method for Powder Coat. . When powder coating, it is very important for the item you are coating to be completely clean of oils, dirt, paint, rust, corrosion, and damaged plating (zinc, nickel, chrome, etc). All of these things can interfere with the powder coating process causing imperfections in the finish or causing it to fail completely. After cleaning your item of all oils and dirt, a Media Blaster does this job very well and very easy compared to other methods.

How to Properly Ground Your Parts



Improve the attraction of powder to your parts while powder coating.

If you are powder coating a metal part, it should be grounded. The grounding is what attracts the powder to the part. The better the ground, the less problems you have, especially when doing multiple coats. Often a powder coating gun or the guns control box will come with a little 18 gauge ground wire and a mini alligator clip that you can connect to your part to ground it. I will call this the "stock" ground. The stock ground continues through the control box, through the wire it uses to plug into a wall outlet and after that is a mystery to me. This is not a good example of a ground. No matter how good of gun you have, you should have a DEDICATED GROUNDING ROD.
Powder Coat grounding rod

Monitor Temperatures using an Infrared Thermometer



Having consistent and accurate oven temperatures is very important when powder coating.  Knowing what temperature your part is at when it is in the oven is essential.  I will be talking about how to do this using an infrared thermometer.

powder coating part metal temp ir thermometerAn infrared thermometer, also called IR thermometer, also called  IR Temp Gun can measure the temperature of an object without actually touching it.  They display the temperature on an lcd screen.  They also usually have a laser pointer to help you accurately read temperatures. I'm sure you can see how a tool like this would be helpful when powder coating.  In case you don't see the importance, take a look at this scenario to see how great these tools can be:  You just finished spraying your powder on your part, and you stick it in the oven. Lets use an example cure schedule of 400 degrees F for 10 minutes(your powder will specify your cure schedule). So you have the part in the oven, you shut the door and you set the temperature for 400 degrees. You DO NOT start the 10 minute timer when you shut the oven door. The 10 minute timer starts when the entire part itself has reached 400 degrees. The easiest way to tell when your part has hit 400 degrees is with an infrared thermometer.

Materials you can Powder Coat



Powder coating can be used to coat many types of materials. The most common material is metal, but you can also powder coat wood, plastic, composites, glass, and MDF. The first consideration for coating objects besides metal, is can it withstand the temperature. Most plastics will melt when subjected to 400 degree heat for any length of time so it is important to research exactly what your object is made of before you try to powder coat it.

powder coating glass
This glass vase was powder coated red for Valentines Day.