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