You’ve probably heard us say, “You can’t machine it until you clean it” more than once. In this Tech Notes post, we’re going to talk about cleaning solutions; both detergents and methods.
There are two cleaning methods that we’re going to talk about in this post – Cold Solution and Hot Solution. Both have their merits and both have their downsides.
Cold Solution Cleaning is exactly what it sounds like. A solution of water (usually) and detergent is mixed and kept at room temperature. This method is not used often in the machine shop for the simple reason that it takes too long since cold solution cleaning is done primarily by immersing the parts and letting them soak to remove the crud.
Hot Solution Cleaning is faster than cold solution cleaning as the heat speeds up the cleaning process. Heated cleaning is usually done in a Hot Tank or in a Jet or Cabinet Washer. Both operate at between 165° and 180°F. The Hot Tank is an immersion cleaning method. You submerge the parts to be cleaned into the tank’s cleaning solution where they are agitated to speed the cleaning process. This can be by a platform that moves up and down, by circulating the cleaning solution with a pump or a combination of both. An advantage of this type of cleaning is that the cleaning solution gets into every single area of the engine part. The disadvantage is that it’s slower than using a jet or cabinet washer. (Photo courtesy of Professional Engine Systems, Inc., Canfield, OH)
Jet Washers and Cabinet Washers are similar to industrial strength dishwashers. You load the cleaning cabinet with the parts to be cleaned and introduce the heated cleaning solution through spray nozzles. Between the cleaning solution and the lightly pressurized spraying force, parts will clean fairly quickly. A down-side of these cleaners can be that some tight areas hidden from direct spray might get missed because the cleaner can’t get in to do its job.
One cleaning method that fits into both cold and hot categories is Ultrasonic Cleaning. For the most part, ultrasonic cleaning can be used for most materials including ferrous and non-ferrous metals, plastics, ceramics, etc. Because ultrasonic cleaning uses sound waves the cleaning solution is able to reach areas such as blind holes that other cleaning methods may miss.
Now that we’ve covered the pros and cons of cleaning methods, let’s look at some tips related to choosing the right cleaning product. This month we’ll focus on detergents and other cleaning solutions. We’ll look at glass beads, tumbler media, steel shot etc. next month.
One of the first things to look at when selecting a detergent is the type of cleaning machine that will be used. It’s not a good idea to use a detergent intended for a non-agitating cleaning solution in one that does have agitation. If you’ve ever accidentally put liquid dish soap in a dishwasher you know what can happen…you’ll get lots of suds and very little cleaning. So be sure you’re asking for the right type of detergent when ordering. If you’re not sure, don’t be afraid to ask the Goodson Techxperts for help.
Most machine shop detergents are concentrated and have a mix ratio that should be followed. The mix ratio is calculated to give you the best cleaning performance. We’ve probably all heard or said at one time, “If a little bit is good, a lot must be better.” For some things; maybe. For detergents; NO. Just as a weak concentration of detergent will give less than desirable results, too strong of a concentration won’t work well either. Nor will increasing the heat if you’re using a hot tank. If the temperature is set too high, the detergent solution will evaporate faster, becoming more concentrated, and, if left long enough, potentially damaging the heating element.
Goodson recommends performing a pH test to check the concentration in your hot tank, jet spray or jet wash at least once a week. You want a pH level around 12 to avoid damaging the parts you’re cleaning and your best guess just won’t cut it. Get yourself a pH tester (Goodson Order No. HT-PH) and use it. Make adjustments to your detergent concentration as needed.
You’ll also need to look at the material you’re cleaning. Is it cast iron or aluminum? You can always use a magnet to confirm if you’re not sure. In a perfect world, you would have two cleaning systems – one for ferrous and one for non-ferrous metals. Of course, we don’t get to live in that perfect world so dual cleaners are available. They do a pretty good job on both ferrous and non-ferrous metals but some after-cleaning may be needed.
We touched on foaming a bit earlier, but there’s a little more you should know. Even with a non-foaming detergent you may get foam. The agitation from your hot tank or jet wash may cause some foam, but it could be something as simple as hard water. It’s probably best to use a de-foaming agent such as Goodson’s D-FOAM, available in 8 oz. or 1 gallon containers.
Whether you’re using a caustic, a solvent or a biodegradable detergent, it is essential that you rinse the cleaned parts thoroughly with hot water and blow them dry. Apply a rust inhibitor (such as Goodson’s RS-16) immediately to prevent corrosion and oxidation. To store your cleaned parts, Goodson recommends storing them in a dry area of your shop, away from cleaning activities. If the part is going to be in storage for any length of time, place it in a plastic storage bag (several sizes are available) to keep it dry and dust-free.
One last caution; take proper safety precautions when cleaning parts. Caustic solutions should NEVER come into contact with your skin, nor should solvents. Always wear gloves, eye protection and an apron to protect yourself. Be sure that the gloves you choose will hold up to the solution you’re using.
This was a brief discussion of cleaning methods and the solutions you can use, but it barely scratched the surface of the topic. Want more? Read Part 2 of Cleaning Solutions for the Machine Shop.
As always, for more information, visit the Goodson Technical Library online or call the Techxperts at 1-800-533-8010.