It’s been a long time (too long) without a tech tip, so here is a good one.
My first introduction to “bead blasting” as it’s most commonly called, was during the fall of 1979 in the Motorcycle Mechanics class at Hutchison Vo-Tech. And what a wonder it was to everyone in the class. Parts that were dirty, carbon encrusted and with burnt-on oil deposits suddenly looked like brand new parts! Of course, every motorcycle shop I worked in from there on out had a bead blast cabinet. A great tool, and an even better one when used properly. Can you believe it took nearly 40 years for me to discover the proper use of that tool?
One of what I considered to be an idiosyncrasy of the bead blaster, turns out to be just a symptom of that misuse, or should I call it misguided use. But recently, I found the answer to the question that I had failed to ask, or rather the observation that I should have put in the form of a question. That observation goes something like this: when you put fresh clean glass beads in the cabinet, you get a bright clean finished product, especially when the part you are working with is aluminum. But when you load those nice clean beads, it always seemed that they just didn’t want to clean all that carbon and baked on grease off of the part as well. Then after running a goodly number of parts through the cabinet, it would seem to remove the deposits more quickly, but as the cleaning improved, the finish went from bright to a dull color that seemed to also pick up any greasy fingerprint that came within spitting distance of the part. I, and I am sure many others, got in the habit of trying to make sure relatively clean beads were in the cabinet whenever a nice final finish on the part was important. I had often considered purchasing a second blast cabinet so that one would always have fresh clean beads for that purpose, but suffered along with changing the beads as needed instead.
So, where did I finally learn the proper use of a blast cabinet, you ask? Probably the last place in the world one would think you would find technical information. Ebay. Yes, … Ebay. It probably began with a general internet search for glass beads because the source I had been using suddenly and without warning tripled its shipping charge to get a 50 pound bag to me from the other side of the city. As is so often the case, a search for nearly anything will come up with a result from Ebay stating “buy fill in the blank on Ebay". But this time it was a winner.
It turns out that Tacoma Company not only sells their abrasives on Ebay, unlike other suppliers I have dealt with, they provide information on the proper application of their wares. Not saying other suppliers don’t have that information, but sometimes you don’t even know that you should be asking a question, let alone what that question might be.
So the answers to some of the questions I had not known to ask are as follows:
1. Glass Beads are round and are meant to “peen” the surface, not to clean it.
2. Glass Abrasives are sharp and do a great job of cleaning but leave a dull finish that dirt will impregnate easily.
3. Glass beads can and should be used at a much lower air pressure which keeps them from shattering and turning into abrasives.
Armed with this information, a couple years ago I added a second blasting cabinet to my shop. Now the first stop for heads and other parts needing the carbon, baked on grease and grim or paint removed is into my old industrial quality blasting cabinet containing glass abrasives to clean then quickly and easily. Then the clean part goes into an economy blasting cabinet at a lower air pressure for a bright finish that does not pick up dirt easily. An added bonus is that the glass beads now last many, many times longer since they are not being broken up by the high air pressure. Who knew?
Now, if you have a supplier of the proper abrasives down the street from you, obviously you can purchase the correct product for your application cheaper if you don’t have to deal with shipping costs. As for me though, I will continue to purchase mine from Tacoma Company since the information they provided has not only saved me gobs of time, it has helped me to present a better looking final product.
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| Shipments arrive with a courteous Thank You note |
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| ... Along with some words of wisdom |
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| And even a pocket size copy of the U.S. Constitution |
My kind of people!