Читать книгу Media Blasting & Metal Preparation - Matt Joseph - Страница 7

PREFACE

I wrote this book because over many years I have often found myself wishing that someone else had written a book like it on cleaning metal. I would have found it very helpful for much of my work on cars. Instead, I had to find out about cleaning on-the-fly by accumulating, sorting, and relating fragments of information from many different sources. I want to save you that trouble and tell you what you need to know about this topic.

Sometimes we are thrilled by thinking about our work on automobiles. Fabrication, restoration, modification, and even maintenance seem exciting. We get to solve problems, do interesting research, talk to interesting people, and, sometimes, produce things of unique beauty. It is exciting to think about these accomplishments.

Basic to all of those endeavors is cleaning metal, because automobiles accumulate grease, grime, rust, destroyed paint and plating, and many other kinds of soils. As interesting and even romantic as car projects can be, we are as likely to find ourselves facing a pile of dirty parts, scrapers, and rags with a can of solvent and a coarse-bristled brush as we are to be called on to converse with talented experts and find and apply brilliant solutions to interesting problems.

Most car projects start with dirty parts and panels and must progress through cleaning these items before much that is original and exciting can be accomplished.

The purpose of this book is two-fold: It is to help you to take advantage of the best and most appropriate cleaning techniques and processes that apply to what you are working on, and to avoid the mistakes in cleaning metal that slow down projects and that can seriously compromise results. It is likely that very few people actually enjoy the cleaning efforts inherent in car projects, but they are nonetheless there and central.

This book is intended to help you spend as little time as is necessary cleaning things and ensure that you get those things clean enough to avoid problems down the road.

The options for cleaning metal parts are numerous. In the past 75 years, new methods, including abrasive blasting, vibratory cleaning, dry ice blasting, and wet abrasive blasting have been added to traditional methods, such as disc sanding and mechanical scraping. Even-higher-tech methods of cleaning parts loom on the near horizon. This book covers both traditional and new metal cleaning methods.

Although cleaning metal may seem like a series of mundane tasks, it is much more than that. If you fail to get the metal that is the basis for your automotive projects adequately clean, you are courting mediocrity, and even disaster, in your results. Some of this is obvious, but much of it can be subtle.

Sometime after we installed a used pressure-blasting cabinet in my shop 40 years ago, I noticed that I was having difficulty with some of the soldering projects that went through our blast cabinet, such as tinning sheet metal. I didn’t make the connection between the used cabinet that we had begun using and my problem getting solder to properly “wet” the metal that we cleaned in that cabinet.

I failed to make the connection between the aluminum oxide abrasive that came in our first used cabinet and my soldering problem. A salesman friend who sold abrasives happened to mention, off-handedly, to me one day that the residues from aluminum oxide abrasive could interfere with certain soldering and welding processes.

My cranial light bulb lit, and I ran some comparative experiments. Blasting with aluminum oxide media does interfere with solder and weld wetting. I wish that I had known that before I experienced the problem. It would have saved me a lot of time and frustration.

Although I cannot claim that this book will inform you about everything you need to know about cleaning metal, I promise you that between its covers is the most useful knowledge that I have gained in more than 60 years of scrubbing metal things to clean them. I hope that this will help you in your own work. After all, as someone once didn’t say, “wisdom emanates from the end of a parts cleaning brush.” Well, okay, someone should have said that.

Here is another example in the metal-cleaning realm of what-you-don’t-know-can-hurt-you: For many years I was on a wild tear to keep silicone-containing items out of my shop. Although some silicone-based products are very good and useful, the danger of getting silicone on metal, primer, and paint is enormous. Sprayed finishes fisheye when they hit it, and that is huge issue.

Accordingly, I banned silicone waxes, conditioners, lubricants, and other formulations from our shop, in the fear that our spray booth air intake would pick up residues and transport them onto the surfaces we were spraying. I went to great lengths to scrub bare and primed parts with silicone removing washes before top-coats were sprayed. For all of that, sometimes we still saw fisheying in our sprayed finishes.

One day, reading the specification sheet for the compressor oil that we were using, I noted that silicone was the basis of that lubricant’s foam suppressant.

Wow! Against my efforts to keep silicone out of my shop and to clean it off all surfaces that we were spraying, I was sending the stuff down our air lines and depositing it on the surfaces that we blew off with compressed air to clean them. I was even using air that contained silicone to propel paint out of our spray guns. I wish someone had told me that most compressor oils contain silicone foam suppressants. Fortunately, a few do not.

I quickly found a synthetic compressor oil that was silicone free. After a few months, and three compressor oil changes, our mysterious fisheye problems disappeared.

My hope is that this book will inform you regarding the best cleaning practices and processes, and that it will help you down the road of discovering more about all of the changing approaches to cleaning metal for yourself.

Matt Joseph

Prairie du Sac, Wisconsin