What is sandblasting?
Sandblasting should be called "Abrasive Blast Cleaning," to be technically correct. This term takes into consideration all of the many and varied abrasives commonly used.
Sandblasting is the cleaning of surfaces by the action of abrasives propelled by compressed air through a nozzle.
Several degrees of surface preparation can be obtained by sandblasting, and the wise purchaser or contractor should decide in advance the exact degree required and expected.
Sandblasting finds its most common application in the cleaning of metal objects, however it is also used to frost glass for decorative purposes, in removing finishes from wood and plastics, removal of latence from concrete, cleaning brick and stone buildings, and many other unusual jobs.
In blasting metal the answer is contained in two words: Anchor Pattern. These words describe the etched surface or tooth obtained by the abrasive striking the metal. The Anchor Pattern provides a clean etched surface to which the modern coatings will adhere.
Cost conscious buyers know that corrosion prevention is cheaper than replacement of the structure or item and as a result very costly coatings are now being used in place of very cheap paints, as in the past. While these coatings may seem costly to purchase and apply, if their greater life is considered the yearly cost to the buyer is substantially reduced. None of these coatings will give their maximum life unless the surface is properly prepared by SANDBLASTING.
Unless all loose mill scale, rust, rust scale, old paint, or other foreign matter is removed, there is no point in using the better coatings - you are bound to have coating failure in short time. SANDBLASTING provides this insurance - and, with proper equipment and methods, at a low cost.
Each coating manufacturer will specify the exact type of surface condition (anchor pattern) required for proper adherence of each coating. It is our recommendation that your coating supplier or coating applicator be consulted before surface preparation specifications are prepared.
Generally one of the first questions being asked of a sandblaster is , "What will it cost me to sandblast this?" This is like saying, "How long is a piece of string?"
It is impossible for anyone to give an exact answer to this type of question, particularly when you consider the intangible and variable factors associated with sandblasting.
All of the above points are intangibles and it would be impossible to sit in an office and determine a cleaning rate of an object in the field, or comparing prices that may be quoted to you over the telephone by different sandblasters.
There are different techniques used in determining the estimated cost of sandblasting a particular item. One, is a visual inspection and a scratch test to determine the surface condition. Second, is an actual sample area or a sample part sandblasted, to determine the rate of production on that particular item. Combining this with the five points listed above an estimator can more accurately determine the sandblasting cost of the item.
Surfaces to be cleaned or sandblasted will vary considerably in size and type. They can be as large as an aircraft carrier of as small as and electronic component.
In order to properly determine the cost of sandblasting an item it is necessary to determine the type of abrasive to be used on the job. Prices on abrasives will range from $4.00 per ton for common sand, to products costing as high as $800.00 per ton for manufactured metallic abrasives. Adding to that the cost of transportation of the abrasive from the source to the point of use, which may cost as much as 2 1/2 times the cost of the abrasive.
In choosing an abrasive for the job certain things must be known:
Abrasives are classified in several ways: