How to choose Ice, Sand, Blasting, Steam Cleaning, Water jetting
Saturday, 8 December 2018 | Admin
How do i choose what blasting / cleaning method to use?
There are many cleaning, blasting and preparation methods available.
We can roughly split them in to two groups- Abrasive and non Abrasive.
Non-Abrasive cleaning / blasting methods.
These are methods of cleaning and removing foreign matter from an item WITHOUT damaging or marking the item itself. You may want this on items like engine components where machined faces like rocker covers are critical to the function of the item. Services in this category include Steam cleaning, Water jetting, Wet ice, and Dry Ice blasting. These methods will also be of benefit on weathered items that may have existing corrosion, and you do not want to cut, or wear away the item, such a rusty wing on a car that you want to repair. They are also typical more gentle, and do not risk warping or otherwise damaging items as much.
Thew drawback is that these processes do not prepare the surface for many types of paint. They may need a high adhesion paint/ coating process, or need abraiding/ keying prior to an effective paint system being used.
Abrasive Cleaning / Blasting methods.
These methods use an abrasive media to cut, chip, and wear away coatings, and rust from an item. They create a waste product which is the "blast media" such as sand. they impact the surface and for most types of use leave an impression on the surface. These methods are no use for machined surfaces, or parts with fine tolerances, as they actually wear away the item as part of the process. Some of these methods will put heat into an item, risking warpage. The benefit of abrasive methods is that they tend to be more aggressive, and the surface once clean, dry, and confirmed free of contamination can be painted as it already has a profile for the paint to adhere to. Abrasive methods we offer include Sand blasting, and hydro (water abrasive) blasting.
From the above you need to decide whether the item you are restoring or cleaning can be abraided or not. If it can then you can potentially choose from any of the above, however if it cannot, you must choose an appropriate non abrasive method.
Blasting / cleaning Processes to choose from at Buzzweld HQ
Using 2900PSI we can clean many items at a cost effective rate. Water jetting at this pressure will remove most things not firmly adherent and operates around twice the pressure of a typical domestic pressure washer. It will not remove sound paints, some grease / waxes. It will remove lots of corrosion, however additional surface prep may be necessary. Items that are water jetting may require degreasing prior to painting. Very useful for larger items that need to be cleaned quickly, and with excessive soiling. We use this method to remove lots of loose paint, reduce levels of rust, and silt in and around chassis and parts.
Steam cleaning at 155C is a superb way of removing grease, and most wax types, as well as contamination. Its superb for engine parts that are heavily soiled. It will not typically remove sound paints unless they have a heat intolerance. Steam cleaning is great at being a cost effective cleaning method, and helping to ensure paints adhere well without other solvents/ waxes/ contaminants affecting the paint. We use this method to remove most underbody waxes, grease, oils, and to provide us with a clean part we can identify for any further work if necessary.
Wet ice blasting uses normal ice cubes propelled at the speed of sound at an item. The ice acts in three ways. the hard ice chips and impacts the surface causing many paints, and all waxes, grease, and harder underseals to fracture and fail. The ice then breaks down and continues on to cleaner harder to reach areas. A side benefit is that the ice melts and washes the surface of contamination and dirt/ debris leaving items actually cleaner that if they were steam cleaned (steam cleaning tends to evaporate and leave a residue of water behind). wet ice blasting is effective at removing heavy rust economically, oils and greases without damaging the item. The wet ice is softer than aluminium / steel and as such is highly effective at cleaning, but does no damage. The limitations of wet ice blasting are that it will find any faults in paint and remove the paint where it is not perfect, but it will not bare metal, or remove sound paint. Rust is also not TOTALLY remove. in all cases it will reduce it significantly. We use wet ice blasting to prepare parts, underbody, and chassis prior to allowing them to dry and then being coated with Rust Encapsulator. Wet ice blasting leaves behind NO blast media. so unlike Abrasive media's it leaves behind no sand etc that can cause other issues for preparation and paint later on. Further reading here
Wet Ice Blasted Rocker cover from a 300TDI land Rover engine
Dry ice blasting is unique in that the item being blasted does not get wet, and no media is left behind. This is because the media used is fully "dry". Dry Ice is made up of C02 liquid frozen to -80C. When this media is exposed to air it will eventually "sublime" which means it transitions from a solid to a gas with no liquid phase the result being your items never get wet. C02 comes from recovered methods from other manufacturing so is also environmentally friendly. Dry ice blasting works be freezing paint, rust and powdercoat to the point it becomes brittle and then chips it off without damaging the surface underneath. Dry ice can be used to remove even tough coatings from delicate items, such as varnish from wood, and powdercoat from aluminium. Being fully dry we use this to clean our machines. Its also used alot to clean engine components, circuits, and electrical items even if still live!
Sand blasting works by propelling sand with air at an item. The sand abraides the surface and leaves you with a keyed surface that should then be inspected, air dusted off, and then painted. Its effective at removing most coatings. It is not suitable for machined surfaces. media is left behind, as well as creating lots of waste media unless the sand is recovered and re-used (which can also become a source of contamination). we use sand blasting on small items we want to be aggressively cleaned. we will not use it on chassis and underbody as the media gets everywhere and cleaning the media out is as much of a job as blasting it.
Dustless blasting combines water jetting, with sand blasting. Sand is combined with the water stream to create an abrasive water jet. Dust is kept to a minimum as the water encapsulates the media. Less media is used, so its easier to clean down after than sand blasting, however wet sand can be difficult to remove from all areas of a vehicle underbody. We trialled Wet blasting, and whilst its cleaning ability is superb, the cleanup and mess created means we no longer use it on vehicle underbodies that are assembled because clean down time, and detrimental effect to other components, as well as damage to machined faces meant wet ice blasting was preferred.