Meticulous blasting
Most vehicles arrive at Autoblast completely stripped and ready for blasting. Once here, the team does a thorough walk-around to discuss and understand exactly what the client’s vehicle needs. Everything is noted down and communicated clearly to their expert blasters before the vehicle is stripped back to bare metal using the abrasive-blasting process, leaving fresh white metal behind. This is, without question, the best way to prepare steel for painting. It sounds simple enough in theory, but abrasive-blasting fragile metal is anything but — it takes a skilled, well-trained and patient hand.
Careful dusting
Once blasting is complete, the vehicle is dusted of all remaining residue using an industrial-scale duster. This stage is almost as critical as the blasting itself, and it demands the same level of patience and diligence.
From there, the next step is applying the chosen coating system. Some of Autoblast’s commercial clients prefer to handle their own priming — but as far as possible, this needs to happen on the same day, because oxidisation starts the moment blasting finishes.
Exceptional coating
In Autoblast’s opinion, the best coating system available is a galvanic metal spray metallisation process, properly applied. For clients who opt for this, the shell is metal-sprayed with a zinc and aluminium coating — 50 per cent zinc, 50 per cent aluminium by volume — which effectively galvanises the car. One of the side benefits of galvanising a shell is vastly improved coating adhesion: the first coat of paint soaks straight into the metal-spray coating.
Autoblast only uses the highest-quality 2K epoxy coating systems. The team knows the best brands in the business, and unless a client requests a specific system, Autoblast will specify one that suits their requirements and matches their ongoing coating system.
I’ve heard that abrasive blasting can warp panels. Is this true?
It is true, but a skilled blaster knows how to protect panels from warping. Blasting delicate panels without warping them comes down to a combination of low pressure, acute angles and constant rotation of the working surface — expert technique, backed by a good amount of patience. Understanding why a panel warps in the first place is key to avoiding the damage. Plenty of people assume heat is to blame, and while that is partly true, it is generally not the real cause, which has more to do with poor technique. A panel warps under blasting when the top layer of metal is stretched, and in this situation it warps towards the operator rather than away from them, because that top layer is being stretched. Blasting at an acute angle of attack means most of the energy from the process is spent on the coating rather than the panel itself.
I’ve heard that soda blasting is safe from warping and is a better process. Is this true?
It is not. Soda blasting can still warp a panel for exactly the same reasons outlined above. On top of that, the soda-blasting process will not leave a mechanical key for the coating system to adhere to. It also leaves an alkaline residue on the steel, which neutralises the acids in epoxy etch primers and nullifies their etching properties. Soda has its uses, but blasting metal ahead of painting is not one of them — a fact the soda-blasting industry has only recently come to terms with. That said, it is recommended for some aluminium, plastic and carbon-fibre parts and panels.
How should I prepare my car for blasting?
For a full restoration, Autoblast recommends the vehicle is completely stripped of all glass, trim, seats, dash, engine and so on. Some of the most vulnerable areas for rust can only be reached once these are removed — underneath windscreen rubbers and mouldings is a common one, as are the chassis rails near the battery and engine. That said, Autoblast has handled plenty of restoration blasting jobs on partially stripped cars. This is fine, but it does mean spending time heavily masking any areas that would otherwise be vulnerable to the abrasive-blasting process. In short, a car can be blasted in whatever state it arrives — the more that is stripped, the more that can be blasted, and the rest is up to the client.
How long can I leave my blasted shell in primer?
When you book your car in, Autoblast’s trained professionals will discuss how long you would like to leave it in primer and spec a paint system to suit. Some primers can last up to ten years — a galvanised shell considerably longer — depending on the atmospheric conditions the car is exposed to. Others have a shorter lifespan when left uncovered but are easier for a panel beater to work with. A common time frame recommended by manufacturers is six to nine months, and all epoxy primers are designed to be recoated, so it pays to know what your restoration time frame looks like. One trick to extend the lifespan of any coating is to store the vehicle in a stable-temperature environment; a dry environment helps too, since an unstable temperature will draw moisture out of the air and onto the car. An insulated garage is the best option for storing your project. Autoblast’s best advice? Once you have started restoring, do not stop. If you do need to leave a shell longer than expected, you can always add another layer of paint over the primer.
