Undercoating - Things to Consider

Some things to consider:

• Whenever you put anything onto a surface, it will work better if the surface is clean to start off with. Ideally, your undercoating professional should power-wash the underside of your car before he starts. This will take time because a good shop will also let the car dry before it proceeds further.  Some cars have crevices that no amount of water can wash away the dirt.  You need to find this places yourself and remove this caked-on dirt.
• Most shops don't wash the underside of your car but you can do this yourself. You can take your garden hose and spray the undercarriage until the water washes off clean.
• Fresh surfaces (like on a brand-new car just driven off the lot) can be well protected by a tarry or waxy undercoating. We don't recommended this for cars with undersides that have started to rust. This heavy coating, sometimes known as sound-deadening, will not wash off even with autobahn road spray and is extremely resistant to abrasion from flying gravel.
• Older surfaces can be well protected with a light oily undercoating. The oily nature minimizes corrosion by penetrating rust and and sealing the metal from air and moisture. This protectant should be applied annually for the best results.
• Although some rust-proofing coatings that have the consistency of grease may appear to be thick, they will soak into rust when applied and the thicker consistency will allow them to adhere better and not wash off as quickly.  Sometimes the coating will even lift off loose rust.
• All undercoatings should be applied to the inside, hidden surfaces of your car like the rocker panels, doors, hoods, trunk lids, and wheel wells. The undercoater has a variety of thin wands that he can insert into the tightest of places. Often, holes must be drilled into the body for proper coverage. Don't bother doing this job yourself on your back in your driveway with a spray bomb.
• Try to avoid doing this job in the winter. If you can, try to schedule it during a dry spell in the summer or autumn so the undercoating can set without being washed off or blasted with winter road salt & sand.
• Undercoating shops often have promotions throughout the year, sometimes in the summer when business is slow, usually the in the fall. Often, they will put a coupon in the newspaper for you to clip and bring in.
• Find out exactly what the shop promises to rustproof. After getting the car back, inspect the work to make sure that you got what you paid for. Pay attention to the rust-prone areas of your car to ensure that they received adequate protection.
• If you're not sure where your car is prone to rust, join an internet forum dedicated to your vehicle and ask other owners what experience they've had. Make sure that the rust-prone areas get protection and don't depend on the rust-proofing shop to know (or care).

Some shops specialize in this service while others offer it as a sideline. There is no magic to undercoating a vehicle and it takes a bit of skill and experience to do it right. The important thing is that all vulnerable areas get a protective coating. Essentially, the cost of this service should not be much more than 1 hour of labour and a pail of material. The going price in the Niagara Region seems to be $80 - $130.