Properly hand washing your vehicle is the best way to prevent paint swirls from occurring. The 2 bucket system (one for your soap, one for rinsing your mitt) works very well specially if you also incorporate a grit guard to trap dirt that is released from your mitt as you wash.
However using some type of foamer to apply the soap onto the vehicle will help reduce even more the possibility of inducing scratches. Using a foamer to apply your soap does not mean you do not need to touch your vehicle but there advantages over just dunking the mitt in your bucket to load it with soap. Most quality car wash soaps include lubricants that allow your wash mitt to gently slide over the surface. The ability to cover your vehicle with more of this lubricating soap than you can administer with just your mitt is a definite benefit. In addition when your car is covered in clingy foam it is easier to see where you have already washed preventing going over the same area more than necessary. The less you have to touch your paint the better!
Having a foamer also opens up the ability to use a pre-wash soap as a first non-contact step.
Pre-wash soaps do not replace the need for a regular soap & mitt wash but they do help reduce the possibility of creating scratches. Pre-Wash products are applied and allowed to dwell for several minutes. They soften dirt and surround the larger dirt particles. As the soap slides down the paint it draws the dirt particles away from the surface of the paintwork. This includes traffic film, grit, insects and bird droppings. There are a number of great pre-wash soaps available. Click HERE to learn more.
Types of Soap Foamers
A hand pump foamer is the simplest and easiest device to apply foam to your vehicle. Griot's Garages Foaming Pump Sprayer is an example of a great quality unit. Its made of chemical resistant polypropylene that allows you to use even the strongest chemicals in your detailing arsenal without fear of harming the sprayer. Once pumped up it holds 43psi of pressure and the specially designed nozzle produces a great amount of foam. Another benefit to using this type of device is it's capacity. The unit holds 60 ounces compared to the 32 oz that most foam cannon jars hold.
A foam gun is like a foam cannon but instead of needing a pressure washer it attaches to your garden hose. The benefit of course is that you do not need to purchase a pressure washer. The downside is that you will not get quite the same amount of clingy foam that you get with a cannon. However these type units still produce quite a good amount of foam and are a great low cost option.
Foam cannons are probably the most popular type foamers but as already mentioned you will need a pressure washer. And keep in mind not all pressure washer wands can accommodate the cannon. Before purchasing a cannon make sure your pressure washer has the right type of wand to attach the cannon...
Foam cannons will apply a clingier foam than a foam gun and will apply the soap faster. There are a huge number of cannons on the market but cheaper is not always better. Remember that the cannon has to hold up to that water pressure going through it. Cheaper units tend to fail rather quickly. There are several things to check that a unit has before purchasing..
Does it have a brass head unit?
Does it include the fitting to attach to the wand?
Threaded bottle (how easy does the unit thread on?)
Foam thickness dial (adjust the thickness of foam)
Foamer nozzle (adjust the vertical height of foam)
Tornador Foam Gun
The final type of foamer is one that attaches to an air compressor rather than a pressure washer. The Tornador Foam Gun is a great unit. Injecting air into your mixture produces that "shaving cream" type clingy foam. Another huge advantage over this type of unit is that it can be used for more than just washing your vehicle. It also works great for cleaning carpets & upholstery! The unit comes with 2 nozzles: a wide one to use washing the car & a narrow one for use inside the vehicle.
Foam Cannon Soaps
Although there are a number of car wash soaps on the market specifically formulated for use with foam cannons (Griot's Garage Foaming Surface Wash & Tornador Sudsy are both great) reality is most good quality car wash soaps will work quite well in a foamer. Stay away from combination wash & wax products and/or ceramic soaps containing Sio2 for foamers. Neither of these types of soaps foam as well in a cannon as just a standard wash soap. Some of our favorites are..
The All-in-One Solution
If you are looking for an awesome solution that covers all the bases look into Griot's Garage BOSS Foaming System. With its stainless steel construction & auto mix metering system the Boss Foam Cannon is one of the top quality foam cannons on the market. The Boss Foaming System includes Surface Prep pre-wash, Surface Wash wash soap & Poly-Gloss. Poly Gloss is a polymer based final step that delivers superior paint protection, intense gloss, and remarkable water repellency.