Huge thanks to Dave KG over on the detailing world forum for letting me use his write ups on here....
In this thread I hope to explain some good practices for washing a car that help in the prevention of inflicting swirl marks to paint.
Whats Wrong With A Sponge?
Millions of people wash their car using a sponge. But if you read the threads on this forum you will see that hardly any members are washing their cars using a traditional sponge... Why is that? It all comes down to the flat flace of the sponge:
Imagine automotive paintwork with your typical dirt and grit paricles sutck on the top of the paint, that you want to wash off to revela your car's shine. Some of these dirt particles are sharp:
Now, if you place a sponge down ontop of these grit particles as you would do if you were washing your car with a sponge, the grit particles become trapped between the face of the sponge and the paint - they have no where to go owing to the flat face of the sponge:
When you wipe the sponge across the paintwork, you wipe the sharp grit particles straight across the paint. As they move over the paint, the dirt particles leave a thin hairline scratch:
These little scratches are highly visible in bright light because they catch the light, and this is what gives you the dreaded swirl marks that rob yuo paint of gloss and colour and ruin the car's look. A pic of bad swirl marks, the result of sponge washing of a car:
Lambswool and Sheepswool wash mitts have been developped to get around the problems of sponges trapping grit particles by the flat face. If you run your fingers through a lambwool mitt, you can see that it is deep pile and not flat faced:
Returning to the grit partciles on paintwork, when the wash mitt is placed onto them, the grit particles are absorbed into the mitt - safely away from paintwork so that they cannot scratch the paint:
Therefore, sweeping the mitt across the paint doesn't sweep the grit over the paint also and so you don't inflict lots of tiny hairline scratches.
Note: While washmitts are considerbaly better than sponges, it is impossible to completely avoid inflicting the odd swirl marks here and there using a wash mitt. What follows in this thread are tips on how to keep these inflicted swirls to an absolute minimum.
Which Wash Mitt?
There are a great number of washmitts on the marked nowadays, ranging from lambswool and sheepswool to cotton chenille to microfibre. In my experience the best mitts are the lambswool and sheepswool. When choosing a mitt, choose one with a soft deep pile that will be kind to paintwork. Two excellent mitts are:
Meguiars Lambswool Wash Mitt
Eurow Sheepskin Wash Mitt
and there are others too.
So Many Shampoos! Which to Choose?
At the end of the day, shampoo choice for your car is going to come down to personal prefernce. But there are so many shampoos on the market its hard to know which ones to go for! A couple of things to look for when choosing a car shampoo:
1. Lubricity in the washing solution - you want a shampoo that makes the washing solution feel nice and lubricated so that dirt particles can be encapsulated by this lubricant and any that aren't absorbed into the wash mitt will slide off the paint without scratching in the rinsing water. Soapy suds are pleasing and can make car washing fun, but lubricated wash solution is more important.
2. A shampoo should contain no harsh detergents if you are washing a car that you have spent many hours polishing, sealing and waxing. Harsh detergents strip wax straight off the paintwork leaving your paint surface dried out and unprotected. Fairy Liquid is therefore a big no no for washing cars. You feel what happens to the sking on your hand if in prolonged contact with harsh detergents, it dires the skin out - it will do similar damage to paint.
With this in mind, there are still a huge number of car shampoos that fit the bill - ones that I have used and rate are the following, so if you're struggling on which to choose, try one of the following:
Meguiars #62 Bodywork Shampoo & Conditioner
Meguiars Gold Class Bodywork Shampoo & Conditioner
Meguiars Hyper Wash
(awsome dilution ratio of 400:1 - lasts ages!)
Poorboys Super Slick & Suds
Pinnacle Bodywork Shampoo & Conditioner
What is the "Two-Bucket Method"
Again, millions of people use a single bucket of car wash solution to wash their car, but if you read the threads on this site you will find most members wash their cars using the "Two-Bucket Method" - whats that?
As suggested by the name, the two bucket method uses two buckets, not one. In thie first bucket, you have your car wash solution as normal. In the second bucket you have clean fresh water. First off you soak your mitt in the wash solution and begin washing the car (as described below). Then, before dunking the wash mitt back into the wash solution, you rinse it out in the second bucket of fresh water - this rinses out the dirt and grit particles from this mitt so that they cannot come into contact with your paint, reducing the number of swirls inflicted.
A grit-guard is also a very worthwhile investment and sits at the bottom of the bucket (I have two, one in the rinsing bucket and one in the wash solution bucket). When dunking you mitt into the fresh water bucket, rub it across the grit guard to increase the amount of grit particles which are removed from the mitt. Also, it keeps them trapped at the bottom of the bucket so even less chance of the mitt picking them back up and them reaching your paintwork to inflict scratches.