Pressure washing - daft questions

[Rich764089]

Hi all,

Total newbie to the world of detailing, but I've decided that I should start taking better care of my newest car! So, I bought a cheap pressure washer and lots of other goodies. Having now used snow-foam (Autoglym Polar Ice) a couple of times, I'm a little underwhelmed by this pre-wash stage - it doesn't seem to remove all that much dirt! Am I expecting too much, or am I doing something wrong?!

I can remove much more dirt if I hold the pressure-washer nozzle very close to the car, but can I cause damage doing this? How close is too close on full power?! It's a Karcher K2, so max. pressure is 110bar/1,600PSI.

Sorry for the daft questions, as you can see, I know nothing!

Rich

 

[bob6600]

Not a daft question, we all start somewhere! Yes you can cause damage, especially if there is a stone chip or any broken paint.

 

[V6GBJ]

Hi all,

Total newbie to the world of detailing, but I've decided that I should start taking better care of my newest car! So, I bought a cheap pressure washer and lots of other goodies. Having now used snow-foam (Autoglym Polar Ice) a couple of times, I'm a little underwhelmed by this pre-wash stage - it doesn't seem to remove all that much dirt! Am I expecting too much, or am I doing something wrong?!

I can remove much more dirt if I hold the pressure-washer nozzle very close to the car, but can I cause damage doing this? How close is too close on full power?! It's a Karcher K2, so max. pressure is 110bar/1,600PSI.

Sorry for the daft questions, as you can see, I know nothing!

Rich

Hi Rich. We live on muddy lanes at this time of year so optimizing a car wash is time saving. I normally blast the loose dirt off first, using a Karcher K3 but avoiding parking sensors etc. I then use Polar Blast snow foam and let it dwell (but not dry out) for five minutes before power washing. You can literally see the dirt washing off the car. Next is shampoo wash etc. Don't forget that the smoother the panels are as a result of proper polishing and waxing, then the easier the dirt falls off and the less effort needed.

 

[Rich764089]

Thanks guys. Yes, black car + muddy lanes = lots of cleaning!

I find the snow foam doesn't remove as much dirt as I expected unless the washer nozzle is held close to the car - perhaps I need to use more of it (using about 150ml per wash I think).

Does anyone have a recommendation for the closest distance I should hold the pressure washer to the area to not cause damage, e.g. am I safe at 1 foot away? Further, closer?

 

[Deleted member 65149]

Not a daft question, we all start somewhere! Yes you can cause damage, especially if there is a stone chip or any broken paint.

Exactly that. Very many years ago when first using a pressure washer on a Jag I managed to remove a large section of lacquer on one door when presumably catching the edge of a stone chip that I didn't even know was there!

I'm not madly impressed with snow foam either - I just use it to get the worst of the muck off so it doesn't get dragged across the paintwork (thus scratching it) when using shampoo on a mit. I only have my Karcher pressure washer set at no more than half power when using it on the car's paintwork and wheels. I made the mistake on my diamond cut wheels of thinking I could use it on high power, but of course there's lacquer on them too. There was me thinking what a good boy I was for not using any chemical cleaners on the wheels and instead the jet washer f***ed them!

 

[Rich764089]

Eeek....better inspect for any damage already caused and amend my ways! I'll reel in my optimism about the snow-foam and factor in more mitt-time

Thanks!

 

[chrisk2010]

Hi Rich,

Not as silly question at all, AG polar blast is very fun to use but isn't that great at cleaning i'd recommend giving Bilt Hamber snow foam a try it isn't massively "foamy" but has a much better cleaning ability than the AG stuff.

A few things to remember for correct use is working out the PIR (panel impact ratio) by filling you snow foam lance wwith water, attached it to the pressure washer as you normally would and empty it into a bucket then measuring how much water filled the bucket and multiply it by 0.04, so if you have discharge 12 litres in a bucket until the bottle is empty 12 x 0.04 = 0.48 which means you'd need to add 480ml of Bilt hamber auto foam to your snow foam bottle. ( i hope i have explained that correctly).

Here's a link explaining how to do it but there are thousands of vids on youtube too.
http://www.bilthamber.com/media/downloads/auto-foam.pdf

The pre-wash stage itself is to remove as much dirt and grime possible before you take your cleaning mitt to it to reduce swirl marks. Is this stage important? To be perfectly honest it really is down to the individual if you just want a clean car and aren't to bothered about fine scratching then no it isn't, if your aim however is to preserve the clear coat for as long as possible then it will be.

Lee done a thread where we discussed pre-washing and he was kind enough to do a few tests and take pictures to show everyone the result, here's the link.

Pre Wash Debate.... Do you pre wash your Pre wash? What Say You?? | Detailing

Keep in mind that pre-washing isn't going to fully clean the car but it is just the first step in a maintenance wash not the beginning and end.

 

[Alex225]

There's never really a daft question OP, everyone starts somewhere.

As said, you can do damage if there is a weakened part of the paintwork from a stone chip or a repair. The pressure washer is no doubt sufficient to remove dirt but there will be limitations.

Like you, I have tried snow foams and generally have felt underwhelmed with the results. Never really seemed to do any more than wetting the car and using the pressure washer to remove the dirt. I did find Citrus Pre-Wash to be better though so I stick with that now. I understand there are some snow foams that are a combination of snow foam and a pre-wash which by all accounts work better.

I'm sure if you mix snowfoam up enough so that it's this shaving foam thick lather that takes ten minutes to run off the car it may be better but my experience of it was a bit underwhelming.

 

[Rich764089]

Hi Rich,

Not as silly question at all, AG polar blast is very fun to use but isn't that great at cleaning i'd recommend giving Bilt Hamber snow foam a try it isn't massively "foamy" but has a much better cleaning ability than the AG stuff.

A few things to remember for correct use is working out the PIR (panel impact ratio) by filling you snow foam lance wwith water, attached it to the pressure washer as you normally would and empty it into a bucket then measuring how much water filled the bucket and multiply it by 0.04, so if you have discharge 12 litres in a bucket until the bottle is empty 12 x 0.04 = 0.48 which means you'd need to add 480ml of Bilt hamber auto foam to your snow foam bottle. ( i hope i have explained that correctly).

Here's a link explaining how to do it but there are thousands of vids on youtube too.
http://www.bilthamber.com/media/downloads/auto-foam.pdf

The pre-wash stage itself is to remove as much dirt and grime possible before you take your cleaning mitt to it to reduce swirl marks. Is this stage important? To be perfectly honest it really is down to the individual if you just want a clean car and aren't to bothered about fine scratching then no it isn't, if your aim however is to preserve the clear coat for as long as possible then it will be.

Lee done a thread where we discussed pre-washing and he was kind enough to do a few tests and take pictures to show everyone the result, here's the link.

Pre Wash Debate.... Do you pre wash your Pre wash? What Say You?? | Detailing

Keep in mind that pre-washing isn't going to fully clean the car but it is just the first step in a maintenance wash not the beginning and end.

Really helpful, thanks Chris. I'll definitely try the BH auto foam next - and your maths makes sense! I'd hoped for a bit more dirt removal from the Autoglym foam to minimise any swirling with the mitts.

Excellent posts and testing from Lee in that link

 

[Rich764089]

There's never really a daft question OP, everyone starts somewhere.

As said, you can do damage if there is a weakened part of the paintwork from a stone chip or a repair. The pressure washer is no doubt sufficient to remove dirt but there will be limitations.

Like you, I have tried snow foams and generally have felt underwhelmed with the results. Never really seemed to do any more than wetting the car and using the pressure washer to remove the dirt. I did find Citrus Pre-Wash to be better though so I stick with that now. I understand there are some snow foams that are a combination of snow foam and a pre-wash which by all accounts work better.

I'm sure if you mix snowfoam up enough so that it's this shaving foam thick lather that takes ten minutes to run off the car it may be better but my experience of it was a bit underwhelming.

Again, very helpful, thanks Alex. I'm glad I'm not the only one underwhelmed!

 

[AltonAnt]

I find it works effectively on a well prepared car. Once your paintwork is well protected e.g. decontaminated, polished and waxed them snow foam is great as a pre-wash.

If using it an a car that is usually cleaned in a car wash then I wouldn't expect it to be as effective.

 

[Rich764089]

Anyone prepared to stick their neck out on the how-close-is-too-close question.....?

 

[merc85]

Anyone prepared to stick their neck out on the how-close-is-too-close question.....?

Nope lol, But keep the lance moving don't stay in one spot would be my advice also adjust the nozzle so its not a solid jet more of a Spray pattern working from the top downwards

 

[chrisk2010]

Really helpful, thanks Chris. I'll definitely try the BH auto foam next - and your maths makes sense! I'd hoped for a bit more dirt removal from the Autoglym foam to minimise any swirling with the mitts.

Excellent posts and testing from Lee in that link

I was gifted some AG Polar Blast for christmas and broke it open the weekend, like i said it was fun to foam the heck out of the car but it didn't really remove much.

I hit the car with 10% Surfex HD gave it a few minutes to dwell and went over that with some BH autofoam and gave that a further 5-10 minutes to dwell which worked out a treat.

To use up the AG Polar blast I'll use it after applying bilt hamber (after my pre-wash) to coat the car for a contact wash with the detail brushes.

 

[merc85]

Think i will have to try some of that BH autofoam,

 

[Rich764089]

I was gifted some AG Polar Blast for christmas and broke it open the weekend, like i said it was fun to foam the heck out of the car but it didn't really remove much.

I hit the car with 10% Surfex HD gave it a few minutes to dwell and went over that with some BH autofoam and gave that a further 5-10 minutes to dwell which worked out a treat.

To use up the AG Polar blast I'll use it after applying bilt hamber (after my pre-wash) to coat the car for a contact wash with the detail brushes.

Father Christmas obviously didn't know you were so particular with your chemicals

I think I might follow suit, given you saw much better results with Surfex + BH. Thanks.

 

[alabbasi]

can remove much more dirt if I hold the pressure-washer nozzle very close to the car, but can I cause damage doing this?

Yeah, you can drill through concrete with a pressure washer if you use the right nozzle. Multiple gentle passes will be better so that you let the water soak in and try to not let it go for so long.

 

[AltonAnt]

Anyone prepared to stick their neck out on the how-close-is-too-close question.....?

With the K2 I wouldn't want to get closer than about 50cm using the standard Karcher lance.

 

[Rich764089]

With the K2 I wouldn't want to get closer than about 50cm using the standard Karcher lance.

Awesome, thanks.

 

[MrGreedy]

Yeah, I was going to say no closer than 30cm at the very closest as you're quickly going over a panel with a nice can jet. Deffo not a concentrated lance jet. The pressure washer is there for powerful, quick, efficient rinsing. Not ebrading the dirt off the surface on the paint.