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White substance on paint?

Posted: Wed Feb 08, 2012 3:25 pm
by laneychief
Please help, I sprayed my minor bright blue and after waiting some weeks for the paint to go off I used a compound and a finishing glaze, on recommendation, it's now left a white almost powdery substance on most of the car, which goes away when wet but returns as soon as it dries!


Any product I can use to rid me of this permenantly??


Cheers

Re: White substance on paint?

Posted: Wed Feb 08, 2012 3:58 pm
by katy
Sounds like your compound was too coarse.

Re: White substance on paint?

Posted: Wed Feb 08, 2012 4:07 pm
by laneychief
So what does that mean?

The residue goes away with water, I was worried it was the primer showing through but it's not

I'm hoping a miracle substance exists for just such circumstances and someone in this fountain of knowledge will know?!

Re: White substance on paint?

Posted: Wed Feb 08, 2012 5:02 pm
by kennatt
if the compound was too course then you have in effect flatted the surface down as though ready for top coating,try to polish it out with t cut,followed by a polish with blue colour back Available at halfords

Re: White substance on paint?

Posted: Wed Feb 08, 2012 7:04 pm
by MarkyB
A picture would help a lot, it's been very cold recently, not ideal weather for spraying <understatement>!

Re: White substance on paint?

Posted: Wed Feb 08, 2012 7:50 pm
by laneychief
I've had this problem for a while, sprayed june last year, just hoped it would of washed away or something

I'll put a picture in the morning. Thanks again all!

Re: White substance on paint?

Posted: Fri Feb 10, 2012 6:01 pm
by Neil MG
At a guess I would think a machine polish with light cutting compound (like G6) would sort it out. If that doesn't seem to be working or there are any marks in the surface you might need to try a heavier cut (G3). If you haven't done any machine polishing before use good quality compounding heads, keep the speed right down, don't let the panel get hot and avoid edges. Ideally get someone to show you. It will take several hours, but if the preparation and painting was done to a very good standard the results will be amazing.

You can use any polish you like when it's done. It will look like it doesn't need it, but you will want to protect that shine.

Re: White substance on paint?

Posted: Fri Feb 10, 2012 7:03 pm
by bmcecosse
What type of paint did you use?

Re: White substance on paint?

Posted: Thu Feb 16, 2012 12:18 pm
by ASL642
Sometimes if you use cellulose paint and the weather temperature is too cold/damp you can get a "cloudy" look. If G3 doesn't work the only way to resolve it is to flat it down and respray when the weather improves.

Re: White substance on paint?

Posted: Thu Feb 16, 2012 6:18 pm
by laneychief
I used cellulose yes, I've got some g3, what's the proper procedure for applying it by machine? Like, g3 on body, or mop head and do I need to dampen anything down, should the car be dry etc...


Cheers

Re: White substance on paint?

Posted: Fri Feb 17, 2012 8:37 pm
by Neil MG
You need to keep the polisher speed down and make sure you have a good quality head suitable for G3. Use a small amount smeared on the head and work in small areas. Make sure that the compound is allowed to break down (spread it across the area being worked before doing several repeat passes) Be sure the panel does not get hot, by touching regularly.

Take your time in the beginning and try not to get over confident as the surface starts to shine! Be very careful around edges and be certain never to let the side of the compounding head touch when working on angled surfaces. It will rub through before you can blink!

No need for any water.

You will need to go over with a lighter cut to remove the swirl marks, but that can wait 'til summer.

The very best is if you can arrange for a professional valeter to give you a demo, or at least watch them at work.

Be warned it will take a long time to do properly. Even the professionals can spend over 8 hours machine polishing a car. You might need to plan for double that, but just do one panel at a time.

Re: White substance on paint?

Posted: Sat Feb 18, 2012 5:20 pm
by lambrettalad
sounds to me as if the paint has probably "bloomed" could have been a combo of temp (too cold and or humidity too high) when applying the paint,some colours show it more than others. :(

Re: White substance on paint?

Posted: Sat Feb 18, 2012 5:36 pm
by MarkyB
Can we not see a picture?
It would really help to see the problem.

Re: White substance on paint?

Posted: Mon Apr 16, 2012 5:01 pm
by laneychief
You can see it there, its hard to take a picture of![frame]Image[/frame]

Re: White substance on paint?

Posted: Mon Apr 16, 2012 11:11 pm
by bmcecosse
I think you are seeing through to the primer.......

Re: White substance on paint?

Posted: Tue Apr 17, 2012 7:48 am
by laneychief
Nah it's definitely not because it rubs off and when it's wet it's perfect!

Re: White substance on paint?

Posted: Tue Apr 17, 2012 7:58 am
by kennatt
what do you mean that it rubs off,can you see it on a cloth not sure what you mean and then is the paint ok. :(

Re: White substance on paint?

Posted: Tue Apr 17, 2012 8:07 am
by laneychief
No it kind of like buffs off, if I put polish on it and rub it really really really hard it goes, but sometimes it comes back after a while after the polish wears off!

Re: White substance on paint?

Posted: Wed Apr 18, 2012 12:07 pm
by tysonn
Sounds like blooming.Mainly caused by moisture trapped in the atomised paint as its being sprayed.As advised earlier a good compounding session should get rid of it.G3 followed by G10.

Re: White substance on paint?

Posted: Thu Apr 19, 2012 7:55 am
by kennatt
well without seeing it in the flesh can't say what it is.but blooming 99% of the time is seen a few minutes after topcoating,caused by too low a temperature,or a cold wind blowing onto the wet paint,the celly thinners drops the temp of the panel as it flashes off causing in effect slight freezing,hence the need for antibloom thinners which have a slower evaporation rate to keep the temp up,it is simple to get rid of by cutting back,and only effects the top of the paint,it just sort or glazes over and rarely effects the paint or primer underneath. I have never seen it reappear after the cutting back,so sorry but don't know what it is.