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Gentlemen drivers,

It appears that we are trying to run a company on half the amount of usual staff during the holidays. One finds himself performing different tasks than usual, off course after hours, in order to keep the customers satisfied and the marriages of co-workes intact.

In this particular case, the bonnet of a Toyota that had just changed owners at our office graced a 30cm scratch. With half of the workers in the paintshop being out of the country, circumstances obliged yours truly to pick up his old trade by taking care of this matter. I was not looking forward to this as its busy enough as it is, but something's gotta give in cases like this.

Whilst on the job I reckoned it would be nice to gather some visual material in order to let this labour spend on mere mortal people-carriers live on in the minds of the true enthusiast with the chance of actually removing unwanted patina from REAL cars like the E34 M5. Bear in mind that the sanding that is involved can be very dangerous and especially when not sure about the condition of the paint on the car ( this was factory OEM) can easily turn into a disaster that can only be reversed by a respray. Ye be warned!


As you can tell from this pic of the scratch, its a bad color to start touching up on. 2K paints require lacquer to be dry and thus be sanded which is not easy as the method shown also requires sanding of the actual "color". However, on cars with normal non-metallic paint, this method can give 100% results. On 2K, settle for 80-90%. Sometimes its just better to avoid any resprays, not only from financial perspective but also regarding resale value on special cars ( like Steve's 964 C4, which is all OEM paint all round)

This is the scratch, color is Toyota 1D2 2K:


At first , the scratch goes all the way into the primer,



after which it follows the bonnet down for about 25cm, only lacquer-deep in this area.

Start off by sanding the entire scratch with orange Scotch Bright, so mask around the scratch first:







Sand thoroughly, as you are about to get some serious polish pressure on the new paint, which will simply be torn out when its not properly attached to the OEM paint. orange SB equals sanding paper wet 2000 , but because of the sponge-like material it travels better inside the scratch, making for a better contact for the paints.

After the sanding, degrease the lot with normal industrial degreaser, NOT thinner as that will weaken the OEM paint you are about to abuse.



Then, get yourself some color. On metallics like this, its wise to blend her slightly too light when it comes to tinting, as the paint will always darken up when polished.



Tools for applying the paint are easy to source, use a normal 3mm pointed brush ( for the lacquer, as it needs to be smeared over the edges onto the OEM paint) and a sharp-grinded piece of welding wire, to apply the actual color INTO the scratch, and not all over the place. You can't sand off excess color-paint, as you will always need to top it with lacquer first, so make sure you don't stick on too much color.:





Use a normal paint-stripper gun to blow-dry the individual layers of color, so they won't "sink" into eachother too much, but the 2K setup of the paint implecates that you won't be able to completely dry the "color" component.:



After the "color" component is stuck on properly ( about 6-10 thin layers, exactly following the "lines" of the scratch, but not over the edges) its time to use the 3mm brush for applying the lacquer:

pic shows 2K paint, on the left side the "color" component, right= lacquer component



The lacquer applied:



Since lacquer has active temperature- related hardener in it, one must dry it thoroughly. Normally we use the spray booth for this as it has a built-in heater, but in this case I can opt for the stand-alone infrared heater that we use in all shapes and sizes. This one will do perfect .




Set the clock for about 30 minutes, then let the bonnet cool down, and repeat for another 30 mins. If you don;t have an infrared heater ( and I imagine not many people having those!) , you could use a blow-dryer, but its very important to maintain a constant level of heat, preferably above 60 degrees celsius!

Make sure the device sits far enough from the car, otherwise you might be catching melted headlight lenses in a cup of coffee!









After all is said and done, the REAL work commences. We use this device



with these sanding pads ( 9 micron)



and a whole lot of water on the paint to sand it down to make it flush with the OEM paint. The lacquer has been applied just a little across the edges of the scratch, in order to create a more solid square over the scratch. If you would look very closely, you can see a microscopic crest over the scratch, caused by the lacquer , gently sanded flush with the rest of the bonnet.



The sanding process demands you to wipe off the water from time to time, in order to see how far you have sanded already, as its easy to go through the OEM lacquer when not paying attention.

Use a regular polish/ cutting paste to polish away the dull spot from the sanding, and if you're in luck, the result should look like this:







Apply some wax to protect the polished paint and you'll be fine.

Hope you guys understand that is not as easy as it looks, and very time-consuming. Its more suitable for use on doors etc than on body parts that are horizontally mounted , as the reflection works against you on the latter. On silver cars, this method is close to useless as the metallic particles are impossible to get right when spraying, let alone when brushing paint on.

Regards,
W
 

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Fantastic stuff!

I will try this method on my Avus blue paint work and see how good I can get it.

I have lots of time on my hands too these days, wife and kids gone overseas for 2 months.


Sal
 

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Discussion Starter #3
thanks mate had been trying to write it all down for some time but only finished tonight..
 

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Thank you for the very illustrative write up of this repair procedure. It will come in very handy. I know it took a fair amount of time to document this procedure, and the effort is appreciated. My hat is off to you. Thanks again.
 

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Thanks for the kind words lads..When I find the time I will put up my pictures from the wheel refurbushing , still got loads of pics from that too..
 

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Wout this is excellent :M5thumbs:

I appreciate from my limited experience in the paint shop
how much tougher a local repair is compaired to painting an
entire panel...this is where true skills & patience kicks in !

Great write up.
:applause:


Alan.
 

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Discussion Starter #14
thanks guys

had almost forgotten about it

I'll launch the thread on the E28 rebuild/conversion soon which will be packed with all aspects of bodywork

Actually, it will be packed with ALL work possible on a car :hihi:
 

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touch-up paint

Excellent guide... thanks for the heads up and guide. i like to buy my paint online, it often matches the cars shade better than the dealer stuff (even BMW, i know).
 
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