Spray Painting

[iain1067]

I got the chance of a used rear bumper for my S6 (the one on the car is pretty scabby) has anyone ever had any success using spray paint and getting a decent finish over such a large area. I would use genuine audi paint to get the right colour match, and also do you need special paint for plastics???


Iain

[volcano rs]

you need to use plastic primer before top coat

[DJones]

Dont bother using an aerosol, you wont be happy. you need to do it in 2 pack with a hint of flex agent in the mix.

if the panel you are spraying has sound paint on it already you wont need to prime it just use a Scotchbright pad to key it up.

But..... use breathing apparatus, it not nice stuff.

[4WheelDrifter]

Test a small area first. The paint already on there may react with the new paint. BTDT.

[A6 2,7Biturbo]

Wouldn't recommend painting large surfaces with spray paint, the result isn't going to be good...
Try to hire a small compressor with spray accessories, the result will be very, very good (the pro way)

[Billman]

a 2 HP 25 liter Compressor from the Baumarkt will be good enough?

Can someone give us Painting Lections or is there any Link on the net about painting on metal, repainting scratches, Clearlacks ect

[DJones]

I can give advice but the questions need to be specific as there are so many different answers to the same question dependant on paint system I.E 2 Pack, celelouse or base coat clear systems.

Just ask.....

[Billman]

aha, lets say we have to paint a fender! Its grinded to the metall! the paint is Audi Vulcanblack metallic!

What about the COmpressor? Will it be up to the task?? I have also a starter compressor kit (with cleaning pistol, spraying pistol ect)!

[DJones]

When you say grinded to the metal do you mean stripped to bear metal i.e smooth.

If you do i would firstly apply a light mist coat say aeresol black, then using 120 grit flat of the panel to see the low spots, which will stay black...

I would then fill these areas and repeat the process until all the mist coat comes of first time i.e no low spots. I would then apply a panel wipe solution to remove all sign of greece etc, then apply an etch primer not to thick. do not flat this off, i would then apply a 2 pack primer 4 parts paint 2 parts thinner 1 part activater. 2 pack is best as it does not sink once dry.

When dry i would apply another light mist coat and flat off with 600 paper until all the black is removed, ensuring you do not rub through on the edges.

You will now have a perfectly flat panel ready to recieve paint. Make sure you have, as the finish is in the prep work not the application of the top coat.

If using metalic i would use a base coat / clear system apply one tack coat followed by two wet coats, allowing the recommended flash off time between coats. Mix base coat 50:50 i.e 1 part paint 1 part thinner do not add activator.

allow appox 20 minutes to dry do not rub down between coats. Mix clear coat 4 parts clear coat 2 parts thinner 1 part activator. Apply 1 tack coat followed by three wet coats again allowing the recommended flash off time between coats, you will be amazed at the finish.

I paint concourse cars as a hobby and with these i take it one step further than the above. Once cured i generally leave it a week.. I spray another mist coat on top, in the case of a black car i would use white aerosol, i then flat this of using 2000 paper with water and a bar of soap (it stops the paper clogging) if it clogs it scratches.

When doing this you always flat off in the same direction to avoid circular scratches showing up in the finish.

I then use a polishing mop to bring out the gloss slowly working up from course to fine compound with plenty of water and stay away from the edges. i then remove the swirl marks with cotton wool and a G10 compound followed by wax. With a black car you should still be able to tell the time on your watch from 2m away.

Big head as i am i have twice won the Autoglm concourse challange using this method so it works for me.....

I am cuurently painting a GT40 in gulf racing colours i will shortly post some pics.

You really do need patience and dont rush if you dont have time to do the job dont start.

if you are painting a panel that is already painted use the same method above but stay short of the shut line with the base coat by say 100mm. Clear coat the whole panel though, this way you will have a better chance of a colour match as you are fadding out as opposed to stopping on an egde.

I have painted many cars with a 2hp 25L compressor (not that i do anymore) just make sure you get a gun with a low cfm requirement.

TIP, if your paint looks to silver i.e. to much metalic leave the paint to settle, once settled spoon of the top it will be darker as the metalflake will have sunk to the bottom of the tin, like wise shake it up first if you need it lighter.

Hppe it helps, have fun and be patient

[Jas11n]

Awesome

[Billman]

Thank you very much for the usefull information!!!

Because i am a beginner in this area i have some questions:

-you said: use a base coat / clear system apply one tack coat followed by two wet coats

What exactly is the tack and what the wet coat?

-You said: Once cured i generally leave it a week.. I spray another mist coat on top,

You mean the black coat mentioned Above?

-You said : I then use a polishing mop to bring out the gloss slowly working up from course to fine compound

Something more perticular about it? Witch kind of compounds? Are you doing this with your hands?? Dont think so...

i then remove the swirl marks with cotton wool and a G10 compound followed by wax

Witch make???

Now something else: What kind of Compounds is good to use in order to make an old metallic colour (with small scratches-scratches on the clear layer not in the colour) to look better?

[DJones]

Tack coat is a light covering of paint, it helps make the panel sticky helps to prevent full coat (wet) from running / sagging.

The mist coat is somtimes refered to as a guide coat it helps to guide where to fill or where to rub down. When the panel is smooth it will of rubbed off hence dont rub it anymore, giving you a guide.

If you are a biginner stop once you have applied the clear coat and just de nib it i.e flat of any fluff or dust that may of landed and use rubbing compound to polish it back to a gloss, if the paint has cured for long enough you can use t cut it works fine. Dont use t cut to soon on fresh paint though, the amonia in the t cut dulls the gloss slightly.

I have cut back many cars by hand with rubbing compound, Farcela G3 to start with then on to G10 followed by a wax of your choice.

T cut will remove scratches. If they are deep but not through the clear coat you can use 2000 paper followed by t cut to bring back the gloss, its like everything practice, practice, practice

The mist coat i mentioned that i apply after one week is only if you want a glass like finish this is where the patience is really needed.

[Billman]

The Dry and flash times are 20 Minutes?? you are using always a painting oven or do you paint also in a smple garage?? What temperature are you using for drying??

And another Question: Does these compounds work also in glass? My front windscreen is not the best when the sun is infront of me! It has many many little dots!

Thanks for your replays and sorry for Hijacking this thread!

[DJones]

Flash time is just when the paint has dryied enough to put another coat on top i.e. dried enough to stop it running, touch dry is different with base coat 20 minutes is normaly fine.

With top coats touch dry is about an hour if you are using air dry activator, which i do i.e. no oven. I usualy leave it a week before cutting back.

Room tempreture is all im at, you do get differenr thinners for different temp though, summer = slow & winter = fast etc.

The compound wont do the glass. You need Glass Rouge i think it is called. Frost Automotive sell it.

[CP951]

Is there any trick to reduce dust deposits?
Do you use any flood lights to speed up the drying time?