new dress for an old girl.... - PeachParts Mercedes-Benz Forum

dunl · #1 07-28-2007, 08:22 PM

Well, just sitting here trying to work up the courage to go out and shoot a coat of new colour over my 82 300SD. She's been sanded, stripped, primed, and resanded....just finished wiping her down with some mineral spirits.

First time ever doing this....hope it turns out nice. At the very least, she's gotta come out looking better than when he went in. There's still some nicks and stuff here and there, but for a first time job, I got rid of quite a bit of the damage left on the old coat, and took care of the rust spots on her.

Wish me luck, and feel free to impart any tips before I do my first spray job ever.

I'm hoping the job is good enough to last for another 25 years like the previous ones, but I'll be happy with 5 years.

RichC · #2 07-28-2007, 10:00 PM

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Here is an odd tip you may never have head of.

It is a good idea to ground your car before you start to paint.

This reduces the amount of static electricity built up in your car.

The static electricity will attract all sorts of dust and particles to your wet paint.

Remember that shock you got getting out of the car last winter.

That was static electricity.

Thank You
RichC

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veg_svc · #3 07-28-2007, 10:45 PM

If you are using a pro paint booth then you don't have to worry about dust so much, but if you are in the garage, hang some of that plastic drop cloth on the walls, it will prevent chemical transmission into the house through the sheetrock (Yeah, it is pourous) and as an added bonus the plastic will attract airborn dust particles and keep them away from your fresh paint!

KAdams4458 · #4 07-28-2007, 11:11 PM

Quote:

Originally Posted by dunl

...At the very least, she's gotta come out looking better than when he went in.

Not just a paint job, but a sex change as well!

Sorry, I'm probably a little late to pass on suggestions. Just take your time, and I hope you avoid the temptation to fix problem spots while the paint is still wet. Wait until it's dry to take care of the bug that landed on the paint you just sprayed!

dunl · #5 07-29-2007, 12:12 AM

Well two issues came up, and I don't know what is more disturbing:

- the spray gun, an HVLP seems to enjoy spattering large droplets throughout the spray, no matter what setting I use or adjust.
- secondly, the colour of the paint is DEFINATELY not what I was looking for. I can't remember who on here painted their Mercedes a blue colour and it came out a gawd-awful looking tint, but it seems that they had an extra gallon of the stuff, and somehow I ended up with it, cause what it looks like in the can is certainly now what is coming out on the car.

Oh well...sitting down with the wife and some beers now, trying not to think of the pain I've caused my girl...

KAdams4458 · #6 07-29-2007, 01:27 AM

What gun are you using, and what are your settings? What size tip are you using?

Also, what paint are you spraying, what thinner, and what's your ratio?

The only way I know how to fix a colour problem is to paint it again, or just stab your eyes out, though some colours can burn out your retinas just by looking at them for two long.

dunl · #7 07-29-2007, 03:14 AM

Quote:

Originally Posted by KAdams4458

What gun are you using, and what are your settings? What size tip are you using?

Not sure on all the details of the gun, using one I bought from Princess auto. It seems to me that there is not enough pressure to atomize(sp?) the paint particles, even though it seems thin enough.

Quote:

Also, what paint are you spraying, what thinner, and what's your ratio?

I'm spraying a single stage enamel, mineral spirits for thinner, and a ratio of 3:7 for paint to thinner.

Quote:

The only way I know how to fix a colour problem is to paint it again, or just stab your eyes out, though some colours can burn out your retinas just by looking at them for two long.

Diito on the "burn out your retinas".

KAdams4458 · #8 07-29-2007, 06:24 AM

Hmm. I was hoping for some air pressures, there. Are you using a regulator at the gun? What are your pressures? A lot of the cheap guns just spit like mad unless you crank up the pressure to them. Remember, tip pressures are never as high as input pressures, so if you're supposed to have 40 PSI at the tip, you might have to put 80 in to it.

It looks like you might have to just experiment a bit. Even a cheap gun should be able to shoot paint without spitting all over. Unless it's really just a cheap piece of junk. It's too bad you don't have one of the purple Harbor Freight guns. I could easily walk you through setting it up, and it's a surprisingly decent gun.

veg_svc · #9 07-29-2007, 07:29 AM

Most, if not all, hvlp guns spit blobs of paint if air pressure is low. Tell us your pressure and we can tell you the fix. What size air lines are you using, etc. Air pressure at the tip depends on the paint sprayed and will be on the order of 20 or so psi. Too much air is also bad. Get a piece to practice on until you get your hvlp set up properly. Once the gun is set up the rest is less difficult.

dunl · #10 07-29-2007, 12:15 PM

Thanks for all the replies guys. I really wish we had Harbour Freight up here too....would save me some headaches.

I will have to check the settings. I am not using a regulator on the gun, but if I remember, the pressure regulator on the compressor was at 120.(?) Seems high to me, but it's a rental unit, and I don't use compressors much.

I got the namual for it online (Makita 700), and cranked the regulator all the way to let the most pressure through. The spray seems better this morning, but it is only spraying a 3-4" diameter spray.

I'll try to get back to you with some more settings and possibly the gun brand.

Thanks again, guys.
Darcy

veg_svc · #11 07-29-2007, 12:28 PM

If you close the size of the pattern down to 3 or 4" and the spray is better you have a low pressure problem. Are you using one of those little tank compressors for painting? A small tank cannot support HVLP.

I looked up your makita (MAC 700) way way too small for HVLP - You will need a compressor with a 35 to 50 gallon tank for your project.

dunl · #12 07-29-2007, 12:32 PM

That's what I figured. I'll check into renting a larger unit and try that out.

Thanks.

veg_svc · #13 07-29-2007, 12:36 PM

Also you will need to regulate at the tank output or at the gun at about 25 to 30 psi. If you regulate at the tank you will need larger diameter hose or higher pressure. I Regulate at the tank at 40 and 25 at the gun using 3/8 hose.

dunl · #14 07-29-2007, 01:31 PM

Well, unfortunately, the only larger compressor the local store has today is one that is used for blowing the irrigation lines out in our prairie fields up here.
Probably about the size of the wife's minivan. lol

Guess I'll keep looking. Thanks for the tips so far.

Darcy

dunl · #15 07-29-2007, 01:37 PM

How long should it take to spray a car anyway? Rough time between coats, etc?