Autobody

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Michael
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Autobody

Post by Michael »

Anyone here ever done any autobody work? I've been repainting and detailing parts of my car for resale. The system I'm using is the standard two part on new cars. Metal paint and then an overcoat. I've never done this work before until now. Everything went okay but when I sprayed the over coat I wasn't told that you sand it down with 2500 grit and then use swirl free compounds to bring back the shine. I thought you had to lay it down flat. Problem was I was getting either an orange peel texture ( which is okay I now know after the fact ) or the coat was running. I thought at the time the peel texture was bad so I laid it on thick and ended up with teardrop runs in it. Here's the problem. I sanded all of that off and started again. I could not see any runs on the surface of the car. I couldn't feel any defects in the surface of the car. I repainted and still could not see any of the old runs. The metal paint goes on matt flat so that's probably why. As soon as I applied the clearcoat bam there it is, shadows from the runs I thought I sanded off. If you can't see the runs after you sand and can't feel them how can you make sure they are gone before you do the work, anyone have any tips? I am hoping when I buff the clearcoat the surface reflection will trick the eye so it doesn't see these slight imperfections, but I don't as of yet know.
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re: Autobody

Post by rlortie »

Michael,

You make for lots of questions :0)

Metal paint, do you mean paint with metal flake?
Are you using an acrylic Lacquer base and clear?
Why are you being so fussy with a car your only detailing to sell, is it a classic or collectors item?

If you are using Acrylic Lacquer, the base or metal flake should go on flat without any orange peel. You can not or are not supposed to wet sand this. If you have orange peel I would guess that either you used a silicone based rubbing compound and did not get it all off before painting, or you have moisture in your air supply. Dietzler has an additive that you can mix into your base that is supposed to prevent orange peel.

IMO The run marks or prints that show up is due to the fact that you put the clear coat to heavy and the runs bled into your base paint absorbing some of the thinner. Even though you sanded them down they still leave a mark in the base paint.

I would say to wet sand and rub out the clear coat and call it good. Do not use a silicone base rubbing compound. If you have any bad spots you can always add a little more clear coat and continue rubbing out.

I just did the hood and cab roof on a black 1992 Dodge pickup. the original paint was rusted and blistered through to the metal. I sanded the rust down, went over the deep pits with UV body filler, sanded that and used spray cans of primer. I then covered that with rustolium rust blocker.

I had some black lacquer but no spray gun, so I cut it 50-50 with thinner and put it on with a brush. I then wet sanded it out and am waiting a couple of weeks before brushing on the clear coat. Right now you would never know that I used a brush rather than paying $80.00 for a spray gun. So far I have $42.00 invested in a job that three local body shops wanted $1200.00 bucks to do. Thank God it was not metal flake!

By the way, if you should sell the car advise the buyer to wait at least six weeks before applying any wax of any form.

Ralph
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Michael
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re: Autobody

Post by Michael »

Hi Ralph,
Metal paint, do you mean paint with metal flake?
It's the standard metal paint used on most modern day cars, metal with pearl.
Are you using an acrylic Lacquer base and clear?
The paint is a liquid pigment that you mix with a basecoat. It is cleaned with varnish cleaner so no it's not an acrylic. The clear coat is also a two part mix urethane.
Why are you being so fussy with a car your only detailing to sell, is it a classic or collectors item?
The car is only 2 years old. It had some chips in the hood and deep scrapes in the bumpers that I repaired. I want to get as much for it as I can.
If you are using Acrylic Lacquer, the base or metal flake should go on flat without any orange peel.
Ralph it's not about laying on the paint. I was ignorant about how to finish clearcoat. I messed it up. I resanded and had to repaint- I had to. The sand job I thought was good enough. It wasn't. I want to know if there is a method to seeing if you've totally taken off imperfections. I'm not looking for the obvious answer. I tried looking under different light sources, and at different angles. I felt the surface. Nothing until after I put on the clearcoat again. Ralph understand that the imperfections are new paint over old imperfect clearcoat that I didn't sand as well as I thought I did, and the imperfections didn't show up until the new clearcoat was put on.
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re: Autobody

Post by rlortie »

Ok! I now think I understand your problem. When clear coating, it said to be advisable to remove the existing clear. I am not familiar with your two part urethane but do know that applying new clear over old will cause blemishes to show and may turn the old clear coat into a foggy white.

That is all I have to offer as I am not a profesional even though I have painted some classics with metal flake in my hot rod days. I always stuck to acrylic as you can rub and paint to your hearts content and end up with a finnish that looks an inch thick. My favorite was candy apple red with a touch of burgundy wine color added for shading. I still have my air brushes but no spray gun.

Gordy may offer some input here, He is known as the Rustolium rocket for a reason.

Ralph
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re: Autobody

Post by Michael »

Hi Ralph,
No that's not it either.

Okay. sanded the clearcoat to be able to put on new paint. I did this because there were chips in the paint and I wanted to do the job right.

I put on the new paint. I ran out of paint. No problem, it looked really good and I bought more paint. I originally used a siphon spraycan. The guy at the auto body store then lent me the real deal, an h.v.l.p. spray gun, it used half the paint as the other one. The paint job was excellent.

I then tried putting on the clearcoat. No one at the autobody store told me not to worry about how it looks at first because you then do a wet sand with 2500 grit and bring the shine back with swirl free compound. No one told me. They also didn't tell me not to put it on in the sun. You would think, well duh of course don't do that, but the paint went on fine in the heat so I wasn't thinking. The first time I put on the clearcoat it dried instantly without setting down and was all foggy.

Errr! So I found out not to put it on in the sun and resanded. I then Put it on again. Reliterating that no one told me you wet sand it flat when it is dry I thought it had to go on flat from the get go. The pressure of the gun was causeing clearcoat I just sprayed to dimple and caused an orange peel texture. This is okay because you sand that down but again I didn't know so I thought I F%$^% up. So I sprayed again really heavy. The coat ran which I though okay, I'll just sand out the runs. When it dried it looked really good except for the runs. I tried sanding just them off but there were to many and they were to thick and in some areas I sanded down to the paint.

ERRR!!! So I resanded the whole thing. This is the problem I am trying to solve.

I thought I sanded the whole thing flat. I applied some UV Bondo in some areas that went down to the paint again and sanded them as well.

I applied the new paint. Everything looked good.

I then sprayed the clearcoat. Bamm, shadows came up caused by the paint sitting on areas that weren't sanded as well as I thought! Eshhh.

I tried to see if the sand was perfect by feel and sight and everything looked good. I sprayed water on the paint when it was dry to simulate the clearcoat and everything looked good then too.

Is there a professional way to make sure all sanding is perfect without having to go down to the surface material?

Entropy at it's finest. It seems like at the tail end everything is going wrong. I have to see the salesman tomorrow. I am trying to get the car finished. I woke up to finish the clearcoat on the other areas of the car and try to fix the shadows in the hood. When I woke up it was sunny, as soon as I started clouds came and it started to rain. Now I can't do anything.

I sprayed the hood again under cover. My driveway holds three cars in length and I'm at the top near the garage. I am using the H.V.L.P. set up so there is a minimum of overspray. The road at the bottom of my driveway has the typical telephone lines and theres a pole at the edge of my driveway. I'm spraying and for some reason turn to look at the road. Just as I do I see two crows that were stitting on the pole, divebomb straight down to the ground one after the other. I think Wow, what are they going after I never saw that before. Then I think, there, no way something could pull up from that dive. I go and look and they are both lying on the ground. Holy Sh*T! I killed them. Then I thought, maybe they just passed out. Another crow came to them and cawed and tried to wake them. The first crow finally came around, and got up. The second then came around. The first flew away. The second couldn't get up then lied still. I went to take a look and it was dead. I picked it up and there was blood on the ground where it's neck was.

The crows were very far away and there is hardly any overspray. Other birds haven't been affected. This stuff smells good and I know it attracts insects. I wonder if they were taking in the fumes on purpose cause they liked the smell and were getting high, either that or they were electrocuted.
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re: Autobody

Post by racer270 »

here is a link that "mite" help you...?
paint a car has too many variables,type of paint,additives,reducers,temperature.....ect...
blending a clear coat is an art form all by itself.....!
this site is a bit old but it might give you some insight on what you're trying to accomplish......


http://members.tripod.com/~bobstory/faq.html
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Michael
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re: Autobody

Post by Michael »

Thanks Gordy, I'll take a look.
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re: Autobody

Post by ovyyus »

After sanding you could try thoroughly cleaning the effected area with acetone - careful you don't get any on adjoining paintwork ;)
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re: Autobody

Post by Michael »

That's an idea, but I'd be concerned about the acetone eating away into the paint and then to the metal underneath. I tried putting the lacquer thinner on it already and that's what happened. Right now I'm just about done, now I need to really give it a good buff.
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