DIY painting

[claymore]

Disclaimer: The following is provided as a GUIDE ONLY, and neither myself, nor Honda Fit Forum take any responsibility for the outcome of someone else doing the following. You follow these steps at your own risk!

Mission: A short lesson on sanding and spray can painting.

Things needed: Spray paint of your choice of type and color, Sandpaper of differing grits, water bucket.


Sanding and Sandpaper selection:

The first thing you need to think about before you even get started is "do I need to paint this part?" and "do I need to sand this part before I paint it?"

Parts seem to come in many types, new painted, new unpainted, old painted with good old paint, old painted with bad old paint, and old with paint stripped.

With brand new parts many guys just spray away without thinking about sanding and sometimes you may get a good result by being lucky.

Any part needs to be sanded before painting for two main reasons, the first reason, which most people understand, is to make the surface to be painted smoother which should make the paint come out smoother.

The second reason is where beginners make mistakes. The new part needs to be sanded before painting so the newly applied paint has something to stick to. If you do not sand new parts the paint on them is so smooth the new coat of paint will not stick properly. I have seen newly painted parts that look great very smooth and shinny but if you blast them with a hit of compressed air from a hose the new paint will fly right off, and the same thing could happen when you get little rock dings in the new paint and drive along the new paint will start to flake off. It may not happen every time because if the new paint doesn't get damaged in any way it may stick.

So lets start with a new part and you have decided to paint it and want to do the right thing and sand it first what do you do next? In this section lets start with sanding and we will get back to painting later.

So now you have to pick out the proper sandpaper and how in the heck do you chose between all the different types of sandpaper out there?

If you are reading this you are most likely to be painting car parts and for car parts you need WET and DRY sandpaper. If the part is nice and new you need only to make the surface a slight bit rougher so you need a sandpaper with a grit of about 1000.

Grit is just how rough the sandpaper is and the higher the number the more fine it is. Sand paper comes in dry paper that you use without water and is normally very rough and wet & dry paper that you use in water and this is what you will be using most of the time. Dry paper can be used on very old bad paint to strip the paint but it is normally very rough and you will need wet & Dry after you use dry. With new parts that may have some rough spots you could start with 400 and when it's smooth then go to the finer 1000.

http://i75.photobucket.com/albums/i311/claymore729/spray.jpg

Time to get started, in the photo you can see the basic stuff you need to sand car parts. Get a bucket filled with water, your paper, somewhere to rest the part and some tunes and we are in business.

http://i75.photobucket.com/albums/i311/claymore729/spray1.jpg

During my apprenticeship at the body shop I sanded cars morning, noon, and night I thought I would never get to do anything else it was 6 months before I finally got off sanding detail so I have had some experience sanding stuff.

This to first step to comfortable, professional sanding. You take your large piece of sand paper and fold it in half and like with a piece of paper just tear it in half.

http://i75.photobucket.com/albums/i311/claymore729/spray2.jpg

Now take the 1/2 piece of sandpaper and we need to fold it into 3 sections so start like this. You don't need to be supper accurate just eyeball it.

http://i75.photobucket.com/albums/i311/claymore729/spray3.jpg

Just take the flap and fold back on top and we are ready for some sanding.

http://i75.photobucket.com/albums/i311/claymore729/spray4.jpg

You need to hold on to the paper and was taught this method of grabbing the paper and it has worked good for me over the years. You just lay the paper in your hand and slide your thumb under a corner of the paper and you get the grip from your thumb and the paper doesn't slide around.

When one side of the paper gets worn out just flip the paper over and start again and then remember you have one more good section folded inside just unfold the paper and flip the inside part to the outside and slide the worn section to the inside of the fold.

Warning: If you do any amount of sanding your fingertips will take a beating from the paper. The more coarse the paper the more damage to your fingers. Wet sanding is less damaging to your fingertips but it still removes some skin slowly.

When I got my police job and had to go in for fingerprinting and it took them 3 tries to get a set they could read because I was doing all that sanding in the body shop, they asked me if I was opening safes with my fingers as some burglars sand down their fingertips so they can "feel" the dial on the safes better.

If you are using dry paper a tip is to wrap a layer of duct tape around your finger tips so they get less contact with the paper but this doesn't work with the wet stuff because the water gets to the sticky stuff on the tape and they fall off. Believe me I tried a lot of things to save my poor fingers when I was sanding all those cars.

http://i75.photobucket.com/albums/i311/claymore729/spray5.jpg


Ok a sanding we will go. First just grab the paper and dunk it right into the bucket of water and start sanding. One mistake beginners make is to use only their fingertips to sand and that is where they go wrong. If you use the tips of your fingers to get at spots that you see needing sanding you will leave "GROOVES" in the finish that you can't see until you paint but they will show up in the new paint. The professional way to sand is use your WHOLE hand held FLAT against the surface that you are sanding. It may take longer but keep you hand flat and you will get better results.

http://i75.photobucket.com/albums/i311/claymore729/spray6.jpg

Another problem amateurs make is sanding in every which direction. YOU MUST SAND ALL IN THE SAME DIRECTION. Look in the photo if I move my hand left and right that is ok but if you start that way keep going in the left/right direction DO NOT go up and down. when you are sanding try in go in the long direction like in the photo the part is longer left to right so sand in that direction if possible.

Every once in a while look at the paper and you can see sanded off paint starting to stick to the paper and clog it up, if dunking it in the water doesn't get it off it's time to turn the paper. I like to dunk the paper very often, like every three or four slides back and forth while sanding, like sand, sand, sand and dunk. You can start to "Feel" when it gets dry when it get slightly harder to slide the paper across the part.

You can see in the photo that this part has raised "ribs" along the side and things like that and other curves and bumps makes it a pain in the butt to sand around them and making sure there is some sanding between them so the paint will stick but it is worth it in the end.

On bigger parts longer sands in the same direction is the way to go keep the sands as long as you can comfortably move you arm in one swing. Avoid at all costs digging in with your fingertips it really does leave marks that you can see only after painting.

When you get good enough you can feel imperfections in the paint with your fingertips and it really helps to close your eyes when you do it so in body shops you can see the sanders rubbing their hands over the car body with their eyes closed and it looks like they are becoming "Fond" of the cars but it really helps to feel the bumps, just try it first with your eyes open and then closed and rub the same part and I am sure you can feel more with your eyes closed.

Some auto parts stores sell a big chunk of rubber called a sanding block that looks like a turtle (body shop talk; Throw me the turtle) you put your paper on the flat bottom and the curved part up into your palm and it makes sure beginners get a flat sand and they are relatively cheap so if you are going to do some sanding it might be a good thing to get.

That's enough for sanding next time PAINTING.

[claymore]

Cleaning: If you have sanded the new part it should be nice and clean unless you have glommed your dirty hands all over it but dirt or sanding slime may be hiding out in any small cracks or crevasses. So in the last step before you paint go over the part and give it a close look especially in corners or seams that may be hiding trapped slime. Dirt and sanding slime trapped under you nice new paint will be the first place your new paint starts to flake off so use a Q'Tip ear cleaner of soft cloth to make sure you get out all the small particles of slime or dirt and we are finally ready to paint!!

Here we go!! So you have your nice sanded part in the shade, on a sturdy support box or table, on a nice day, the floor is wet, and you have your spray cans at the ready it's time to paint!!

But first you need to shake the can really...... shaking the can mixes up all the ingredients and they need to be mixed together more so with metallic paints. So now you are shaking the can and looking at the part wondering what to do next.

I like to paint in three easy steps, the first pass I make is to get paint into all the hard to get to spots like along the bottom edge, into and around any brackets or clips that you need to spray from several directions and you are just getting paint onto the surface so don't worry too much about shine or anything this is just the first step. But try not too get the paint very wet looking on the first pass as the paint may not stick if too heavy and you end up with fish eyes. (small imperfections that look like a bunch of fish eyes looking back at you.)

Then for the second step I just put down a layer of paint all over the part to get everything colored and covered in paint not too worried about shine yet.

Finally the third pass to make sure everything is nice and shiny. this is the most important step and you need to pay attention to the shine you end up with.

[claymore]

So now you know what you are going to do but ..... how do you do it?? Since there are some beginners here we have to start with holding the can.

http://i75.photobucket.com/albums/i311/claymore729/spray7.jpg

No comments on my hairy hands thank you! Anyway you start about a foot away trying to make sure the can is straight up and down aiming as level as you can. If you are a beginner now is a good time to try a few practice passes, just spray at whatever you are using to hold up the part and see how if feels when you are spraying.

Since we are using a spray can we have to talk about the nozzle. With a professional spray rig you have a trigger and can control how much paint you are applying with the trigger but with a spray can it's either all the way on or all the way off, no in between. So nozzle control is very important.

http://i75.photobucket.com/albums/i311/claymore729/spray8.jpg

When painting any style you need to start the paint flowing BEFORE the part. So when you start press the nozzle down just before your arm starts to swing by the part on your first pass.

It's VERY IMPORTANT that you move the can parallel to the part making a straight line with the can, not moving your arm in a sideways C where you start far away but as you swing your arm you move closer to the part and then farther away as you finish your pass as this will result in the middle of the part having lots of paint but the ends will have less.

http://i75.photobucket.com/albums/i311/claymore729/spray9.jpg

Then when you get to the end you have to keep spraying as you pass the part and continue to spray for a short distance past the part. And let go of the nozzle at the end of every pass so it's like stopped, spray, stop, spray kind of rhythm.

When you are spraying "Overlap" your passes, like make sure after the first pass when you start your next pass you start painting so this new pass of paint sprays partially onto the last pass of paint you sprayed.

Now to the hard part... how can you tell if the paint is being applied not too thick or not too thin.

All spray paints start out of the nozzle as aerosol particles which is paint particles mixed in with air and floating toward the part you are painting and they are changing toward a liquid state.

When they get to the part they are in a semi-plastic liquid state moving toward being solid (it's still a liquid but getting close to a solid, like if you touch it you will leave fingerprints in the paint.)

And finally when it's dry it's a solid.

I know you all are thinking here goes claymore off on one of his science lessons again but stay with me a little longer.

When you are painting you are trying to balance spraying on enough paint to end up with a shiny finish and NOT spraying on too much resulting in runs or not enough and ending up with orange peel (rough surface that looks like the tiny holes on an orange peel) you are trying to get just the right amount.

But paint makes this hard to balance because it is ALIVE no not really but it does continue to move after you spray it on!!

An important step is to wait for each coat of paint to flash (dry) before putting on the next coat. Yea I know it's hard to wait but you need to do it. You can check if the paint is dry WITHOUT touching the part simply but touching the box or stool you are using to hold up the part or any paper you are using to protect any areas you are not spraying. It can be a little sticky but should not leave any paint on your finger after touching the new paint.

What you are trying to learn every time you paint is how the paint set-up you are using is putting paint onto what you are painting. Some put out more some less so you have to WATCH THE PAINT AS YOU ARE PAINTING. With practice you can tell right away if the surface you just painted is too dry or too wet. When you make your first pass painting the edges of the part watch how the paint comes out, you are trying to end up with the new paint looking like water WITHOUT putting too much on so it runs while drying.

And that is the problem, paint when wet flows like slow moving water and it doesn't stop flowing until it "FLASHES" which means it gets dry enough that it stops flowing. If you paint everyday you can watch the paint and see it flash all that means is you can tell when the paint is going to stop flowing and can put just the right amount of paint onto the surface knowing it is going to keep flowing even after you stop spraying. Paint flashes sooner in hot weather and slower in cold weather and enamel flow longer than lacquer.

So now you have done your first two steps and are getting ready to apply the last coat which you want to come out looking nice and shiny.

When you are spraying this pass spray slow enough to leave the paint surface looking like something wet and STOP. Three coats are plenty of paint you do not need to load stuff down with 10-20 coats of paint.

Clear coat? I like to clear coat with clear lacquer as it leaves a nice smooth shiny finish and could be sanded and buffed if any bugs mar your new finish. But it's optional and if you are going to do it now is the time or wait overnight and fine sand your new paint carefully and spray on the clean and your DONE.


When we left off we were learning about sanding and I have gotten quite a few messages and emails with some question that I will try and answer before we move on to painting so if you are up to speed on sanding just jump to the section on painting.

[claymore]

When we left off we were learning about sanding and I have gotten quite a few messages and emails with some question that I will try and answer before we move on to painting so if you are up to speed on sanding just jump to the section on painting.

The most asked question is about which grit of sandpaper to use. I will answer that one first.

If you have an old part and taking off many layers of paint or have defects in the metal you can start with a very rough paper up to 220 grit but then you need to gradually work up to finer grits. If you start with 220 and it's clean enough of defects then go over the whole part again with 320 or 400 grit to get rid of the bigger sand marks, and then go to 600 and do it again and finally 1000 for the last finish sanding. If you started with 400 then just the 600 and then 1000 what ever grit you use just go up at least 2 grits to finish. Don't worry the finer paper is easier on your hands and it takes less time with the finer paper because you are just taking off the sand marks from the heaver grit paper.

If the part is new and you are trying for the very best finish the best last grit to use is 1000. If you are not to fussed about the job or the part is going under the car or something 600 can do in a pinch just sand a little longer to get the marks out.

If you have a part with lots of curves and lines on the plastic like an air box you can get into the small spaces using a Scotch-Brite backed sponge. Or you have a nice new part with good paint and you just want to change color you can use the Scotch-Brite and not sand because Scotch-Brite is just like a very fine sandpaper.

The best method to use to check your progress is to use the closed eyes trick while rubbing your hand over the wet part or dry the part with compressed air if you have access because it's quicker or just dry it off with some CLEAN soft cloths and then lift the part up to eye level or bend down to it's level on the car and look the long direction at an angle. Like if you were doing a motorcycle gas tank and lifted it up and looked from the seat end out toward the fork end along the tank AT EYE LEVEL because at that extreme angle the sanding marks or low spots or scratches will stand out making it easier to see.

Ok the second question is why do you fold the paper into three sections why not just fold it in half?
The front of the paper is rough but the back is just paper that is slippery when wet so if you fold a piece of sand paper in half two sections of slippery part will be rubbing together and you will just slip the two parts together and won't be able to sand. If you fold it 3 times no parts of the slippery part rub together and the rough part rubbing against the other rough part doesn't slip around so you get a good no slip blob of paper in your hand.

Painting: Ok you expert sanders can start reading again.

Weather: before we get to painting we need to talk about the weather a little bit ( no groaning we will get to painting later). When professional body men paint stuff they look at the weather and can "Adjust" how fast the paint will dry. There are several types of thinner that you can use in hot, cold, or humid weather that makes the paint dry either faster or slower BUT since we are stuck using just spray in a can we have to check the weather but can't do too much about it.

The best climate for spray bomb painting is a typical "Nice day", between 20-30c no wind, and low humidity.

If it's too hot or cold you can adjust a little bit by the speed of your hand moving while painting therefore applying more or less paint with each spray but we will get into that later.

You can use the sun to help if it's cold and you want to paint. If it's like 15c out try painting in the direct sun after letting the part warm up in the sun for awhile. If it's very hot out never paint in the direct sun.

BUT if it's very humid and you are spraying a dark color you could end up with opaque spots that look like tiny clouds in the paint because that is what they really are small spots of moisture trapped into the paint. So if you are looking for the best job don't paint on very humid days or do it at night when it's less humid.

Location: Wet paint always seems to me to be a magnet for bugs, dirt, or anything flying around they always land right in the center of my new fresh paint. So try in pick a painting spot that is someplace with no wind and if possible screened in so no bugs are flying around. And try not to piss of your mother, girlfriend or wife in the process. And make sure you are not near any OPEN FLAMES spray paint can and will burn.

If you get a small bug in your drying paint try not to panic if it's not stuck too deep wait until the paint is dry and you MAY be able to pull it out and buff out the mark with compound.

A trick to keeping the dust down is to simply wet the floor with a bucket or hose being careful not to get water on the part you are about to paint.

Primer or not? This is another subject that many people have differing opinions on. If I have a metal part and the paint is off and it's all bare metal I will always primer before painting. If the part took lots of sanding and has some old paint and some bare metal I will use primer. If it is a plastic part I will primer on spots that have the paint sanded off down to the plastic. I primer and let the part dry overnight then sand the primer with fine 1000 sandpaper to prepare fro painting.

Primer can be an indicator for coming problems with the paint because if you spray on the primer and it "Lifts" (causes wrinkles around the edge)the edges of the old paint it means that you need to get rid of the old paint before applying your new paint.

Picking your paint type: You should have done this already and had the paint standing by but here is some advice.

If you are a novice and just starting out flat black is the easiest to apply and very hard to screw up. It goes on wet looking but dries with no shine so you don't have to worry about shine when painting and just have to concern yourself with getting all the part covered and it's hard to get too much on so you don't end up with runs.

High Temperature paint is also easier to use and comes in more colors than flat black. It also dries with no shine but you can get runs if you put too much on. The only tricky part with high Temperature paint is it has to be heated to dry properly and if you pick up the part before it's been heated it's VERY EASY to leave marks in the soft paint.

Runs just mean those spots where there is too much paint so it starts to droop leaving marks that look like an ice cream cone melting.

Red crinkle paint: Ok here is my advice for doing your valve cover in the hot crinkle paint found on some hot Hondas.

If you have red crinkle paint on your valve cover already and just want to refresh the color you should not have to sand if the paint is in fairly good shape. BUT you still have to make sure it is REAL CLEAN because the cover may have a film of engine oil covering it. I would take it off and using some straight dish washing detergent and a plastic bristle scrub brush I would give a real through cleaning and rinse it with lots of clean water. You may not want to sand the whole cover and lose the crinkle effect so you could sand spots that do not have crinkle and use Scotch-Brite on the rest of the crinkle paint just enough to remove any shine but not all the paint.

If you are changing from a non-crinkle finish you first need to locate some red crinkle paint and then spray as usual after washing the cover.

Normal paint types: If you have used paint before or need more color choice you are left with acrylic lacquer or acrylic enamel or maybe new polyurethane.

The following are my opinions based on my years of using paints but you may have a different opinion so use what you feel most comfortable with.

For working on cars using a spray can I like to use acrylic lacquer because it finishes with a good shine and is easier to apply with a spray can than acrylic enamel. It does have the problem of being stronger than enamel in a chemical reaction manner because it will react with other paints and will "Lift" the corners of old paint more times than enamel and it will not "Hide" a bad sanding job as good as enamel.

Enamel is a little harder to use in a spray can because part of it's properties is that is stays "wet" longer and that may lead to runs if you are not careful when spraying but it does a better job of "covering up" bad sand paper work.

Polyurethane is still new stuff so there are not a lot of color choices around. It has a great smooth shiny finish but is a bitch to remove or sand off.

[BullFrog]

Thanks for the excellent introduction to painting!

I would add that if the part is steel and you have exposed any bare metal or removed any rust, then it helps to clean it with an evaporating solvent to remove any oils (brake cleaner followed by alcohol is good), and then spray it with diluted phosphoric acid (metalprep). Allow the phosphoric acid to dry (the bare steel turns gray) before the primer is applied. This helps reduce rusting under the paint and improves the bond of the primer.

If the part is aluminum, then a light coat of zinc chromate primer should go on bare aluminum surfaces before the primer.

If the part is plastic, then a slight sanding to break the gloss and use of alcohol or similar evaporating gentle solvent will improve the surface bond (careful, brake cleaner may etch or dissolve some plastics). There are some commercial bond promoters available at auto stores that will also improve the primer grip.

Most plastics expand and contract a lot with temperature changes, making a good paint bond very important if the paint is not going to flake off. Keep the paint thin on plastics to reduce flaking (it helps for the primer color to match the final color).

[claymore]

Good stuff but never use brake cleaner to clean parts before painting. I don't know which ingredient causes it but I have had problems with paint "Lifting" or "crazing" from people using it first. There are plenty of cleaners out there that give better results.

[BullFrog]

No arguments with your caution!

That's why I suggested wiping the surface with alcohol (to remove any residue left after cleaning with a solvent). The solvent would be used to remove any heavy oils or grease, fingerprints, dirt, etc.

I have not been able to find an inexpensive, safe, petroleum based solvent that would not leave a visible film. Varsol, paint thinner, etc. all have that problem. Acetone and xylene are much better, but relatively expensive and there are health concerns. I have had mixed results using water/detergents.

I have had good results with several applications of the phosphoric acid diluted with water (1:7 is a good ratio) with the first applications for cleaning and then letting the last application completely dry for a good primer bond. In addition to removing any slight surface rust - this is how Naval Jelly works, the phosphoric acid also converts the bare steel to an iron phosphate (turns a gray or black color - see Wiki for details) that is an excellent anti-rust preparation layer ready to accept primer.

From your experience can you suggest a good cleaner?

[claymore]

We used commercial cleaners in the bodyshop but they would probably be expensive. For my at home projects plain old washing with liquid dish soap, through rinse, and good drying time works out for me. Some projects just sanding the part and a dry clean rag wipe down works ok.

From your advice and products it sounds like you do more aviation painting than automotive. I haven't had anyone mention zinc chromate since my old USMC days of fixing phantoms.