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Basic painting guide

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Pugsport

Member
Joined
Sep 21, 2011
well i made a painting guide for another site and thought i would share it with you guys aswell

Basic guide to spray painting

In this guide I’ll go throw the following things

1. Common types of Automotive paint
2. Using a guide coat to flat back old paint or filler - along with what to use for a guide coat
3. Surface prep for unpainted metal
4. Surface prep for already painted surfaces with an egg shell finish where you want to remove the eggshell finish
5. Surface Prep for already painted surfaces with an eggshell finish where you wish to keep the eggshell finish for the new paint
6. Surface prep for already painted surfaces with a smooth finish
7. Applying primer
8. Flatting the primer down for painting in solid colours
9. Flatting the primer down for painting in metallic or pearl colours
10. Applying colour
11. Applying lacquer
12. Flatting the lacquer and compounding
13. Polishing paint
14. Waxing
15. Using a sanding block
16. Hand sanding for small areas
17. Masking tip

1: - Common types of paint

1k or better known as cellulose paint and 2k also known as 2 pack paint

Cellulose paint is what you find in most rattle cans in car shops such as Halfords but can also be bought in spray gun form. In order to put Cellulose paint throw a spray gun it will need to be thinned down with Cellulose thinners

2 pack paint can be found in rattle cans but you need to go to an automotive body shop supplier in order to get them as they are made to order and once opened wont don’t they cannot be saved and used again as 2 pack paint contains a hardener which has to be released via a tab on the bottom of the rattle can in order for the paint to go off. 2 pack paint can also bought to put throw a spray gun but along with the paint its self you will also need 2 pack thinners and 2 pack hardener (you can if you wish also use a product called rocket that you can add to standard 2 pack hardener to speed up cure time even more if you don’t have a heated spray booth).

2: - Using a guide coat to flat back old paint work or filler

Using a guide coat to flat back fillers or old paint works in the same way and allows you to see low spots in the filler and orange peel in paint work and will help you to get a smooth surface to apply your new paint to.

Apply guide coat is simple as all you want to do is apply a dust coat along the piece you wish to flat out.

DSC_0304.jpg


You can see the guide coat applied in the photo above. The top left side of the piece has had a light sand and as you can see the red guide coat has stayed in the scratch marks made by the last grit of sandpaper as these are lower than the rest of the surface. The top right side has been sanded down more than the left side but you can see from the photo that there are some small areas where the red guide coat is left and these are lower spots in the filler that will need another small skim in order to build them up. The bottom front edge gives you an idea on how you want to apply your guide coat in order to get the best out of it.

So using this method you want to continue flatting back your paint until all of the guide coat has gone and if your using filler then you want to do the same although you will have to apply small skims of filler to the low spots in order to get the panel flat.

2: - What to use for a guide coat

You can use normal spray paint as a guide coat. Just apply a different colour and one that will show up well on the surface. As you can see above I had some old unwanted red which I used but you could have used black, green etc. but one thing I will say is matt colours seem to clog the sandpaper up less than gloss colours do if you working with dry paper. You can buy products that are made to use as a guide coat and these come in powder and spray paint form but do cost a lot more than a normal can of spray paint.

3: - Surface prep for unpainted metal

At this stage you can apply the guide coat as we went throw before to check the panel is flat if you want to have the best finish possible and if it’s not apply filler to get it flat and smooth or you can go straight in to the next stage which is to sand the surface with some 320grit paper in order to key it up which will help your to stick better. The next stage is to get the surface clean and free from dust, grease, oils and whatever else maybe on the surface that will cause the primer not to stick. There are a few ways to clean the panel ready for paint

1. Auto panel wipe. which when it evaporates takes dirt away with it and also breaks down grease and allows the rag/paper to pick them up and remove them from the surface which is to be painted.
2. Tack rags or Tack cloths. Which are rags or cloths that have a sticky surface which picks up dirt’s and other nasty bits off the panel.
3. Alcohol wipes. Which work in the same way as the panel wipe
4. Petrol. You can use a rag with some petrol on it and wipe over the panel to be painted. This works in the same way the panel wipe dose although wipe the prices of petrol at the moment it may not be such a cost effective way of doing things.

Once you have cleaned the panel try to avoid touching it with your bare hands as this could leave oils from you rskin on the surface and cause a reaction

Really it comes down to which method you like best or works better for you. I like to use the tack cloth method followed by some panel wipe on a rag best but they all really do work just as well

Now you have a keyed up surface which is clean you can now go ahead and apply 2 or 3 coats of an acid etch primer to the surface leaving 5-10mins between coats or as listed on the can. When applying the primer you want to go from left to right and as you move down you want to cover the last spray line about a third to make sure you get all the panel covered evenly and leave no unpainted areas. Once you first coat is tacky around 5-10mins or as stated on the can you need to turn the panel 90 degrees or rotate the way your spray direction 90 degrees if you cannot move the panel around and apply the next layer in the same way as last time this type of spraying is called box coating and helps to get a nice even coverage across the panel. The acid etch primer is used as a first coat on metal as the paint eats in to the metal giving you a good base to apply the rest of your paint to. Also when using the etch primer you don’t have to but I normally do apply standard primer over the top of most of them as this give you more material to flat back to get a nice even surface to apply colour to so if you feel you have enough etch primer to flat back and get

an orange peel free surface you can save money by not adding extra primer but that’s going to come down to how you want to play it as if you sand back throw the acid etch primer you will have to then add another coat.
Acid etch primer also gives you corrosion protection as well and comes in white and grey colours

4: - Surface prep for already painted surfaces with an eggshell finish where you want to remove the eggshell finish

For eggshell finished paint you will need to block it flat if you want your new paint work to be flat and not eggshell finish.

You can apply guide here in the same way we have already been throw or you can use the paint that is already on there and watch for it to change to a dull shade all over to know its flat and smooth as the paint that is not sanded will stay shiny and sanded paint will go a dull/matt look. At this stage you will need to use a sanding block and some 320 grit wet (you can start with a lower grit paper in order to get it smooth faster but you need to make sure you don’t sand throw the paint surface to reveal to much bare metal) and dry sandpaper along with a bucket of warm soapy water (the soap will act as a lubricant to keep the sandpaper from clogging up with paint dust and will also help to remove any grease and dirt from the surface). If you’re going to be starting with a lower grade of paper and working your way up to the 320grit you will need to change the water every time you change grit as little bits of the old grit may have come off the paper in to the water and could be pick up on the next leaving the surface with some deep scratch marks still as well as changing direction by 90 degrees to the last stage. If you just going to use the 320grit from the start then you won’t need to change the water at all. So using the sanding block in a forward and backward motion you just need to keep going until the whole surface is the shame dull shade all over with no shiny bits left.

Now you just need to dry the surface off and give it a clean with a method below

1. Auto panel wipe. which when it evaporates takes dirt away with it and also breaks down grease and allows the rag/paper to pick them up and remove them from the surface which is to be painted.
2. Tack rags or Tack cloths. Which are rags or cloths that have a sticky surface which picks up dirt’s and other nasty bits off the panel.
3. Alcohol wipes. Which work in the same way as the panel wipe
4. Petrol. You can use a rag with some petrol on it and wipe over the panel to be painted. This works in the same way the panel wipe dose although wipe the prices of petrol at the moment it may not be such a cost effective way of doing things.

Once you have cleaned the panel try to avoid touching it with your bare hands as this could leave oils from you rskin on the surface and cause a reaction

I will give you some tips for using a sanding block later on in the guide

5: - Surface prep for already painted surfaces with an eggshell finish where you want to keep the eggshell finish for the new paint work

For this stage all you need is a medium scotchbrite pad and with even pressure run it over the surface of the panel in the same way you would if you were using paper until the surface is dull all over. The scotchbrite pad won’t make the sure flat so you will still be left with your eggshell finish. Once this is done all you need to do now is to clean the surface with a method below

1. Auto panel wipe. which when it evaporates takes dirt away with it and also breaks down grease and allows the rag/paper to pick them up and remove them from the surface which is to be painted.
2. Tack rags or Tack cloths. Which are rags or cloths that have a sticky surface which picks up dirt’s and other nasty bits off the panel.
3. Alcohol wipes. Which work in the same way as the panel wipe
4. Petrol. You can use a rag with some petrol on it and wipe over the panel to be painted. This works in the same way the panel wipe dose although wipe the prices of petrol at the moment it may not be such a cost effective way of doing things.

6: - Surface prep for already painted surfaces with a smooth finish

For this stage there are two methods which you can use depending on how fussy you are or how smooth you want the surface to be

Method One: - if you don’t mind the odd mark bit of orange peel or just want to do a quick job in order to change the look/colour of your case or part this is the method for you. If you want more than that you will need to move to method two.

For this method you will just need some medium scotchbrite pads and with even pressure run it over the surface of the panel in the same way you would if you were using paper until the surface is dull all over. With this done all you need to do now is clean the surface with a method below

Method Two: - if you want a really flat panel that will show off your finished paint work well this is the method you need to use.

For this method you will need a sanding block and some 320grit wet and dry paper along with a bucket of warm soapy water (the soap act as a lubricant to keep the sandpaper from clogging up with paint dust and will also help to remove any grease and dirt from the surface). If you’re going to be starting with a lower grade of paper and working your way up to the 320grit you will need to change the water every time you change grit as little bits of the old grit may have come off the paper in to the water and could be pick up on the next leaving the surface with some deep scratch marks still as well as changing direction by 90 degrees to the last stage. If you just going to use the 320grit from the start then you won’t need to change the water at all. So using the sanding block in a forward and backward motion you just need to keep going until the whole surface is the shame dull shade all over with no shiny bits left. Now you’re ready to clean the surface with a method below

I will give you some tips for using a sanding block later on in the guide

Now you just need to clean the surface with a method below

1. Auto panel wipe. which when it evaporates takes dirt away with it and also breaks down grease and allows the rag/paper to pick them up and remove them from the surface which is to be painted.
2. Tack rags or Tack cloths. Which are rags or cloths that have a sticky surface which picks up dirt’s and other nasty bits off the panel.
3. Alcohol wipes. Which work in the same way as the panel wipe
4. Petrol. You can use a rag with some petrol on it and wipe over the panel to be painted. This works in the same way the panel wipe dose although wipe the prices of petrol at the moment it may not be such a cost effective way of doing things.

Once you have cleaned the panel try to avoid touching it with your bare hands as this could leave oils from you rskin on the surface and cause a reaction

7: - Appling primer

Now you have a flat surface that’s also clean you can now apply your primer to your panel. The first thing to do is to get the paint mixed up so you will need to shake the can for at least two minutes or whatever is stated on the can itself. Once your paint is mixed up you should apply thin layers of paint from left to right over lapping the above stroke by a third as you move down and once this layer is dry turn the panel 90 degrees so you painting across the last direction you sprayed (this is called box coating and help to get a nice even coverage across the panel) and the panel should be turned or the direction of spray should change with each layer (so first layer you could put on from left to right and then turn the panel again and go left to right or if you cannot turn the panel first coat could go on from left to right and then the next coat from top to bottom and then back to left to right etc.) You should apply two or three coats unless stated otherwise on the can. Two thin coats are better than one thick coat of paint as the thicker the coat the more chance there is of it sagging and the more flatting out you will have to do later on.

8: - Flatting the primer down for painting in solid colours

Method One: - if you have left your standard eggshell finish paint work underneath because you want to keep it then you will need to key up the surface again with some scotchbrite pads only this time using a fine or ultra-fine grade instead of the medium grade. Use the pads in the same way as you did the first time.

Once you have it all dull and keyed up you can now move on to cleaning the surface with one of the methods we talked about before and then move on to applying your colour

Method Two: - Once your primer is dry depending on the temp it could take up to 24 hours but primer usually dries pretty fast but it worth waiting for as long as you can or for the minimum time stated on can. You can now go ahead and apply some guide coat to the primer normally I would use black guide coat on white and grey primer as it standards out well enough to see. Once the guide coat is dry (5-10 mins for a dust) you are ready to get your sanding block, some clean warm soapy water and some 600grit wet and dry and begin to flat back in a backwards and forwards motion until all the guide coat has gone and the panel is flat and smooth.

You can now move on to cleaning the surface with one of the methods we talked about before and then move on to applying your colour

9: - Flatting the primer down for painting in metallic and pearl colours

Method one: - if you have left the standard eggshell finish then you will need to use a ultra-fine scotchbrite pad to key the surface up as you did before. Once the surface is keyed up then you can move on to cleaning it and applying the colour.

You can now move on to cleaning the surface with one of the methods we talked about before and then move on to applying your colour

Method Two: - Once your primer is dry depending on the temp it could take up to 24 hours but primer usually dries pretty fast but it worth waiting for as long as you can or for the minimum time stated on can. You can now go ahead and apply some guide coat to the primer normally I would use black guide coat on white and grey primer as it standards out well enough to see. Once the guide coat is dry (5-10 mins for a dust) you are ready to get your sanding block, some clean warm soapy water and some 800grit wet and dry and begin to flat back in a backwards and forwards motion until all the guide coat has gone and the panel is flat and smooth.

You can now move on to cleaning the surface with one of the methods we talked about before and then move on to applying your colour

10: - Applying colour

This will be the same method used as for primer and will also be the same for solid and metallic colours.

Only difference here from applying the primer is that you need to add as many coat as it takes to get a nice even coat across the whole panel. So again applying the paint in thin even coats overlapping as you move down by about a third and turning the panel or changing the direction you spray after every coat is completed and dry

Solid colours: - usually only take around 2 to three coats like the primer

Metallic colours: - these usually take a few more coat than solid colours but it all depends on brand of paint and the colour your painting. I would say you will be looking at 3 – 5 coats depending on the colour

When applying colour think of it more as colouring in rather than spraying as once the part you are colouring in is all covered then that’s it job done. Quite a few people seem to add way to much colour paint thinking this will help improve the look but from my experience it just makes the colour a little darker than it should be and also makes the drying time longer as there is more thinners that needs to evaporated.

11: - Applying lacquer

When applying lacquer you want to do it in the same way as you painted the primer and colour on. Apply thin coats and build it up slowly allowing each coat to go tacky before applying the next coat with a left right direction and then turning the panel or changing direction to spray across the last coat for an even coverage. You should be looking at a minimum of 3 coats of lacquer but the more you apply the better as you will be able to sand or use compound to remove scratches and marks more times than if you just had 3 coats but lacquer dose take a long time to even go touch try let alone to a full cure. You should be leaving your lacquered part for at least 24 hours before thinking about touch it and two to three weeks before sealing it up.

12: - Flatting the lacquer and compounding

If you went for an eggshell finish there is not much you can do to remove the orange peel from the lacquer so you should move to the next step

Once the panel is dry is you’re ready to start flatting back but this time without guide coat and just using the shine of the lacquer to tell when its flat. With you sanding block, some warm soapy water and some wet and dry paper

You should work from 1000grit wet and dry up to 1500grit on the sanding block changing water everything you change grades of paper and working the block in a backwards and forwards direction. Also when changing grades of paper as well as changing the water you change direction of the panel by 90 degrees so you cutting across the last direction as this will help you see when the last grade marks have been removed and you can move on to the next grade.

Compounding

Once you have flatted the lacquer with your last stage wet and dry paper 1500grit + then you can use the compound to remove the marks that were left by the finale sanding.

start with Farecla G3 rubbing compound: - if you have a spray bottle you can put water in then use that to mist some water on to the panel but if you don’t have a spray bottle you will need apply a little water to the panel . once you have the panel wet then apply a small amount of the compound to the panel and with a polishing cloth start rubbing the compound in left, right and up, down motion until the panel shows no sign of sanding marks its best to do a small area at a time and them do another area. You need to mark sure you don’t let the surface dry out or you can burn the paint.

You can also use this compound with a machine polisher but due to the parts being small you would need a 2inch polisher and mop head set. If you are going to use a polisher Rotary or Dual Action type you need to be even more careful or keeping things wet otherwise you will very quickly burn the paint. Rotary polishes cut faster than an Dual Action polisher will so I would if this is the route you want to take then I’d start out with DA (Dual Action) polisher to get the feel for how they work.

Once you are done with the G3 compound you can move on to the G10 compound which is extra fine and works really on dark colour paints but this step is optional and just if you want that extra smooth finish .

13: - Polishing Paint

Once you have finished the compound stage you can now apply some polish to the surface to improve the shine. You can use all automotive polishes as its car paint but I would recommend using a good quality brand like 3M or Meguiars etc. I use Meguiars speed glaze or ultra-finishing polish which can be applied by hand or machine

14: - Waxing

Two to three weeks it’s time to seal up the paint with wax as the paint should have had enough time to go to a full cure and be fully hardened. At this stage you can if you wish apply another layer or two of polish before applying your wax. As with the polish you can use all automotive waxes but I tend to stick to 3M and Meguiars products

15: - Using a sanding block

DSC00656.jpg

This is photo shows the way most people use a sand block when flatting out paint work or filler but this is not the best way of doing it as I will try to explain in a second.

The green arrows show direction the sand block is moving in and the blue line show the edge contact.

Now using a sand block like this would be fine if you can keep even pressure on both side of the block as if the pressure is a little uneven one tends to dig in to the surface and leave a low spot while the other side of the block dose little to no work but in the photo below ill show you the best way to use the sanding block to minimize this.

DSC00657.jpg

Now as we can using the block in the same direction (green arrows show direction the block is moving) but at a 45 degree angle which as you can also see from the contact patch of the edges is reduced (blue lines show outer edge contact patch) meaning even if the pressure on the block is not even your less likely to end up with one of the outer edges making a low spot.

Sanding blocks also come in all shapes and sizes and some flex a little more than others do. If you’re going to be doing your pc case you’re not going to need a very large block but you might want one with a little bit of flex to it.

16: - Hand sanding for small areas

When hand sanding its best to place three fingers on a piece of sandpaper and instead of going forwards and backwards like most people do move your hand left to right.

Hand sanding and going forward and backwards leaves tram lines from where your fingers meet but by going left to right the joins don’t matter and it won’t leave you with tram lines.

17: - Masking tip

When masking up for a two tone panel or where two colours join in a straight line you cheat a little and get a better edge by masking up with the tape rolled in half down the length like in the photo below

DSC_0028.jpg

It helps to stop the paint building up and you can buy soft edge masking tape but it’s not cheap so you will be able to save money like unless you doing curves then it’s a bit tricky to do and you may be better off with the shop bought stuff.

if you have any comments or things to ask feel free and ill do my best to answer them