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  1. #1
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    Default How to paint your car. Tech Guide

    I will be painting a Holden VT in its original factory colour.

    This will demonstrate how I went about getting rid of ripples in the metal work, and the steps I use to get my paint shiny and flat comparable to a quality job done in a spray booth. (at fraction of the cost)

    This car was in average condition, it required lots of work to get all the panels to line up again, there was also evidence of small bumps and dings in the metal work. It required some light panel beating and a lot of repair work to get these panels to a better than factory condition.

    The methods I use are not really recommended by paint manufacturers but before that puts you off, I will explain why I have changed my process where applicable and the reasons behind what I am doing. If you still disagree strongly then please don’t follow my guide, but I have used my methods and almost all the other ones, and this is how I tackle all my cars now whether they 5 grand or 50 grand, I’ve had excellent results, and also a lot of mistakes, this is the summary of my ten years of learning and streamlining the process.



    Air and Tools
    You’re going to need some tools; I won’t explain them in great detail as I’m assuming everyone is familiar with basic tools in the shed.
    A compressor, preferably with a minimum of around 12 to 15 cfm (this is the air delivery rate)

    Some spray guns, I recommend 3. One for heavy coats, primer filler etc. Another one for colours and base coats and another separate one for clear coats, this helps with colour contamination across the guns.

    I’ve got an HLVP (high velocity low pressure) for my filler primer coat materials; I use a 3.5 nozzle and tip.
    I have 2 gravity fed high pressure spray guns also, for base coats I use a 1.5 nozzle and tip and for the clear coat gun a 3.0 nozzle and tip. These are important because they spray out with different looking textures due to size of the flow in the nozzle.

    picture

    You’re also going to need some sanders and drill attachments like wire brushes and sanding pads.
    These take care of all the detail work around door edges and inside petrol flaps.

    Sandpapers
    40 and 80 grit > for cutting back old paint

    180 and 320 grit > for smoothing repairs and filler coats

    800 and 1000 grit > for smoothing primer and some colour sanding

    2000 and 2500 grit > for finishing off with polish work

    How much you’re going to use of these will depend on how much you are prepared to use a raggedy piece of old sandpaper. You will find out this is different for everyone.

    4 Picture of sanders and sandpapers and 4 kinds of blocks

    My buff wheel comes with a 8cm diameter rubber pad for felcrow sanding disks, I use this to do most of my paint stripping, I use 40 grit sanding disks and grind off old paint on large panels like bonnets roofs and doors.

    The other sanders I tend to use a lot are a good rotary sander, an air sander if you can get one, and a finishing sander (or orbital sander is pretty much same)
    Then you need your sanding blocks. I have 4 that I use and these cover all the different surfaces and hard to reach places that I need to cover.

    Long block (speedfile) > this is for getting your panels really flat, it’s easy to use and is the secret step to getting rid of all that ripple and low spots.

    Medium flat block > this is great for doing large areas like bonnets, roof’s and doors.

    Small hard rubber block > this is like the chef’s knife, it does all the detail work like where doors meet and panel edges line up.

    Small soft foam block > this is for getting into all the hard to reach places like inside your petrol flap, or along the inside edge of doors and sills, basically areas that have lots of curves and corners. Here it’s not important to maintain large flat surface areas to get the paint on flat. More on that later.

    Extraction fans and heat
    Your also going to need some way to ventilate your work area and if it’s cold you will also need to think about how to warm it up, the warmer your shed the better the paint will go on (this is known as flow)

    To ventilate my shed I have two extraction fans temporarily fitted to the windows, with a hepa filter on the other side, this cuts down most of the overspray and keeps the fumes from going to the neighbours and upsetting everyone.
    For warmth I use a pair of gas heaters, one is like a heater cannon and is super efficient at warming everything up. I will run it for a couple hours before I paint, and it makes a noticeable difference. Without it the paint will be cold and go on very peely with problems, when its warm it will flow better and go on shinier.

    5 Picture of heaters
    Some other bits and pieces you are going to need around, tack rags, a painters mask, lots of masking tape, guide coat powder, gunwash and prepsol and lots of rags. Also you’re going to need lots of plastic or sheets or something similar to cover areas of your job while you work.

    6 Picture of solvents and mask

    ok let’s get into the process


    Part 1- Stripping the Car

    There’s lots of ways you can go about this I will explain the various options below. I personally go with sanding using sanding disks.

    Media blasting. (this option costs money) Basically it involves sending your car away on a truck or trailer to be blasted with sand, glass shot, soda whatever is available in your area. It gives the most superior finish to your job, and is the least amount of work for yourself, but for me it’s not really a realistic option due to the costs involved, so I will move onto the other methods, if this if for you however, get into your yellow pages or on the internet and find out who’s close to you, shop around for quotes and talk to the service providers about what they blast with, pricing time frames etc. They all want your business so will be more than happy to work something out with you.

    Paint stripping with chemicals. This is also a good way to go but the things to consider here, are that paint stripper to by in small amounts for the home user is really expensive. It can cost up to $20 a tin, and one tin doesn’t get you very far. If you can come by it cheaply or freely then this is not a bad way to go about it, but your situation and connections will determine whether you go this avenue of not. It makes a mess on your floor and its nasty stuff to work with, it burns your skin on contact, something else worth considering is if you have a lot of old paint on your car, paint stripper tends to only bite down into 3 or layers of paint before it stops working. Lots of layers of paint will cost you a lot in chemicals to peel it all back. Just as effective and cheapest of all is sanding it back yourself,

    7 Picture of vr paint stripper

    Sanding it back to metal. This sounds like the worst way to go about it, and if you do it wrong it can be, but it’s your cheapest option and if you use the right grits, can be very aggressive and effective. It’s not for people with sore backs though. My strategy is always getting my buff wheel, swapping over the attachment to the felcrow sanding disks and hitting the large panels first such as bonnet roof doors etc. Then come back with my wire brush attachment on the drill and pick up any small
    jams, door handle recesses and detail work.

    To make your sanding cost and time effective, start out using 40 grit sanding disks, at the start of a job I buy a pack of 40 grit and 80 grit disks, they are a dollar a disk but the more you buy the better the deal they give you, I usually get 50 for $25 of each giving me half a box of 40 and 80s.

    8 -9 Picture of vt doors and rear quarter pillar

    When you begin to strip with your buff wheel or sanders, don’t press hard onto the metal, making scratches will only be making more work for yourself. Hit it with 40 grits and try strip old paint back to its first layer of primer, a door done this way will take about half an hour. You then switch out to 80 grit and using an electric sander, smooth out corners, edges and go over your whole panel to sand out any deep scratches or primer patches left on your panel. The 80 grit leaves sanding marks
    on your metal but this is actually a good thing, you do not want to polish your panel or make it shiny, your paint won’t stick to it nicely making it weak to chipping and scratching. The sanded metal gives the paint more surface area to bond with making it stronger.

    Once you have your car body completely sanded, give it a blow down and wipe it over with prepwash, you want it nice and clean to start doing your repairs.


    Part 2- Getting your Metal Flat

    Equipment:
    Dolly’s, panel beater hammers, plastic mallet, cut pieces of timber if necessary

    You’re basically going to try and fine tune your panels, so that you can lay down as little filler as possible. Where you can, strip the interior parts of the car, like door trims and roof lining, so that you can gain access to the dents from behind, you want to use the dolly’s and gently tap the low spots back out until they are level with the rest of the panel. It’s good to check the straightness with a metal ruler turned on its side, and low spots carry on tapping with the dolly’s and hammers as needed until it is as straight as you can get it.

    10 Picture of doors minus door trim

    Here I had to use timber to get the bottom door line straight with the other one, I’m not sure what happens to cause this but it doesn’t look right when the car is back together so must be fixed, it’s a bit brutal but does the job, what I did was lay the timber against the sill panel and then applying pressure to the door I pushed until I could see the metal bending out to the correct place. It took several goes at pushing on the door until finally when its closed all the panels lined up nicely.

    Its not a big deal how you go about getting things to line up or what you use, it’s really a bit of macgyvering in the shed. Even at a panel shop they will improvise with what they have to get the job done. At the end a straight car looks better than one that’s not.
    Last edited by EV1LVT; 18-06-2012 at 09:40 PM.

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    I’ve also had to go about filling some low spots here with filler along the doors and on the boot lid, I was unable to dolly these place because they are on the crimp lines and for the boot it has the supports welded underneath, the glue is responsible for pulling the panels out of shape, and years of opening and shutting doors and boots will put tension on your metal causing it to have subtle ripples and dents on it.

    11 Picture of filler in boot lid

    12 Picture of filler in the door

    13 Picture of mixing filler

    Once you have filled your low spots you use your long block to begin sanding on your repairs to get them flat.

    Using the long block and 180 grit paper, you sand in a criss cross direction but diagonally across the repair, think of a giant X pattern. This is to get the most surface area of the block onto the panel at one time, so anything between the ends of the block will be levelled. Below is a diagram, explaining what I mean. It’s important to use the long block as much as possible, it averages out large areas when it comes to getting them flat. It takes longer and will often seem easier to use a small block, but this will show up in your paint job, a small block can sand in between your repairs. Check the diagram below.

    14 Diagram of low high spots and blocks small and long.

    15 Picture of sanding filler

    16 Picture of sanding filler


    Part 3- Laying down your Filler Coat

    This is where some painters will begin to lose some confidence in what we are going to do next, but I will explain why I have changed my process to this and what the alternative is and you can decide for yourself what you wish to do.**

    To cover my repairs I lay down a one pack filler coat, paint manufacturers don’t recommend you interchange one and two pack systems, but this truthfully applies more to paints than actual fillers, its do with dry times or ‘curing’. Two pack systems are far superior for hardening times and durability, especially when you paint in a professional environment and time is money.

    One pack systems take a long time to cure, so in a shop if they begin to paint on their repair that same day there can be problems like shrinkage and tail fumes escaping from the filler coat into the paint in top as tiny bubbles. To avoid this we allow plenty of drying time, once again I want to mention painting in your shed is different to in a booth, as long as you allow things to properly cure and dry you will have no problems.
    The product I use is a 3M one pack coat filler putty. It comes in pressure packs and also in tins that you can mix with thinners to get the consistency you want and this can be sprayed from your HVLP gun.

    17 Picture of 3M filler coat and thinners. With HVLP gun.

    This can be purchased at any auto shop, it’s even stocked at supercheap and autobarn, but I wouldn’t recommend buying your paint from those kinds of stores, find a local auto paint store in your area because they will have appropriate products and be far less expensive.
    Before we lay this down we need to etch prime the car. This is a light mist coat to ensure that all the products on top bond nicely with the metal. This is very important otherwise you will have a weak layer in your paint job that will cause rapid stone chipping and scratches because the surface paint can easily move along the surface and be stretched due to not having an anchor point. (essentially the etch primer)

    18 Picture of epoxy primer

    19 Diagram of paint layers

    Start off by masking up your job, get it ready by taping up cracks and door jams and anywhere else you do not want your filler coat to land. Generally I try to seal up the car and only lay down filler coat on my large flat panels such as doors and bonnets. You need to be really picky about your masking anywhere you miss, fumes and dust will get in. You would be amazed at how much extra work this can cause at the end to clean all your interior and in some cases can leave traces of your respray such as grey streaks of primer that were hidden under making tape etc. Check your work until you happy that your only putting paint on the surfaces you want it on.

    20 Picture of masking up the door jams

    Give the car a blow down make sure it’s nice and clean, get your mask and fans ready, you want to have a nice warm shed when you lay down your filler coat,
    Last edited by EV1LVT; 04-08-2010 at 01:55 PM.

  3. #3
    Should be banned...again! Schnoook's Avatar
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    Munching on peanuts, watching updates and for neighbours to appear out of nowhere!!!

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    Mix your filler coat with the right consistency adding thinners I tend to go about a 25% thinning ratio to filler, this makes it nice and thin and easy to spray.

    21 Picture of wet spray on door

    You want to spray with nice even passes about 4 to 6cm away from the panel, if you miss small spots don’t go back just keep spraying evenly working your way trying to get the coat as even as possible, then when it flashes off, re-apply another coat.

    22 Picture of spraygun doing a pass on the door

    Coat the whole car so you have nice even coverage, this puts a nice even surface over your metal and filler repairs, wait for it to flash off, (this means dry to the touch) then re-apply another coat until you have a solid even coat across the whole car. You can do this panels at a time or in one go whichever you find easier, but to sand them you will want to have all your panels on the car so you can ensure they line up correctly. More about this soon.

    23 Picture of ruler on doors

    24 Picture of ruler on doors

    Make sure you keep checking your work as you go, anything you miss you have to pick up again later so keeping everything straight and lined up while you work is good practice. Sometimes to paint inside front quarter panels and inside edges panels will be removed again and those areas masked and painted off the car, if you have a good handle on everything that’s going on you will do these parts before you hang the panels on the car.

    25 Picture of front quarter panel off the car inside edge

    We are ready to let this cure and then begin our blocking down to get everything nice and flat.
    **To address the concerns of why we went one pack. basically one pack and two pack is the same thing but they react differently. Two pack filler requires hardener, and one pack reacts with air. The longer its exposed to air the harder it gets until it reaches its curing point. Bog however reaches a cure point because the hardener makes it “go off” but it takes months for filler to completely dry to a point where it won’t want to shrink. Wherever you use filler you want to keep it as thin as possible.

    The filler coat seals in all your metal and repair work with one even coat that when sanded flat gives the next layer of paint a consistent surface right across. This is again important in your end result if you don’t want to see any traces of repairs under your work. The professionals here will use many coats of 2 pack high fill primer. But for a car in the condition of mine, it would require several litres of primer, a 4L kit for me costs around 150 dollars. To get the coverage on all the low spots on my car I would probably need to do the high filling process 4 or 5 times to really be sure that I have everything flat and even. One pack costs 22 dollars for 4 litres, and allows me to build up my low spots cheaply, allowing me to use less bog I will about 2 tins to do a whole car, this is much more cost effective for me. And I’ve had excellent results doing it this way on my cars.

    If you’re not comfortable with mixing the products then you need to skip this step, you do your repairs as mentioned in getting your metal flat, with filler and your speedfile, then high fill the car with 2 pack primer. You will need to guide coat and block it down being careful there are no high and low spots, if you come across any you will need to refill them with bog and 2 pack prime again or keep priming and blocking until this area is filled.


    26 Diagram of pink one pack filler next to just filler and highfill

    27 Picture of bootlid before with repair and after coat

    28 Picture of drivers door before with repair and after filler coat


    Part 4- Blocking down your filler coat

    You will need some form of guide coat here, I recommend using 3M graphite powder, it’s a bit expensive but its value for money because it helps you easily find low spots scratches and pinholes when you are blocking. You can also however spray a light mist of just some black paint even from a spray can if you have to, you want little speckle dots so that as you sand them off the speckle dots will stay in the low spots showing where you need more attention.

    29 Long Block

    30 Picture of the car with guide coat on it
    Last edited by EV1LVT; 04-08-2010 at 01:59 PM.

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    31 Diagram of speckles in low spots and block on top

    Next you’re going to select your long block and a 180 grit to sand down the filler coat and get all your panel edges ‘synced up. 180 allows you to sand through the bulk of the material quickly, and getting your overall shape of your car right, you might need to tweak some panels here with some more filler coat if necessary, this often happens to me, but it’s worth the extra work at the end, I will also pick up any miss alignment and adjust door catches and bonnet latches as if this was my final dress rehearsal before painting. After I have finished I give the whole car a light sanding with the 320 grit paper to smooth out any scratches and rough edges I might have missed, this just allows you to use less primer, and the thinner your paint the stronger it will be. (as-well as cheaper)



    34 Picture of the car nearly finished

    We are nearing the end of this phase for this car. I’ve unmasked everything and washed and cleaned all the areas like windows and door jams to make sure I haven’t got overspray on the areas it shouldn’t be. Now’s the time to clean any rubbers or seals and glass of any little dots or overspray you don’t want to be doing this at the end when you have nice new clear on the car. (blades and little scrapers can sometimes jump onto places you didn’t want them too)
    Get everything nice and ready for your priming stage, this is really where you start to see the fruits of your labour.



    Blow down all the cracks and door jams and seals and make sure you have wiped up, and blown away all the dust, so that it doesn’t get in-between your primer and panels, this will once again cause weak spots in your paint.

    Finally prepwash everything and wipe it down make sure its dry and clean and then re-mask the car ready for the next step.



    Part 5- Priming the Car

    We are now ready to apply our primer coat, I’m using a 2 pack primer which is also known as high fill, but because I’m a home painter I call my bog; bog, one pack putty; is filler and high fill; is primer. Sorry if this is confusing, but you can decide to call them whatever you like as long as you apply them correctly.
    Here once again I will be using my HVLP gun to lay down the primer, I’m going to prime everything as if it was colour, meaning in all the same areas that I didn’t let the filler coat bleed to, this covers the edges of the spray putty like the spray putty covers the edges of the bog repairs, giving an even surface for the next layer to sit on.


    Mix your paint correctly, make sure you have also warmed your shed prior to applying this coat, treat it as if it’s a colour coat its good practice and the smoother you can get this coat on the less work you will have to sand it all. No runs!

    Start by painting the panels with even passes the same as with your filler coat, you want to try and make sure the paint edges just lightly overlap and that it looks nice and wet as you lay down each new pass. I will run my spray gun needle at about 4 or 5 turns out from closed so that only a small fine spray will go down, it’s better to do lots of passes building up your surface slowly than laying it on thick and having runs, runs are very difficult to block out, once you start to block out a run you almost always notice flat spots in your finished paint. The secret if to not make the mistakes as you go, unfortunately in painting if you make a mistake and take one step backwards it usually requires 3 or 4 steps, not 2 to get you back to where you started.




    Part 6- Sanding your Primer Coat

    Once again you need your guide coat. This is all the same steps as with the pink filler coat, you’re sanding the panels smooth to get them ready for the colour, and the primer helps pick up any minor detail work you might have missed with scratches and rough spots near panel edges. It also seals in the one pack with a 2pack system giving it more strength. This is where I find the one pack filler is so thin after sanding that the 2pack primer sticks through to the etch paint underneath and doesn’t seem to cause any problems, the paint is tough and can handle some pretty good abuse before it will chip. I have discovered this by doing it, I’ve tried other methods too, but stick with this method because it has worked the best in my shed environment and the paint holds up better than cars I have covered in a lot of coats of primer and colour to hide the flaws.
    Last edited by EV1LVT; 18-06-2012 at 09:40 PM.

  6. #6
    been here .......too long Smitty2's Avatar
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    keep it coming..good tips hints

    I like doing cars & have done a few
    one Torrie I did a few years back..before and after
    [IMG]http://i6.photobucket.com/albums/y233/smitty1955/Car%20Pics/ljtorana-before-after1.jpg[/IMG]

    one tip..Preparation is what makes a paint job!
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    Last edited by EV1LVT; 03-08-2010 at 12:41 PM.

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    Good Thread EV1LVT,..but I really do cringe at the idea of using single pack primers, putties and top coats, it really is 50's 60's technology,. I would never use that old shit on my pride and joy!

    Nevertheless, keep up the good work dude, it's the only way beginners can learn easily.

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    Last edited by EV1LVT; 03-08-2010 at 12:41 PM.

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    Got ya,. the single pack filler you use will still be a weak link in the system, that stuff is a real underperformer,..But years back I did it like you for the ease,..you really only need the TWO products to do a perfect job,.

    Etch, Primer, & Filler, = 2 pak primer filler ( 3 products in one)

    Topcoat = 2 pak topcoat

    Just two products do the lot,..Done this way you have the performance of an original factory job, second to none.

    Cost more tho for your pride and joy!

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    Last edited by EV1LVT; 03-08-2010 at 12:41 PM.

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    only thing i would add in there would be to guide coat your spray putty before blocking........i know it's stating the obvious but it is for beginners.
    keep up the good work
    Some people are just jerks

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    Last edited by EV1LVT; 03-08-2010 at 12:41 PM.

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    Quote Originally Posted by EV1LVT View Post
    yeh im with you now, and agree, but takes more 2pack high fill to do it like that, which isnt a bad thing but costs bit more. how weak a link is it in the system? the oldest job i have on the road is about 8 years now and its wearing as good if not better than a factory, has some chips and scratches but nothing out of the ordinary and its a daily driver.
    part of my reason for moving to single pack filler coat is spraying in your shed isnt an ideal spraying environment for yourself or the neighbours, so by doing this step i found i saved myself a lot of hours of actual painting (making fumes) by having to lay down several coats of high fill, this way i get it in one sweep of filler coat, then one sweep of high fill primer and after that good to go with colour. anyways i like any feedback different approaches the more knowledge here the better.
    what you say, is why, I did it your way years back, yes it is a bit more expensive and not quite as simple a process, and your way will work quite well if after that putty you go back to using 2 pak for the under coat and top coat.
    It still is a weak link but will be masked very well with the quality on top, especially if your repairs are done to a high standard and your single pak putty is not too thick and is very cured prior to applying subsiquant coats.

    Your system is very not recommended by paint manufacturers, but I know it does work quite well, Keep up the good work dude.

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    Last edited by EV1LVT; 03-08-2010 at 12:42 PM.

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