mx5cartalk.com

Firstly im not a professional, I work in a paint store so I know what the rules are and have some, but still limited experience. If anything is out of order, correct me, or let me know so I can correct it, figured I would put this up because I couldn’t find a thread about it.

Alright, the bare basics.

Step 1 - Choose your Product
By this I mean what system are you going to use?

2 Pack - The good > Strong, long lasting system, better finish.
The Bad > More difficult, generally more costly.
There are some systems where a single pack colour is compatible with a 2 pack clear, great system, makes life alot easier however generally not cheap.

Acrylic Laquer - The good > Simple, comparitively fairly cheap, still a full system, doesn't always require a clear.
The Bad > Not as strong, generally doesn't last as long, weather play a big part of your overall finish.

Enamel - The good > Cheap, fairly strong, can be brushed or rolled and still look half decent.
The Bad > Its cheap, you get what you pay for, generally fine for trailers, ute linings, marine enamel for boats etc. Generally not the best finish, but depends on what you do and what grade you get, system is different, not as much flexibility as far as filling etc. goes.

Step 2 - Preparation:
First of all, your finish depends on your beginning, clean the area you wish to paint, remove and flaking, peeling, cracking, bubbling or otherwise unsound paint, if its bare material, clean it, remove anything thats sticking up etc.
Depending on the surface, this may include sanding, grinding, cutting or any other means to make the surface 'sound', if what you need to do to make it sound would make it worse, consult someone.

Step 3 - Priming:
Depending on the paint system you choose and the substrate your painting this varies greatly, basics are as follows.

Everything - Clean it, whether it be Methylated Spirits, Wax and Greas Remover or Prepsol, get rid of anything that could affect your paint in any level. Run over the area with a tack cloth if you want to put all the effort in, a tack cloth is basically a tacky cloth, they're cheap and can be bought at automotive or paint stores, come in handy and just help your finish.

Bare metal - Etch Primer, according to what your topcoat is, you will find most etch primers are fairly universal, however avoid mixing enamel and anything else thats not enamel.

Bare plastic - Plastic primer, yes it exists, yes its important, no it doesn't make a visable difference, you WILL have to overcoat this with another primer of sorts, depending on what your doing, primer filler is generally the best as it covers two steps.

Vinyl - Yes vinyl, there isn't much in the way of primers, however, use the specified cleaner, it generally has a bearing on how the topcoat bond here.

Pre-painted surface - Alright, this is a very loose guide in this area, adapt it to what you have. Spot prime any bare areas, double check to make sure its a sound surface, if the paint you're going over is'nt bonded properly to the substrate your topcoat is only as good as what under it. If you have no idea what kind of paint it is, be very wary of what you put over it, generally its best to get rid of it if you aren't sure whether its acrylic or enamel, this will almost always cause issues if you use two contradicting systems.

Step 4 - Filling:
Alright, its recommended you fill after priming, why? Because then you have the filler between coats of primer and therefore sealed in, onto your bare surface your depending on its adhesion so said surface, you can fill before priming if you wish, it is easier, means less painting and general work, in general it won't affect the overall finish by much if at all, this is personal preference, however, if your doing large amounts of bog or bodywork, only prime the area where it will be going as you will just sand off the primer around it anyway.
Filling depends once again on your topcoat, how much you have to fill, and how good you want it to be.
Large dints, deep scratches, warped ares, are all easiest to do with bog, find a good bog, it'll save you time and effort.
Small imperfections, light cuts, dimpling etc. You can use primer-filler, easy to use, good build, there is single pack and two pack options here, once again, depends on your topcoat, dont build it up too thick or it will take a long time to dry properly and you may get cracking, solvent traps and other various issues. Spray putty is another alternative here, slightly higher build however you will have to prime over this, once again, time, effort and money play a role here.

Step 5 - Preparation... Again:
Make sure the surface you have is as smooth, blemish free and overall looks like you want it to look minus the colour. Sand what you have to sand, prime what you have to prime, fill what you have to fill and repeat if nessecary. After this, it becomes expensive and frustrating, these first steps are very important, if you skip through these it take alot more effort to get your finish looking decent and you'll probably have to do them again anyway, so do it once, do it right.
Clean the surface, something like Prepsol, Methylated Spirits or wax and grease remover (be careful with this, may react with your products), and use a tack cloth if nessecary, a tack cloth is basically a sticky cloth, will pick up and dust, dirt or fluff from the cloth you probably just cleaned the surface with, any contaminants may affect your topcoat, so, clean while you can.

Step 6 - Basecoat:
This will generally look patchy but don't worry, its all apart of the process., this is mainly for better adhesion.
If you're using a spray gun thin exactly as the can says or as you were directed, changes per system per brand. Put your pressure as low as it will go then turn it about a quarter notch up (depending on the sensitivity of your controls) , spray onto a sample board of some sort, if it spits, oozes, or does nothing at all, turn it a quarter up again, repeat until you get a steady spray with no oozing or spiting. Then cover you whole area in a fine mist at this consistancy.

Step 7 - Colour:
Now your colour should be the same TYPE of paint as your basecoat < this only applies to people who need an undercoat for thier colour.
If you're using a spray gun, turn the pressure up a quarter notch of what you had it for your basecoat.
You can now apply a regular coat, depending on the system changes how thick your coat should be.

Acrylic Lacquer - Quite light, the more light coats you do the better, go in fairly large sections though, to allow the acrylic lacquer to flash dry before going over it again, acrylic dries fast and makes it easy to do this. Make sure you don't do this in cold or wet weather, do a test patch somewhere to make sure it doesn't cloud up after about half an hour if you're not sure.

2 Pack - Decent Coats, now im not saying throw it at what you're painting, but you want to get a decent coat on there, do this by going over the same area a few times before moving on, panel by panel, it will level itself to some degree and because you can only mix up certain amounts at a time you use what you make.

Enamel - Alot like 2 pack, if you're using hammer finish, the thicker you do it the heavier the hammer will be.

Repeat this step till you have a solid colour, if your have a metallic or pearl make sure its all uniform and has all been layed off in the same direction. If you're using acrylic lacquer and doing a solid colour you will have to buff it before doing your clear, you also have the option of not doing a clear, however it wont last as long as it would with a clear, your choice.

Step 8 - Clear:
This is sometimes tricky and easy to screw up, once again, make sure the surface is clean, if it’s a solid acrylic lacquer, make sure you’ve buffed it.
If it’s a metallic or pearl colour and you’re using acrylic lacquer, you don’t have to clean your pot before going to the clear, just get the extra paint out of it, put your clear in and do a light coat, then empty it all out, give it a quick clean and continue with your clear.

Do at least 2 coats of clear, the more you can do the better the finish, should be similar pressure to your colour, check the can!
Last coat, thin out more, and do a very fine coat, if its acrylic lacquer be careful not to thin it too much or it will dry to quick and dust up.

Problem solving:

Orange peel – Too Much Pressure

Runs – Thinned too much or you’re putting too thick of a coat on, possibly being too close to the surface when spraying.

Clouding – If its acrylic lacquer, the weather is probably doing it.

Dusting – Either your tip isn’t clean, you’re too far away from the surface, you have thinned it too much, or your not putting a thick enough coat on.

Staying Soft - Various causes, from contaminents underneath to doing your coats to quickly or to thick over eachother creating solvent traps.

Feel free to PM me if you have any other questions I haven’t covered or you want me to correct something in what I’ve written. I did this quite quickly with the knowledge I have so its not perfect, but its better than nothing.

I couldnt fault that, maybe add a part about what all the gun adjustments do?

Stick for sure.

Dann

Differs for the gun, but in general, knob at the back and bottom will change air pressure, knob either above that or closer to the front of the gun will adjust quantity of paint, may be in different areas, may be only one knob (which would be air pressure) etc. Depends on the type of gun and brand.

I meant an explanation as to how the adjustments work and why you would change them.

Dann

Oh, well to get the right consistancy, you dont want to have too much pressure with not enough paint, different consistencies of paint for example between spray putty and acrylic lacquer needs different pressure to push it through, however if your pressure is too high it will push through too much paint or give an uneven finish, may creat dusting issues, too low and it will spit or run. Changing the amount of both paint and air depends on the product, because you want to do lots of thin coats of acrylic lacquer you dont want to push too much paint through your gun or you would have to move very quickly, opposed to 2 pack which goes on thicker so you adjust it so you can move at a comfortable pace and still put enough on. Finding out happy mediums takes practice. Only having used two different guns I found a basic way to do it stated in the massive instruction list haha. If you're not sure about how your doing, do a test piece on a spare sheet of something or in a inconspicuos place, saves having to sand more.

Would I be able to edit this whole thing? I've just painted my car and want to do some minor changes.

Having initially read and followed these steps, it's also corroborated with heaps of other online articles and forums, and hours of videos, and tried three attempts on a bonnet, in black acrylic (possibly too large for a first timer, and not the most ideal colour) I'm now ready for my fourth and final go. Re-reading this thread has all the words reinforced and found myself nodding and smiling to so many of the points The_Darkside pointed out.

I just want to add my own experiences here for any newcomers:

It's taken a while to learn the spray gun i have (a gravity fed one) you'll honestly need to play about. Practice on your mate's car first or a spare panel to learn the mixtures settings/airfeed, etc. Get a regulator with a display for the fitting just before the gun too, they're only $10.. - and that in 35 degree heat it's too hot to paint!
The gun behaves differently for primers vs the acrylic. I know there's a minimum temperature to paint above too but havent got to that yet (been a bit of a heatwave at home until a week ago)
You need to find a pace for the mixture of the primer or acrylic at which to spray at, and work out the best distance for good coverage.
outstretched hand width away and outstreched hand worked for me with the acrylic but was very different for the primer. I couldnt get the density right at a hands distance away, so i ended up having the gun closer to the panel.

Have a bunch of butchers paper and tape to practice this on a wall.
By a bunch, i mean, have 2-3 meters width x 1m tall of paper on a wall to trial different settings.
You'll likely need A LOT more on a first time to get your spray pattern right.
I first borrowed paper from work's A3 copiers, then found a source of board paper for meetings. With permission I took that with me.

This will give you a good starting point to play with BUT paper absorbs the paint VERY differently then the way it sits on a panel.



Dust - it's a B*stard.
Have a bloody clean shed! Use an air blower on your compressor to clean out as much dust airborne particulates as you can.
Let it settle for an hour or two.

Close off all air flow entry to the area (i.e., avoid an open garage door)


Spray fly spray on all surfaces, and especially around the entrance points into the shed space / install an insect zapper. I've had mozzies coming in and landing on my painted surface, and no matter how loud i exclaimed F*CK, it didnt reduce the extra work to sand them out.
Leave for an hour or so so the flyspray to settle before doing any paint/prepwork. (also cover your painting surface so the flyspray chemicals don't touch it)

Isolate any cupboards, desks, draws, shelves and walls with drop sheets taped sealing the areas off, and in a way that the drop sheets don't move about with airflow.
This will protect the contents of the shelves from paint dust/overspray, as well as eliminate any future dust from the shelves being unsettled into the painting space. It'll also make visitors nervous as you can say you love watching Dexter.


20 min before basecoat jobs, spray water on the floor if you dont have polished concrete, to settle any further introduced contaminants, making sure not to have water on any walls and definitely not anything dripping from the ceiling.

Have a decent ventilation mask.

Make sure if you have to leave the area once painting starts or is in progress or has immediately finished, that you open your exit door and briefly as you can then closing behind you. Reduce all chance of dust going in. If you have the space, use a drop sheet as a second door / poormans wind break. Drop sheets arent really suitable for covering the floor in a shed where your boots are damp and dragging it about, it's only going to end in tears and more swearing.

For etching and primer filling/primer surfacing, it's not so critical as you'll be sanding down via a guide coat.
For basecoat or clear coats, isolating bugs and dust is super critical.

I know my setup described doesn't allow for ventilation, my shed is really small and i'm in there for as little as possible to not have to saturate my masks filters. This description is what's working for me. Hopefully you have more space and an option for a fan in the wall with a filter sponge in between for fume extraction. My mask has filtered all the air into my nose, i essentially couldn't smell anything but air through it.

Also, have a LOT of latex gloves and a roll of clean rags on standby to wipe up and protect your skin. Thinners, and paint stripper sting like F* if you get even a little bit splashed onto you. Have spare filters for your mask. The moment you smell the thinners or fumes coming in, stop, leave, and change the filter. If you have facefur like me, make sure the mask is a tight fit!

6 weeks ago, i knew none of this process. I'd only used rattle cans on small projects and they are very different in their use and application to this. Today, i feel empowered with a few trials behind me with very promising results. It can be bloody frustrating for a first timer, but so completely worth it in the end.

Thanks for the addition man, just realised, aside from my bad spelling, I hadn't covered the environment to spray in. Glad to know someone made some use of it.

Also it's worth buying a little bottle of "SILRID". A few drops mixed with the paint in your pot will neutralise any silicone that causes those horrible little craters.