Understanding the In's & Out's of Paint System Selection

[JackIIA]

Anyone have a good site(s) that will cover all the broad basics on automotive paint SELECTION? Or feel like giving the forum a tutorial??

I've found some pretty good ones discussing painting technique and prep, but none that clearly layout actual selection of a painting system and the best brands for each choice. Sites like Dupont, PPG, and House of Kolor, assume you already know what you're doing and are just need to know color or chemical specs. And it's not even clear if these are always chemically cured paints, or still offer more old fashion alternatives.

Originally I was going to go with the isocyanates for a durable fade-free finish, but the more I read about the paint vapor particle 'hang time' even long after painting (UK Health Services have some great videos on this) and skin absorption risks, the more scared I got (e.g., hardener setting up in my lungs). Even with a self-contained breathing system, I think it's just not safe for my hobby-level of tools/skill.

I'll be using a HVLP set-up, with a good CFM compressor; painting 'booth' is a basement room with limited ventilation. Breathing is a self-contained fresh air unit half-mask, and 'curing' will be around 65 degrees using a small oil-filled portable radiator.

So....I'm probably going semi-old school, something along the lines of the 1970's era of painting. I believe that's post-laquer stuff and were known as urethanes? Downsides? Not the best choice??

Thanks all, as always.

[kevkon]

I think this site will help you;http://www.roverlanders.bc.ca/faq/LRpaintMain.html

[Bertha]

The steps laid out in Kevkon's post pretty well cover the process, however I will add a few points:
I would not paint in your house. I think your best bet is to buy one of those outdoor tents that kmart/wallmart sells for $150.00. You can buy the sides for another 30.00. Its large enough to fit all the pieces of a disassembled Land Rover. I would also get a fan for sucking the air out of your "spray tent" Total investment may be somewhere in the 300.00 range, but you will be saving thousands $$$ by doing yourself, so a few dollars thrown at the right equipment is not money wasted. I would also wait until spring time to spray. It is very hard to work against mother nature. You can strip and prep all your parts over the winter and spray once the weather is a steady 65-70 degress with avg humidity. The paint will lay out really nice at that temperature.

[JackIIA]

Kevkon - thanks for the site. I'll give it a good read. Bertha, good thoughts. The outdoor approach is much better from a venting perspective to be sure.

In terms of waiting for Spring, I may be able to do so for the tub, doors, wings, etc., but will go nuts waiting if I hold off for the bulkhead, since it is integral to getting things mechanically back together. When I settle on a painting approach I'll have to see about accelerators for the paint (if those are used with anything but isocynates).

[kevkon]

Jack, a few thoughts. I'd definitely follow Bertha's advice on the outside painting. But if you must move on with some painting and that means the basement then there are a few things to consider. I think after you look at the paint options it will be pretty obvious that an acrylic base is the only way to go. They are safe, low VOC, and durable. Downsides are that they can be a little more difficult to apply and they don't tolerate surface contaminants. Also, while temperature is a factor to consider, humidity could actually be more of a problem for you. Is your HVLP a turbine system or a conversion type? Also, you can buy paper paint booth matting to cut down on the over spray. It's relatively cheap and disposable.

[thixon]

Jack,

In addition to the tent recommended by Bertha, you can also build a temporary paint booth using PVC as the frame. after you build the frame, you can then skin it with plastic sheeting and duct tape from the paint section at home depot. Get a cheap box fan, and some regular HVAC filters and your set. Google something like "temporary paint booth" or "garage paint booth" and you'll find some info. The best part is, you can just take the PVC apart if you dont glue the slip joints, and save it for the next job (yes, there's one on my top shelf right now!).

As for your paint selection, I'm glad to see you did your research. I'm also glad to see you bought a forced air respirator. If chaps me to hear stories of people who bought 2K paints from the auto paint shop, and had the counter guy tell them they'd be fine with a cartridge style respirator.

With the water based paints, its important to have your gun set up and adjusted right. Practice on something first. It sucks to have to start over because you put runs all over.

Good luck man. Nothing beats that look of disbelief on someones face when you tell them YOU applied that awesome looking paint job.

[JackIIA]

I think after you look at the paint options it will be pretty obvious that an acrylic base is the only way to go. They are safe, low VOC, and durable. ......Is your HVLP a turbine system or a conversion type? Also, you can buy paper paint booth matting to cut down on the over spray. It's relatively cheap and disposable.

I THINK, I'll be going with a acrylic enamel. I'm going to post a write-up from two different sites which goes into paint selection, largely to see what you all think in terms of it's accuracy, or any other comments. One downside to the enamel is the claim that it will only last 5-7 years before fading.

I know it's not a turbine system, no heating involved. Just hooked up with a shop compressor, so I'm guessing it's the other one.

[JackIIA]

The steps laid out in Kevkon's post pretty well cover the process, however I will add a few points:
I would not paint in your house. I think your best bet is to buy one of those outdoor tents that kmart/wallmart sells for $150.00...I would also get a fan for sucking the air out of your "spray tent" Total investment may be somewhere in the 300.00 range,

Bertha - is your indoor painting concern from a hazmat perspective? This is largely why I'm trying to avoid the isocynates. The only other thought I could come up with is that if I spray in a weakly ventilated area, much of the paint particles could dry in the air and settle on the work as 'dust', thereby impacting the finish.



I would also wait until spring time to spray. It is very hard to work against mother nature. You can strip and prep all your parts over the winter and spray once the weather is a steady 65-70 degress with avg humidity. The paint will lay out really nice at that temperature.

Can you tell I don't want to wait? What about spraying the bulkhead as mentioned earlier with good ventilation (e.g., basement bulkhead door opened, box fan howling) and then closing all up shortly thereafter and running heating elements to bring the room up to a balmy 68?

[greasyhandsagain]

Back in the 70's.....very "old school" I made my extra income painting cars. My Father taught me how, and while we weren't going to win the Pebble Beach Concourse, the results were quite acceptable. Nothing more than a 2 cylinder Sears air compressor, a Binks spray gun, acrylic enamal (sometimes with hardeners) and a nice day outdoors.

We painted out last, about 1988 or so, a 1967 VW beetle..... as a hurricane approached. The results were just fine.

Neither of us succumbed to paint related fumes/toxins...though when Imron first came out, one guy who my Father used to work with at the Boat Works stole some...took it home and painted his car in his garage. He died.

[JackIIA]

Jack,

In addition to the tent recommended by Bertha, you can also build a temporary paint booth using PVC as the frame. after you build the frame, you can then skin it with plastic sheeting and duct tape from the paint section at home depot. Get a cheap box fan, and some regular HVAC filters and your set. Google something like "temporary paint booth" or "garage paint booth" and you'll find some info. The best part is, you can just take the PVC apart if you dont glue the slip joints, and save it for the next job (yes, there's one on my top shelf right now!).

This is brilliant.



Jack,

Good luck man. Nothing beats that look of disbelief on someones face when you tell them YOU applied that awesome looking paint job.

Yeah, assuming I do it right! (Thanks!)

[JackIIA]

OK, last of my spam for the next few hours....

These two long excerpts are from two different sites talking about differences in automotive paints. If you are pretty familiar with automotive paint, you'll find nothing new here, so I'll save you the read. But, if it's all a mystery to you, then give it a quick read.

One confusing point remains however. I thought only the modern isocyanates were truly toxic because of the use of hardeners. Seems you can find paint hardeners in other paint choices too (like enamels). Also seems like there are 2 stage systems (base and clearcoat) for more than just the most modern painting systems. So, my question is where does the toxicity reside? When you use hardeners? When you use clearcoats?

Might be time to sand it all down to a buff aluminum and be done!


EXCERPT 1:

From WiseGeek.com:
Lacquer-based auto paint was popular between the mid 1920s and 1960s, and is still available today, though it has become illegal in certain areas. Lacquer paint is cheap and goes on easy for the inexperienced painter, plus it provides a nice high gloss. However, it also chips easily being a relatively “soft” paint, and it doesn’t stand up well to UV and chemicals, making it a short-lived paint job.
Enamel paints dry to a hard shell making them tougher than lacquer paints. Professional shops bake on enamel paint in heated bays or "ovens," but enamels are also available in aerosol cans and for use with spray guns. Enamels, while tougher than lacquer, do not lay down as easily as lacquer paint, making them trickier for the Do-It-Yourselfer (DIYer) to apply. This translates to more finishing work. Some enamel colors require a clear topcoat, known as a two-stage system, while others can be used alone, referred to as a single-stage system.
Urethane paints are newer than enamels, are more expensive and more trouble, but they lay down easily like lacquer while having the toughness of enamels. This auto paint requires three products: the color, a reducer to thin the color to the right viscosity for the spray gun, and a catalyst used to accelerate drying time. Urethane auto paint is highly toxic, and though a facemask is standard for all paint jobs, gloves, coveralls, and a respirator are mandatory for working with urethane auto paint.

* * * * * *
EXCERPT 2:

From YouRepair.com

Single Stage v. Two Stage
Single Stage is usually limited to enamels and urethanes where a single can of paint includes both the base color and the clear shiny finish. You usually apply one half coat and 2 full coats of a single stage paint and do not need to clear over it for your final finish.
Two Stage or base and top coat finishes require that you apply a base color coat that looks flat and then paint over it with a clear top coat for protection.
When you are asking for paint most beginners should use a single stage paint because the results are more forgiving and the paint is always even if you apply it correctly.
There are 3 basic types of car finishes Lacquer, Enamel and Urethane
Lacquer paints are really an historic paint choice and are not used on new vehicles. Lacquer paints also require a larger amount of hand work. You can expect to sand color coats between the many top coats that are needed for a full paint job. Most Lacquer finishes will require more than 5 top coats.
Synthetic & Acrylic Enamel Paints are a medium range paint that is stronger than Lacquer Based Paint.
Synthetic Enamel should be thought of as a Utility Grade Paint. Although you can probably get the same metallic finish mixed in Synthetic Enamel based paints they are not as strong as a urethane and will last only a short time. For this reason they are great for vehicles that will see short lives in the field and many box and tractor trailers which have their side logos changed can be painted in a lower cost enamel. Synthetic Enamel is usually only available in premixed colors without the option for tinting.
Acrylic Enamel paints are used with a Urethane Hardener which will increase their durability. Acrylic Enamel Paints can be produced in a standard Batch of premixed colors or they can be mixed to match your car. Technically the introduction of a hardener brings the standard Enamel paint into the Urethane category but they are not quite the same.
If you are painting a Tractor or an old beater a gallon of Acrylic Enamel with a Hardener can be purchased for maybe $125 and should produce a quality finish that may last about 5 to 7 years.
Urethane Finishes are probably the best commercially available paint choice the variety of colors are unlimited unlike Synthetic Enamel that comes in a standard set of premixed colors, Shop Grade Urethane paints can be mixed to match any car color or tinted to match variations in colors that happen due to the finish ageing from exposure to sun and the elements. This is why Urethane paints are the best product for repairs and full paint jobs. Unlike Acrylic Enamels that have a Urethane Hardener paint that is produced as a Urethane Paint must always use a hardener.
Other Paint types you will run in to
Epoxy Paints are not usually used on automotive vehicles but are great for boats, airplanes and other vehicles that require an extremely durable surface. If you paint with epoxy paint you need to wear an in-line forced air respirator or you will die…. well maybe not die but epoxy paint is very toxic so only use it in a professional booth with a forced air respirator and a full tyvek paint suit. This paint is also good for Frames and suspension parts but because it is so expensive don’t use it unless you need to.
Powder Coating is a special process that requires bakeing and is not used normaly on exterior finishes but may be used on your engine especially the valve covers. This process produces toxic fumes during baking although there are nontoxic versions coming to market. NEVER use your home oven for baking parts if you ever intend to cook food in it again.
________________________________________
TOXICITY OF PAINT
For the most part Lacquer paint is the least toxic followed by straight enamel then urethane then epoxy each require the use of a respirator however urethane and epoxy paints contain poisons and should only be used in professional booths with inline forced air respirators. Always read warnings and directions and then actually follow those directions… don’t just read them and then say Yea Sure I Read it.. Or you could DIE.
________________________________________
Paint Additives additives allow you to add features to your paint to adapt their qualities for your application.
Flex Agents are used when you are painting a part like a bumper cover or ground effects that will flex and move with the car. If you were to use a hardened paint you will probably endup with chips and cracking. You should also use a flex agent when you paint a plastic car like the Saturn.
Hardeners were already mentioned they are a catalyst that is added to urethane or enamel paint that improves durability.
Fish Eye Eliminator is an additive that is used when you are painting a car that might have oils from wax or your hands. It is good when performing touch-ups or in an emergency during a full paint job.
Chip Guard is a product not always used but can be used around wheel wells to reduce the likelihood of debri causing paint chips. It takes on a textured appearance and is not very attractive.
Flattening Agent will turn any paint into a flat color. This is good for custom stripes it can also provide a low gloss for engine compartments.

[kevkon]

Man, there's not much besides water that gets sprayed on a car and that isn't toxic. The issue is how much so. That includes sanding as well as spraying. For a one shot deal you will be fine with the proper protection. The bigger question in choosing the best paint is what you are looking for in terms of finish, how hard is it to apply (and correct), and how it will work in your painting environment. Given what you have said so far, I might opt for an acrylic lacquer. It's easier to apply and it's easier to correct mistakes. It takes multiple coats to achieve a good finish, but that might work in your favor. You can always color sand it and you can apply a clearcoat if you wish. Just depends on what you are looking for in a final appearance. I'm sure everyone will have their own opinion on this and a favorite paint. I'm just basing this recommendation on your lack of experience and no environmentally controlled spraybooth.

[lovely09]

Tips in applying paint on your car
*Do not try to use the paint pen on areas larger than a pencil eraser.Larger areas must be sprayed.
*Do not try to brush areas larger than a dime.Larger areas must be sprayed.
*Use an approved automotive paint respirator and wear safety goggles and gloves when handling automotive paint to protect your eyes and skin.
*When spraying,always test for paint compatibility.Paint an inconspicuous part of the vehicle,let dry and see if there is any reaction.
*Do not spray our paint over enamel paint that is less than two years old.
*Do not spray primer,paint or clearcoat in direct sunlight.

[greasyhandsagain]

One thing Ill add is that you should avoid the use of a jitterbug sander when you are working on aluminum. The small circular scratches are much deeper than you get with steel and it will take a LOT of primer and sanding to get rid of them. The Previous Owner painted mine...and used such a sander, and the marks are still evident when you search for them.

Ive always been amazed that many Rovers have great paint jobs when they are carefully painted with a brush...and the right paint.

[JackIIA]

One thing Ill add is that you should avoid the use of a jitterbug sander when you are working on aluminum. The small circular scratches are much deeper than you get with steel and it will take a LOT of primer and sanding to get rid of them. The Previous Owner painted mine...and used such a sander, and the marks are still evident when you search for them.

Good to know. I used glass bead on the the bulkhead (SkatMagic). I will actually have to hit that again before primer out of fear of flash rust. (I sandblasted it over a year ago originally). I could use that on the rest of the body parts, but it does leave a very slight pitting, so the only quick alternative would probably be walnut shells or something.

Maybe I'm kidding myself...but my current plan is to hit the fenders, tub, etc with sandblock, water, and muscle in the Spring. I have aircraft stripper, but I'm afraid it will get in the seams. Just not worth the risk to me.

[Bertha]

Good to know. I used glass bead on the the bulkhead (SkatMagic). I will actually have to hit that again before primer out of fear of flash rust. (I sandblasted it over a year ago originally). I could use that on the rest of the body parts, but it does leave a very slight pitting, so the only quick alternative would probably be walnut shells or something.

Maybe I'm kidding myself...but my current plan is to hit the fenders, tub, etc with sandblock, water, and muscle in the Spring. I have aircraft stripper, but I'm afraid it will get in the seams. Just not worth the risk to me.

You can't use skat blast on any aluminum parts-it will destroy them. As far as the bulkhead, high build primer will fill any sandblast pits(not rust pits). Walnuts shells are to light a media for the job. Wet sanding is only for sanding down primer before painting or nibbing a new paint finish. Aircraft stripper works best on aluminum. If you are worried about the seams, tape them off, before applying stripper. When I use stripper on aluminum parts , I wipe off as much excess as I can and then wash the stripped part with soap and water(if it is aluminum), dry it, prepsol it(degreaser used before painting) and etch prime or epoxy prime the part. You can also use a DA(dual action orbital sander) with 180 grit. This also works well(use a mask for the dust). I would stay away from any coarser of a grit, as it will leave marks in the aluminium/birmabright.

[thixon]

he doesnt need me to, but I'll x2 Bertha on the 180 grit, and blasting alum parts.:thumb-up:

I know the temptation is there to use 60 or 80 grit pads on the DA, but you'll regret it. You can cover up the marks, but it takes ALOT of building primer and sanding to do so. Not worth it.

[JackIIA]

whew! thanks guys. what would I do without you?...oh i know, destroy the bodywork of my IIA!! :D

aircraft stripper it is then.