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Technical Difference in Paints. 1k and 2k enamels, base, urethanes etc

Discussion in 'The Hokey Ass Message Board' started by Paint Guru, Jan 21, 2017.

  1. Paint Guru
    Joined: Sep 9, 2015
    Posts: 522

    Paint Guru
    from Bowdon, GA

    What is the difference in paint? 1k or 2k Enamel, acrylic Enamel, Acrylic Urethane, Polyurethane and base coat clear coat

    Picking the right paint for your vehicle can be confusing and going to the paint store and asking this question can be embarrassing at times to say the least. So here is a quick paint reference for you to decide what type paint fits your preference, budget and skill level. **Note this is not about water-based paint nor lacquer – just solvent that’s easy to buy just about anywhere!!!

    What is 1k and 2k?

    1k comes from the term Komponent (i.e. component). 1k means simply just the paint is required to dry. 2k means an activator or hardener is required to dry/cure.

    What types of paint are 1k?

    Lacquer, Enamel, Acrylic Enamel and Base Coat

    What types of paint are 2k?

    Acrylic Urethane, Polyurethane, Clear coat

    What types of paint have an option for a hardener?

    Every type has an option – however some brands the way they are made – a hardener is not compatible. Look at the data sheet for instructions to see if a hardener can be used.

    What does a hardener/activator do? A hardener crosslinks or bonds the coating to a denser/harder film. This gives durability, chemical resistance and color holdout.


    There are 3 types of Enamels – Short Oil, Medium Oil and Long Oil Enamel.

    Long oil is what you see in tractor supply stores, home improvement stores etc. They are super easy to get a shine, but have no color holdout. The product fades very quick and chemical resistance is very low. Long oil takes a long time to dry, and can even get retack (gets sticky in direct sunlight). Long Oil in direct sun has a Gloss life from about 6 months - 2 years. Repair-ability is very difficult. The paint rolls instead of powder when trying to sand, when painting on top of it, very high possibility of wrinkles. Usually stripping is the best method of repairing, but with a very low cost – sometimes this is a consideration. Price ranges from about $22-$38/gallon

    Medium Oil is what a lot of heavy equipment is sprayed with. It’s very easy to spray, dries faster than a long oil (but still a slow dry product), a little more durable and only goes through a few retacks. Medium Oil is more solvent resistant and last double the life span of a long oil enamel. MOE in direct sun has a Gloss life from about 1.5-3 years. Repair ability is difficult without an activator. Paint will roll up when sanding and has a very high possibility of wrinkles when using an automotive paint. Usually best to repaint with the same product. Can use VM and P Naphtha to reduce in a lot of moe type paint, which is not a harsh solvent and has less of a possibility to wrinkle. While not as inexpensive as a Long Oil enamel, MOE is still an economical choice from prices ranging from $35-$75 gallon. These can be purchased from specialty industrial store.

    Short Oil is what most all car enamels are. It has a quick dry time, hardly noticeable retack, fast dry times, more durable than long oil and easy to apply. Metallics can be a challenge due to the faster dry times. Short Oil in direct sun has a gloss life from about 1.5-6 years. Short Oil enamels are still inexpensive depending on brand. Prices range from $65-$150 gallon.

    Acrylic Enamel

    Acrylic Enamels are built into Short oil enamels. Acrylic is added to make acrylic Enamel. Acrylic adds durability, quicker cure times, and great repair ability. Acrylic is soft in nature and makes buffing a lot easier. Acrylic Enamel works best activated. A/E in direct sun has a gloss life from about 2-6 years. Has little to no “retack”. Skill level is a little more advanced due to adding an activator, but should be considered. Prices for A/E are the same as a Short Oil Enamel but you have to consider the activator. Price range $65-$150 gallon plus half pint of activator (in most cases) costing from $10-$25

    Acrylic Urethane

    Acrylic Urethane is the standard in the automotive repair industry. It’s the most used due to its great color holdout, excellent repair ability, ease of buffing, good chemical resistance, fast cure times and great flexibility. Clear coats are in most cases Acrylic Urethane and a lot of single stage paints are acrylic urethane. Metallics can be difficult to spray with acrylic urethane. Skill level to spray is more advanced, not as easy to slick out, can orange peel and run/sag. Must use an activator to cure the product. A/U is soft and can scratch with minimal effort, but can be repaired by buffing in most cases if not too deep. Pricing for Acrylic Urethanes are higher than Enamel mainly due to more activator having to be used to crosslink the product. Usually the mixing ratios for Acrylic Urethanes are 4:1 or 2:1. Cost can range from $80-$700 gallon plus activator ranging from $35-$150 quart depending on brand. Durability 4-7 years.


    Polyurethane is mainly used in fleet applications where strength and durability are demanded. Polyurethane is the most chemical resistant of any of the above topcoats. It has excellent flexibility, color hold out and scratch resistance. The one downside to Polyurethane is, because it gets so hard, sanding and buffing is nearly impossible after full cure. It’s also slower to dry than acrylic urethane. Polyurethane is a great choice for chassis, under hood, race cars, fuel tanks, engine blocks, big trucks, boats etc. Metallics are difficult to spray in Polyurethane as well. Polyurethane cost about the same as Acrylic Urethanes and mix ratios usually are 3:1. So some shops order 3 quarts of color and 1 quart of activator. Durability 5-10 years.

    Base Coat

    Base coat can be made out of acrylic, polyester and vinyl. Base coat is an excellent choice for metallic colors. Metallic single stage cannot be buffed properly because you actually scratch the flake itself and hard to polish correctly. With base coat you can spray, lightly sand trash out, rebase then after everything looks correct, apply a clear coat. Base coat is very easy to apply, however clear coat, after the 1st coat, can be difficult because it’s hard to see what you are painting. Doing a period correct restoration (pre 80’s) – base/clear is usually not the right choice due to its gloss level. However you can get most any color in basecoat. Base/clear is easy to repair (same as acrylic urethane) however some basecoats if you sand through the clear, will lift and wrinkle and become very difficult to repair. Durability is 3-10 years clear coated and 1 year without clear. Base coat has to be reduced with solvent, usually 1:1 or 2:1, so 2 quarts can get you a gallon sprayable. Prices range from $120-$1200/gallon

    Hope this helps with choosing what paint to use with your next project. Please note this is just an overall review of types of paint, and while your enamel might have lasted 20 years, there are a lot of things to consider shade, wax, dirt/grime etc. Also application plays a huge roll in durability. While clear coat might peel off a new car in 2 years, with proper application it can last 20 plus years as well. The durability is based off of no maintenance in direct sun. I have seen Enamel and lacquer paint jobs that are well over 30 years old, and don’t want to have a debate about durability. This information is based on real testing in worse case situation. The durability is lost when the coating starts to fade. Sometimes to go from fading to cracking can take 10 plus years. There are also junk brands of product out there, resin, pigment and the way the product is developed can all change the durability of the product. Hope this helps.
    32ford5, clem, ROUXGAROUX and 32 others like this.
  2. Thanks for that very informative read,gotta save this.
  3. Fitty Toomuch
    Joined: Jun 29, 2010
    Posts: 239

    Fitty Toomuch
    from WVa

    Thanks for the write up, can you reasonably match colors from original paint charts, in a acrylic urethane? Iv`e bought paint from online suppliers that come in not even close to their color charts.
    Iv`e even bought their printed color chart thinking that maybe their might be differences in computer monitor colors , still not even close. thanks
    Paint Guru likes this.
  4. rust&patina
    Joined: Jan 21, 2007
    Posts: 474


    Great information :) thanks for posting
    Paint Guru likes this.

  5. henryj1951
    Joined: Sep 23, 2012
    Posts: 2,304

    from USA

    good INFO...
    Paint Guru likes this.
  6. elgringo71
    Joined: Oct 2, 2010
    Posts: 3,022


    Thank you very much for taking the time to help us understand the basics
    lothiandon1940 and Paint Guru like this.
  7. wicarnut
    Joined: Oct 29, 2009
    Posts: 4,696


    Thank-you for the info
    Paint Guru likes this.
  8. Kan Kustom
    Joined: Jul 20, 2009
    Posts: 2,648

    Kan Kustom

    Like the others,Thanks. I have painted with about everything but water based and never will but after using all of them,I like catylised acrylic enamel best overall.
    lothiandon1940 and Paint Guru like this.
  9. What about alkyd enamel? Is that short, medium or long oil enamel? And is it compatible with hardener?
    Paint Guru likes this.
    Joined: Jan 13, 2004
    Posts: 2,757


    Thanks for posting this ,this is a better explanation than any I have read. Thanks again.
    lothiandon1940 and Paint Guru like this.
  11. belair
    Joined: Jul 10, 2006
    Posts: 8,571


    Thanks. Glad you're here.
  12. Paint Guru
    Joined: Sep 9, 2015
    Posts: 522

    Paint Guru
    from Bowdon, GA

    Alkyd is the resin. So it can be all the above. If you order Alkyd enamel from a auto paint store its short oil.

    Sent from my SM-N920V using The H.A.M.B. mobile app
    lothiandon1940 likes this.
  13. oldrelics
    Joined: Apr 7, 2008
    Posts: 1,728

    from Calgary

    What about synthetic enamel? I bought some at a tractor dealer, it came out super glossy, sprayed easy and hardened quick.
    Paint Guru likes this.
  14. The37Kid
    Joined: Apr 30, 2004
    Posts: 27,535


    Thanks Paint Guru ! Wish I could take close up photos of flaws in finishes, once you start will poor primer finishes there is no way to have the paint look right. Bob
    Paint Guru likes this.
  15. AVater
    Joined: Dec 9, 2008
    Posts: 2,374

    1. Connecticut HAMB'ers

    Thank you!!
    Paint Guru likes this.
  16. BJR
    Joined: Mar 11, 2005
    Posts: 6,623


    Great info thank you!
    Paint Guru likes this.
  17. I believe part of the problem lies in the fact that some of the original toners that were used are no longer available so unless someone is taking the time to colour match by eye and develop new formulas that way they are going to be off as the replacement toners are not the same colour so the cross over formulas to the new toners do not produce the original colour.
  18. metlmunchr
    Joined: Jan 16, 2010
    Posts: 752


    Thanks for taking the time and making the effort to do this writeup. Very informative.
  19. Great info. Thanks for taking the time.
    lothianwilly71 likes this.
  20. kbgreen
    Joined: Jan 12, 2014
    Posts: 338


    Thanks Dan, you are a real contributor to this hobby!
    lothiandon1940 likes this.
  21. atch
    Joined: Sep 3, 2002
    Posts: 4,581


    Thank you for making voo doo / black magic into something that even someone as ignorant about paint as I am can almost understand. I'll never be a body man or painter but it's nice to have a little of this information inside my pea brain.
  22. As one who has been mystified by paint, thank you!
  23. Binger
    Joined: Apr 28, 2008
    Posts: 1,694

    from wyoming

    Thanks for the information!
  24. Paint Guru
    Joined: Sep 9, 2015
    Posts: 522

    Paint Guru
    from Bowdon, GA

    Technically all paints that are man made are synthetic. So Short, medium, long, urethane, polyurethane is all synthetic. Some companies give paints names to sell it... like synthetic enamel or modified enamel. Unfortunetly one downfall is that there is no law or no code/standard as to what can be put on the can as far as a description. Also there is no standard as to what is a High Solids or Low Solids. Some companies call 38% solids a high solids product, while another company says 36% is medium. Just food for thought.
  25. You've always provided great information. This info is excellent!
    Thank you
    lothiandon1940 likes this.
  26. 1-SHOT
    Joined: Sep 23, 2014
    Posts: 2,001


    As always very informative. Thanks Frank
  27. hdman6465
    Joined: Jul 5, 2009
    Posts: 651


    Thanks for taking the time to produce a very informative article. It was explained in a manner that almost anyone can understand. Most chemical companies forget who they are writing the articles for!
  28. To be fair to the chemical companies they know exactly who they are writing articles for it's just not Joe public. Home use isn't even a blip on most automotive chemical companies radar.
    Paint Guru likes this.
  29. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 1,098

    Flat Six Fix

    I have sprayed many things including my truck in the avatar with Hardware Store Long chain oil enamels, but when I have reduced them with both urethane grade reducers and acrylic enamel reducers, this worked well and sprayed nicely. I would also add 1 ounce of Evercoats generic acrylic enamel harder to every 8 ounces of paint.
    This resulted in a very fast dry and cure time, color and gloss hold out with this is not bad, and is great with some things that stay inside the garage most of the time.
    What would you designate a hardware store implement synthetic enamel once a hardener is added?
  30. Can you give an Example of these?
    What brand?
    What to ask for?

    And where does imron fit with re coating, shine, hold out, fade, uv ?

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