On to Paint!

Discussion in 'Materials' started by CatBuilder, May 11, 2012.

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  1. CatBuilder

    CatBuilder Previous Member

    Me too. Very confused.

    What Pauloman is saying isn't making sense to me. I can spray any paint I want, from what I understand. The laws in some areas require HVLP systems, but that's about it.

    Paul, can you classify the paints above listed in to the various types you are saying they are?

    Also, three other companies are spraying paints around my shop. I am not seeing where there would be any problem.
  2. mydauphin
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    mydauphin Senior Member

    I have sprayed, roll and brushed. Personally, give me a two part poly, someone to roll, and I follow with a brush. The end effect is very good, thick in two coats and lasts along time, and I don't have all the problems with spraying. Then let it cure for a couple of weeks and spray whatever designs you want on it. As a good amateur I can get the look I want. Spraying a large boat is better left to a professional. Color selection has a lot to do with method, dark or metallic colors are better sprayed. White, Gray or Almond is easy to brush.
  3. CatBuilder

    CatBuilder Previous Member

    I'm either looking to do some bright colors (bright hues and pigments) or to mix some effects into the paint. I think that's a spray job.

    Also, I hear it's a snap to use an HVLP gun and spray things. I hear it's no big deal and people get it right the very first time they try it. I'm actually a very good painter with rollers and brushes. I used to do the interior of houses in college in the summers. I kept up with the seasoned pros who taught me how to do everything. We banged out commercial buildings and large houses every day.

    That kind of leads me to roll and tip, but with the sheer area of my boat, I figure HVLP spraying will go much faster. I have 3000 square feet to paint just on the outside.

  4. mastcolin
    Joined: Jun 2005
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    mastcolin Senior Member

    You are all confused because you are meant to be.

    All the gobbledy-gook over LPU is marketing bs.

    Think of it like this (and bare with me, I have a chemistry degree:))...

    All you need to know is that there is a base (acrylic/polyester..LP even perhaps) and a curing agent (isocyanate, the bad bit health wise). These react together.

    But think if you went to the worlds biggest bakers and asked for a cake. There are all sorts of cake. Some are light and fruity made with care and attention, some are twinkies (a sort of mutant chemical cake for my european friends). You have chocolate, you have vanilla, cherry etc. You get my drift.

    A LPU is not instrinsicly better than an acrylic, a non linear polyester is not better/worse. Even within the polymer differences, all the suppliers use different pigments and curing agent ratio etc. All these have an effect. And then you have an idiot painter who puts it on...and can have an effect on durability. Not all chocolate cakes are alike and even if they did have some similar ingredients they wouldn't taste alike.

    Car paints are acrylic because they give best results for that market. Aircraft paint (and I mean airline aircraft paint) is more acrylic then polyester. With the right "cooking", you can get any performance you want with regards hardness, durability, polishability...cost.

    Awlgrip make a big song and dance about LPU because they thought that sounded cool. Forget about it. You don't care what grade steel your car is made of do you? The build quality etc is not dependent on this. Of course there is some cause/effect but you shouldn't let marketing bs cloud your judgement.

    Back to the original post.

    My comment on "mixed schemes" was regarding primer system UNDER topcoat system.

    Glad you think you can paint. You probably can. You sound like you are thoughtful and you seem to want to learn. Then again be prepared for problems. You may get them. The issue is that I think your quality eye may be fussier than your skill (to begin with.)

    "special effects" - whoah! Are you nuts? They look great. They are difficult to apply well...and impossible to repair without loads of luck and much skill. In fact I would actually say they are impossible to repair. You can do a car no problem as you paint a complete panel to a hard breakpoint. You get a scratch on the side of a hull and you are repainting the whole side I guarantee.

    These must all be sprayed. Dunno what system you are looking at but they are normally mulitple coat basecoat/clear systems. You also have to be very particular with sanding - everything has to be machine sanded evenly otherwise you get the effect pigment not lying good. Do your hand sanding in difficult corners radii 1st then machines sand everything so you minimise handscratchmarks. Buy a foam interface pad for between the machine and the paper. You can then sand reasonable roundings.

    Most of these systems are clearcoated. As I suggested, you can put Alexseal clear over the colour system paint (it is a 2 pack system right?). Do NOT use Awlgrip clear (the LPU:)) It will start go straw/yellow after a year. This way you get a yacht clear over the automotive effect clear. Sand the clear with p400. Make sure you apply the clear over the effect colour thick. You absolutely do not want to sand through. Don't worry about orangepeel. Spray 3 coats and let it dry. Sand it.

    Nor entirely sure you will get much "effect"on your hull shape. Most catamarans I have seen look pretty flat sided. The "effect" relys on a change in line of sight. So it looks great on a curve but on a slab side you will have to walk around boat to see change.

    It is nice idea but personally I'd just paint it white. Do it 2 times. Sand in between. Add 50-75% clear in last layers. This give you best gloss (new), best flow, best durability and easiest repairability.
  5. Herman
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    Herman Senior Member

    The only thing I want to add (not really related to Catbuilders boat). For making polyester moulds of plugs, paint the plug with 2K polyurethane, not acrylic, or you will think about me when trying to demould.

    Effects on boats usually only have a very limited effect. Not only the viewing angle should vary, but also the distance of the viewer should be within a certain range.

    And metallics are a pig to apply on large surfaces. The effect is different when applied from a different angle, which is almost unpreventable on large surfaces. I know of a large (23 meter) boat which was sprayed 3 times before the effect was acceptable, and even then it was hardly noticable from a distance.
  6. mydauphin
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    mydauphin Senior Member

    Now a days ... On speed boats must of the effects are stick on applique. These are very durable and I have seen boats that the whole side is one piece, and we are talking 40' boats.

    I have been building and painting boats for over 30 years, and I don't do the fancy yacht painting. I tell people I paint boats not yachts. I know how to do it , just not worth the work for me. I have inhaled too many paint fumes over the years. The prep work and time to shoot a large boat is very high. I can do a boat with roller and brush, in a forth of the time than it takes to spray it with one gun. You can't tell from 3 feet away much less a boat length. Never painted with Hvlp gun, but I would guess you thin the paint less.

    Three people can paint your whole boat, one coat in one day. Of course you need several coats, and you have to have everything ultra-prep before.

    Another thing for you to think about. When you finish building your boat and paint it, you still have to get it to the water. Chances are it may need to some touches either from trip or from launch. KISS so you can touch it before or after splashing.

    On Acrylic vs two-part poly. Acrylic is harder and more water proof, but may crack more than the more flexible poly. Acrylic give better metallic colors. I believe poly covers faster, it is a thicker paint. Acrylic needs more coats. I am not sure because it may have to do with brands and systems that I used, perhaps they are all not that way.
  7. tunnels

    tunnels Previous Member

    Not only speed boats !! Last lot of match racing yachts we just gel coated the boats a nice natural nutural colour for hull and deck and everything else was stick ons !!.
    The young lady designer did all the graphics on her computer and the boat numbers port and starboard sent the info off and when was required arrived in a great big box all in order and each boat was done as required after it was transported to the venue !!
    My son is in the airforce and a good percentage of there stuff is stick ons as well !!!
    Its the only way to go ,want to change for some reason its easy to remove and redo in a short time !!.:D
  8. Steve W
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    Steve W Senior Member

    There is nothing special about Awlgrip,it just been marketed well in the marine industry. The original awlgrip is a Polyester urethane, comes in a limited number of boring colors, is very hard and is not easily repairable. When everyone started comlaining about having to paint a whole side for a realativly small repair they came up with Awlcraft which is a acrylic urethane, just like the auto industry has been using for eons, because car paint systems need to be easily repairable. Its a fallicy to think that boat paints have a hard life, they have a cushy life compared to a lot of cars which live their whole life outside,where i live we get sub zero temps in the winter and salt and grit dumped on the road in a very concentrated form and when you are driving at 70mph its like being blasted by salt in a hurricane. Three part auto paints are tough, repairable and available in an almost unlimited pallet of colors and are available off the shelf in any town, mixed to a color code that, you can have matched years down the road for repairs, even if you lose the code you can have the bodyshop supply guy come down with their camera and match the color perfectly. Its not neccesarily cheaper but very convienient. Companies like Dupont and PPG have been at this for a long time.
  9. CatBuilder

    CatBuilder Previous Member

    That is exactly what i heard from a guy who has a brother in the paint industry. I heard a lot of the new megayachts out there are being painted with car paint because it's better. Better in terms of maintenance.

    Mydauphin: You answered my next question before I could ask it! :) I was wondering if roll and tip or spraying was faster. Anyone else care to elaborate on relative speed between roll and tip and hvlp spray?

    Spraying seems much more labor intensive for some reason due to the number of passes required. Is that correct?
  10. missinginaction
    Joined: Aug 2007
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    missinginaction Senior Member

    I'm the rank amateur in this thread. That said I've used Interlux Perfection (pretty much the same as Awl Grip a 2 part LPU).

    I followed the directions to the letter and got great results.

    I did the boat in a bright white and simply rolled it out. The rep I spoke with said that with light colors the tipping wasn't all that important. With darker colors tipping was recommended.

    I found that the spots on my boat that are not quite 100% have much more to do with surface prep than with the paint. At 56 my eyes are not what they were and the light color of fiberglass and the primer tends to be blinding as well.

    Catbuilder, you're perhaps much more fussy than I but I think the boat LPU's, rolled and tipped will work great for you. Just be very mindful of temperature and humidity and practice on a few pieces first.


  11. Steve W
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    Steve W Senior Member

    People seem to get confused by the chemistry of the 2 part paints,myself included. To my knowlege all af the paints are blends, i dont know of any that are just polyurethane, i am however no expert, there may be some. As i mentioned before Awlgrip is a polyester/urethane, Awlcraft 2000 is a acrylic/urethane, PPG concept is an acrylic/urethane, and on and on and on. I use Nason Fullthane on all my own boats and love it, i still generally use awlgrip 545 epoxy primer just because i like it and we get good pricing on it. There are a lot of good paints out there, i choose car paints mainly because i like colors and am tired of the boring colors available in boat paints,I think if we ever have to paint another flag blue boat ill put my head in the oven and end it all. If you like to do colors there are thousands of auto colors to choose from and you have the advantage of being able to look at them on something large(a car) out in the wild rather than a stupid little color chip on a chart. Last summer we painted my P cat with Audi TT papaya orange hulls in Nason with Awlgrip cream decks, same as we did my old Macgregor 36 cat some years ago.

  12. pdwiley
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    pdwiley Senior Member

    I am no expert at all but I can say that if I hadn't sprayed the interior of my boat, I'd never have gotten it done properly. Just doing the keel recesses with a roller & brush is driving me (further) insane.

    I also get a thicker, more even paint coverage with a spray gun.

    My original plan was to use a roller on the exterior but now I plan on spraying it. We'll see how it goes.

  13. CatBuilder

    CatBuilder Previous Member

    The plot thickens! :)
    Thanks for the input, PDW. I have heard others say the same thing you are saying about spraying going faster.
  14. mydauphin
    Joined: Apr 2007
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    mydauphin Senior Member

    Spraying is faster for one person, but look at the time to prep. Also time mixing paint. Spraying is fast, everything else takes time. Only way to speed up is have two people spraying.

    With roll and tip, one person rolls, one person brushes, and one mixes and cleans up mistake or whatever. You don't have to prep half of what it takes to spray.

    One coat on roller and brush is worth three on the gun. Spraying also uses more paint, or applies less paint on boat.

  15. tunnels

    tunnels Previous Member

    One of the biggest problems with spraying paint or anything for that matter is most peolpe think if there 100 psi then lets use it all !!!, so theres overspray for miles and drifts and carries every where except on the job !!Most times i find you can spray paints down to 25 psi or a little higher to 30 psi or even 40 psi .
    My personal choice is a Pressure pot!!! they are easyer to use and will spray any angle you like to point the gun .
    Knowing your equipment and what it is capable of doing and fully understanding the functions of all the knobs on the gun its self and what they are for and how they work . No two guns ever work the same and the array of spray gear is endless these days

    Same applies to gel coating like i keep saying ,its an art form!!! . Some got it and can make a beautiful job and others just never get it no mater how hard they try !!!. :D
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