Announcement

Collapse
No announcement yet.

Gel Coat vs. Urethane Marine Paint

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Gel Coat vs. Urethane Marine Paint

    I am doing all my research and looking for a project boat, specifically I want a Mako, Models that surround the 25, 254 and the 26, 260 series. I will have a specific post soon asking for help locating something. So more on that later.

    However, I am curious to those that have done significant work to your boats, did you use Gel Coat, or just Fair out and Prime and Paint with Urethane Marine Paint. I would like to know what you chose and why. Also, if you painted, did you finish with a clear coat?

    This is not a one is better than the other, this is about the options available and why each one was specifically chosen.

    Thanks

  • #2
    Some considerations depending on how you use the boat, budget and time...

    If the boat is wet slipped or spends extended time in the water, paint might not be the best choice. Awlgrip and other paints can't be submerged for extended periods of time or the paint will blister and peel off. Consider this also if you use a bunk trailer with carpet on the bunks. None of this is really a concern if using bottom paint.

    Some paints are difficult to repair (Awlgrip) and some can be repaired but might not be as durable (Awlcraft 2000).

    Gelcoat is time consuming to finish because you need to sand it to get a smooth finish (probably 400, 600, 800, 1000, polish). This takes a lot of time so if you are doing it yourself, expect lots of work here. If you are paying someone to do the work, expect lots of money. Adding Duratec to your gel might reduce the sanding a bit but it adds cost in materials. Sanding around corners, edges, strakes, etc takes a lot more time and skill than the flats.

    Will you be working in a clean shop or outside in your driveway? If a bug lands in your fresh Awlgrip because you are working outside, there will be a bug mark in your paint or a repair. If this happens in your fresh gelcoat, you are sanding it anyway so no big deal.

    Some paints use clear coat (Awlcraft SE) some don't (Awlgrip, Awlcraft 2000). There are advantages and disadvantages to each type. Awlgrip is quite tough but can't really be buffed, so repairs are difficult. Awlcraft 2000 tends to be a bit softer but it can be buffed and is considered repairable. I've never used Awlcraft SE but I understand that it is nice to use, durable and repairable but expensive.

    I find gelcoat easier to apply. You need to thin it a lot to get it to spray and laydown without too much orange peel but 30% styrene and a large tip (2.5mm or so) or 50% duratec high gloss additive should work. If your fairing isn't perfect, you can often fix small issues by loading the gel up on these spots and sanding them out in the final sanding. Keep in mind that you will sand off a lot of gel in the sand/polish stage so it needs to be on thick. Think 8 or more medium coats in one long day of spraying.

    Paint is nice because after a day of spraying, you are done and don't need to sand for a month. If your fairing isn't perfect though, these spots will be there forever. There is a lot of fairing and sanding to do on a 25 foot boat and it is easy to either miss some minor issues and not find them until the final paint is on or spend forever sanding and sanding and sanding.

    Hope that this gives you a few things to think about.
    Toronto, Canada
    76 Mako 23
    https://forum.classicmako.com/forum/...t-s-23-rebuild

    Comment


    • #3
      Well, I do and don't have information. I was like you and did my digging/research early.
      I am trying to gelcoat almost un-thinned. What I got was a 4.8mm tip and a spare for just in case 3.5mm tip on a 1 Ltre or 1000 top fed gun.
      Not had any time to try anything... but when I do.,.. it will be many test runs to know my product and application method.
      So in short Gel-Coat was my choice. But I have to learn my way.
      And from what I understand its sand, sand, sand, X's2 and polish. or very labor intensive.
      In my research, I read a good analogy. gelcoat is like chicken soup. the more water you add the less its like chicken. {however I don't plan to eat it}
      Styrene can cause yellowing, so theres that unwanted gremlin. (I'm using creme or off white so thats probably ok for me)
      But styrene seems to be the most compatible with gel for chemical or meshing of components.
      I am using waxed Gel, and duratec is not recommended with waxed. (trying to figure all that out)
      And then theres the whole debate of acetone as thinner. (some say yes, some say never)again trying to sort the facts.
      Like I said. Theres so many do's and don'ts or mixed opinions on all these topics. I plan to do my own trial and error. and what works for me.(before I put any product on my boat)
      I will probably shoot in winter under cover and then heat area to give working time and control curing or tack between coats. is my plan. If you gel in summer you better be on your game and know you'r product and working time, and especially if sun gets on product, that just turbo's everything. and you probably can't out run things at that point.
      And don't forget acetone through gun between coats, as you don't want to give any chance of gumming up your gun. DONT FORGET PPE. respirator.
      If you want order info I can provide that. Think I was under $150. for what I purchased. (from canada)
      You need driers on air hose regardless what you choose. paint/gel.
      Now keep in mind Everything I have said is from a stance of, I have not done this before. the seasoned guys that do this day to day know how to allow for all I have listed.
      My information is from a NewB to a NewBe. not that I'm an expert or claim to know anything, I'm telling you what I have researched. or found.
      Well thats my .02 cent spill.
      Almost forgot. I am kicking around the idea of clear with pearl as a last finish. I have to figure what products allow for that. So I'm playing pretty deep in this too.

      Hope there was something of use in this for you.

      Best to you.
      Last edited by Lectro88; 07-29-2021, 08:03 AM.

      Comment


      • #4
        Originally posted by Lectro88 View Post
        Well, I do and don't have information. I was like you and did my digging/research early.
        I am trying to gelcoat almost un-thinned. What I got was a 4.8mm tip and a spare for just in case 3.5mm tip on a 1 Ltre or 1000 top fed gun.
        Not had any time to try anything... but when I do.,.. it will be many test runs to know my product and application method.
        So in short Gel-Coat was my choice. But I have to learn my way..
        You can spray gel un-thinned. That is how your boat was made at the factory. But, at the factory it was sprayed into a mold and that is where the smooth finish came from and it isn't an option now for you.
        The reason that people thin gel coat before they spray it is so that it will lay out smoothly on the surface. If you spray it out of a gun with a big tip, it will have a lot of texture when it cures. This comes from the thickness of the gelcoat. It just doesn't flow to a smooth finish because it is so thick. Your finished spray will have a lot of orange peel that will need to be sanded smooth. You will need to put a ton on so that when you sand it you don't go through the low bits of the texture, especially on corners and radius'.

        And from what I understand its sand, sand, sand, X's2 and polish. or very labor intensive.
        In my research, I read a good analogy. gelcoat is like chicken soup. the more water you add the less its like chicken. {however I don't plan to eat it}
        Styrene can cause yellowing, so theres that unwanted gremlin. (I'm using creme or off white so thats probably ok for me)
        But styrene seems to be the most compatible with gel for chemical or meshing of components..
        Yes, lots of sanding and lots of paper. I've never sprayed un-thinned gel and tried to sand and polish it. I have sprayed a number of boats with thinned gel and sanded from 400 grit up to a 1000 grit before polishing. Count on 100+ sheets of paper at each grit to get it smooth. You would probably have to start around 300 grit to get through an un-thinned spray of gel.
        I'm not sure that I like your chicken soup analogy. Unlike the chicken soup, the styrene evaporates out of the gel as it is curing. When the project is done, the styrene is gone and the gel is all that is left, it is just much smoother than if you hadn't used the styrene.
        I sprayed the topside of a 21 foot boat a few weeks ago with Matterhorn white gelcoat. Matterhorn is a slightly greyish white although you wouldn't say that unless it was beside a brighter white. There is no yellowing of the white on this boat, I don't think that you will have a problem with a cream or off white color.

        I am using waxed Gel, and duratec is not recommended with waxed. (trying to figure all that out)
        And then theres the whole debate of acetone as thinner. (some say yes, some say never)again trying to sort the facts..
        Gelcoat and other polyester resins don't cure completely in air. You need to do something so that they can cure without being exposed to air. The wax in your waxed gelcoat does this. Duratec or Air Dry also do this if you are using unwaxed gelcoat. If you spray waxed gelcoat, you need to do all the coats in one continuous spray. Keep mixing gel and spraying around and around and around the boat until you have all the coats that you want. If you have to stop for some reason part way through and the gel cures beyond the sticky stage, then the wax will prevent the next layers of gel from sticking. You will need to sand the surface to remove the wax before you can continue spraying gel. If you spray unwaxed gel then you can stop part way through and continue at a later time without sanding. You will just need to use Air Dry or Duratec in the last coat(s) so that the gel cures to a non-sticky finish when you are done. You can also put air dry or duratec into all of the coats of unwaxed gel as long as you will be spraying all the coats in one continuous spray.
        You can use acetone as thinner, but the finished gel won't turn out as well as if you use styrene. The acetone off gasses in the curing process and tends to leave bubbles/blemishes in the surface of the gel.

        Almost forgot. I am kicking around the idea of clear with pearl as a last finish. I have to figure what products allow for that. So I'm playing pretty deep in this too..
        You can do this too. It takes a lot of experience to match metal flakes and pearls but if you are doing it from scratch it can be done. I'm not sure what you would actually see though if doing a pearl on a cream gel.

        Hope this helps a bit in your process
        Toronto, Canada
        76 Mako 23
        https://forum.classicmako.com/forum/...t-s-23-rebuild

        Comment


        • #5
          Thank you Jamie for the reply.
          NO intention of hi-jacking.. just replying as you quoted me.
          Everything you said is pretty much what I expect or expected.
          The good thing is My labor is more like a hobby from my standpoint. And I have the sanders and air AND time to play the game and get it how I want.
          Even if that means several failed attempts after my practice runs (not on the boat) I will get it right before that.

          Quote:
          I'm not sure that I like your chicken soup analogy. Unlike the chicken soup, the styrene evaporates out of the gel as it is curing. When the project is done, the styrene is gone and the gel is all that is left, it is just much smoother than if you hadn't used the styrene.

          I don't claim this as mine, It's just what I had read in my digging.
          But I respect your experience and point of view.
          I will try several ways with/without sty.. and different tips. to find what I like the best

          Thanks again.
          Lectro.
          Last edited by Lectro88; 08-02-2021, 06:12 PM.

          Comment


          • #6
            I had many large divits in my hull bottom due to botched barnicle removal from previous owner. This was my deciding factor to re-gel. It cost me about 7k for my bracketed 261

            also had him fill, glass & gel over my trim tab pockets
            Attached Files

            Comment

            Working...
            X