quick paint question: silver tip yacht primer

Discussion in 'Boatbuilding' started by Charly, Jul 19, 2013.

  1. Charly
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    Charly Senior Member

    when fairing epoxy/ply hull for first time paint, and using phenolic microballons with aerosol and epoxy as fairing putty, should the putty be sealed with another neat coat of epoxy before applying the paint? I notice that, when cured, the putty "skins" over with a gloss from the epoxy in it, and then when sanded, it seems to open up the pores, and needs resealing to keep water out.
    So the question is , does the primer itself do this sealing well enough? (Silver tip water based yacht primer)

    I called tech support, but they were swamped, and I had to leave a message. I had hoped to roll some on this weekend.

    Thanks!
     
  2. Charly
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    Charly Senior Member

    Hey FWIW, System Three tech support did call me back.

    He recommended that just to be safe, coat it all with neat epoxy one final time and re-sand... I really didn't want to hear that: D
     
  3. michael pierzga
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    michael pierzga Senior Member

    Fairing compund..micro ballons need to be sealed.

    Epoxy or Primer is the way to seal , fill small imperfections and create a base colour for topcoats. I dont know silvertip brand.

    Primer suc as Awlgrip 545 is easy to use and sands easily. Epoxy is hard to sand.
     
  4. pauloman
    Joined: Jun 2010
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    pauloman Epoxy Vendor

    best to seal all fairing projects and give the topcoat of paint a uniform surface to bond with as well. You can use ESP 155 or make your own solvent thinned epoxy.

    I like using pigmented MCU aluminum paint Aluthane as a primer. Uniform color tells you if your repairs are as complete as you thought. Also when sanded any high spots show darken in color. Also, as an MCU - amazing bond and easy to apply
     
  5. Charly
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    Charly Senior Member

    Hey thanks you guys. I went ahead and flow coated the whole topsides. Here are a few shots of the job to date. The photos don't show the imperfections very well, but you can REAlly see them now in person, especially with a light. Jeeze,... epoxy is b*tch to sand. To make it fair and beautiful, now I have to fill all the little crevices and dimples that have shown up out of nowhere. I have been using epoxy with aerosil and phenolic microballons as filler. On the vertical surfaces, using a bit more aerosil to prevent slumping. Is there something I could make up here at home as a filler for these smaller places that would speed up things a bit? Something softer? Any recommendations?
     

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  6. michael pierzga
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    michael pierzga Senior Member

    Really challenging to mix up fairing compound at home with fillers and resin

    The best fairing compound is pre mixed. The filler ratios are correct...its density and sandabilty always the same

    When you mix yourself , the compound is always a bit dry or a bit wet. Wet compound is hard to sand.

    When you have different layers of wet and dry fairing compound...different denisities...it becomes tiresome to sand.

    Unfortunatly pre mix fairing bog is expensive.

    Awlgrip fairing bogs are very good.

    Many other premixes avaible. Ask around to see what is avaible in your market
     
  7. PAR
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    PAR Yacht Designer/Builder

    This is only true of novice laminators. Working with goo is all about procedures. If you follow them, including filler formulations, you'll have consistent results. My fairing compound mixtures are all the same consistency and viscosity. In fact, I have pre-mixed the materials and have them in sealed containers, waiting for resin. These mixtures are just as smooth and easy to apply and sand as any store bought stuff and a lot cheaper.
     
  8. michael pierzga
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    michael pierzga Senior Member

    If you go with expensive pre mix, avoid waste.

    With big bog jobs waste is minimal. Once the surface is fair and you start the spot filling small low spots and details phase , bog waste really goes up.

    Ive had good luck minimizing waste by transferring part A and part B into empty caulking tubes. When you need a bit of bog, squeeze out an appropriate Worm of part A on a bog board, complement this Part A worm with a part B worm, mix up and off you go.

    Very little waste and accurate mix ratios via visual Worm length
     
  9. Charly
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    Charly Senior Member

    I spent yesterday sanding the flow coated surface again to prep for the primer coat (100 grit). It occurred to me then that I was re-opening the pores on the previously sealed bog surfaces at every high spot! :D I guess the silver lining here is that the flow coat must have still done some good, and further filled and sealed the low spots, if only a little bit. And, neat epoxy is at least cheaper than the primer.

    So now I must decide whether to flow coat Again or just go on with the primer. There is still some filling to do, although now it is very thin filling. I figured maybe I could make up some soft, more porous mix with more balloons and less silica, apply and then then lightly sand that, and flow coat it one last time. Then the final sanding would be light, (maybe a higher grit?) and not cut through the flow coat.

    I am ready to paint the damn thing and go a fishin.:D

    Par, what do you suggest as a bog recipie?
     
  10. PAR
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    PAR Yacht Designer/Builder

    100 grit is pretty aggressive on a single coat of straight epoxy, maybe 150 or 180, so you get the tooth, but not eat right through. Also on a final coat like this I use a boogie board (long board). The shine of the last coat makes it real easy to see low spots, which you can focus on, instead of knocking off too much. In fact, I'll do this with 220 wet, so it's just a light "exploration" scratch, not material removal. Circle all the low spots and plastic applicator another straight coat, maybe with some filler if it's fairly deep. We all get to a point where our elbows are pissed enough at us to just say "it's good enough". Of course we regret this surrender when the glossy stuff goes on.

    Fairng compounds come in different shapes and sizes (literally). I have three mixtures I use, all premixed in plastic jars, each a little short on silica. I have a stiff cosmetic mix, that I use for unsupported finish fillets or non-structural gap filler. I have a general fairing mix which is a Q-cell batch, with about 20% balloons and 20% talc. I have a finer balloon mix, with 20% Q-cells and 20% talc. Each of these will get it's viscosity controlled with silica. Because the materials are premixed in a jar, I can get very accurate and repeatable mixtures.
     
  11. Charly
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    Charly Senior Member

    THanks, I will go up on the grit, and make another pass this weekend
     
  12. MoePorter
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    MoePorter Junior Member

    I use Sys3's silver tip yacht primer on all my epoxy projects - I use it as a sanding sealer and I'd have used it instead of your flow coat because it's
    1. epoxy & does the same job as a flow coat
    2. sandable
    3. water based & nicer to use than regular epoxy
    4. you can see your surface much better
    5. it's a UV barrier so if you are working outside it lets you leave the job for a while without worrying about UV degradation.

    I've used it as a finish coat on outdoor industrial stuff - it's not pretty but holds up well.

    Par's approach about making you own bog with strict consistency is the way to go - Moe
     
  13. Charly
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    Charly Senior Member

    This is my main concern these days- the glass on some places is two years old. It is time consuming to keep it all covered up.

    I am getting system three primer from Merton's for about $89/gallon

    http://www.mertons.com/Paints/system3/yachtprimer.html
     

  14. PAR
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    PAR Yacht Designer/Builder

    Epoxy primers aren't the same as a straight epoxy coating. It's not waterproof and doesn't seal the surface. I do use primer, usually real cheap acrylics to protect a surface if it'll be outside for a while, before paint. This gets wiped or sanded off as I prep for the paint job, but can serve to keep UV off the surface for a while.
     
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