gelcoat spraygun

Discussion in 'Materials' started by JEFFHEENAN, May 2, 2015.

    Joined: Oct 2014
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    JEFFHEENAN Junior Member

    Hello everyone. I need some help, I am recoating my boat and cannot get my spray gun to shoot gelcoat well. It sprays a little but not much. The gun has a 70 thousands nozzle. Should I get a new gun? Should I roll on the gelcoat? Any help would be much appreciated.
  2. waikikin
    Joined: Jan 2006
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    waikikin Senior Member

    Not sure on your sizing there sounds about 2-2.4mm so "should" be possible, is it a gravity gun with cup on top?
    I'm sure poster Onarvre will give best advice here but there's a coupla things you can do but with disadvantages.

    One is thin with styrene, you need wax in styrene added so air dont get to gelcoat & stay sticky anyway, but apparently extra styrene can lead to yellowing later.
    next is thin with acetone so it come s out - test as low an amount as possible & let it breath between passes, at lot of a thinning solvent will disperse within the spray fan, but acetone can make the gelcoat chalky.
    Use an additive like Duratec that can be added up to 1:1 from memory to the gelcoat, I've never used that much just enough so it does what I want prolly about 15-25%, no need for wax additive either & makes gelcoat behave more like paint, disadvantage is cost & hide as it's a clearish thin resinous material, no idea what is actually in it though but goes high gloss.
    Also some don't use wax additive but will mist PVA over the surface to keep air off for cure.
    Other duratech products use MEK as the thinner, never tried it in gelcoat though,

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    JEFFHEENAN Junior Member

    Thank you for the information. Also no it is not a gravity gun the cup is on the bottom. Is this a problem?
  4. ondarvr
    Joined: Dec 2005
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    ondarvr Senior Member

    Siphon guns don't spray gel coat very well unless it's been thinned a great deal, which can create a bunch of other issues later. They can work on small repairs and with patchaid, but on large areas and unthinned the results are poor at best.

  5. micheal william
    Joined: May 2015
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    micheal william New Member

    According to me gravity guns are good for shooting gelcoat well on your boat.
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