Print blocker vacuum infused epoxy layup

Discussion in 'Fiberglass and Composite Boat Building' started by Gasdok, Aug 4, 2020.

  1. Gasdok
    Joined: May 2020
    Posts: 10
    Likes: 0, Points: 1
    Location: Florida

    Gasdok Junior Member

    Seeking advice on a means to prevent print through.
    Gelcoat/ 2 csm layers vinylester hand layup followed bt 1708 vac infused epoxy.
    Is there an additional step or product to
    Minimize print through?
     
  2. ondarvr
    Joined: Dec 2005
    Posts: 2,312
    Likes: 248, Points: 63, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    Why are you mixing resin types?
     
  3. Gasdok
    Joined: May 2020
    Posts: 10
    Likes: 0, Points: 1
    Location: Florida

    Gasdok Junior Member

    What would you recommend for surface coat and printblocker other than csm?
     
  4. KD8NPB
    Joined: Mar 2018
    Posts: 88
    Likes: 18, Points: 8
    Location: South Carolina

    KD8NPB Junior Member

    If a laminate that thin is getting heat distortion, your skin coat is massively undercured.

    At 85F, I usually run about 2.25% MEKP9 @ 90 mils (2oz CSM).

    Either that, or distortion is transferring from the mold.
     
  5. Gasdok
    Joined: May 2020
    Posts: 10
    Likes: 0, Points: 1
    Location: Florida

    Gasdok Junior Member

    Have not laid up part yet.seeking advice on what surfacing veil or print blocker to use for best surface quality.
     
  6. ondarvr
    Joined: Dec 2005
    Posts: 2,312
    Likes: 248, Points: 63, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    It depends on the type of print through. Are you seeing fibers, or is it from the core or support structures within the laminate.

    And again, why are you mixing resin types?
     
  7. Gasdok
    Joined: May 2020
    Posts: 10
    Likes: 0, Points: 1
    Location: Florida

    Gasdok Junior Member

    Have not done layup yet. Would prefer in mold gelcoat rather than post finishing part. Concerned w print through of biaxial cloth.
     
  8. ondarvr
    Joined: Dec 2005
    Posts: 2,312
    Likes: 248, Points: 63, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    Use an epoxy compatible gel coat.

    You will get less shrink with epoxy, so less print.

    If you want even less print, the first step is a barrier coat behind the gel coat.

    After that to reduce print even further a veil is used against the barrier coat prior to the skin coat.

    Or do those things and don't use a skin coat, go straight to infusion.

    You will need to make a couple of small test samples to see which method yields the desired results.
     
  9. Chris Rogers
    Joined: Apr 2020
    Posts: 20
    Likes: 6, Points: 3
    Location: Boston, MA

    Chris Rogers Junior Member

    I agree on the mixing materials thing - probably best to avoid that... and no need really to skin coat an infused epoxy part. There's also no need for mat anywhere in an infused epoxy laminate - so just use 17oz biaxial without mat instead of 1708.

    If you are infusing epoxy, that should be quite stable and if it prints it will be solvable with a surface ply that acts to isolate larger fiber bundles from the surface. Surface plies / "print blockers" give you a resin-rich layer against the mold. They look kind of like thin breather cloth - a fuzzy non-woven.

    In-mold epoxy-compatible gelcoat is good - but often for one-off parts people apply an in-mold primer or prime and paint after. Post-curing the epoxy laminate before demolding (and ideally while still under vacuum) will help too.

    Test panels are always a good idea. Good luck and please report back with what you end up doing!
     
  10. Gasdok
    Joined: May 2020
    Posts: 10
    Likes: 0, Points: 1
    Location: Florida

    Gasdok Junior Member

    Would a 40 percent resin to 60 pct reinforcement ratio by weight be a reasonable real world target for a vac infused laminate?
     

  11. ahender
    Joined: Jan 2009
    Posts: 72
    Likes: 2, Points: 8, Legacy Rep: 10
    Location: Athens, GA USA

    ahender Junior Member

    I'm waiting to recover from foot surgery before finishing my resin infusion project (a 12' canoe). What are you infusing? From what I have read, a 40/60 resin/reinforcement ratio is certainly achievable if everything goes as planned.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.