wax, pva, and gelcoat

Discussion in 'Fiberglass and Composite Boat Building' started by JEFFHEENAN, Nov 9, 2014.

  1. JEFFHEENAN
    Joined: Oct 2014
    Posts: 26
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: MONTANA

    JEFFHEENAN Junior Member

    Hello All,
    I am nearly finished with my boat model and am starting to look into wax, pva, and tooling gel coat. I will be using the mold many times and want it to be perfect. What should I use and where should I order it? Also is there any need to paint or gel coat my model before I take the mold? currently the model is made of fiberglass and filled spots of bondo. Thanks for any help.
     
  2. gonzo
    Joined: Aug 2002
    Posts: 16,357
    Likes: 1,409, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    If you used bondo, it will first need a sealer. Otherwise the styrene will lift it and make a mess. Also, if you want it perfect, the finish needs to be like a mirror. There is no way bondo can be polished.
     
  3. JEFFHEENAN
    Joined: Oct 2014
    Posts: 26
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: MONTANA

    JEFFHEENAN Junior Member

    Gozo, do you think a couple coats of polyester resin will seal it enoff
     
  4. gonzo
    Joined: Aug 2002
    Posts: 16,357
    Likes: 1,409, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    You can't polish polyester resin either. It may seal it enough to lay gelcoat over it after. The finish needs to be able to be sanded and polished.
     
  5. garrybull
    Joined: Nov 2010
    Posts: 508
    Likes: 16, Points: 18, Legacy Rep: 143
    Location: portsmouth england

    garrybull Senior Member

    i would use duratec surface primer to seal it.

    you can also polish it up to get a good finish to take a mould from it.

    once the mould is made you'll need to wet flat and polish it up to a mirror finish.

    i use merguiars number 8 wax.

    i do use pva now and then on any tight area's.

    just built my new boat without using pva in the brand new mould i built.

    i put on 6 coats of mould release wax and it all popped out there moulds perfect.
     
  6. JEFFHEENAN
    Joined: Oct 2014
    Posts: 26
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: MONTANA

    JEFFHEENAN Junior Member

    Thanks for the information. What grit sandpaper do I need to prep for gel coat and duratec?
     
  7. garrybull
    Joined: Nov 2010
    Posts: 508
    Likes: 16, Points: 18, Legacy Rep: 143
    Location: portsmouth england

    garrybull Senior Member

    i would prep the plug with 80 or 120 grit sandpaper and then apply up to 6 coats of duratec surface primer.

    then start with 240 sandpaper sand the plug down and then wet flat using 600 up to around 1500 wet n dry paper.

    then you can polish the plug.

    i use farecla G3 advanced to polish my plugs and moulds.

    once polished you'll have towax it with mould release wax up to about 5 or 6 times.

    i use merguiars number 8 wax.

    then apply a coat of pva release agent.

    you can spray it on or use a sponge or clean cloth.

    i use a clean cloth.

    only needs a very thin coat of pva.

    you can get clear or blue pva.

    i use blue as you can see where you have applied it.

    that will dry in a few minutes.

    then your ready to make your mould.

    2 coats of gelcoat followed by a skin coat of mat.

    i use 450gsm csm but a lot of people use 300gsm.

    then you can build the mat up to thickness.

    the more parts you want out of the mould then i would suggest laying it up fairly thick.

    once mould is popped off you may have to wet flat and polish it up to get the best finish on it.

    again when making the first part in the new mould put on 5 or 6 coats of mould release wax and your ready to make the first part.

    the actual jobs you'll make from the mould won't need to laid up as thick as the mould.

    are you putting a flange around the edge of the mould?

    that will help with releasing the parts from the mould as you can use a wedge in the flange to pop it out.
     
    1 person likes this.
  8. JEFFHEENAN
    Joined: Oct 2014
    Posts: 26
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: MONTANA

    JEFFHEENAN Junior Member

    choosing the right fiberglass

    Garry, you helped me earlier on some gelcoat questions and now I have more. I am working on a drift boat mold and starting to research fiberglass. I am thinking about using a poly resin and am wondering what the best fiberglas combination would be. The boat will be 16x5 and I want it to be strong and weigh around 200 lb.

    Also I have a roll of this. does it have a part in this?

    I Boat "D" Midweight • 7532

    Has a more open weave and conforms to MIL-Y-1140. •Width: 38"
    •Wt: sq yd 7.25 oz
    •Thickness: 10 mil
    •Count: 16 x 14 (warp x fill)
    •Standard volan finish is compatible with polyester, epoxy, and vinyl-ester resins.
     
  9. garrybull
    Joined: Nov 2010
    Posts: 508
    Likes: 16, Points: 18, Legacy Rep: 143
    Location: portsmouth england

    garrybull Senior Member

    i don't think you'll get a finished boat to weigh around 200lb.

    thats not even 100kg and will be too light in my opinion.

    i would do this layup

    2 gelcoats
    1.5oz csm skin coat
    2oz csm.
    600/300 combi mat
    1.5oz csm

    that will give you an 8oz lay up which for a 16ft boat should be fine.

    just make sure you fit plenty of ribs/stringers.

    you'll need 2 layers of 18mm ply bonded in to the transom to take the weight of the engine.

    i reckon you'll be looking more around 150kg in weight for a bare hull.
     
  10. ondarvr
    Joined: Dec 2005
    Posts: 2,863
    Likes: 519, Points: 113, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    Drift boats are totally different from a typical boat, there are no ribs or stringers, and hull thickness and laminate schedule varies in a way not normal for other craft.
     
  11. tja
    Joined: Sep 2004
    Posts: 126
    Likes: 1, Points: 18, Legacy Rep: 11
    Location: canton oh

    tja Senior Member

    mold help

    I think that you should contact a product supplyer in your area that could lead you in a good starting direction. There are guys on here like myself that have been doing this for many years that do not always want to just give you all the information you want without working for it. There is something to be said for solving the task at hand on your own. That being said I will give you one good contact that will enable you to make good plugs to build your mold on. Look up Advance Coatings there products are the best I have used over the past forty years. Just realize that you will make mistakes and will learn from them. Good luck.
     

  12. gdavis
    Joined: Dec 2014
    Posts: 72
    Likes: 1, Points: 0, Legacy Rep: 17
    Location: belfast,maine

    gdavis Junior Member

    jeff, the folks at Fiberlay are great to deal with..www.fiberlay.com have fun...g
     
Loading...
Similar Threads
  1. itchyglass
    Replies:
    5
    Views:
    350
  2. sunbelt57
    Replies:
    11
    Views:
    3,770
  3. Cjmac
    Replies:
    2
    Views:
    1,054
  4. brokensheer
    Replies:
    8
    Views:
    1,712
  5. burke
    Replies:
    8
    Views:
    3,430
  6. seby
    Replies:
    1
    Views:
    2,223
  7. garrybull
    Replies:
    18
    Views:
    6,455
  8. midcap
    Replies:
    6
    Views:
    3,532
  9. aaronhl
    Replies:
    18
    Views:
    36,561
  10. brokensheer
    Replies:
    12
    Views:
    3,835
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.