filling and fairing - basic question

Having removed the layers of old paint on a Marblehead hull, I’ve discovered that when popped out of the mold there must have been numerous areas where the hull didn’t pop out cleanly - so many small ‘pits’ in the carbon that have been filled and faired.

I just want to get this M on the water for my son; I don’t want to spend a lot of money on micro-ballons or peel ply or whatever so what can I use to fill these areas, get it faired and sanded to the point where I can get a decent smooth finish? What’s on there currently looks like what we used to call in NZ builders bog… apologies to the purists(!) but any Aussie brand names of a standard el cheapo filler that would do the job (and any other advice) gratefully received.


Here is what I do for filling pinholes and small voids:

  1. Squeegee drywall spackling paste over the entire hull. Use a piece of plastic milk jug or Clorox bottle or something of the like. Cover the entire hull and really force it in. When you are done there should be very little to no spackling outside the hull.

  2. When dry, lightly sand off all of the excess drywall spackling.

  3. Mix epoxy resin with rubbing alcohol until it is just about water thin, maybe 25% alcohol. MAKE SURE THE ALCOHOL IS THE 91 OR 92% STUFF. The lower concentration has too much water in it and the epoxy will not set correctly. smear the resin/alcohol generously all over the outside of the hull.

  4. Let it soak into the spackling for a couple of minutes and the wipe off with lots of paper towels until the hull is pretty much dry.

  5. When the epoxy cures lightly wet sand the entire hull with 400 paper.

The spackling paste fills all of the holes, including the ones that you can not or so not see. The resin soaks into the spackling and hardens it and makes it water proof. I do thison all of my hulls and it works great.


Or once you have a coat of primer on use automotive spot putty on all of the bits that need smoothing out. You can buy it in a tube from Super Cheap Auto Stores

Thank you Gregg and TF for your input, really helpful. Cheers.


Home Depot sells Spackle with microballoons already mixed in it. Very lightweight. I usually mix it with a little water to thin it out. Then like was said before, coat the hull with it,wait a day for it to dry all the way. You can sand it sooner but it does a better job if its entirely dry. Then brush thinned epoxy over it and when cured sand it.
Do microballoons cost a lot where you live? I got a lifetime supply bottle from amazon for like $12.