Thursday, October 26, 2017

Gelcoat vs. Paint

Gelcoat is the usually white layer that covers a fiberglass boat.  It's kind of like paint but much thicker.  It is actually just pigmented fiberglass resin. The same thing that the boat is made of.   Normally it is the first thing sprayed into the boat's mold and becomes the outer surface when the hull is removed from the mold.

Over time, gelcoat get oxidized and pitted from UV and the elements.  Sanding to deoxidize, compounding, and waxing only go so far.  Dirt and stuff sits in the porosity and the color just becomes dingy.   

One solution is to paint the entire boat with car paint.  Quite a few older boats have this done and it looks good for a few years but scratches easily, is hard to repair, and needs to be done again every 5 years.  The going price in the Caribbean and Mexico for a monohull was around $6,000 USD.  
$20K Paint Job
There is a catamaran here that was just painted for $20,000 and the guy thinks he got a pretty good deal.  Once you paint a boat, you can never go back to gelcoat unless you sand off all the paint.  

 In my opinion, the only reason to paint a boat is if it is constructed out of Epoxy or if you are selling it and don't care much about the future owner. To me, painting a boat is not something that you want to build into a continual maintenance schedule.  There's enough of that already.  My goal is to do it once and have it last for 15-20 years.

The Preval can cover about 2 square feet
I have done quite a few gelcoat repairs in the past.  Both gelcoat and paint surface preparation is extensive. Gelcoat, however, can bury small scratches whereas paint is so thin that the surface needs to be perfect before spraying.  With small repairs, a disposable spray bottle like the Preval is used.  The gelcoat is thinned down with styrene, extra wax additive, the material is catalyzed, and is sprayed like spray paint out of a can.  The real work comes after it dries.  Since gelcoat is thick, the surface has an orange peel texture that needs to be sanded to get to a smooth surface and then sanded with finer and finer grit sandpaper and compounded until it has a brilliant shine.

So my real challenge is to scale up what I have done on small areas with the Preval and make it work in the 90 degree heat of Malaysia.   No worries.

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