Wavy Hull fix?

[wgt500]

What do you guys recommend to use for skimming a wavy hull with before I board sand? I'm restoring an '83 Thundercraft 15' runabout so there's not a ton of surface area. The factory laminate just isn't straight enough to make paint look good. To be honest, it's the worst fiberglass I've ever seen. It's so thin that in some places I added additional roving on the inside using epoxy resin to strengthin the hull. Thanks for any help!

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[DukesFin]

Re: Wavy Hull fix?

A lot of it will depend on what you define as "wavy"... Are we talking 1/8" over 3' or 3' over 1/8"?

 

[lowkee]

Re: Wavy Hull fix?

I used a mix of poly, 3m bubbles and cabosil. The most important rule to follow is to not get lazy. Put on one coat, sand, put on another, sand. Don't chunk it on or you'll pay in sandpaper and elbow grease (and you'll still end up needing another coat). USComposites sells some stuff called "Featherrite" which is just poly mixed with talc, but I'd be leary of that, as talc isn't meant for below waterline usage.

 

[wgt500]

Re: Wavy Hull fix?

Wavy to me is 1/16" x 6" high and low spots all over the sides of the boat from poor quality construction. These will look very bad after I spray the topcoat.

 

[ondarvr]

Re: Wavy Hull fix?

There is no easy way to get rid of waves in the surface and the longer the span of the wave, the harder it is.

Fiberglass tends to shrink over time, but on an older hull it should be done moving from it continuing to cure. It will also change shape from temperature and that will never stop, so depending on how perfect you want it, you may be chasing a moving target.

Epoxy sanding fillers will be more durable than polyester ones and if the hull is thin and flexes, polyester may crack if its very thick, it will also shrink and change shape more. Epoxy can be more difficult to sand though.

Just because the hull side flexes doesn?t mean its weak, it just means it flexes. Frequently in production boats products are used that reduce flex, but add nothing to the strength. Customers may perceive flex as weakness or poor quality, so for marketing purposes they try to reduce or eliminate it.

 

[wgt500]

Re: Wavy Hull fix?

So far I've used West System Epoxy to glass in a new beam, new stringers, new transom,and floor. Pretty easy stuff to work with. Should I just mix up some Epoxy and low density filler, (microspheres) into a paste and use that for skim coating the sides ofthe boat, then use the air board and 36 grit paper to level. Skim again and block sand with 80 grit then 220 grit to prep for primer.