Blister Preventative Maintenance

[David]

I bought a 1999 Hunter 260 last month that was hit by lightning. I took it home and had my fiberglass/gelcoat guy look it over and fix all the obvious affected areas (about 14 spots). Im sure that some were missed are not visible to the naked eye (and Im sure Lake Michigan will find THOSE this summer). Does anyone have any suggestions on how to seal the bottom of my boat before I re-bottom paint it? It curently has nearly all of the bottom paint stripped so preventing the problem now some way would be ideal. Im not sure if I should use a type of sealer or go so far as gelcoating the entire bottom, but I want to limit my potential blister problem before it occurs. Also, if there are cracks in the gel, will damage start occuring right away or am I alright if I notice it after the season and correct matters when and if they are more apparent. Another note...it will be at a mooring all summer so regular inspections will not occur.

 

[dave]

gelcoat is not the problem

gelcoat will not provide a barrier for blisters, don't waste your time or money!! I saw a recent website that was recommended here and the technical data was great , unfortunately I can't remember the site address. it pretty much debunked using a barrier coat and blames the problem on uncured chemicals residual in the layup and the ability of the layup to absorb water which combined with the styrene and other chemicals turns into a mess that expands and causes blisters. they claim that heat lamps applied to the hull to complete the curing cycle which builders do at room temperature for convenience but which really want to be at say 160 degrees accounts for a lot of the problem. Another culprit is the glass mat versus a chopper gun for the layup. glass mat provide a wicking path for the water further exacerbating the problem. Anyone remember the web address?dave

 

[Rob Rich]

Dave. Read it, Loved It, Can't Find It!

Possibly at www.marinesuvey.com?I know the exact one you are talking about, it targets the concept of osmosis in hulls. If anyone knows of its location, please post!Thanks!Rob

 

[R.W.Landau]

Interlux System 2000

This is a two part epoxy that you can put on with a roller. The bottom should be sanded down to gel coat and you should apply a minimum of two coats. Then apply your bottom paint of choice.Remember a dry bilge is a good preventitive also.r.w.landau

 

[dave]

RW- Read Osmosisinfo.com

The osmosisinfo.com web site basically describes the chemistry in the blister process and don't recommend a barrier coat of any kind. In their view only an elevated temperature cure will eliminate the problem.dave

 

[R.W.Landau]

Dave, Experience is all I have

Dave,Yes this is probably good to raise the temp but is not possible for many people.I have seen the benefit of a barrier coat first hand on many boats and I am still convinced that this is the way to go as a cost effective method of protecting against blisters.I will qualify that the boats I have seen are not in the water year-round.I have seen some pretty badly blistered boats that after proper repair, the barrier coat has completely protected the boat from any further problem. r.w.landau