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Re: The Holy Grail
By:Ian Johnston
Date: 9/8/1999, 2:46 am
In Response To: Re: The Holy Grail (Dean Trexel)

> Ian,

> Please keep us posted on the polyurethane clear-coat info. Since I'm
> working out of my apartment, I like the idea of taking the boat to an auto
> body shop. One draw-back would be that you wouldn't be able to do
> touch-ups or re-coats yourself, either.

Actually , minor touch-ups are quite easy. Minor scratches can be cut polished, more severe scratches can be wet sanded and polished. Deeper scratches can be repaired by wet sanding the scratch and immediate area,mixing a small amount of product, applying it, with a brush, to the scratch only, wait for it to dry and then wet sand and polish again. Fast and easy. Recoats would have to be done at the bodyshop, but the life expectancy of an automotive finish is 10 years with little maintenance and continual outside exposure.Not to mention travelling down the highway at 100 KPH and getting sandblasted by road debris.

> Are the 100%-solids polyurethanes what's refered to as '1-part
> polyurethanes'? I saw 4 CLC's done in 1-part poly paint applied with
> rollers, and they looked very professional (only little ripples from the
> rollers' fibers that gave it a slight 'orange-peel' look), but this was
> shortly after they were built, so I don't know how they hold up to
> scratching.

100% solids are 2 component products. They cure quicker, because of the isocyanates used in the hardener. The difference in the 100% solids and the high solids is in the amount of solvent used to thin out the product. High solids use minimal amounts of solvents while 100% use no solvent. This means that there is no film shrinkage (die back)during cure so "orange peel" is eliminated. Orange peel from high solids is also almost nil, but VOC emissions are higher. The benifits of two component over one component are mainly cure times and chemical resistance. 100% solids and high solids can be applied with a roller or brush as well as spraying, but the hazard is in the isocyanate hardener and only a positive presure, fresh air respirator with suit, gloves and face mask will protect you. So don't use them at home.

It is hard to explain all the benifits to these products without getting fairly technical, but here is a practical example. I have an old fiberglass kayak that was given to me awhile back. I repaired the weak spots and one small hole with glass and polyester resin, filled minor surface imperfections with polyester body filler, epoxy primed, and then applied automotive basecoat(urethane) and a urethane clear coat. After a year and a half of kayaking there are only minor polishable scratches on the hull and deck. The one exception is a deep gouge on the deck caused by the attack of a rogue nail sticking out of a fence. This gouge went right down to the fiberglass, so I suspect that even gel-coat would not have helped.

I have not received a reply to my inquiries as of yet but will keep you informed when I do.

Ian

Messages In This Thread

Clear scratch resistant finish
Bobby Curtis -- 9/6/1999, 8:28 am
Re: Clear scratch resistant finish
Ken Katz -- 9/8/1999, 10:56 pm
Re: Clear scratch resistant finish
Bobby Curtis -- 9/10/1999, 8:48 am
Re: Clear scratch resistant finish
Ken Katz -- 9/16/1999, 9:37 pm
Re: Clear scratch resistant finish
Ian Johnston -- 9/10/1999, 10:41 pm
Re: Clear scratch resistant finish
Jeff DeJongh -- 9/7/1999, 5:42 pm
Re: Clear scratch resistant finish
Bobby Curtis -- 9/7/1999, 6:03 pm
Re: Clear scratch resistant finish
Pete Campbell -- 9/7/1999, 12:27 pm
Re: Clear scratch resistant finish
Ian Johnston -- 9/8/1999, 3:04 am
Re: Clear scratch resistant finish
Bobby Curtis -- 9/7/1999, 5:59 pm
Re: Clear scratch resistant finish
Peter S. Mclaren -- 9/12/1999, 3:16 pm
Re: Clear scratch resistant finish
Bobby Curtis -- 9/13/1999, 8:37 pm
Re: Clear scratch resistant finish
Pete Campbell -- 9/8/1999, 2:28 pm
Re: Clear scratch resistant finish
Bobby Curtis -- 9/8/1999, 7:09 pm
The Holy Grail
Dean Trexel -- 9/6/1999, 6:17 pm
Re: The Holy Grail
Bobby Curtis -- 9/7/1999, 8:49 am
Re: The Holy Grail
Ian Johnston -- 9/7/1999, 1:56 am
Re: The Holy Grail
Dean Trexel -- 9/7/1999, 4:12 pm
Re: The Holy Grail
Ian Johnston -- 9/8/1999, 2:46 am