I found that the smooth prime gets bubbles in it and you need to sand almost all of it off to get the pits out of the surface where the bubbles were. Sanding with 180 paper before the last coat then rolling on one last thinned coat seemed to do a great job of filling in the bubble craters for me. You don't need to sand a lot before the last coat, just enough to trim the tops off of the rough surface and pop all the dried bubbles. It leaves a lot more of the primer on the surface and takes a lot less sanding.
-----Original Message----- From: Steven Eberhart <newt...@newtech.com> Sent: Nov 14, 2003 1:00 AM To: KRnet <kr...@mylist.net> Subject: Re: KR>Filling pinholes Hi Leigh, Two things come to mind. First, U.S. Chemical & Plastics "Icing" is a polyester product. I don't like to mix polyester products with epoxy products on a project. Other than preferring not to do it one isn't recommended for use over the other. I can never remember which way it goes - polyester over epoxy or epoxy over polyester. Doesn't matter to me too much as I never mix the two. I have found that most of the polyester products will shrink somewhat over time and you will be seeing the weave of the cloth showing through. I only used epoxy finishing products on the wind tunnel wings for the new KR airfoils and the finish today is still just as good as the day they went in the wind tunnel. Second, Poly Fiber has changed the directions they print on the Smooth Prime can. Originally they recommended thinning the Smooth Prime and then rolling six coats on the fiberglass surface and waiting to sand until the last coat was dry. The last gallon of Smooth Prime I bought, for use on all of the fiberglass parts of a Van's RV-8 I am finishing up the fiberglass work on and painting, recommends rolling on the six coats full strength and only thinning if you are going to spray it. Thinning the Smooth Prime and rolling on the six coats has always taken care of the pin holes on all of the projects I have used it on. Rolling on full strength seems to give a rougher finish and uses more material than necessary IMHO. I sand just about all of the Smooth Prime off and only rely on it for filling the pin holes. I use an epoxy primer over the Smooth Prime. I am rapidly becoming an advocate of PPG's Concept acrylic urethane finishing system. All of the fiberglass parts are first filled with Poly Fiber Super Fill till you have a good smooth finish. Then six coats of thinned Smooth Prime are rolled on. THis is sanded and PPG DPLF epoxy primer is sprayed on. I generally let this cure and wet sand it before spraying on the PPG Concept for the final finish. THis works very well for me. On the RV-8 I am just finishing up the paint job on took five quarts of DPLF primer and six quarts of 2001 Corvette yellow. A KR should use a lot less. Steve Eberhart Leigh Plymale wrote: > I was talking to a friend that builds Drag Cars and consequently uses a fair > amount of fiber glass. He said to try a product called icing. It is a filler > that can be squeeged on and then sanded. It seems to me that with the amount > of coats of smooth prime and sanding that many of us report on, this might > be a way to fill the dimples first. then use the primer as a final finishing > step. I'm not a body man but am looking for a quicker answer, any comments? > > Leigh Plymale > flyboy...@adelphia.net > > > > _______________________________________________ > see KRnet list details at http://www.krnet.org/instructions.html > _______________________________________________ see KRnet list details at http://www.krnet.org/instructions.html
