Russ, Long answer to your question but it shows what can happen with painting an old boat. It also illustrates that preparation is 80% of most jobs. Kinda of a primer on primers. :)
I'm not sure if the contractor long boarded between or after primer coats. I wasn't there when the contractor did that portion. However, there was more to it than just removing 40 years of scratches and dings. First, some history. A close examination of the existing paint showed numerous "fish eyes". Tiny pinprick size holes in the paint where it apparently didn't completely lay down. I had heard "dock tales" about how a PO had hired the local boat yard's painter to paint the boat in the water over a weekend. Rumor was they tied it side to at a bulkhead, set an anchor a ways out and careened it slightly with a masthead halyard. The guy painted it from a dinghy. The next day they swapped it and painted the other side. The rumor was they used Imron paint. This dubious story led the painting contractor and I to question everything about the paint job. On his advice, I scrubbed a 3 x 3 foot section of the hull, repaired some dings and sanded it with 320 grit. He was painting a nearby boat with white AwlCraft. At the end of that job, he came over with the paint gun and sprayed the test area. What??? The paint beaded up in spots. Where I had done the repair exposing underlying coats of paint, it reacted with those other paints. Some layers peeled up slightly and other layers reacted turning the white AwlCraft pink. Upon seeing this, we decided we needed to sand the entire topsides to remove all the layers of unknown paints. When working with $250/gallon paint and the risk of a botched job, we decided removing the old paints was the safest course of action. I did most of the smoothing myself with a Hutchins straight line sander like this: http://www.hutchinsmfg.com/View-Product.aspx?group_id=424043 If you use a disc sander, you risk creating gouges or divots in the hull. Especially if using a smaller sander like a 4 or 5 inch diameter. When applying a high gloss paint, it is critical that you have a very smooth surface. The straight line sander is held horizontally and moved up and down the hull at a slight angle to vertical. That is, in a "V" pattern. If you got up close and personal with Touche's topsides prior to the painting, you would have noticed a lot of imperfections. Much was due to post cure shrinkage. I could see the pattern of the underlying roving as well as the vertical "dimple" at the upper shroud brace. The sander removed nearly all the imperfections. As I sanded, I definitely saw several layers of old paint. I even found the original name "Touche" in the gap in the cove stripe under the shrouds. It was under at least 2 layers. Even though I removed as much of the old paint as I could, there were still small spots in recessions in the hull. When the contractor shot the primer, he saw small spots where the primer reacted with the old paint. Additional coats where required to "bury" the old paints. So, to answer the question of why 3 coats of primer, it was both for smoothing physical imperfections as well as for "burying" spots of the old paint. Dennis C. Touche' 35-1 #83 Mandeville, LA On Mon, Mar 28, 2016 at 11:08 PM, Russ & Melody via CnC-List < cnc-list@cnc-list.com> wrote: > > Hi Dennis, > > Was the 3 coats of high build primer for long boarding to a fair hull? > > When I did the decks I was set to do high build primer and the paint rep > suggested going the regularly spec'd (2 pot) primer. > > I have a hull paint project coming up next year and the hull needs > fairing, so I'm looking for best practices. > > Cheers, Russ > *Sweet *35 mk-1 > > At 09:00 AM 28/03/2016, you wrote: > > My only substantive comment on paint is to consider Awlcraft vs Awlgrip. > Particularly true if you're concerned about scratches. Awlcraft is easier > to repair and blend. > > Touche' is Sunfast Red Awlcraft over 3 coats of high build primer. The > Awlcraft looks great! > > Dennis C. > > > _______________________________________________ > > This list is supported by the generous donations of our members. If you > like what we do, please help us pay for our costs by donating. All > Contributions are greatly appreciated! > >
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