NICE to hear from Jerry great reply. On Fri, Apr 26, 2019 at 1:02 PM <jerry@jerrymontgomery.org> wrote:
Dave's right, but there's more to it. Backup is for three reasons; the laminators can see air bubbles much better laying up against dark gel coat, the dark layer cuts out most of the UV getting to the polyester resin, and the third is as Dave says.
Another matter- I've done a bazillian repair jobs over the years (the true value of a bazillian is arguable, but it's ALWAYS more than a dozen). For nearly everything, polyurethane auto paint is far better than gel coat. It's WAY more UV resistant and therefore stays shinier longer and doesn't fade as much as re-sprayed gel and is much easier to apply. Also, any auto paint guy can do a great job, and in most areas they're way easier to find than boat guys. With auto paint, after the actual damage is repaired, the repaired part should be strayed with epoxy primer, the orangepeel should be wetsanded off and finished with 320 grit paper, then sprayed with the polyurethane. The finished topcoat probably won't need wetsanding and polishing except around the edges, same as a repair job on a car.
LPU doesn't work work well for this because of the difficulty in blending in the edges. For years I used PPG Deltron, which was used for hi dollar auto paint jobs but mostly for airplanes, but in it's wisdom EPA outlawed it because it has .0000001% more emissions than they thought it should so it was replaced with Omni, which costs more and isn't as good. Way better than gel coat, tho. The beauty of gel coat is that is so simple to just spray it on the mold, laminate over it, and pull the part the next day, with no more painting necessary. Amazing. Applying the gel coat on a 17' boat takes about an hour, including cleaning the gun. Better living thru chemistry!
Hope this helps to confuse you!
-----Original Message----- From: Dave Scobie Sent: Friday, April 26, 2019 8:34 AM To: For and about Montgomery Sailboats Subject: Re: M_Boats: Gelcoat; great info!
When I've talked with Jerry about this the usual practice would have been spraying black (aka 'back black') after spraying the hull and boot stripe colors.
The reason black is used is to limit seeing the sun through the hull. Seen boats where this isn't done and you see this round circle of the sun when in the cabin.
:: Dave Scobie :: M6'8" #650 :: SV SWALLOW - sv-swallow.com :: former owner M17 #375 SWEET PEA - m17-375.com :: former owner M15 #288 SCRED - www.freewebs.com/m15-named-scred/
On Fri, Apr 26, 2019, 7:42 AM <swwheatley@comcast.net> wrote:
The red is the first layer of polyester resin. I believe it is tinted on purpose to help the builder see whether there is thorough coverage over the gelcoat. Presumably they use a different color tint when spraying over red gelcoat.
Based on your photos, you do not need new gelcoat but you should apply an epoxy barrier coat. I have had good results with the Petit product. I don't know if this is still true, but it used to be the Petit product was thicker and required fewer coats than the Interlux product.
-----Original Message----- From: montgomery_boats <montgomery_boats-bounces@mailman.xmission.com> On Behalf Of Gerry Lempicki via montgomery_boats Sent: Thursday, April 25, 2019 6:47 PM To: Dave Scobie <scoobscobie@gmail.com> Cc: For and about Montgomery Sailboats <montgomery_boats@mailman.xmission.com> Subject: Re: M_Boats: Gelcoat; great info!
If I had to guess I'd say there is both a red and a white gelcoat. Here's a photo from today when all the paint has been removed. Maybe a red gelcoat under the white? The red stripe is definitely not paint. And if I sand through the white gelcoat below the waterline, I hit red.
-Gerry
On Apr 25, 2019, at 6:29 PM, Dave Scobie <scoobscobie@gmail.com> wrote:
Garry:
is the red her original gel coat color?
is the white being sanded off old bottom paint or a later finish?
:: Dave Scobie :: M17 #375 SWEET PEA - https://m17-375.com/ FOR SALE! :: SV SWALLOW - https://sv-swallow.com :: Montgomery 6'8" #650 :: Truck camper - https://truckpopupcamper.wordpress.com/ :: Ramblings - https://scoobsramblings.wordpress.com/ :: former M15 owner #288 - http://www.freewebs.com/m15-name-scred
On Thu, Apr 25, 2019 at 2:55 PM Gerry Lempicki via montgomery_boats <montgomery_boats@mailman.xmission.com> wrote: Thanks for the replies! I'm going to try to attach a couple photos. If they come through, one is the underside of the lapstrakes, a few areas with lots of little holes (bubbles when applied?) And a flat area with similar sized spots. Fill the holes with my epoxy fairing? Then prime over it all?
-Gerry