If you use quality epoxies with modern compositions, the whole blush thing is much reduced or even eliminated. I have been using epoxy from Raka, which is more affordable than the "big bucks big names" and have had no issues with blush. A light sanding of the cured epoxy surface with fine grit (180-220) is good for smoothing and also varnish adhesion. Raka epoxies (and cloth and fillers etc. etc.): http://raka.com/epoxy.html His web site is crude but his products are good, and he charges actual calculated shipping cost for weight (not inflated "flat rate" or based on cost of order, like some places). In fact I think I first found Raka from someone here...? Painting on epoxy has very limited penetration. For truly penetrating and sealing (like plywood edges and end grain of any wood), CPES is the stuff: http://www.smithandcompany.org/CPES/index.html Another crude web site, and excellent product. I actually met this guy (Steve Smith) when I bought some CPES at their retail site in Richmond (CA). He is a real mad-scientist type genius, and can tell you waaaaay more than you want to know about epoxies and their chemical formulations and blah blah blah... It looks expensive, but a little goes a long way when you actually use it. cheers, John On 1/28/21 10:52 AM, Dave Scobie wrote:
Paul:
Do two coats of epoxy. The second just as the first coat gets very sticky but and not hard.
After epoxy wipe of blush with water. Wipe again. Let epoxy cure a full week and twice again wipe with water. Then apply seven coats of varnish. If the epoxy isn't fully cured and blush completely removed the varnish will never harden.
If boards are a tight fit in the companionway, meaning in the grove behind the teak keepers (called cleats), as Jerry mentioned take off some of the hatchboard material at the edges. After all the coats of epoxy and varnish you don't want the boards sticking.
:: Dave Scobie :: M6'8" #650 :: SV SWALLOW - sv-swallow.com :: former owner M17 #375 SWEET PEA - m17-375.com :: former owner M15 #288 SCRED - m15namedscred.wordpress.com <<-- new site!
On Thu, Jan 28, 2021, 10:25 AM Paul Baker <avalonjazz@gmail.com> wrote:
Thanks Dave, I use West Systems a lot. I think I will coat the boards and put some UV satin varnish on them. That way the entire thing should be pretty waterproof. I would have rather used teak oil like on the rest of the trim, but I want the boards to last. I like the way teak oil looks more. It will be more work up front, but then I can forget about it. I'm also going to make a separate lower board for my compass when I'm sailing. Thanks for your input. Paul
On Thu, Jan 28, 2021 at 8:20 AM Dave Scobie <scoobscobie@gmail.com> wrote:
Paul:
The issue is the glue may react poorly to any water if it isn't exterior rated. The inner layers of the plywood may have voids ... as the hatch boards are not structural nor being bent small voids isn't much of an issue.
If you wish to give it a try epoxy the edges. If any voids along the edges fill the gaps with thickened epoxy. The edge are where water will easily enter the layers and delam the plywood and rot the wood. The outer surfaces finish how you like. If you accidentally put a gash in the teak veneer epoxy the spot soonest as water will get into the layers (with problems as noted above for the edges).
IMO that plywood will have a limited lifespan depending upon how much water (or even high humidity) gets into the layers.
:: Dave Scobie :: M6'8" #650 :: SV SWALLOW - sv-swallow.com :: former owner M17 #375 SWEET PEA - m17-375.com :: former owner M15 #288 SCRED - m15namedscred.wordpress.com <<-- new site!
On Thu, Jan 28, 2021, 7:22 AM Paul Baker <avalonjazz@gmail.com> wrote:
I have located a 4 X 8 Sheet of Teak Plywood, but it is not marine grade. If I use teak oil, I'm wondering if it will be okay. Does anyone have an opinion on this? Thanks, Paul
On Wed, Jan 27, 2021 at 7:41 PM John Schinnerer via montgomery_boats < montgomery_boats@mailman.xmission.com> wrote:
Yeah 12mm of whatever kind of wood is a wee bit less than 1/2" - .47" in decimal. It fits easily but not too sloppy in my M17 slots even after glassing one side.
cheers, John
On 1/27/21 4:32 PM, jerry montgomery wrote:
Original boards were a bit larger than 3/8"; some 1/2 will fit but barely. With 1/2, you might need to put a slight bevel on the outside top so the slider will drop over it.
jerry
-- John Schinnerer - M.A., Whole Systems Design -------------------------------------------- - Eco-Living - Whole Systems Design Services People - Place - Learning - Integration john@eco-living.net - 510.982.1334 http://eco-living.net http://sociocracyconsulting.com