I agree with Mark on using solid wood. I used mahogany to make my hatches for Seaweeble. I just routered the edges and they’re still sliding easily after several years. If you don’t want to spring for teak or mahogany you could try ipe ( yes, i-p-e). It’s very dense and cheaper than teak and very strong. It should work well also. Ian M-17 Seaweeble M-15 Judi B Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10 From: Mark Dvorscak<mailto:mdvorscak56@gmail.com> Sent: Thursday, January 28, 2021 11:30 AM To: For and about Montgomery Sailboats<mailto:montgomery_boats@mailman.xmission.com> Subject: Re: M_Boats: Marine plywood - hatch boards I used solid lumber rather than plywood for the hatch boards on my M23. I'm very pleased with them. The boat lives in a slip on the Oregon coast for 3/4 of the year in all kinds of weather. I made the hatch boards at least 10 years ago. I simply routered the edges sufficiently for them to slide easily behind the companionway cleats. The nominal thickness of the material was 1". I pretty sure the wood is mahogany, but I don't remember for certain. Mark Dvorscak M23 Faith M15 BC On Thu, Jan 28, 2021, 10:53 Dave Scobie <scoobscobie@gmail.com> 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