Teak Doors

[Asleep Helmsman]

I built some replacement doors for the companionway.

They're made out of teak and the styles and rails are going to be glued together. The pieces are coped to fit each other

There will be a panel of solid teak on each door, and a Plexiglas window.

So two issues:

If I glue the teak panel into a groove will it check (split) from expanding more across the grain? Or maybe I should varnish it first and let it float in the frame with maybe some silicone sealer around it?

If you have a better suggestion, I would appreciate it.

And the second is sealing the Plexiglas window. Silicone is always recommended for acrylic but if some gets on the teak it may make it difficult to varnish.

I thought about using some black rubber type material that doesn't cure hard and leave the paper on the Plexiglas except where it fits into the grove of the frame. Maybe even sand it rough in that area. After the black goop sealer cures it could be cut off around the window and then peal off the protective paper.

What do y'all think?

 

[gonzo]

It is better to varnish first before applying any sealer under the plexiglass. A rubber gasket can work fine too.

 

[Asleep Helmsman]

Thanks for the info on acrylic panels.

I found this article on wood shrinkage:

http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/ch03.pdf

You'll notice that teak is at the bottom of the scale for shrinkage. Which would indicate a less propensity to split in small panels, where end grain is glued to edge grain.

But still hoping to hear from people that have experience with glued in teak panel.

 

[gonzo]

The holes in the plexiglass need to have enough clearance to allow for movement too.

 

[PAR]

The panel in the door (between the stiles and rails) should float, meaning no glue or potential sticking from fresh(ish) varnish. This permits the panel to move around with moisture content changes, without being captured and splitting.

As far as the glazing (glass, acrylic, etc.), set it into a rabbet and caulk it in place. Silicon works well, but it also will contaminate any surface it touches, so finishes will not stick. To cure this, carefully tape off the rabbet, apply the goo, set the glazing in place, then peel the tape off, with care to not let any silicon touch anything.

If you're going to varnish this piece, apply varnish to the assembled panel, once the edge glue has dried. Insure this is well dry (a week or more) before placing it in the rail/stile assembly, which also can be pre-finished. Account for the thickness of the finish in the rabbet and along the edges of the panel that'll live in the rabbet, so it still has room to move.

Gluing teak is a pain in the butt, though a scrub with a 50/50 mix of toluene and acetone, using a fine and relatively stiff brush, will remove the oils that tend to screw with glues and finishes. Scrub the faying surfaces just before you apply glue, let dry, then glue up. The same is true of the finishing. When ready to finish, scrub up with the solvent mix, let it dry and soon as it is, get a thinned finish on it. If regular varnish, use a 70/30 varnish/mineral spirits mix for the first coat. Let this dry, then use a 80/20 mix, then a 90/10 mix after the 80% cut has dried. After this you can likely use the varnish straight out of the can or with a subtle cut (5%), if only to remove brush marks. A 5% Penetrol cut along with the mineral spirits will help with brush strokes.

 

[Asleep Helmsman]

I probably should have premised this. I've owned commercial wood working shops, off and on for 30 years, so I get finishes and floating panels.

I think what sent me down the broken path was the Plexiglas glazing and the desire to keep water from running into the space between the panel and the frame.

For some reason I originally thought to install the Plexiglas at the glue up stage, what a dumb idea that was. Since then, like Par, I decided to glue up the doors and then cut out the back side of the grove to create a rabbit. later I'll use a piece of trim to hold the window in and provide decoration from the inside.

Here is where we differ, the reason panels must float in normal doors, is that the expansion rate is different across the grain as it is with the grain. So panels that are glued tight will tend to split.

I'm thinking that I will use the ultra clear West System hardener and prefinish all of the teak parts prior to gluing them all together. Once the panel is encapsulated with the epoxy it will no longer expand and contract from changes in moister. At the end I'll use some kind of thin filleted crystal clear sealer like Henry's to keep out the moister. I'll varnish the whole door at once and install the glazing last with a carefully silicone caulk around the outer edge and cover it with the trim.

As far as the finish is concerned, I used shellac under varnish in an experiment on the solon table 3 years ago, and it turn out to have beautiful grain depth. I may try some kind of experiment with Shellac, West System, Varnish combination.

I'll keep you informed and post some pics.

 

[gonzo]

The wood may not change dimension too much, but the plastic will with temperature changes.

 

[Asleep Helmsman]

I get that, definitely going to leave an eight all around for that.

Thanks guys, I appreciate the input.

 

[PAR]

If you use epoxy properly (encapsulation), you'll have no need to seal the wood with anything else. Shellac can be used over epoxy, though it's need is questionable. It shouldn't be used under epoxy, in fact epoxy should be the first product (if desired) on raw wood. Which brings up a big set of issues. You're looking for a bright finish on teak, so maintenance will be a concern. If you build this door conventionally (no epoxy) you can touch up and refinish as needed, assuming you don't let these coating get away from you. Over the years I've discovered that epoxy under clear coats tends to increase maintenance chores, so you have to stay on top of the finish condition, otherwise you'll be repairing finish and epoxy coatings, which is a lot more troublesome.

Download:
http://www.westsystem.com/ss/assets/HowTo-Publications/GougeonBook 061205.pdf
and have a look at these user's guides:
http://www.westsystem.com/ss/use-guides/

A conventionally built door will expand and contract with environmental changes, but if the door is done right, it'll tolerate this easily, assuming sufficient gaps, where appropriate. If you entomb the wood in plastic (epoxy encapsulation), it will stabilize (no more moisture gain/lose), but epoxy isn't particularly UV stable, so the finishes need to be closely managed or you'll have to repair both epoxy (not easy) and varnish. This is why I'm shying away from epoxy under clear coatings, unless there's a real need for the epoxy. A door doesn't take enough abuse to warrant a sheathing, so I don't see a need, but you may find one.

 

[Asleep Helmsman]

I'm concerned about all that as well.

But I still don't like the idea of water running down into the end grain of the panel.

By the way, the shellac really doesn't seal in the way that epoxy does.

What it does do very well, is bring out the grain, and adds depth and clarity to the finish.

 

[PAR]

Shellac doesn't seal wood. As far as moisture vapor penetration, it's literally at the bottom of the list of permeability. Only a traditional oil (Dutch oil, etc.) is worse, in this regard.

If you use rift or quarter sawn rails and stiles (assumes mitered corners), the only end grain you'll need to worry about will be the raised panel insert. The top of this panel will be protected with the rabbet to some degree, in the upper rail. As far as woods go teak is fairly stable, so long as you make good piece selections and the door construction is solid (tight). Additionally, you can smear a slightly thinned coat of PVA (TiteBond III) on the end grain of the panel, though be careful, because it will leave a brown color, so just the end grain in the rabbet.

If really worried about moisture, then epoxy encapsulation is the only good choice. It does add considerably to the cost and effort on this little project, but (again) if done right, it will embalm the wood, making it stable and safe from moisture ingress.

 

[Asleep Helmsman]

Cost is not a factor, but my dad was a professional captain, who was probably the best varnisher in the world, maybe not the world, but he produced flawless finishes.

And, he agreed about not using epoxy under varnish.

He did like catalyzed varnish, but that is another story.

So final procedure:

1. Put 2 thin coats of varnish on the panel.

2. Glue up the frame with the panel floating.

3. Rabbit the back of the window to for the glazing (Plexiglas)

4. Cut the acrylic 1/8th all around smaller than the opening.

5. Varnish the entire doors including the separate interior glazing strips.

6. Using silicone sealer install the acrylic sheets.

7. Install the interior trim strips.

Next Project: Replace the port hole acrylic sheets.