Doing the window job this fall

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Doing the window job this fall

Postby Sleepah » Sat Jul 12, 2014 5:48 pm

I will be r & r'ing all my widows this fall. There is a lot of rot around and I will have to fabricate some new wooden outer frames. I am now in the research phase and have questions.

As I understand the many postings here it seems to me the following sequence is followed. 1. remove outer mahog frames. 2. remove glass. 3. clean up rabbit and paint/varnish from inside. 4. Reinstall glass 5. reinstall frames. I'll also be painting the deck house, fly bridge and decks (my teak decks were at removed before I owned her.)

My glass is delaminating at the edges so I will want to get new glass. What type of glass do you recommend? How thick is it?

Recently I built some boarding steps for my dock and framed it with pressure treated 2 X 4's ripped in half. I was very surprised at the high quality of the ripped P-treaters. I may use this wood to build new frames. The lumber is cheap enough that I can work around the frequent knots. People say that one must wait several months to paint P-treaters. Comments?
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Postby Bob Lowe » Sat Jul 12, 2014 7:02 pm

You will have to determine if you will need to remove any interior teak trim to access any window fasteners or if they are all from the exterior.

The glass is safety glass, 1/4"~ laminated.

Do not try to use cheap home building lumber. If is typically a white/Doug fir, very grainy and you will be penny wise and pound foolish as you watch the grain telegraph through the nice finish you so laboriously applied. Use Honduras mahogany. Forget Philippine mahogany as there is no reliable supply in the US. The version one can buy in the lumber yards is luaun and can rot out in a couple of years.

Do it right and enjoy it. :)
Good luck,
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Postby Marin Faure » Mon Jul 14, 2014 1:12 am

Our fiberglass 73 GB36 has mahogany frames that are removed from the outside. There is no need to remove any interior components to completely remove all the window components-- frames, track, and glass. As I understand it, this not true of the woodies.

On our frames there is a plug covering a screw in each corner of the frame. These do not need to be removed because the screw underneath holds the frame sections together but does not hold the frame to the cabin side.

We take the frames home and strip them of the old paint and primer using a heat gun and scrapers (today's consumer paint removers have been so depleted of strength due to "safety" regulations as to be almost worthless). We do not remove the old paint and primer using sandpaper as this invariably removes wood, too. Once the paint and primer have been removed we prep the frames with a very light finish sanding and then give them several coats of CPES. Once the CPES has completely cured, we give the frame another light finish sanding to remove any roughness as a result of the CPES coats.

After installing new track and glass, or just glass in the case of the non-opening windows, we reinstall the frames using white Dolfinite as the bedding compound, install new plugs over the mounting screws, fair the plugs to the frame, and give them a couple of coats of CPES. Then a final finish sanding on the outer face of the frame, followed by primer and paint.

Since we want to use the boat while the frame and glass are out we make a temporary Plexiglas window cover using the outside edge of the frame as a template and using the frame as a guide to drilling holes in the plex. We then mount the plex over the window opening using the same holes used to mount the frame. We run a very thin bead of sealant around the top and sides of the opening but not the bottom to keep rain from getting under the plex and into the cabin.

We've gone an entire wet winter with no problems with one of these temporary plex covers in place while we stripped and epoxy-sealed the frame at our leisure at home, waiting until warmer spring weather to install new track and glass and reinstall, prime and paint the frame.

As Bob advises, use laminated safety glass for fixed and sliding panes. Never use tempered glass. For obvious reasons, you want a window to crack but remain in place when struck, not shatter into a zillion pieces and fall out of the frame.
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Postby Sleepah » Mon Jul 14, 2014 7:00 am

Marin,

My boat is the 6th or 7th fiberglass GB42 built and may have a different system. From what I see, the corners are mitered and not ship lapped as you describe. I can see a crack in the paint to indicate a 45 degree joint. Were your joints at an angle at the corners? At any rate I'll be careful as I expose the frames to find the bungs.

Currently I am replacing my starboard fuel tank and have my plate full. Besides it is too hot to work outside in Florida in July. Surprisingly it is pretty cool in the engine room where I am working. I have lots of fans going.

Note that my 40 year old GB had 4 alum tanks installed in the 80's;two 100 gal tanks on each side. The leaky tank failed since it was apparently dropped and dented when it was installed as there is a lot of curious welds on one corner which is where it leaked. Fingers crossed on the 80's port tanks which are not as accessible.

Thanks,

Howard
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Postby Bob Lowe » Mon Jul 14, 2014 7:42 am

GB used a combination joint, half miter on top and the bottom half was lap joint for strength. You will see the miter joint on the surface.

Marin's description of the process is good. I would however, apply the first coat of undercoat on top of the CPES an hour or so after the CPES is applied though. This will ensure a chemical bond.

There is nothing to gain by letting the CPES cure and then sanding it. Your paint film will then be relying on only the mechanical bond instead of a combination of mechanical and chemical.

I would sand the wood down to about 100 grit, apply 3 coats or more of CPES followed by a coat of undercoat same day. Next day you can start applying as many coats of undercoat as you think you will need to fill any grain and minor defects as well as maintain color after finish sanding.

Then finish sand and touch up any "dark" areas with a spray undercoat, lightly sand, followed by topcoating. First coat should be thinned down to penetrate into the surface as well as flow out. Keep sanding to a minimum.
Good luck,

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Postby Stretch Head » Mon Jul 14, 2014 11:07 am

I have been buying lumber on a regular basis for the last two years and you will probably only find African mahogany now. My lumberyard said that's all they can get today as all sources have dried up except African.

It's good and definitely not Luaun. I made mine 1" thick, my old ones were 3/4 to 7/8 and when you cut the window track into it it's too thin.

I soaked all sides well with CPES.

Good Luck, The angles and cutting the lap to match the angles isn't easy but if I can do it, you can too.
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Postby Bob Lowe » Mon Jul 14, 2014 11:52 am

Most African mahoganies are of good rot resistant qualities, some perhaps even superior to Honduras mahogany. Not too sure about their other qualities.
Good luck,

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Postby Marin Faure » Mon Jul 14, 2014 2:48 pm

Sleepah wrote:Marin,

My boat is the 6th or 7th fiberglass GB42 built and may have a different system. From what I see, the corners are mitered and not ship lapped as you describe. I can see a crack in the paint to indicate a 45 degree joint. Were your joints at an angle at the corners?


Our GB36 is from the first batch of fiberglass boats built, so I suspect our window frames are identcal to yours. Yes, there is a 45-degree joint line visible in each corner of the frame when they are stripped. I don't know the name of the joint, but it you take the frame apart, one piece is cut half the thickness at the joint and the connecting piece is cut to half the thickness at the joint (but the other half) and the two halves are mated together. There is a a small screw right next to the 45-degree joint line with a plug over it. The little screw under it simply provides additional strength to the joint, which is glued together.

We discovered this when we removed the frame of the first window we ever overhauled. (We have since overhauled or partially overhauled 20 of the 23 windows in our boat.) I removed the four corner screws and plugs only to find they had nothing to do with holding the frame to the house. So on subsequent window overhauls we have left the corner screws and plugs in place.

The only time we have ever had to dissassemble a frame was when we found rot in the lower frame piece of the big opening window over the galley. We made a new frame piece using the same kind of mahogany American Marine used and reassembled the frame.
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Postby Sleepah » Mon Jul 14, 2014 3:33 pm

Good info, Marin, Stretch and Bob,

Well call them mitered lap joints. In today's vernacular, a hybrid name, eh?

It is damn hot in Florida right now so this job will have to wait for winter. And like Stretch, I'll have to be milling some new trim and working out the joints as best I can. I do have the time.


Do I really have 23 windows? You shouldn't have told me that before I started!

I just went out and counted them and discovered that the v berth windows have rounded (radiused) corners whereas all the rest and angular. Is that what you have or have my V berth windows been changed? And I did find that the numbered in the low twenties.



Howard
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'73 GB 42 CL #362

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Postby Marin Faure » Mon Jul 14, 2014 6:38 pm

Sleepah wrote: I just went out and counted them and discovered that the v berth windows have rounded (radiused) corners whereas all the rest and angular. Is that what you have or have my V berth windows been changed? And I did find that the numbered in the low twenties.


With a GB42 I would imagine that there are at least a couple more windows than our GB36 because (I assume) your boat has a port main cabin door as well as the starboard one. So that would make for two additional windows right there-- the door and the window just forward of it.

All the corners of all our frames haved a relatively hard angle to them where the frame meets the house. However the corners are rounded off some toward the outer edge. So far as I can recall, all our window frames have the same configuration, but it's not anything I've thought to compare so I could be wrong. I'll try to remember to look next time we're at the boat, which will be to go out for the weekend after next.
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