Mast Step/ Core

Is the core directly under the mast step, and over the compression post,
reinforced in any way? Or is there simply balsa under there? My Commander
shows mild signs of compression in this area as evidenced by the inner-glass,
around the C-post's wedge. First explorations reveal dark and dry, flakey balsa.
Rather than take out the wedge and post I'm thinking of going the injection route.
After all, the mast could only compress 3/8" and couldn't work much with the rig
down- tight, hard agaist the post and probably not at all if the remaining voids were
epoxy-filled. As long as the exterior glass does not start cracking or crazeing I'm hoping
to avoid more invasive surgery and forestall a gut-job for a few more years.
Does anyone else have this situation going on?

What is it about the interior glass that suggests a compression problem? Got any pictures?

Maybe you could get somebody to jump around on deck while you checked underneath for unusual sound or movement.

Might also want to check the base of the compression post down in the bilge.

Don't know that continuing to haul the mast down into the boat is a quick fix. The deck lamination, balsa core & inner lam is an incredibly strong, stiff and almost incompressible composit, even with the point load of the stick on its pad against the opposing post inside.

Any depression or flattening of the designed curve of the deck you can see inside has got to be a fault in the compression post support.

338 had a depression that turned out not to be rot, but just settling, old age shrinking and constant rigging pressure.

Any fix has to take place without the mast up and with the deck in its natural arch. Then like the V.C. sez: get the post fitted exactly bottom and top - with the deck up in its relaxed state.

After tapping the suspected area on the deck for hollow sounds (assuming that you don't have a trampoline effect by jumpin on it,) and finding what the probable cause for the problem is (thru holes for electrics and/or fittings) - here is a idea for a temporary fix:

Chart the suspected area with a pencil. Start drilling 5/16" holes thru the top deck only into the balsa. Stop drilling where you bring up pink wood. Space the holes maybe 1 1/2" apart. Inject low viscosity epoxy into the holes until they top out. I've found 2 ounce syringes at my local plastics emporium that work well. The idea is to create little I supports in place of the rotted stuff. Low vis epoxy will soak into and replace the rotted stuff. There may be moisture inside but if you are lucky you'll get enuf epoxy in for new support and the moisture will eventually disapate Comments anyone?

If consensus sez go for it - the deck lamination is about 5/32" on top of the 3/8" balsa and less than 1/16" on the inside (338), so watch the drill pressure, or you'll go right on thru and will have to tape alot.

What was visible was a depression around the compression post pad in
the inner skin as if the pressure from above is pressing down and bottoming out on
the post , crushing the core. As I was able to find dark, flakey, but dry, core material in some
exploratory holes I think what has happened is that prior to my owning the boat the core
in this area may have gotten wet. When I sealed everything up the core dry rotted. The same thing
happened in an area of the foredeck. The previous owner pulled out the pulpit and made no attempt
to seal up the areas. When I got the boat I sealed them up right away. Five years later
explorations reveal these ares to have,in some places, no core at all, just big voids with
black dust in them. I believe this to be dry rot caused by succesfully sealing wet material.
This leads me to believe that anytime the core is exposed to water, long enough to soak
in, that extensive work is around the corner. It also leads me to believe that when re-
coring with Baltec that epoxying between the squares, while not required, could slow down
the migration of water through the core area. I saw evidence of this where new rot surrounded
but did not violate an old repair whose boundary was surrounded by solid epoxy.
Cheers, B.
Commander# 215

What do you think might happen if you drill a few holes from inside up into the suspect areas?

I don't see any downside to doing a "drill and fill" job on that area. Except that if you later want to do a re-core job in the future, you probably wont be able to get the two skins apart.

I would use the slow hardener. If its still cold out, you could also warm up the boat and/or resin to improve flow.

If the balsa core is all flakey and dusty, you might try sticking a wire into the core after injecting the resin to slurry up the dust and help reach any voids.

well then, if it is truly a TEMPORARY repair
(can I have that in writing?)
put in some polyester.

Copy that about the polyester, but I'm still gonna use some
somewhere.
Cheers, B.
Commander#215;)

what I meant about drilling up (carefully) from the inside into suspect areas - is to see if water drips out.

I have had success with drilling a couple of 1/2" holes and hooking a shop-vac to one and drawing the water out .

There isn't any water in the core under the mast as evidenced
by the dry flakey material that I've exumed thus far. That it is dark
its safe to say that it was wet at one time and I probably sealed
it up 5 years ago when a new mast step was installed. Also,
I've got 3/16" holes where I suspect water would congregate.
These holes are a good idea as they will allow the water a way out
and the intrusion to reveal itself. 10 holes- foredeck, chainplates,
and around the mast step and some low spots on the side decks
will keep you well informed. The surest way to spot water intrusion and
ongoing rot (wet), is look for signs of brown liquid, stains or drips. This
stuff seems to dry in place and can be wiped off with water. This is your former
resin reverting to its liquid state. A brown
ooze that collected around on of these weep-holes tipped me off to my
current,ongoing re-core of the starboard chain plate area.

I think this area of the Commander is perhaps its weakest link. There is
no evidence of an effort to seal up the core where the chainplate passes
thru. Instead, you rely on the seal of the chainplate cover whose screws
bed directly into the outer glass and core. Bad plan. This is just the kind
of area that water finds and through its persistence defeats. Before I go
back in I am going to epoxy in the chainpates (waxed) and throughbolt the covers
on through solid,re-inforced epoxy. I think an inch of epoxy all around each chain plate
area is my goal. The only thing to fear is dry-rot.... and taxes.
Cheers, B.
Commander#215

You have an interesting solution there with yer chain plates. It probably should have a new thread, so that replys can be found later.

Interesting that you would mount waxed plates with epoxy thru the deck with the beauty plates over bedded in rubber.

Why the wax? I would think that any working of the plates in the deck would compromise any seal that epoxy would give waxed or not.
The primary seal woukd only be from the covers and what rubber you chose for bedding.

Removal of the balsa in way of the thru deck slots and fastenings is what I'm doing also, but considering an enlarged slot and using 5200 around the plate thru the deck - also the beauty plates. Don't know that they need bolts, but maybe you are right there. More holes.

Seems to me that making a rubber gasket that tenaciously sticks to plate, epoxy and deck is the way to go. Gives more.

I 'cheated' by holesawing the top of the deck in way of the slots, spinning a nail around the circumference, laying in a cabosil/epoxy gel, with some chopped glass, glueing the reduced disk back on top. Later, of course, I plan to paint the whole deck, and apply some sort of new non-skid to make the blemishes disappear. I made sure the inner skin was not cut.

Looking at the circles there waiting for the plates to be cut in, I can't see what's wrong with circular beauty plates. Beveled edges and a lot more rubber surface against sweeping water going down the deck! Don't even have to be bronze, do they? oh well, just dreaming.

I'm going to glass them in. With a 2 1/2" holesaw from the
outside, I'm gonna cut out the outer skin and the core in a
circle encompassing the chainplate cover screw holes. These I'll change to
to machine screws through solid glass. I'll bring the level of the
fill up to the surface fair, and then grind a recess under the
cover that will be receptive to 5200 and hidden, for the most part from
UV degradation. Even in their current form the chainplates don't move or
work. Fully glassed in the core will be protected and if the 5200 failed
the worst that would happen is that you'd discover a little water running down
the chainplate but unable to seep into the core. Eliminating the cover screws
that die in the core, through bolting them in solid glass, will get rid of 12 of the
most destructive holes in the boat. Also key in this area is to make sure the chainplate
bulkheads are not getting wet from above. If a water path is created the glass-wrapped
bulkheads basically fill up with water and the plywood plywood rots unseen. This happened to
to my backstay bulkhead. A slice down either side and the thing came off with my hand.
note: If you leave 1"of the sides, the fillet, when you scrape out the mushy plywood,
you can fit your new wood bulkhead, protected on top, in the old slot. Some of the tabbing
and fine glasswork requires inspection. These bulkheads are the heart of the rig. I recomend
sealing the core around the chainplates in addition to the 5200.
Cheers B.
Commander #215

YUP! (on all counts)

:D

My original question has been answered. There is no reinforcement under the mast step in the core
area. The compression I noticed was not simply from old age and settling. The reason for
this settling is rot. I know because I cut out a roughly 14" square area around the step
area from the inside. Alot of black rot and some wet core mostly towards the fore-hatch.
crushed black dust immediatly under. This abruptly fans out to nice dry stiff, not seen for
forty years, core. I'm going to replace the inside wedge and core with solid glass and treat this area like the chainplates
but on a herculean scale. Strong, solid, water tight, with well protected core,should the inevitable
happen in say 40 years.
Cheers, B.
Commander#215

Brendan et al,

I have been watching the compression in the wood wedge? between the post and the ceiling. It has cmpressed enough that the glass around the wedge has failed at the edges as the wedge? has moved upwards. This would lead me to suspect the area in the deck/ceiling as being a problem.

The wooden piece at the ceiling can be driven out if I recall other messages but is the post going to move forward or aft at the top?

John

I also vaguely remember a post about removing the compression post. The guy said (sorry but I don't remember who) that the post goes forward and comes out the forward hatch.

Ok, I have routed roughly a quarter circle in the deck in a 5" radius around the center hole of the mast step. My bit is set for a 1/2". What I have coming up is white dust, probably fiberglass/resin, and then a brown furry-fuzzy substance. Some of this feels slightly damp. Beneath that is what appears to be solid glass. There is no give in the area where I have already cut.

What is the schedule for the deck area underneath the mast step. Should I stop or keep going

John,

Several skippers have discussed this subject already. Search on deck core, mast step base, etc. Or, maybe one of the earlier posters will provide a link to their discussion of the mast step removal, etc.

John

I would highly recommend you not cut so deep in the first pass. You could be cutting into the bottom skin of the deck at that depth. Sneak up on the total depth and don't try to cut it all at once.

The white stuff is probably the fiberglass from the top skin (hopefully not the bottom skin) and the brown fuzzy stuff is probably the balsa core material.

I was hoping someone who has had that area open would come up. Light has gone now, but tomorrow I will be on deck. I will decrease my depth to just where the brown fuzzy-furry stuff (to use a technical description) starts.

Given that the depth of the whole deck, how did you stuff epoxy back in the corners? Bye the way, a material source suggested I add sand to the mix. He said that it adds strength and also absorbs some of the heat. I have some epoxy in the shop and may mix a bit up tp see if it sets ok. Gotta get soem cabosil, Maybe a trip to New Hampshire is in my furture.

deck repair under mast

Echo what Jerry and Brendan have posted.
Proceed cautiously with your router setting - start with 1/4" - just enough to cut through the top. By measure the thickness of the composite on A338 is 9/16" - but will probably vary.

I recommend a 14" X 14", or there abouts, excavation.
You want to leave strips of decking in place so your router has something to ride on as you clean out the rotten and still good balsa in the square. You do want to remove ALL rotten balsa. So you may find your original square extended.
You want to ride on the curve of the cabin and avoid cutting into the thinner inner layer of glass.
Use Bacho carbide hand scrapers to clean up the surface in your excavation.
Then rout out your rider strips and work your way in one direction to clear the whole.

Now that there is a clean depression, feather the perimeter by grinding back two to three inches.
You can't just fill the hole. The glass has to lap onto the cabin, has to lap onto the good stuff without leaving a ridge, ergo feather the top all the way round so that some layers of fiberglass over lap the hole all around. Some recommend even wider feathering of the hole.

Recommend that you fill the entire thickness with Xmat* and/or woven cloth.
No filler core of balsa, pvc foam, honeycomb, or non-fiberglass filler. Solid glass and epoxy.
This way you mold the curve of the cabin top. No downward pressure from the mast can change the curve or flatten the deck. Before layering undercut the composite 1/4" or so by pulling out the balsa. Use a chisel - don't need anything fancy like a slotting cutter on the router. Don't need to go deep. IMCO.

On A338 I made a pattern of the cabin curve before cutting into the deck.
That way I had something to come back to to fair it with the rest of the cabin.
But you can spring a batten - sand the highs down - then fill and sand the lows with fairing compound. When painted or gel-coated it'll be factory.

My guess is, not having worked on a Commander, that it would be best to have your compression post removed and a piece of longer/wider plywood propped against the roof inside so that it fits SNUG with the general curve - and perhaps returns the cabin arch to its original curve, if that is an issue.

Adding a piece of Mylar or SeranWrap on top of the jamming ply will create a dam against gluing the ply to the roof in case you have made holes in the interior lam of the composite.
__________________________________________________ __________________________________________________ _________
*Xmat is Knytex's biaxial mat and cloth material. Comes in19oz and 24oz and is extremely thirsty stuff. It is mat that doesn't have binders holding it together like the mat used for polyester, which can't be used with laminating epoxy. Use a reputable 100% solids laminating epoxy.

Ebb,

Thanks for your guidance. I don't believe that I have peirced the interior roof. After reading the comments, there is no question that I have compremised it though. Plan now is to fill the crease I cut with filled epoxy and then make sure I get a layer of mat across that area to back it up. I wasn't sure how I was going to maintain the curve but springing a batten across the area makes sense.

What I think will do, is wait until I have opened up the area above the compression post, and then attempt to remove/move the wedge (being the "gentle"man that I am . If it will not move then I will cut some 1/8" ply in a semi-circle around the wedge/pad and cut 2 2x4's to add some hummppff and try to lift the cabin top. If not, then it stays and I don't hve to worry about the compression post moving.

Given the small depth that I have to work in, it does make sense to open a larger area and then plan on some white gelcoat to make it pretty. I was having trouble envisioning how I was going to fill the area underneath the deck if the balsa was damp/fuzzy/furry that far out. Then I can grind down the deck for 2" to rebuild the deck itself. This is going to be a short sailing season. I am hoping for a great September.

On another note, completely changing the subject, Is ebb short for Eben....That's my brother's name. Anyway, thanks for your thoughts

Hey John,
Thanks for the back.
Couple things then, if you are not layering a wide excavation and you insist on using a filler
then I hope it is not some offtheshelf stuff but something you make up:
Epoxy, fumed silica (cabosil), and chopped strand fiberglass will make a good filler.

The chopped strand comes in many forms, I have success with 1/4" chopped strand. Without this fiber reinforcement you risk the downward force of the mast cracking the filler if the cabintop wants to move.

Being a gentleman you don't want to change or strain the original arch of the cabin composite. The original molding of the cabin/deck was done with pure curves and chords. If you manage to to bulge the original arch, you will have the problem of your work cracking as the 45 year old mold returns to its original form. You want to merely persuade things back into shape.
Instead of a single layer of ply to snug against the inside arch use a couple or three layers. Even thin pieces will stiffen up and take a better curve.
Try using more bendy pieces instead of 2X4 for props
Original spring battens are maybe 3/4 X1 1/4 that are a little too long for the prop and you have to bend then slightly to get them in to fit, creating the pressure you want. Make up a bunch. Way better than jamming a piece of 2X4 or 2X2 in with a hammer.

[Got saddled with an incredibly Scandanavian moniker at a time when I couldn't defend myself.
Been spelling it out for people at least 79,000 times. When I got divorced I decided I needed to change my name, so I dropped the e off of Ebbe.. Ebbe (not pronounceable in american) is a form that comes into English that means father, It shows up in words like Abba, abbot and abbey. Maybe even Shabbadabbadoo.
Now I say Ebb when ordering something over the phone and it comes to me addressed to Ed.:D]

Ebb,

I either mispoke or at the least, spoke unclearly...(that is an ugly sentence).

My original thought was to follow Jerry's suggestion of working filled epoxy into the deck area outside of the central 5 In (approx) under the mast, and build up the central area with mat and no core. I had the impression that I could, at the least, work a putty knife in to clean out the balsa layer. Now having it open a bit, I don't think that option is as feasible. Your suggestion of opening a larger area (somewhere between 8x8 in. and 14x14in makes sense,) filling it all with mat, and especially the part about leaving rider strips in place for the major part of the cleanout. My router has a base about 5" in diameter, although I could make a bolt on wider base if a bridge is required.

The job continues

1 Attachment(s)

Attachment 6880Women and small children should not be exposed to this picture.

This is about a 5" circle in the area underneath the mast step. I don't think I need to scrape to remove the balsa you see. My fingernails will lift the punky mess. Tomorrow I will extend out to 8 in. square. The area foward of what I have opened seems siolid. I may take a harder look at that before pulling it up.

Healthy balsa core would be beige color, more pink.
Make your planned cut out, peek, probe and poke the core.
Decide if you can pull out bad balsa be fore cutting open morr deck -
can always puush it thickened epoxy where you've removed tuna fish.
Knocking on the deck can often tell how extensive the rot is,
or how lucky for you there isn't. any.

By rights you should replace all rotted core.
But see Mark Parker's Triton 516 AllWays here in the Forum.

I recommend something like the system outlined in an earlier post.
Read what others have done.
Mike Goodwin, an early poster with a no-putz attitude, replaced the core in his whole deck.
Tim D did as well, I think. Nice work.
Others, many others, have done it with these '60s boats. It's not a big big deal.
Except we're repairing a big dumb mistake made by Pearson.
It's only that you maybe have limited experience.
And there is a learning curve using epoxy and fiberglass.

But it's all pretty logical.
Can always cut and grind out a big dumb mistake!:D

ebb,

The plan is to draw a square about 8" x 8" and clean out that area. It looks like I have good balsa just forward of the area I have already opened. Nice light brown balsa! So I might cheat a bit on the length. There is no doubt that what I uncovered has been wet.....I might have to squeeze it dry to throw it away.
On a related subject, I was going to look for a less expensive source of cloth and resin, but for the little I think I will need, West Marine is close and West Systems worked well for me last time. I still have some resin and hardner. If it rains today, I am going to squirt in a cup....resin that is, and a squrt of hardner to make sure what I have cures. Maybe I will get some sailing in on my own boat.

3 Attachment(s)

Attachment 6917 Attachment 6918 Attachment 6919
Here are the picures from todays work. Light rain drifted in and out. Deck_1 is another picture with the deck open as is Deck_2. You can see what wonderful core I have here, Not quite the golden stuff that ebb was refering to. Deck_3 is where it now stands, about 30% clean and down to the bottom glass layer. It appears that there was a layer of laminate directly above the Compression post and I will remove that. I lost some time searching for a router bit. The glass burned out the steel bit I had. The carbide bit is cuttling a lot better, and I am not pushing as hard either.. Another lesson learned.

Waiting with bated breath..........

wholey moley John - you OK?

Waiting with bated breath..........

......what.... w..h..a..t
WHAT DID YOU FIND IN THERE? ? ? ?

Mice?
Moles?
A former owner?......

ebb,
If you look at the first picture you can see on the left, one of the additional deck layers I removed today..The other is a mirrror on the other side. I literally picked out the first bit of balsa. The chewed up stuff is what was underneath. It did not come quietly into the night In the for what it's worth department, my deck is a 1/2" give or take a smidgeon. At the bottom of the third picture you can see a very thin layer of balsa. I will just scrape that out.

ebb et al;

Well, the area underneath the step is open and fairly clean. The bad news is that the compression post pad has already fractured the ceiling. I will have to lift the ceiling and then repair the entire area. So......I am going off to Home Depot and hope I can find a small piece (1/4 sheet?) of 1/4" plywood that I can cut in semi-circles to use as initial support. I have some 2x4 that I will cut to use as braces for the plywood support. Then I will attempt to knock the wedge out. I am short on time the next few days and I am open to suggestions. My thought is to drop the compression post, annd put a piece of 1/4" plywood up as a form for the first layer. What can I use as a release to coat the plywood form? then a second layer of glass fabric, followed by fiberglass mat and then enough fabric to restore the deck. Any other thought as to what the glass schedule should be to rebuild that area?

John:
imco you don't want to force a new curve into your roof.
Just persuade the old composite that is still there to what seems like its original arch.
If you will use 2X4 for props on 1/4" ply, you can distort the curve.
Try orienting the ply. In one direction it bends easy, at 90degrees it bends a little harder.
Try doubling the ply to find a fair curve and spread the point load of your props.
Pad the prop with its own piece of ply. Many props better than one or two.

It sounds like your deck might be like A338, whose inside fiberglass layer is very thin and may even be composed of mat with no cloth - can't remember.
I used the small Bacho carbide scrapers (triangular blades about 3/4" wide.
These are sharp tools that in the small size doesn't require a whole lot of pressure to move old balsa off the inner frp layer.

When you get into the good stuff and maybe have a knobeldy surface in the rotten zone IMCO you can leave some attached balsa wood behind. The epoxy repair will soak into it and you'll get a bond. Don't have to have a squeeky clean smooth surface on the glass in the excavation. Though it's arguably better - but not at the cost of making the inner frp layer too thin - or breaking through.

Have had great success with a material called Mylar. It comes in roll sheet form, is relatively thick and stiff for a film. Epoxy won't stick to it. Epoxy molded up against it will come out looking as smooth as glass. You can't wrap it or bend it into a compound curve. I have my work table covered in a sheet of it. When wetting out pieces of Xmat or fabric, as you will for your repair,
you can do it right on the table, peel the wet-out off and put i in the repair. Take a piece of Mylar up on deck
wet stuff out there, peel it off, put it in.
Can't do this wet out on wax paper, SeranWrap, or most vinyls.
Of course you can do wet-out on a piece of plywood!!!

If you can't source this wonder material, you can just use SeranWrap on you plywood form. That stuff is very thin and sometimes difficult as it likes to cling to itself. But you can use multilayers as it is so thin it doesn't build up. SeranWrap is polyethylene. If you are using another brand make sure it is not any other material, as that plastic will probably stick to your work. SeranWrap will peel right off, if not fall right off.

If I understand you are not using the inside plywood form/prop to apply wet glass and epoxy, correct? That is a different kettle. Assuming all your restoration is from the top on deck?

You may have some compound curves going inside on your roof.
The form/prop you are putting there in lieu of the compression post is only to guarantee a fair restoration curve to the roof. Applying wet frp inside to the roof is another kettle entirely. It can be done.

Imco you can use ALL biaxal (Xmatt) without using any woven fiberglass. On the top layers at the original deck level you can grind on it to get it fair without loss of integrity. If you broke through woven glass layers in theory you would be loosing that layer's strength. If you are using all glass and epoxy without a core filler, it won't matter at all in a 1/2" thick repair if you have to grind through a couple layers of cloth. BUT

Assumption is that you will be using very little thickened epoxy.
Tuck individual layers into the excavation between the glass sandwich around the edges, Just slip regular pieces over into the cove and alternate with other pieces going in. There is your lock.
Depending on how well you do this depends on how extensive the final lapping layers, the ones that over lap the excavation are. You have feathered the surround of the hole so that when the stuff is faired with the deck the over lapping remains. You'll be feathering the 1/4" deck laminate. There is plenty of room in a wide 'chamfer' for two or three wide pieces of Xmatt to overlap the hole. Technically, lay in the widest overlapping piece first then the smaller ones, all should overlap the excavation.

Punch the wet layers when assembling with a stiff bristle brush to get the air bubbles out. Put in a dry piece at times to soak up too much epoxy. Strength is in the glass, so you don't want it sopping wet.
Overlapping is important as you want to marry the restoration to the deck. If things go awry just let the partial fill set up and then grind away on the surface to dish out the overlap.
People will say this isn't as strong since the bond is mechanical. Good epoxy is the answer.
Filling the excavation with mutiple pieces of Xmatt should come out pretty close to the deck camber, if your inside fiberglass has kept its original curve.

Before any epoxy hardens use denatured alcohol to clean surfaces including the Mylar on the table and the boatdeck.
Imco if certain places are a little low after the final piece is layered on and hard, it is way easier to use (West System) 407 filler mixed with your repair epoxy in a putty consistency to fair in the new surface rather than epoxy mixed with cabosil.
If you have a sharp edged batten to check your arch, like an aluminum strip, you can tilt it slightly off vertical and drag the whole length of the strip over wet fairing compound to develop the smooth fair deck. :D
__________________________________________________ __________________________________________________ _______
These pontifications are just tips from my limited experience. There are 100 other ways to do a job of work. ebb is not an expert in anything, merely an observer, and at that: suspect.
Good luck, you guys!

ebb,

Wow...Thanks for your observations. What do I know....let me count the ways. It looks like the cabin roof is a layer of light cloth. But it's hard to tell. I do have a boo-boo where I pushed a bit agressively and now have a short puncture in the cabin liner. i also have the area where the post wedge has broken though the cabin roof layer. My thouught there was to lay down a small piece of glass cloth to close the hole, and then fill it with some filler, West System Cobisil is what I have on hand, after I make up the new deck.

The laminate that popped up where the compression post wedge punctured the cabin roof is no more than 1/16" and probably lighter than that. I did'nt mike it and probably won't. I will lay down some more glass ccoth there as well to close the cabin roof inside. I am not sure how much the mat will compress after wetting it out. I have never worked with mat. When I filled the hole where my mechanical speedlog resided, I just used glass cloth. So worst case, I have to put in 2 layers of mat and then glass to bring the open space to the bottom of the top deck. I plan on grinding, (borrowed a friend's 5 in grinder) about 2 ins. out on the deck and taper glass cloth across the the wound.

Oh yes, the surrounding deck. I will use something to gouge, pick, pry out the rotten balsa on the edges of the opening, and use filled epoxy to fill it in there. If I have lost the deck curvature, I will lay on a light coat of epoxy and filler and then grind it back. Finish with a layer of gelcoat outside of the circle that the mast steps sits on and it is all done. Thanks for the tip on mylar. I had planned on using saran wrap. That is the plan, anyway.

I had hoped for some sailing but this job keeps growing.

no sweat

John,
If you are supporting the underside as we have been saying and I understand,
Then why not do that and proceed from the top with ALL the wet stuff.
IE don't try to repair the broken in pieces.
Just push them down against the backing 'form'(with the SeranWrap on it!) to their almost original position befor they got pushed in.
If there is a chunk missing cut a filler piece of your Xmat to fit and just lay it in place.

Scrape clean whatever size excavation you end up with that has all the bad balsa removed.
Size of excavation doesn't matter unless it's ridiculous.
Shape doesn't matter, just cut the mat and/or cloth to fit, put both in the hole if you want to.

Scrape the excavated area so that you have even depth all round.
That way when you put in all the layers you end up even at the top.
Remember to leave room for the three(?) overlapping pieces.
If it isn't coming up even then shim with a shorter piece on the low side,
just lay it in and continue with a full piece.

I think that the 24oz Xmatt stuff I used takes 5 layers of it to get 1/4" finished thickness.
You don't need much pressure when assembling*. No stress. The epoxy and the Xmatt like each other.
You have to put too much weight on a flat area to get much reduction in thickness.
Use a piece of SeranWrap over your gloved hand and push the wetout down tighter and into corners.
Use the same SeranWraped hand to push a dry piece into a too wet area.'Make sure you have no dry white glass holidays!
It is good to have it a little wet so it goes into all little spaces.

You probably will find that the broken through areas you describe have repaired themselves when you take the jigs away.
If any liquid leaks through, which from your description seems minimal, it will take the form of the impress you put there. The epoxy would rather stay with the Xmatt than run out of it.
It could happen that nothing but very little leaking will occur.

You might have some vinyl film spread out inside under the repair.
But I don't think much will dribble much!
If it does you'll have just a little filling to do and some sanding.

If it's hot where you are, but cooler in the mornings, you might put the epoxy in the fridge at home, or overnight in an iced portable cooler. If you have the whole campaign prepped at the boat - maybe even a dry run - then it ought to be a piece of cake or toffee as the case may be. Cover the job with a towel to keep dew from forming. Epoxy likes between 60 and 70 degrees, in my experience. Above 70 it becomes a fire drill.. If the parts are cold and thick just give them a extra stir. Keep the epoxy out of direct sun. Mix small quantities of liquid so you don't end up with your repair smoking!
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* Epoxying is a gentlemanly diversion - unless gentlemen don't sweat.

more on propping the inside under the mast

John, must br tired of this, huh?
Hesitate to say this as you may misinterpret.
Not sure of the inside finish of a Commander - or whether you have a flat arch in way of your repair - or have some other minor curves going.

If you do have other curves to the roof going on and you don't see that your prop plywood can snugly cover the area of repair, try something like this:

Fold a piece of stiff canvas into a pad. You'll have to figure out what thickness will work best.
If the cloth is relatively stiff and you press the wad against the roof one assumes it will span small imperfects but conform to the arch you are preserving.

In other words try putting a folded cloth like canvas on top of the plywood prop to get a tighter fit against the roof. Don't know if you need this. Something like this, stiff but bendy foam for instance, might get the snugness you need against the holes you think might leak.

ETHAFOAM
Foam sheet called Ethafoam is used for packing. Usually 1/2" thick, comes in big rolls, I get it at my local plastic supply, TAP Plastics, cheap. UPS store might have it. It is poyehylene foam. You could put that foam naked against the holey roof, do your wet repair from the top, and after the epoxy sets this foam will come right off. If you use that on top of the ply form/prop you'd close any small spaces that might leak.
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www.tapplastics.com
that's the web site if it comes up.
You won't find this foam in that catalog
but call this number: 1-800-246-5055 and ask the guy for three feet (it's four feet wide I think), or whatever, of the 1/2" Ethafoam on special order. The guy says they'll do it.
[Once saw this white ethafoam as a candidate for hull insulation, which it would be great for. BUT there is no glue in this world that will stick it!!!!]

ebb et al;

Well, my experiment with wedges was interesting but not enough. Once I got them really loaded, they tended to kick/slide out rather than increase the load. As I think I mentioned, I have the deck opening pretty well cleaned out. The deck has been raised a bit but I still it to go about 1/4" or a smidgein more to have the compression post clear. On the starboard side of the opening, the compression post has punched out a semi-circle and this now intrudes into the open deck space. We have had about 2 days of rain so not much progress. I have purchased 2 bottle jacks and if the wet stuff subsides a bit this afternoon, I will continue my efforts to raise the roof (smile...sort of).

So now I have an hole in the deck that at least in a few areas goes straight through. I have been thinking of how to fix this. Current thought is to lay down 2 layers of cloth and bring the edges up the side and over the tapered deck for at least 3 inches. That will be a pan that contains everything else. Then fill the pan with mat up to just below the deck and use glass cloth to cover and fair the entire area including the edge tapers.

Thoughts are welcome

It stopped raining long enough... The compression post is hanging loosely with a slight gap above the wedge.. The answer is beg,borrow or purchase 2 or so bottle jacks. So now to West Marine. They aren't inexpensive but they have what I need. Rain, Rain, go away

John

A few of my thoughts about where you should go from here.

First, BE VERY CAREFUL with the bottle jacks. They are surprisingly strong and you could do a lot more damage accidentally. Try to look very carefully at each step you are doing and allow for ways to keep anything really bad from happening.

Next, around the edge of your existing hole through the top of the deck dig out any wet core that still exists from between the top and bottom of the deck. Then using a putty knife force thickened epoxy in between the deck skins. You could mix in some micro fibers and cabosil to thicken it.

Then you need to bevel the edge of the top skin of the deck around the opening you have cut into it. The idea is the have the repair invisable after the work is done so to blend the new glass into the old you have to bevel the edge of the hole to give the glass a surface to bond to yet not stick up higher than the deck did originally.

After that follow my previous post to you here...

http://www.pearsonariel.org/discussi.../page4&p=21959

Agree with that caution.

You could start with one bottle of jack

I thought that I would update things as I look out at the snow and my Commander snug in her bed, err...cover. Life and weather got the best of me but (if you believe that weather is not punishment for past deeds) and then I am not paying the price for past deeds. Rather the Scientific types say that we are in the negative phase of the North Atlantic Oscillation and thus subject to "winter" conditions more often and for longer periods.

I think the idea of making a pad from some old canvas to try to preserve the ceiling curve makes sense. The ceiling is now down to the top of the pad. I did not want to distort the cabin top too long. And I have cleaned out the balsa for the most part. Because, I am guessing here, that the balsa is made up from 2" pieces of end grain balsa, there are areas in the roof where the balsa seems to be fine. My hope is that by packing filled epoxy in aLL the areas I have cleaned out, that the good areas will stay sealed and in good shape.

Soon, I hope, I will be able to remove the cover and continue the patch job. I have most of the materials on hand so with the return of good weather I will be able to proceed. SPRING IS COMING!