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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?
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.
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.
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*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
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.
Attachment 6917Attachment 6918Attachment 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..........