Dropping and Re-Hanging Cast Iron Stub and Swing Keel

[Noemi - Ensenada 20]

Welllllll......best to do it right.

[Wyb2]

If you are up for a bit of a science project, I've had some luck drying out deck core with a vacuum pump.  It took some trial and error, and a bit of patience, but less patience than waiting for it to dry naturally.

You'll need a pinless moisture meter so you aren't flying completely blind.  A vacuum gauge if the pump doesn't come with one, so you know if you are actually pulling enough vacuum.  Sealing up the area in question can be finicky, and you need high ambient temps (probably 85+, higher is better) but if you can get both those things, it does work. 

I was able to dry out (meter went from pegged to 15%) half my cabin top core in a few sunny hot days.

Edit: re-reading, I missed that you mentioned vacuum bagging, so maybe you already have everything you need.  The only nuance is, I'm thinking of pulling enough vacuum to boil the water out at ambient temp, not trying to suck the liquid out.

[Spot]

Edit: re-reading, I missed that you mentioned vacuum bagging, so maybe you already have everything you need.  The only nuance is, I'm thinking of pulling enough vacuum to boil the water out at ambient temp, not trying to suck the liquid out.

Yeah, I have the goods but apparently not the skills on any given day, my tale of vacuum woe below:

I was able to pull a vacuum on a small section yesterday, 22 inches Hg below atmospheric pressure. The result was an immediate but small amount of water, 1/4 cup or 10 ml or so. Letting the pump run a couple more hours did not gather more. This morning I decided to grind off all of the gelcoat as I had made it unsmooth digging out the eyelashes/pops. I did not notice any big wet spots as before, but maybe felt one small damp one...? I went and got my finest breather fabric and finest vac bag film and set up to vacuum the whole area. I could not get the bag to draw down past 2 inches Hg, even after adding tape and kneading the mastic and plugging holes inside the boat. I also tried doing smaller areas and removing the quick-release with no improvement. Last picture is after a denatured alcohol wipe after using spec thinner to remove the leftover mastic from the hull. Perhaps I was just dealing with a small local inclusion between gelcoat and fiberglass.

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[Spot]

My 3M rep at work sent me 2 tubes of black 5200, a little unexpected but very much appreciated!

Is 3/16" (4.8mm) enough for this application? Does it expand any when curing? Checking in hindsight makes my estimate of 2 tubes seem a bit short.

I am planning on using masking tape on the neighboring surfaces and peeling it before it skins over. Any other 5200 tips a novice should know?

I am off to watch some more keel-hanging videos online. I am hoping to barrier coat this area later today.
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[Wyb2]

Yeah, it took me a lot of trial and error to pull an effective vacuum on my deck.  Some areas I still haven't.  You really need close to 29, that brings the boiling point of water down to about 80F.

https://www.engineersedge.com/h2o_boil_pressure.htm

Sound like you're moving on though.  That probably makes sense, you aren't dealing with a wet wood core that will rot.  As long as you have a clean, dry surface, you are probably in good shape.

[Spot]

Yeah, it took me a lot of trial and error to pull an effective vacuum on my deck.  Some areas I still haven't.  You really need close to 29, that brings the boiling point of water down to about 80F.

https://www.engineersedge.com/h2o_boil_pressure.htm

Sound like you're moving on though.  That probably makes sense, you aren't dealing with a wet wood core that will rot.  As long as you have a clean, dry surface, you are probably in good shape.

Yes, progressing. I had to sand off a little more gelcoat as I had not measured how far the keel went past the fore and aft mounting holes. I am stepping through barrier coats, 2 yesterday and I think 2 more today and that will be done. Since I am using epoxy, I am waiting until the relative humidity dips down for the day before I start. Weather is looking good, warm with no rain.

I think I'll get one more tube of 5200 so I can have a bigger margin of error and inexperience applying it. Someone elsewhere mentioned a notched trowel, like as is done for floor tiling. Do people do this? I was thinking a little high in the center and around the bolts and let it squeeze out a little. I saw a video of a large sailboat boat being fixed from a grounding and they squeezed more out goop resetting the keel than I will apply. I would like to be somewhere in the reasonable middle.

[Spot]

Been progressing slowly on the hull between work, storms, hail, and high humidity.
I have 3 coats of epoxy on the bare spot I made on the hull, 1 neat and 2 with West 422 barrier coat additive. I am hoping to do a final sanding to the area and make up an off white top coat to blend in better with the hull's natural colors.

I had a good chat with tech support at 3M to confirm application details of 5200. The 3/16" planned depth is centered between their suggested min/max of 1/8 and 1/4". Flat tooled or notched trowel is acceptable, user preference. It should stick to itself if a touch-up is needed, one can sand the skin of the old a bit first if desired. I asked about butting up colors to one another (black and white) in case I needed more volume, they do not test the product this way, so they did not have a ready answer. White is easier to get, half the driving miles and almost half the cost compared to black. Since my two tubes should make 3/16"-ish I am not as concerned, would rather not end up with 3/4 of a tube of black for which I don't have an immediate use.

I have also considered a plug in the big hole of the keel stub to prevent glopping down the hole and laying in some 3/16" strips of polyurethane rubber to take up some of the volume in the big flat section to give me a little extra volume to squirt around the bolt holes and tool around the outer edge. Does this sound reasonable or a fool's errand? I am also considering some 3/16" pieces of metal along the perimeter, to prevent me from overtightening the works during the inital assembly (remove after cure and fill holes). The urethane strips would probably limit this as well.

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[Spot]

I went outside to work on the blade. Everyone in the neighborhood was out doing this and that enjoying the nice weather (partly cloudy, 79 F, 55% RH) and before I knew it, I was going over to the neighbor's gear in tow to help him weld something. I decided to make a push on the blade, finishing up on one side, moving it to a better dolly, and getting into a first coat of epoxy. I thought I'd try a different base color...
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[Spot]

Let's see, where did we leave off?

-Cast iron bits painted green
-bottom of boat drilled, tested for water, filled, epoxy/barrier coated
-3M rep for my work got me some 5200(thanks!)
-keel stub got hung today

Top of keel stub and bottom of boat freshly washed for amine blush and sanded.
Aluminum shims placed to maintain 3/16 thickness.
Keel stub was rigged to raise on two jack with a safety line running through the boat (would not be able to hit the ground if jacks failed).
Goop applied, had plenty in 2 tubes with about 1/3 tube squeezeout.
5 of 6 shims removed succesfully after keel was checked for position.
Tape drip edge installed during sudden downpour
Consumed about 8oz paint thinner cleaning up. It gets everywhere as the rumors say...
Consumed 12 oz of barley pop to celebrate after 2-3 glasses of water.

Didn't expect it to take an afternoon but so glad it is done.
Thanks for all of the thoughts and tips!

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[Noemi - Ensenada 20]

That's a lotta 5200!

Looks great!

[Wyb2]

Looks like it went well.  I wish I could actually remember to take pictures during a project, I always think of it at the end.

Is the plan to re-tighten the bolts after cure, or leave it as-is?

Wait, is the 6th shim still in there?

[Spot]

Noemi, thanks.

Looks like it went well.  I wish I could actually remember to take pictures during a project, I always think of it at the end.

Is the plan to re-tighten the bolts after cure, or leave it as-is?

Wait, is the 6th shim still in there?

Plan was to re-tighten the bolts.

I used some 5-minute epoxy to hold the shims together and in place and made the mistake/good practice of sanding the aluminum before epoxy which gave it amazing grip to the keel. I should have used hot melt glue or double-sided tape. The one did not want to come out and the 'handle' tore off while I was working it. Had I machined 1/4" down to 3/16" instead of stacking 1/8 and 1/16" I may have had an easier time as well.

So yes, there is a 1" x 1/2" x 3/16" piece of layered aluminum embedded about 1/4" deep into the 5200 for the archeologists to find and speculate on sometime in the 23rd century...

[Spot]

I got to re-tighten the keel bolts and hang the blade back on the boat today.

It was relatively uneventful, which is good when rigging/lifting heavy objects is concerned. I installed the new cable for the winch and used the winch to help stand the blade on edge and get it into the slot. A floor jack midway got it in rough position. A second jack on-axis with the keel allowed me to lower the midway jack and push/pull until the inner bolt holes saw daylight. A quick wiggle-wiggle with a 3/8" drive extension got the holes in line and the new pivot bolt and fixings were installed. Next steps will be to re-install the trailer and touch up the green paint.