DECK RECORE WITH NIDA CORE

Jeff Maher, #30, DasBoot

(See Jeff's progress in the Project Showcase)

When I cut the top deck (I use a 4.5" angle grinder with an abrasive cut-off wheel, rather than a circular saw: I can "feel" when the edge hits the balsa) I cut along the outer contours of the nonskid...about 1.5" from the edge. There is core under the lip that remains at the edge. You have to use a variety if tools to rout the balsa out of the crevice. I find a 16" handled fish gaff with a flat-ground chisle tip, and an 8" wood-cutting sawsall blade held by visegrips very handy for the job. Routing isn't necessary if there's no wetness and good adhesion in the material left inside. If you take it out, you fill it with thickened epox, solid. I also sand inside the slot with two 36grit discs, mounted back-to-back with a spacer between, and mounted on a drill arbor.

I simply cut the top panels, lifted out the old core, routed the flanges, sanded the inside surfaces of both tops and bottom skins, wet the Nida and skins w/ unthickened epox, applied thickened epox w/a trowel to the skins, put in place, and compressed it against a forming support structure underneath with about 200lb of brick.

Kate used an additional layer of mat on both sides of the core; I found that it caused the panels to set too high above the flanges. I was assured by tech support at Nida that the additional material wasn't necessary.

The Nida does the job and is rot-proof; but flexes more. I don't know if that's a bad thing, but I like the rock-hard deck that balsa or ply will provide. I guess one should do a dance on both types of deck and determine preference. Especially if one weighs more than 200 lbs. :^)

After the panels are glued, I fill the gaps with unthickened epoxy. then I use the same 4.5 cutting wheel, held about 30 degrees from horizontal and perpendicular to the seam, to rout a 3/16th (approx) by 2" wide vally , into which I lay a mat-cloth-mat-cloth series of strips tho bond the deck plates to the outer edges. Then I sand the repaired seams flat and fair and sand as necessary. This is where it pays to be artistic. Often the panel is not exactly flush with the flange. You gotta average out the variances and achieve a passable contour.

Tim Lackey's "restoration of Glissando" site has a nice series of photos and info on the process. I'll also be submitting a bunch of photos to the list of what I did. As of yesterday, I completed my coring. 100% no-balsa on the boat!. I'm pleased with the Nida. Not ecstatic. Next one will be balsa.

One other thing I did that I'm really happy about: I laid up a 3/8" thick by 8" wide glass mast beam inside the panels on the trunk under the mast step, straddling the actual mast beam inside the boat: ran the edges right into the flange. I think thing will support the mast by itself. My original beam is in good shape, but I wanted to give it some help without having to mess with the beam itself.

I just went out and took another bounce test of the cabin top, and I'm pleased to report that the thing is a lot stiffer today than yesterday. It seems that 24 hours was not long enough for the resin to cure to complete hardness and lock everything rigidly together.

Lesson: keep the bridgework in-place for a couple days!

There is no deflection, and the rigidness approaches that which I would expect with plywood. Whew! I had already done the decks and the results were similar to Kate's; but this was the first time I had covered such a large expanse with it and I got a little concerned that it wasn't up to the task. I have little doubt that had I kept the bridging in place another 24 hours, that the contour would be right where I wanted it to be. I should have taken the clue that some fairing filler (applied at the same time I completed coring the top) was still too green to sand when I removed the support. Bad me. So, anyway, Nida-core is OK.

Over time the salon top has hardened a lot, and as I tape the plate-joints (the untabbed seams are a hinge-point), the feel underfoot is within the range of a balsa deck. I took a tour of a '76 Pearson 10m with balsa decks the other day and took careful note of the deck's flex. I can say now the Nida is right in that ballpark. So, I have reconsidered my position on Nida...with the ease of installation, waterproofness, 1/3rd cost of balsa, and tensile strength of the stuff, I'm gonna use it instead of balsa or ply in the future.

Oh yeah, Kate could recore with newspaper and her decks wouldn't flex: she only weighs 95 lbs.

Kate Ambach, #80, BELLATRIX

The recore was BY FAR the EASIEST job I have done on the boat... really.. thinking back ... it was SOOO easy! (seriously.. anybody who wants me to do a deck recore for them.. NOT the grinding part.. but the recore part.. just give me a call.. I'll be MORE than happy to help!!!)

I had balsa planks in my deck so the whole thing was completely saturated with water. I believe Jeff had the same issue. We cut the top of the deck off of the core, making the cut about an inch from the toe rail/cabin top all the way around just back to the aft edge of the cabin (if you go to the end of the non skid on the side decks.. it ends up being solid glass) and scraped out all the soaking wet core.

I used my top deck pieces as patterns to cut out the nidacore.. we wet out the bottom of the decks.. and the "down" side of the nidacore.. stuck a layer of mat to the core and stuck it in in the deck (this all went surprisingly smoothly, I was always shocked at how well everything fit!!) then we wet out the top of the nidacore.. stuck on more mat on top of that .. wet out the top deck piece.. and stuck that on top. Then we got all the extra buckets of resin around the place and used them (and other buckets full of water.. we are really very highly technical!!) to keep everything in place (you can see that pretty sight online too!). I think altogether it took about 4 days ... I had help cutting the deck.. and wetting out most of the core pieces.. this was really important. I think this is definitely a job for two people. You just need someone to hand stuff up to you.....

Polyester is definitely less expensive than West Epoxy.. (you will save a TON of money if you buy two five gallon drums of polyester for the deck job). With West though.. you don't need the two layers of Mat.. which makes the top deck piece lie exactly flush.

My deck just looks like it has raised non-skid... it's great... it looks great. we taped the seams with cut layers of mat and fiberglass "tape" and then I ground the paint off the whole deck (that was the hard part) and now I'm all done... the deck is the easiest part of the boat... it's flat.. the flat parts are SOOOOO easy...

Matt

I completed the recore of my port side and port fore deck last night, using nida-core(thanks B&B), and west system epoxy w/ slow hardener(206). If it hadn't been for the slow hardener I couldn't have done it by myself, an extra hand mixing up batches of epoxy would have been great. I used both cinder blocks, jugs of water and pool cover hold down bags full of water, as well as screws to pull everything down tight. The one thing that I have done that has been very different from any other recore is that I ran my deck panels

through the time saver at work(I also do custom woodworking. Imagine a big planer that a 36" belt sander that we use to sand raised panel doors, counter tops etc. after glue up. It did two things for me, knocked all of the gelcoat(Bye Bye crazed gelcoat), and it smoothed the bottom side which previosly joined up with balsa planks. The down side was that it flattened the panels a bit, which was easily fixed with a few cabinet screws where the panels stuck up a bit. My only real mistake was epoxying a cinder block to my fore deck, then hammering a very large part of it loose and watching it jump off and land in my toolbox! DOH! The decks seem very solid after less than 20 hours I'll let you know more soon.