Re-bedding Hardware

[Dave]

My technique is to drill 1/2" hole straight thru the deck. Then I have an allen wrench that I've ground the short end down to a beveled stub about 1/4" long. I put the long end of the allen wrench in a drill chuck, turn it on, and use the sharpened end to cut out the balsa 1/4" in all around the hole. This creates an undercut that widens the resin plug and holds it firmly in place. Vacuum out the undercut.
Tape the hole on the inside and fill the hole and the undercut with thickened epoxy (I use West System with 406 filler) -- be sure it's just thin enough to flow into the undercuts (though you can force it in with a small tool).
When the epoxy has kicked and cured I remove the tape, and drill a small pilot hole from the underside half way through, then a pilot from the top till I feel the first pilot -- almost every time, I'm straight through the center of the resin. Then larger bits till you get to the size you need. It's bullet proof and any leaks are harmless to the core.

[commanderpete]

Here's an old thread.

I changed my mind about how to bed hardware.

I don't use the bent nail/allen key method for removing the core. I think its much faster to use the overdrill method Mike mentioned. Just drill a big hole, fill it with thickened epoxy, and drill through the epoxy plug for the fastner.

When injecting the epoxy, I don't try to top off the epoxy in the hole. Instead, I'll let a shallow dish form at the top of the hole. This provides for a nice pool of sealant around the fastner that can't get squeezed out.

I don't use the "gasket" method anymore. That's where you come back to tighten up the fastner after the
sealant has partially cured. It sounds good in theory. But, I found its nearly impossible to tighten the fastner without having it move slightly, which would break any seal.

With the overdrill method you just tighten up the fastner. Done, finished.

I buy mostly from Bolt Depot.

http://www.boltdepot.com/

I got tired of wasting time sorting through all my screws. Dozens of different types of screws, nuts and washers. Bought ten of these

http://www.boltdepot.com/product.asp...2&cs=120&cm=57

Somebody probably sells them cheaper

[mbd]

Holy Cow Peter! I could be in trouble...

[tha3rdman]

'bout the solo over drill method mentioned above I have a problem with said method. If you drill and then remove core it is a pain in the keester to get a good section of core removed 'round the entire circumfrence.

However if you just over drill and fill iin there is nothing holding the "plug" of filler in the hole and chances are it will crack around the circumfrence and leak (unless you scarf the area and lay some glass down)

My method (The one which I used on 97), I belive i read on here, I drilled a 5/8 hole (maybe it was 1/2) then allen keyed the core out, This leaves the filled something to hold onto, especialy when 90% of your hardware will recieve some sort of pulling force, and with filled tucked in behind the top skin, I would imagine it's less likely to crack.

My 2 cents

[ebb]

2cents more.
Second on the 1/4" undercut with the altered allen key. And a steady hand. Whomever invented the method did a remarkable service for the balsa core deck crowd. It is tedious but there is imco no better way. With our boats, with decades of unprotected thrudeck holes, better hope that there is solid balsa in there where the old fasteners were! Sometimes it seems a little too easy to do the cleanout. You may have to dental pik out some more.

Let's hope it's not a preview of real deck problems. May have to dry the hole with a heat gun if you use normal epoxy.

I prime the hole using an acid brush with plain epoxy. It may also be good to use the brush to load the indent with the thickened stuff. Poke it in. [Did this with the chainplate deck holes which had some tuna mush in them. But then decided to holesaw a disk out of the top skin at each location. Did not go all the way thru. At least it was easier to access the core that way. Epoxied the skin disks back it.]

Also, don't you think it's important to oversize the backup plate? If you drill oversize and don't evacuate between the skins, then you better glue in the backup plates. 338's original Pearson plates were disks and squares of fiberglass, some with gelcoat on them! - but undersized.

[commanderpete]

I decided not to oversize the backing plates for the bow pulpit. There comes a time when you end up bumping into something, and I didn't want the installation to be too rigid.

Anyway, re-bedding hardware is an important project on any boat, but most people don't do it. I've probably done 120+ holes and I'm still not finished.

Anybody have a source for cheap syringes? I've been getting the whopping big 40 and 60cc syringes from a medical supply house for about $.75 each. But, they don't have the nice tapered tip like this

[ebb]

C'pete,
TAP Plastics has 2oz syringes with a taper tip. But the tip doesn't get as narrow as the small ones. The larger syringes seem to have got expensive since I got em last: $3.10. TAP is not a discount store - might look in places like Harbor Freight, or other glass, marine or aircraft catalogers.

On the other hand these are crossovers from some maybe medical supply. They are well made, sterile, the plunger rubber fits perfect and doesn't leak, there are graduations on the containor, there's a cap. I use the 2oz for thickened epoxy. But it works with liquid as well. (338 had her keelvoid filled this way, 5 gallons worth. You can reload the syringe by dipping the the tip and pulling back on the plunger. Thickened epoxy has to be loaded thru the top. Messy.)

When you need em you need em. It is hard to toss 3 bucks. Can clean them, but there's time and effort and solvent (which the syringes survive) and towels and so forth. Could toss one less microbrew and call it even...

[Mike Goodwin]

I get mine from my vet , they have the ones with the curved tip too.

[commanderpete]

Might be called a piston type irrigation syringe, like this

http://www.vitalitymedical.com/Vital...--340-KND67000

[ebb]

Fantastic price! Have to restrain myself from ordering a box. How much more injecting of epoxy is there to do in this life? Basting birds?

Now.
Has anybody got a great (foolproof) method of laying out a bead of thickened epoxy to create a fillet? Or is it still: use a ziplock bag with a corner cut off?

[Mike Goodwin]

According to my vet, the ones I get are for expressing the anal glands of dogs , so there are things worse than epoxy to work with !

[ebb]

Hey Mike, Briefly looked into your four legged friend:

Likes the water.
Intelligent, often smarter than the owner.
Loyal, gets along with other dogs and cats.
NON-SHEDDING, hypo-allergenic, medium sized.
Makes a good watch dog.
And inho, very good to look at, well proportioned.
Somebody you'd like to know and talk with.

Sounds like the PWD HAS to be the companion of choice for sailors
with an active lifestyle.

[c_amos]

I have overdrilled / filled all the holes in the deck, and have a third option to offer. I started out overdrilling like Mike suggests, but then started using a 5/8 paddle bit to drill through the top layer of glass, and core... but stopping short of the second layer. It is then easy to chip the surrounding core back about 1/4" (so the thickened epoxy tucks under the top layer of skin, and you have good access to get the chips out.

Ebb said;

Also, don't you think it's important to oversize the backup plate? If you drill oversize and don't evacuate between the skins, then you better glue in the backup plates. 338's original Pearson plates were disks and squares of fiberglass, some with gelcoat on them! - but undersized.

I agree. The backing plates I have made are 2x, and some times 3x the 'footprint' of whatever they are backing.

I also see a problem with the way some things are backed, like the stanchions. The stanchions on #226 are bolted through the deck right where the cabin liner meets the underside of the deck. Backing plates used will not touch anything but the thin strip of the cabin liner right down the center between the holes. I think this is why most every Ariel I see has gell coat crazing in this vulnerable area.

I have encountered the same problem with the backing plate for my bow roller. The underside of the deck is curved, and the inside bolts run right next to the raised strip down the center of the foredeck. The backing plate that I have made for this rides on the very edge of the 1/4" strip.

A friend of mine (the owner of #243) first suggested using polyester filler to distribute the stress behind a backing plate. The more I look at some of these problem areas, the more I see he is right.

So, my latest method of applying backing plates is;

Epoxy coated plywood, with rounded corners, 2x to 4x the size of the 'footprint' of the piece being mounted. THis is bedded in polyester filler, so it mates to the underside of the deck. Holes in the plywood are overdrilled slightly and filled with epoxy .
Then for the heavy hardware (so far the aft cleats, and soon the midships cleats) 3/8" aluminium plate backs the plywood, and the bolts get regular flat washers and lockwashers.

So far the backing plate for the bow roller has gotten the polyester filler to 'spread the load'. I did not use it for the stern cleats, as the underside of the deck was pretty much flat there. I plan to use it for the midships cleats, and will make new backing plates for the stanchions. I will extend both plates so that both the stanchions and the midships cleats are on a common backing plate.

I know this needs pictures, so I will get some soon.

Some of this may make more sense if you look at Deck hardware plan thread.

______________________________

Now, I know some will ask why I want to put the plywood between the deck and the 3/8" aluminum backing plates.. my thinking (may be off in left field) is that I can spread the load over a greater area (less pressure, more strength) but as much for the reason that I see a natural stress point at the edge of the backing plate... the plywood allows me to move that stress point out from the mounting, and the plywood would have at least some flex, where the metal would not.

[ebb]

Good show Craig!
Plywood imco also has a little give to it that I think is kinder to fastenings under stress and under tension. I'd guess that smaller bolts like those that hold stanchions will last longer with the ply backup plate, and because of the give may also help in preserving the stanchion base as well. The give may also help in holding the caulk and not opening it up to leaking. A little flexibility! Maybe when you get up into 3/8"/ 1/2" bolts it doesn't matter, go totally solid. Especially if you are attaching plate. ???