Chainplate Bedding

[theonecalledtom]

So I've finally got a shiny set of new 316L chainplates and am ready to start replacing the originals.

The plates are externally mounted but a bugger to get to on the inside. In fact the boat is never going to be the same after my efforts to get to them in the first place and while I'm putting it back together a bit differently to make things easier its not going to be trivial to pull and re-bed them on a regular basis.

I feel like I've read about the same number of posts saying bed in 5200 as I've read saying stay away from the stuff. Alternative choices seem lifecaulk and 4200.

What are the options here?

Also - if I do use 5200 it has a 7 day cure period. Does that mean you lightly tighten the plates then retighten properly at the end of the curing period?

[smurphny]

Put mine on with 5200 and never plan on taking them off to re-bed in my lifetime! I plan on painting them right over when I Awlgrip the hull next time. Used the old ones for backing plates which worked out very nicely.

[theonecalledtom]

Ha!

Not sure you want to awlgrip them - sounds like that leads to some serious trouble.

Because I'm keeping the mast up while swapping the old ones out I had small backing plates made for a small extra charge. Also needed to keep them thin to fit in the original space - they original bolts just had large washers and corresponding compression marks on the fiberglass.

[svtadpole]

Lifecaulk is cheaper & cures faster than 5200 ... but it turns an ugly yellow within a couple of seasons ... this occurs on external bedding applications - I think it may be a reaction to UV - ... having turned yellow it then goes hard & "crispy" with signs of lifting & "peelback" ..... these days I only use Lifecaulk where it cannot be exposed to UV ...

I am in the process of renewing all my topside bedding from Lifecaulk to 5200 & hang the expense ....

As far as I am aware ... the only difference between 5200 & 4200 is that 4200 cures faster ...

There should be no need for 2-stage tightening as long as you get plenty of the goop in & around the bolts & holes ...

[avb3]

Originally Posted by smurphny

Put mine on with 5200 and never plan on taking them off to re-bed in my lifetime! I plan on painting them right over when I Awlgrip the hull next time. Used the old ones for backing plates which worked out very nicely.

So you didn't use washers? Was there enough room to use the old ones... I think this makes great sense, as it should help distribute some of the stress forces.

[sww914]

I used Sikaflex because you can get it apart again later. It does turn a bit yellow. Oh well...

[cabo_sailor]

I think the only reason to use 5200 is if you don't trust the structural connection. If it's weak enough to use 5200 then I'd do some other method of attaching. The 4200 should work just fine and give some future owner a fighting chance. None of these parts last forever.

Rich

[theonecalledtom]

Any reason not to use 4200?

[smurphny]

Originally Posted by theonecalledtom

Ha!

Not sure you want to awlgrip them - sounds like that leads to some serious trouble.

Because I'm keeping the mast up while swapping the old ones out I had small backing plates made for a small extra charge. Also needed to keep them thin to fit in the original space - they original bolts just had large washers and corresponding compression marks on the fiberglass.

Have thought about what problems painting them might create. Awlgrip has a s.s. priming procedure. Haven't really decided 100% on this yet.

I moved the chainplates outboard from the original thru-deck plates which are impossible to seal. Went from 1 1/2" to 2" x 1/4." The common bulkhead rot in these boats is caused by these thru-deck leakers. Once water gets into the end grain of plywood, trapped between glass it's all over- a bad design idea from the start. Was a major job to replace one of the bulkheads which was totally rotted.

All of my backing plates are hidden inside lockers so there was no problem with clearance/appearance. Was therefore able to use the old ones for backing. Just thought they were more substantial than washers and they were there. Drilled them right along with the new chainplates. The hardest part of the whole job was filing the holes in the new plates for the 3/8" carriage bolts with a hand file...whew. My old boat is 1/2"-5/8" thick even up at the gunwales, plus, where I drilled through was in the glass buildup for the bulkheads, so it was easy to do. With a modern thinner hull doing it would probably require some additional glass inboard and you'd have to be careful not to distort the sides with the s.s.

[JiffyLube]

Originally Posted by svtadpole

As far as I am aware ... the only difference between 5200 & 4200 is that 4200 cures faster ...

4200UV won't yellow.

[imagine2frolic]

I use Dolfinite, it starts out looking like peanutbutter, but turns eggshell white after a short time. Easy to clean up, and redo.......i2f

[allanpeda]

FWIW The replacement chainplates for my Catalina 30 came with a tube of 4200.

[minaret]

Originally Posted by svtadpole

Lifecaulk is cheaper & cures faster than 5200 ... but it turns an ugly yellow within a couple of seasons ... this occurs on external bedding applications - I think it may be a reaction to UV - ... having turned yellow it then goes hard & "crispy" with signs of lifting & "peelback" ..... these days I only use Lifecaulk where it cannot be exposed to UV ...

I am in the process of renewing all my topside bedding from Lifecaulk to 5200 & hang the expense ....

As far as I am aware ... the only difference between 5200 & 4200 is that 4200 cures faster ...


There should be no need for 2-stage tightening as long as you get plenty of the goop in & around the bolts & holes ...

4200 UV is the way to go for exposed seams, 4200FC (fast cure) for non-exposed bedding where a long working time is not required. The big difference between 4200 and 5200 is viscosity. 4200 is thick like sika, and makes a nice clean bead. 5200 was formulated for bedding and bonding wood to wood, and as a result is much thinner. It can be much harder to get a nice clean bead and keep a clean workspace with 5200 than 4200.
Use 4200 for anything you dont want to have to use dynamite to blow apart later. If you use a fine misting spray bottle of alchohol on a fresh tight bead of 4200 and then finger it off with no tape you'll come out with a slick shiny bead that's glossy like paint, and no tape edge to hold dirt. It's an art form to me, too much working on megayachts where they care about that sort of thing...

2 stage tightening is a cardinal sin. If you let the 5200 come to even a partial cure and then spin the bolt after the fact you've just made the goop you put all over that bolt break loose. Never spin a fastener after it's started to set...

[roverhi]

I've been using LifeCaulk for going on 40 years. Haven't ever had it harden and flake away. It may yellow but not enough to bother about. Pulled up my solar water heating system that I had bedded in Life Caulk 25 years ago. It was still soft and pliable despite having been exposed to salt air, intense sun, and nearly daily rainfall in the wet season here in the tropics. I'll stick with something with a track record that I've verified to work long term.

[kiper204]

Chainplates were made and installed in hell .... do some daily stretches, then go pick up some 4200 UV and a case of beer ... then count how many new curse words you come up with while getting the job done .....