FAQ: Re-bed ?
Should I re-bed Exterior Teak trim when I replace it?
Subj: Rebedding Exterior Teak Trim
The screws on these initial pieces do not extend beyond the outer skin. For pieces that are thru-bolted, such as the cabin-top handrails, should they definitely be rebedded?
Bob Mann, "Windcatcher"
I would bed all deck fittings/trim. I do not like to use adhesive compounds and instead use dolphinite for anything, which is not through bolted and butyl tape for all through bolted items. It is also important to get bedding compound on/around the screw where it goes through the item. I sometimes use 3M's 101 on the fasteners as it is one of the mildest adhesive bedding compounds. A nice trick is to countersink the deck a bit so that some bedding compound gets trapped there and acts like an o-ring. If you are using a bedding compound which cures (like 101, 4200, life-caulk) it is a good idea to not tighten the hardware down completely. Tighten up the fasteners after the compound has cured. I also recommend against using silicon with the exception of where the glass meets the aluminum frames in the portlights. Silicon is very hard to remove and prevents any future compounds from sticking, including silicon. As for the deck, I wet them out with epoxy and then fill with thickened epoxy. Then redrill when cured.
Loeb, Mechatronics Product Design Engineer
Any screw or fitting that goes through the outer fiberglass layer and into the core material needs to be rebedded.
Steve Schultz, "Relaxer"
Several people who have responded have commented about "rebedding" the trim. I was originally only going to put the old screws back in the way they were (I am not aware of any water problems). However, the term "rebedding" implies to me that I should drill out the hole in the fiberglass at least one size larger than the screw and insert some kind of bedding compound (such as 101). When hardened, drill a hole in the bedding compound to the correct size for the screws being used and re-attach the trim.
Is this latter part the agreed-upon process? If I need to remove the pieces again in the future I shouldn't have to redo the rebedding process, correct?
Bob Mann, "Windcatcher"
That is not what "rebedding" means. Bedding compound is a flexible compound, which forms a "bed" under the hardware being attached to the deck. The purpose is preventing moisture from getting behind/under the hardware by filling voids and providing a seal. Compounds with high adhesive qualities should be avoided in bedding applications, as they make it difficult to remove the hardware in the future. That is why I have in the past strongly recommended against using silicone as a bedding compound, as so many do it yourselfers do.
Rebedding is the nautical term that means Reattach the piece. By far the best practice is to drill oversize holes, add epoxy and then redrill the correct size holes. This is to protect your decks when water penetrates the bedding. But this is not really rebedding. When a fixture is installed it is bedded in a thick rubber or like compound (polysulfide or dolphinite) that is designed to keep water out of the screw holes. Rebedding is just doing the same thing again. When I rebed something for the first time, I usually go the drill/epoxy/redrill/rebed routine. If I ever have to rebed again, I just remove the fitting, clean and apply the polysulfide. Hope this helps to clear things up.
Ric Blamer, "miss Higgins"
The decks on Catalina’s have marine grade plywood core which, if it gets wet and remains so for a period of time, will rot away, leaving hollow, weak areas in your deck. I don't like silicone sealer -- its messy, attracts dirt, and doesn't maintain a good seal over time. Polysulphide sealers are removable and last longer than silicone and seal well, remaining flexible. Polyurethane sealants are for permanent adhesion -- you would have to saw off your deck fittings. You should check and see if you already have water in your deck -- if you do, displace it with rubbing alcohol until it is dry. Once dry the recommended practice is to drill out the hole a little bit larger, fill it with thickened epoxy, after wetting the hole out with unthickened epoxy, let it set, and then redrill the hole. Then rebed the fitting with polysulphide.
Brian Wheeler, "Palmetto Blues"
Important: The opinions expressed here are those of the individual contributors to this page, and not those of the Catalina 34 National Association or Catalina Yachts, Inc. Additionally, this material has not been reviewed by Catalina Yachts, Inc. for technical accuracy. This page's maintainer cannot guarantee the accuracy of this information or the desirability of suggested modifications or upgrades. Please obtain assistance from a competent marine mechanic or boatyard prior to making any significant modifications to your vessel.
Last modified by Phil Imhof, Wednesday, August 11, 2004 . Copyright © 2001 by Catalina 34 International Association. All rights reserved.