Bedding teak to fiberglass?

[Jim Newton]

I am about to undertake my first “Teak to Deck” job and need some advise. I am pulling a couple of dead instruments from the bulkhead on the port side of the companionway and will be covering the resulting holes with a teak panel on the exterior and the same on the interior. I have three questions:
1) What is the recommend bedding between the teak and the fiberglass? Do I want just a bead or do I really slobber it on? It is a good size panel (18 X34).
2) I’ll be putting Cetol on the teak, should I varnish the side to be bedded to the fiberglass as well or leave it bare?
3) The plan was to use stainless wood screws (recessed & plugged) to attach the teak to the fiberglass. Any recommendation on size & length or other considerations?
Thanks,
Jim Newton
“Alcyone” CD30



jnewt@oakeselectric.com

[Rom]

I am about to undertake my first “Teak to Deck” job and need some advise. I am pulling a couple of dead instruments from the bulkhead on the port side of the companionway and will be covering the resulting holes with a teak panel on the exterior and the same on the interior. I have three questions:
1) What is the recommend bedding between the teak and the fiberglass? Do I want just a bead or do I really slobber it on? It is a good size panel (18 X34).
2) I’ll be putting Cetol on the teak, should I varnish the side to be bedded to the fiberglass as well or leave it bare?
3) The plan was to use stainless wood screws (recessed & plugged) to attach the teak to the fiberglass. Any recommendation on size & length or other considerations?
Thanks,
Jim Newton
“Alcyone” CD30

I usually use dolfinite just for old times sake, but for environmental reasons they've taken all the nasty stuff out of it that used to make it work so well. A lot of people use lifecaulk or even silicone sealant. The idea is that you don't want any air gap where condensation can collect and cause rot so a bead won't do. You have to slather the whole area press down and then remove the excess that squeezes out.

If you're attaching teak to fiberglass you probably don't want to use wood screws. Wood screws work on the principle of a wedge and force themselves into the wood by spreading it. Since fiberglass is rigid and doesn't spread, wood screws will often crack it. One usually uses stainless flat head sheet metal screws on fiberglass. Sheet metal screws are the same diameter all the way down the shaft and not tapered like wood screws are. You predrill the fiberglass with a bit that is as thick as the body of the screw but not as thick as the threads on the screw. The threads eat into the fiberglass and the body of the screw goes into the drilled hole.

The size depends upon how much stress is going to be put on the teak later. If it's just a decorative piece and will never have any strain the fasteners can be small. If you go smaller than #6 though, the usual screwdriver bits won't fit the screw head and you have to get a special small screwdriver so I usually don't go smaller than that. The length should penetrate the fiberglass but since there is no wedge action a longer screw doesn't give you any more holding power once you're through the fg. Measure from the bottom of the countersink hole through the fg and add an eigth or quarter of an inch. If the fiberglass is very thick you wouldn't have to penetrate it completely, but usually they lay it up thinly.

Finishing the back of the board is a good idea to keep moisture out but it doesn't have to be Cetol if it isn't going to show. You can use plain paint. Remember that Cetol or Armada aren't supposed to seal the wood, but allow it to breathe - unlike varnish. Real varnish or paint is better for a seal.



TomCambria@mindspring.com

[Fred]

I am about to undertake my first “Teak to Deck” job and need some advise. I am pulling a couple of dead instruments from the bulkhead on the port side of the companionway and will be covering the resulting holes with a teak panel on the exterior and the same on the interior. I have three questions:
1) What is the recommend bedding between the teak and the fiberglass? Do I want just a bead or do I really slobber it on? It is a good size panel (18 X34).
2) I’ll be putting Cetol on the teak, should I varnish the side to be bedded to the fiberglass as well or leave it bare?
3) The plan was to use stainless wood screws (recessed & plugged) to attach the teak to the fiberglass. Any recommendation on size & length or other considerations?
Thanks,
Jim Newton
“Alcyone” CD30

Two of the best are boatlife, or sikaflex. Two you don't want to use are 3m 5200 or silicone. 5200 it too strong an adhesive, and you will probably break the wood, should you ever have to remove it. silicone will cause any finish you put on the wood to "fisheye" or crawl.

If there is any chance that in the future you will varnish the teak, the back side should be sealed, bedding compound is not enough. It can be sealed with several coats of varnish, or two of epoxy.



fred@hotsheet.com

[Joel]

The link below is a primer on sealants that answers your question. Good luck.

Joel
Pokey II
'73 Typhoon/#549

I am about to undertake my first “Teak to Deck” job and need some advise. I am pulling a couple of dead instruments from the bulkhead on the port side of the companionway and will be covering the resulting holes with a teak panel on the exterior and the same on the interior. I have three questions:
1) What is the recommend bedding between the teak and the fiberglass? Do I want just a bead or do I really slobber it on? It is a good size panel (18 X34).
2) I’ll be putting Cetol on the teak, should I varnish the side to be bedded to the fiberglass as well or leave it bare?
3) The plan was to use stainless wood screws (recessed & plugged) to attach the teak to the fiberglass. Any recommendation on size & length or other considerations?
Thanks,
Jim Newton
“Alcyone” CD30

Bondy_Joel@hotmail.com

[Kurt B. Kaiser]

3M has a fairly new product, Fast Cure Adhesive/Sealant 4200, which, according to 3M, is half the strength of 5200, "which allows for
disassembly of parts"

http://www.3m.com/marine/images/Marine_1999_3.pdf



kbk@shore.net