Ken,
Good answer. My experience is 3 decks, all 1/2" thick, but with 1/4" seam
depth and I cannot say you are wrong or right, but the break bond tape makes
sense to me. One deck I did that did not work well occurred because the teak
shrank too much. Once the teak deck was 2 years old and the deck was
recaulked, there were no more problems, so using teak of correct moisture
level has to be the greatest risk of new decks as it takes a very long time
to cure teak. I am inclined to think your bubble problem was linked to the
calk material you used as opposed to anything else. When doing a large deck,
labor savings is serious money and I think I will still sand last, but
thanks for your explanation anyway.
Steve

"chayco" wrote in message
news:aldvf.251660$ki.204315@pd7tw2no...

"Steve Lusardi" wrote in message
...
Ken,
Why do you sand first? I never do. I fill fat (that's push fill not pull.
Pull creates the bubbles and concave seams) with Sikaflex 290 and sand
flush. The mess is inevitable, but never an issue if you sand last. I end
up
using more caulk, but a lot less labor, no bubbles and no concave seams.
Who
said teak decks are cheap. You must tape the bottom of the seam, before
you
caulk or you get peel separation under thermal expansion and contraction.
Also, you must clean and prime first. From a personal point of view,
Silicones have no place on a boat period. The stuff seems to go
everywhere
and then nothing sticks to anything. You want grief, use silicone. Who
said
teak decks are slippery when wet? Only a wet rug maybe better than raw
unfinished teak and a proper boat shoe.
Steve

Hi Steve,

I started out by caulking first and sanding it all later and inevitably
some
air bubbles would show up. Really hard to repair and look seamless once
they
are evident.
When I was doing the decks of a retro 50's Chriscraft Riveria, look alike,
I
was using white Sikaflex and sanding all later....what a mess. The tiny
air
bubbles were more pronounced in the white and the belt sander actually
imbeded teak fibers into the white Sikaflex. I reccomend the sanding
first
approach now simply because there are no surprises later. You immediately
see the finished deck as you walk away from the job while it sets up.

Ahh, the tape on the bottom of the caulking groove question....I'm of two
minds on that. The elasticity of the caulk is compromised when attached to
three surfaces.
Okay, but I believe the thickness of the decking should be taken into
consideration and I do not know where that point is. On 3/16" decking I do
not use a 'break bond' tape (less wood movement). On 1/2" decking I do.
On
3/8" decking....I'm not sure. What is your greatest consideration ?
Prevention of water getting to your subdeck of course. I think there is a
greater chance of occasional 'non adherance' of the caulking material to
the
side of the caulking groove than from deck expansion problems on 3/8"
minus.
I have found this especially when you run a wee shy on filling the groove
and have to add more later... and also when your 'close up glasses' have
sticky goo on them and you are maybe missing the small details. My primary
concern is that the subdeck is sealed effectively from upper deck water
leakage and in 3/8" minus I don't use a 'break bond' tape ....unless the
client requests it.

...Ken