ccscott49
Active member
Also to smooooooth the seam, use a cut potato, sikaflex doesnt stick to them.
Tips for applying new Sikaflex on teak decks
- Thread starter JustinC
- Start date
vas
Well-known member
chinita
Well-known member
impressed!
still I'd really like to know HOW you found this out
'Damn, this scalpel doesn't seem to be working, I think I'll try a cut potato'
OldBawley
Active member
One very important trick is never to apply the Sika ( Or anny ather chaulking ) with decending temperatures. Not in the sun. Wait until the sun goes down.
The reason for this : Teak is wood. Wood is cellulose. Cellulose are tubes wich contains air. ( Look at wood head cut with magnifying glass. ) In the sun, the air in the wood will expand, and sorting by the sides of the seam. The minicule airbubbles rise to the surface of the Sika in te middle of the seam and partley form a sponge like trail. Hence the small bubbles in the cured sika. With movement the sika will tear on the bubbletrail.
Onley apply with constant or decending temperature.
I did a prof Sikaflex course.
The reason for this : Teak is wood. Wood is cellulose. Cellulose are tubes wich contains air. ( Look at wood head cut with magnifying glass. ) In the sun, the air in the wood will expand, and sorting by the sides of the seam. The minicule airbubbles rise to the surface of the Sika in te middle of the seam and partley form a sponge like trail. Hence the small bubbles in the cured sika. With movement the sika will tear on the bubbletrail.
Onley apply with constant or decending temperature.
I did a prof Sikaflex course.
lenseman
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vas
Well-known member
looks like a typo,
from what it reads, ascending /rising temps are a no no since the gases in the wood tend to exit and are trapped in the sikaflex
Descending temps should be fine as it looks like sikaflex wont become bubbly and if it was thin enough it would possibly bond better to wood and into the porous surface of the cut.
Makes sense, what is not mentioned is what range of temp and humidity is appropriate?
This descending temp thing in Greece is going to be fun, I'll be chaulking from 7pm till 2am next June...
from what it reads, ascending /rising temps are a no no since the gases in the wood tend to exit and are trapped in the sikaflex
Descending temps should be fine as it looks like sikaflex wont become bubbly and if it was thin enough it would possibly bond better to wood and into the porous surface of the cut.
Makes sense, what is not mentioned is what range of temp and humidity is appropriate?
This descending temp thing in Greece is going to be fun, I'll be chaulking from 7pm till 2am next June...
ccscott49
Active member
impressed!
still I'd really like to know HOW you found this out
Ita a trick I learned from somebody else, tried it and was very impressed with the results.
I am also just embarking on a deck job, have already replaced 300 plugs, removing the bronze screws, with bit and brace type screwdriver, deepening the holes with 1/2" countersink and replugging, every screw came out, some damage to a few, which I replaced with like. Now its caulking and groove deepening (in some places) I use a rotozip, with a wood guide, bent to follow the grooves and a 3mm cutter. It will be fun in Corfu!
OldBawley
Active member
Mea culpa,
never rising temperature.
Also the air traped under the teak and into the seam gap will expand and try to escape through the curing Sika.
One other thing, on has to be absolute sure which chaulking was used originally. Some buiders like Hallberg Rassy use ore used Silicone. Nothing else will ever adhere where silicon has bein applied. Cleaning with solvents dos not help, one only moves the silicon from one place to an other.
The Sika apply course guy said “ min seam width 6 mm” A long elastic stretches better than a short one. Logic ain´t it?
never rising temperature.
Also the air traped under the teak and into the seam gap will expand and try to escape through the curing Sika.
One other thing, on has to be absolute sure which chaulking was used originally. Some buiders like Hallberg Rassy use ore used Silicone. Nothing else will ever adhere where silicon has bein applied. Cleaning with solvents dos not help, one only moves the silicon from one place to an other.
The Sika apply course guy said “ min seam width 6 mm” A long elastic stretches better than a short one. Logic ain´t it?
Tradewinds
Well-known member
vas
Well-known member
not necessarily as in order to get the longer stretches, you shouldn't go very deep as it flexes less and it wont accomodate expansion very well. So overall it should be more or less the same (in theory at least)Also uses more Sikaflex
OldBawley
Active member
Correct, more Sika ( or any other polyurethane ) The cost of the chalking is absolutely negligible.
The amount of work is so much, you do not want to do it twice.
Laid only one teak deck with my one hands, never again. Knees gone for the rest of my life.
The amount of work is so much, you do not want to do it twice.
Laid only one teak deck with my one hands, never again. Knees gone for the rest of my life.
vas
Well-known member
if you were any closer, I'd come and have a chat/look, but Corfu is not quite next door to me
V.
steveh2112
New member
Hi all
i've been looking into how to recaulk my teak deck and i've seen videos and forum posts where people recommend placing tape in the bottom of the groove
"Most seams are 6mm wide, you need to then apply bond breaker tape (choose 4mm for a 6mm gap as it is a sod to get in place). The bond breaker tape is to allow for movement as the Sika is designed to adhere to two surfaces only."
the thing is, according to the sika website here
https://dnk.sika.com/dms/getdocument...ak_Decking.pdf
it doesn't say anything about taping the bottom of the slot
any thoughts? thanks
i've been looking into how to recaulk my teak deck and i've seen videos and forum posts where people recommend placing tape in the bottom of the groove
"Most seams are 6mm wide, you need to then apply bond breaker tape (choose 4mm for a 6mm gap as it is a sod to get in place). The bond breaker tape is to allow for movement as the Sika is designed to adhere to two surfaces only."
the thing is, according to the sika website here
https://dnk.sika.com/dms/getdocument...ak_Decking.pdf
it doesn't say anything about taping the bottom of the slot
any thoughts? thanks
Chris_Robb
Well-known member
Go to these guys for your bits.
https://www.boatpaint.co.uk/acatalog/TDS-Teak-Decking-Systems.html
You will need;the following: (taken from my order to them)
TDS Caulk Seam Removal - £28.60 Reefhook
TDS Teak Deck Seam Sander 1 £44.50
Saba Bond Breaker Tape 4mm x- 1 £5.07
The tape is essential as you must not bond the sealant to the deck.
The choice of caulking is down to you - either the appropriate SIKaflex of TDS one
As for finishing - on new decks or ones with plenty of spare teak, you literally sand off the spreaded mess of the caulking following trowelling it in. If you dont want to sand, you masking tape up the seams.
Goldie
Well-known member
If you dont want to sand, you masking tape up the seams.
I use a plastic or silicone kitchen spatula to sweep along the fresh caulking which beds it in firmly (don’t be too sparing with the caulking) and gives a nice smooth finish flush with the tape such that I haven’t needed to sand afterwards.
I use a plastic or silicone kitchen spatula to sweep along the fresh caulking which beds it in firmly (don’t be too sparing with the caulking) and gives a nice smooth finish flush with the tape such that I haven’t needed to sand afterwards.
Poignard
Well-known member
Do you need to wet the spatula before doing that?
Goldie
Well-known member
No, I use it dry.
BrianH
Active member
When I applied caulking level to the planks I later found that the hardened caulking had dried with a shiny surface that just didn't match with the older, matt-black seams. I also found that it contracts slightly during the hardening process so that a level surface at application dried with a faintly concave surface.
The solution to both for me was to ensure a surfeit applied with masking-tape on both sides that must be removed while still partially mastic then, when hard, a sharp chisel, bevel edge down, run obliquely along the groove, left a level and matt surface.
That has been with many years on my knees, tending to a very old HR laid deck, with silicon-based caulking - all under a searing Italian summer sun that could have hastened the drying process compared to UK conditions.
The solution to both for me was to ensure a surfeit applied with masking-tape on both sides that must be removed while still partially mastic then, when hard, a sharp chisel, bevel edge down, run obliquely along the groove, left a level and matt surface.
That has been with many years on my knees, tending to a very old HR laid deck, with silicon-based caulking - all under a searing Italian summer sun that could have hastened the drying process compared to UK conditions.
Caladh
Well-known member
Great info and tips on this thread and I'll be visiting the Boatpaint site - thanks Chris.
However when you remove old caulking (at least on my yacht) there is no bond tape at the bottom of the seam that would I guess have been applied originally - so what's that all about then ? I note that some makes of caulking do not appear top require bond tape.
However when you remove old caulking (at least on my yacht) there is no bond tape at the bottom of the seam that would I guess have been applied originally - so what's that all about then ? I note that some makes of caulking do not appear top require bond tape.
Tranona
Well-known member
Thge use of bond tape depends on the method of construction, thickness of teak and type of caulking used. The purpose is to only allow bonding to the edges of adjacent planks to accommodate movement of the planks if they are not firmly attached to the substrate. Thick, wide planks screwed to the substrate clearly have the potential to move more than thin narrow ones glued down with no fastenings.
So there is no universal "must use tape" rule, although with some caulking it is essential to clean and prime the seams to ensure the caulk adheres fully.
If there is no sign of tape when the old caulking is removed, nor signs of caulking breaking away from the sides in otherwise sound seams then it is reasonable not to use tape in the replacement.