Today’s task was to put the tabernacle back into position with sufficient sealant to prevent water from getting down the bolt holes.
The first part of this exercise was to chamfer the bolt holes a little so as to allow the butyl tape to squeeze into the hole.
The tape itself was wound around the thread on the bolt as shown. As the nuts are tightened up the tape is pushed down into the chamfer creating a very tight seal.
I also used an exterior grade sealant on the deck so that the entire thing is sealed. It is important not to use an adhesive sealant here as that would make getting the tabernacle off again very difficult. The purpose of the sealant here is just to prevent water ingress. As for the spots of sealant splattered on the deck, I’ll pull those off once the sealant has dried.
From the inside the bolts and nuts are easily tightened up with the larger recesses allowing better access to the nuts.
It is very important when using butyl tape in this manner that once the bolts are located in the holes that they are not rotated as this has the unwanted effect of stripping the tape away from the thread. Instead the bolts must be drawn directly down into the hole by tightening the nuts, even it this is the more difficult option, as it was in this case. It would have been easier to attach a vice grip to each nut in turn and then tighten the bolt from the outside.
I’ll need to sand the backing board a little and then add another coat of varnish as the last coat of varnish has not covered very well, but since it is now dark outside, that is a task for tomorrow. Once that has been done and the varnish has dried, I’ll put the clock and barometer onto the board.
Time for a cup of tea.