this video is about things to watch out for when gluing up and varnishing a tabletop like this one
mostly stuff i left out of the other video i got all the underlying wood ready but this one has
got quite a twist to it so i'll rip that down the middle and that'll make that twist less pronounced
and that piece of wood also had quite a lot of tension in it which really pinched down on the
blade at full width i would have had to plane this much off of top and bottom to get that end flat
but as two narrow pieces i only need to plane off half as much to get it flat
i was about to run this twisted wood over the jointer to plane out the twist
but then i realized if it's twisted now it can twist more or untwist later and that could give
this whole tabletop a very slight twist so i got another piece of wood that i'll use instead the
boards for this tabletop are actually just spruce with lots of small pieces of oak glued on top that
turned out really nice but i don't particularly recommend it because it was tons of work this is
getting into woodworking geekery but this board has cupped on me a little bit you can see there's
a gap of about a millimeter in the middle of this so the whole board has gone this way a little bit
and it's gone even further than that actually but i clamped these calls onto the ends so at least
the end would be straight while i glued these bits on there and i think the reason it cupped
is when i glued all these oak strips on here that added a lot of moisture to the side which caused
that side to expand and that caused it to come this way or the other way if it's upside down
the other thing that will be interesting going forward is i've got two different types of wood
here and oak expands probably about one and a half times as much more seasonally than spruce does
which means as the seasons change this table top may want to cup as a whole and
whether or not that's a problem whether or not i can hold it flat with a big brace across the
bottom that is to be determined and in terms of avoiding table tops cupping it's important to
put varnish on the top and bottom otherwise if the humidity increases there will be more humidity on
the bottom than the top so the bottom expands and the whole tabletop will cup like that a little bit
and then it'll reach equilibrium and then when the humidity decreases the bottom will be drier
and it'll warp like that so having the same amount of varnish on top and bottom avoids that
sort of out of equilibrium problem but even if humidity changes are completely even in the wood
the wood itself will warp a little bit like this and like this as the humidity changes
and even if you cut all the ends so that they're perfectly square as the humidity decreases for
example they'll all go a little bit like that and if they're cut to be square like that
and then it increases of course they'll go the other direction and the way to counteract this
is to alternate the direction of the grain in the pieces like so and that way if all of these pieces
warp by alternating it it just creates a slight waviness instead of one big arc
a comment i always get when laminating pieces together like this is why not reinforce the joint
with dowels or biscuits or dominoes and that will also force the two pieces into alignment unless
of course i cut it slightly wrong which i did here in which case this forces it out of alignment and
that could be very frustrating of course i could leave it a little bit loose so i could still tweak
the alignment but then what's the point of it and in terms of reinforcing sure this will reinforce
this area here but the fact is the wood is not that strong across the grain like this
and a glue joint like this is as strong as the wood so if i reinforce it it will still break here
just like this this is likely to break next to the glue joint as it is on the glue joint
and in terms of getting a panel into alignment almost all the time one of my long reach c clamps
reaches onto the panel joint and i can just tighten that up and that will force that joint
into alignment and if it's wrong a little bit i can always shim one side or the other whereas
with this i'm kind of stuck with what i've got i just glued the last plank on and the glue joint
is along this line and you can see a little bits of uh glue that squeezed out i actually scraped
off all the squeeze out earlier but uh some more came out and that's good that means i've
got enough glue in there and i don't sand the top i just use a cabinet scraper to smooth that out
just look at the shine on it can you see how that spot right there doesn't shine
well there's a knot right here so i sanded that to get that smooth because the scraper
didn't work on it and the sanded finish just doesn't have that same gloss as a scraper finish
fixed right here is one of the joints that didn't line up perfectly that
i have to smooth out with the scraper and if i move the dial indicator across
you can see there's a difference of about 15 000 of an inch that's about point four millimeters
which is about four times as big a step as a thickness of paper but most of it worked out
much better here's another joint between planks and if i move a dial indicator across that there
isn't any worse bump there than there is on other parts of the tabletop i started by putting a few
dabs of varnish on places where i had tiny gaps before applying it to the table top as a whole
the instructions say to put on thin coats but i like to put it on really thick first coat of
varnish is dry normally a sanding comes next but i prefer to do that with a cabinet scraper
because that's much better at taking out a lot of these little bumps
and i varnished it on the top and the bottom to allow the varnish to dry on the bottom i support
it on these little triangles which ended up being stuck to the varnish but that doesn't
really matter that much because it's the bottom that oil-based varnish takes a while to dry and
after four hours at about 16 degrees or 61 fahrenheit it was still tacky to the touch
but for subsequent coats i turned on my air cleaner and had it blow air across the table
and that dramatically sped up the drying process the varnish was dry to the touch in two hours
so for the past 15 years i've mostly been using this verithane diamond water-based varnish mostly
because it's more convenient because it used to be once you open a can of the oil-based stuff
once that seal is broken the rest goes bad in a matter of months no matter what you do
whereas this stuff i can put some of it in a plastic container and it stays good in there
and i can clean the brushes with water but this stuff for places that get wiped down frequently
like a table i know this will crack so i got a small can of this knowing that the rest of it go
bad anyways when i built the chairs but this time working on the table top it had not skinned over
surprisingly so there's something different about it and it also wasn't this smelly and it dried
much quicker than i'm used to for this stuff so this must be some kind of a new formulation
and it makes this stuff almost as convenient as this in fact cleaning the brushes for this stuff
even though i need paint thinner it doesn't take any longer than water with this stuff question is
is it as good as the old stuff so this is an old dribble of the water-based varnish on my workbench
and it seems to just turn into flakes when i scrape it off and this is an oil-based dribble
and that comes off as one flexible piece and more water-based dribbles
and more oil-based dribbles
and this is some water-based stuff i dribbled on for a test just yesterday
and that comes off and nicely flexible but this stuff is still fairly fresh so i guess it takes
more than a day for the stuff to harden and these oil-based dribbles they are a few days old so i
think this stuff does stay more flexible than the water-based stuff does here's some two-month-old
varnish on the bottom of the chairs and let's see how that comes off yeah still flexible
and here's what this varnish looks like in a glass jar totally different from the old stuff
so i think i'll start using that obey stuff a bit more again going
forward because it seems to be much more convenient than it used to be