Questions
& Answers
A forum where our experts
take on some of the questions uppermost in your minds
From
the Sept. 25 - Oct. 09, 2001 issue of Woodworker's
Journal eZine
A forum where our experts take on some of the questions
uppermost in your minds
Q.How
to Begin: This woodworker is evolving beyond deck building
and 
wants
to try his hand at cabinetmaking. Is there a good book—for
a beginner to use? And are there any tools he will definitely
need?
(Michael Dresdner) "There are many, but I suspect
starting with a good magazine, like Woodworker's Journal,
will be even more valuable than the best book.
The tools depend on what he defines as cabinetmaking, but
my minimum must-have shop includes hand planes and saws,
chisels, a table saw, a band saw, a drill and a planer.
And believe me, my friend, that will be just the beginning..."
Please
send your questions about woodworking directly
to us.
Q.
Band saw tracking: This reader just loaded
a 1/8" blade on his new 
band
saw and can't keep it centered on the wheels. Is the blade
supposed to run on the front of the wheel or should it be
centered?
(Michael Dresdner) "It should be centered, but
some band saw guides don't have enough adjustment to accommodate
a 1/8" blade centered on the wheel. You might have
to modify the thrust-bearing stem or reposition the guides.
Otherwise, if the wheels are aligned, the blade should track."
Please send
your questions about woodworking directly
to us.
Q.
What is a shiplap joint, this reader
wants to know, and when is it used - (long dash, not hyphens)
besides for building ships, of course?
(Michael
Dresdner) "Most joints make wood come together
to make angles, or to make the wood wider. Shiplap joints
make the wood longer by cleaving one piece to the end of
another. Some musical instrument makers also use shiplap
joints, and I am sure there are many other uses outside
my sphere of experience."
(Ian Kirby) "A shiplap joint is used for wooden
sheathing where the boards are rabbeted so the edges of
the adjacent board overlap to make a flush joint. You may
find it is used incorrectly on houses where the planks have
overlapping clapboards. These houses are known as 'clinker
built' and also known as 'lap strake' or 'lapstreak.' We
suffer from mixed up terms from place to place.
At it's worst, I've heard shiplap used to describe the
joint used to join boards end to end. There are a variety
of design details for the joint-from tapering each end to
form a glue surface to a half lap joint with wedges- (use
the same dash) but they are all scarf joints also used in
shipbuilding. That may be the cause of the confusion."
Please send
your questions about woodworking directly
to us.
Q.
This woodworker has an involved question:
"Each type of finish has its good and bad points, e.g.
oils and thin oilbased finishes give better results as a
base coat for popping the grain, while waterbased finishes
build up quickly and level well. Poly makes a good tough
topcoat. I once read that you can use shellac on top of
anything and it will bond. Question: Could you use shellac
as a bonding coat between an oilbase coat, a waterbase middle
and a Poly top coat? Would there be any drawbacks ?
(Michael Dresdner) "Actually, it is a simple
question with a simple answer. Yes, you can use shellac
between oilbase, waterbase, and poly provided it is dewaxed
shellac, like Zinsser's new SealCoat™ (a premixed dewaxed
shellac). There are no drawbacks related to the shellac,
but putting layers of finish with different color gradients
(oils and shellac are amber, polyurethane is bluish gray,
acrylic waterbase is clear) and different refractive indices
(the speed at which light goes through, and is therefore
bent by, a clear material) can make it (the shellac?) less
clear. Think of what a pencil in a glass of water looks
like. It appears to change its direction and angle as it
enters the water. Imagine that happening with each layer
of finish. Now imagine the different color gradients added
like sheets of tinted plastic wrap. Get the picture?"
(Ian Kirby) "The fancy name for what goes on
when one finish is put onto another is 'interface adhesion.'
In this scenario, you are messing with four interfaces.
The variables are too many to contemplate, but if you think
it's a good idea, try it on some scrap wood."
Please send
your questions about woodworking directly
to us.
Q.
This woodworker wants to know when enough
is enough: "When I'm ready to clamp my gluedup
panel, how tight is too tight? The directions on the Titebond®
bottle says to allow the glue to set for 15 minutes. Does
that mean at least 15 minutes or should you unclamp after
that time so the wood can regain it's natural shape?
(Michael Dresdner) If you are crushing or deforming
the wood, it is too tight. All you really need is for the
surfaces to be firmly in contact with one another. The 15
minutes is a minimum, and it certainly does not hurt to
leave the wood in clamps until you are ready to machine
it, or until the clamps get in your way or are needed elsewhere.
(Ian
Kirby) "If you're clamping a mortise and tenon,
a dovetail or a butt joint, you can see when the shoulder
lines are closed—that's all the pressure you need.
When you can't so easily see the joint line-say, two blocks
face to face-enough pressure is when you squeeze out beads
of the glue. But this goes to the question of how much glue
do you use. A good rule of thumb is "as little as possible."
You have to wet every surface and you should roll it where
you can roll and brush or paddle elsewhere. Brush it on
and then try to brush it off, but wet every surface. The
aim is to get the smallest line or bead of squeeze-out.
Gobs of the stuff squeezing out don't help the joint, but
it does make Titebond richer.
The length of time glue can be stored before it deteriorates
is called its shelf life. The amount of time you have to
leave the clamping pressure on is call the closed clamping
time. The time you have between starting to put glue on
the parts and getting them into clamps is called the open
clamp time. Some glue makers strive to provide a product
with a long open time and a short closed clamping time.
For my money, a job that relies on glue to hold it together
is worth more time, so I leave stuff in clamps a couple
of hours.
And about that last sentence: clamping shouldn't distort
the work! If it does, you're clamping too tightly or using
clamping blocks incorrectly. But yes, Titebond says you
can take the clamps off, but you don't have to."
You can review the other articles in this issue
of Woodworker's Journal eZine by clicking on the links below.
Today's Woodworker
Tool Maker Insider
Websurfers' Review
Q&A
Tool Preview
Return to the Woodworking.com
home page.
