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Finishing With Urethane?
I just stumbled across your web site as I
was looking for some information about wiring and breaker boxes. Found
that article and decided to go to your home page where I found the article
on Assembling a Bookshelf From Pre-Finished Components.
I just finished a bookshelf project this afternoon and am kicking myself
for not finding your site sooner. I could have saved myself a lot of
frustration by incorporating a number of your ideas, especially that Kreg
jig kit! I wound up using dado joints done on my brother-in-laws table saw
(sans dado blade... D'OH!) but I would have rather gone the route you did.
I also like your idea of using pipe clamps to deal with the warp I had.
Great idea using the carpet and the C-clamp, too.
I will say that I, too, went back and forth as to whether I should finish
first or assemble first. Since I was working with pine, I opted to
assemble first. The problem here was that I also included a 1x3 piece of
trim for the face and it was tough getting into those corners. I wound up
going with a Minwax Golden Oak and their Antique Oil Finish product. It
came out pretty good but still don't have the intestinal fortitude to work
with a polyurethane finish yet as I tend to screw up stuff like that.
Anyway, the last step I did was put the luan backing on and now my 27
month old has a 3ft high X 4ft wide shelving unit in his room to organize
all of his trucks and tools.
To sum it up, you've got a great site and I'll be visiting quite often now
that I've been bitten by the woodworking bug.
Cheers!
- Ed.
Thanks
for your feedback. That Kreg Pocket Jig is a pretty neat tool. But it
goes to show that there are many ways to join wood components together,
some involve simple machines and a lot of labor, others involve exotic
machines and little labor. I like to examine how mass-produced furniture
and cabinets are made to get ideas, but that's the engineer in me.
As for finishing with urethane, I think that the biggest issue is having
a good brush. Oil-based coatings can be applied with natural bristle
brushes (which are made from the hairs of hogs, oxen, or other animals),
as well as some synthetic brushes. I understand that natural bristles
are sometimes hollow inside. Hair certainly has a more elaborate
structure than polyester or nylon, which are just round fibers extruded
from a machine like fine spaghetti. And since hairs tend to be tapered
at the ends, they naturally have the fineness that is needed at the tip.
I've noticed that some high-quality synthetic brushes have fibers that
are divided at the ends. The bristles really look like a nasty case of
"split ends".
As much as I hate spending money, I'm a firm believer in buying only
top-quality paint brushes such as Purdy, which are available at
Home Depot and contractor-oriented paint stores. Sears has some good
brushes too.
To get a really nice urethane finish I use the finest natural bristle
brush I can find. Many years ago a neighbor, who worked 45 years in the
high-end furniture industry, gave me a couple of ox hair sign painters
brushes. These things are unbelievably soft. And they leave virtually no
brush strokes in varnish or urethane. But I've also used a Purdy brush
made from Chinese bristle and had good results.
People seem to like paints that dry fast, but slow drying coatings have
more time for the liquid to "level out". Paint stores sell
retarder that can be added to paints and urethane. I believe they are
used for oil-based and not latex.
I would stay away from water-based urethanes, unless there is some
compelling reason such as needing to do the work indoors and having no
way to get good ventilation. I've seen some problems with water-based
urethanes.
Cleaning Oil Paint From Brushes:
A lot of people don't like oil-based paints because they seem so hard to
clean up. I can clean oil paint from brushes much faster than I can
clean latex. I've developed kind of a technique: First of all, I don't
throw away mineral spirits when I'm done cleaning paint brushes. I pour
the dirty solvent back into an empty mineral spirits jug (and label it
with a permanent marker, on all four sides, as USED ).
- The first thing I do is pour a
generous amount of used mineral spirits into the plastic paint cup.
Hey, the stuff is free.
- I swish the brush around
slowly, pressing down slightly.
- When it seems that the paint (or
urethane) has been mostly dissolved, I pour that cup of solvent back
into the jug marked USED, and I go outdoors and shake out the
brush. I stay away from the cars in the driveway so they don't
get splattered.
- Then I wipe out the plastic
paint cup with a paper towel.
- I pour a few ounces of clean, new
mineral spirits into the cup.
- I clean the brush again.
Since the old residue was wiped away, I can tell how much paint is
in the brush my how murky the solvent gets.
- I pour the solvent into the USED
jug, and shake the brush again.
- Then I sort of wipe the
bristles with a paper towel to absorb some more of the solvent. I
wrap the brush in a paper towel to keep the bristles together, or I
put the brush back into it's package. Purdy brushes have a good
paper cover that helps the brush retain it's shape.
When I follow these steps, I can clean oil paint from a brush in less
than 3 minutes, and the brushes NEVER have a problem getting hard
because some paint was still deep inside. Except for urethane. For some
reason urethane doesn't clean up as easily, so I always do 2 rinses
with clean mineral spirits. That seems to work well. I do a lot of
painting in my work, especially the last few months, and I've had to get
efficient.
If you are having reservations about urethane finishing, I suggest doing
some trial runs on the back side or the bottom where nobody will see any
mistakes.
Painting Tips:
Another important thing to know is the proper brushing technique:
- Dip the brush into the paint (or
urethane) and tap each side of the brush on the side of the plastic
cup to remove excess, otherwise the paint will drip. This isn't so
easy when painting directly from the can, so I usually use a plastic
cup: pint-size for small brushes, quart size for 3" brushes,
gallon bucket for house painting.
- Swiftly draw the brush across the
surface, with no regard for getting perfect coverage. The idea is to
unload the paint from your brush. Do this a few times to get a heavy
but perhaps spotty coat of paint on the surface.
- Now spend a moment to smooth out the
finish. I do a few quick strokes from one side to the other to make
the paint cover all the bare areas. Then I carefully brush the paint
from one edge to the other, dragging slowly and smoothly and not
pressing too hard.
- The key to a good technique is "back-brushing",
which just means brushing from the dry area back into the wet area.
As you gently lift the moving brush off the wet surface, there will
be few marks left behind. If you stab the brush into the middle of
the wet paint, and then drag it, you will see the point where you
first made contact. Not good. Try these techniques and you'll see
what I mean.
There is a surprising amount of skill
and subtlety to painting, which I suppose is exactly how professional
painters make their living. Anybody can paint, but it takes a little
practice, patience and experimenting to paint well.
Bruce W. Maki, Editor.
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