Not exactly woodworking, but ...
Two custom-built wooden exterior doors have developed cracks in the
paint, mostly where the original pieces of wood were joined. The paint
has flaked off to bare wood in those areas, leaving maybe 1" exposed,
but the rest of the paint is in reasonable shape.
We're having a guy come paint the door (this is a commercial building,
not my house), but he's a handyman at best (I didn't pick the workman).
We'll have to guide him.
After scraping away the cracked paint, what can we do to smooth the
edges that are left, and prep the door for (primer and) paint? Do we
sand down the edges? Or "putty up" the low spots? Hand sanding? Sander?
Grinder with flap disk? Something else?
Even better would be to sand the bad areas down to feather edges, then
prime the bare wood to build up a primer layer, which may take a couple
of coats of primer. Then sand this primer area down to flat with the
existing paint, and finish paint. Just feathering out the damaged area
will most likely result in the repair showing.
My experience is feathering paint to bare wood generally doesn.t work
too well. Prime the wood, - several coats if necessary, then feather
the repair - then paint.
This way you do not have a "raw" paint edge to work with - the paint
is always "sealead" to the wood when you are sanding and painting.so
the edges won't lift, cut, or curl.
Someone didn't clean the wood down to solid wood.
They covered over the weathered cracking window and
painted over. The hot sun simply steamed moisture
from behind and did the 2-step on the fix.
Epoxy resin is used as a wood preservative. But the
wood is cleaned up and bad taken off then it is poured on.
That was like putting on a bandage on a wet wound and the
glue doesn't stick.
On 5/17/2016 5:09 PM, Leon wrote:
That and the fact that it was used so extensively. Bondo works well for
smallish areas but over large areas it will eventually fail. It fails
because the wood expands and contracts differentially to the Bondo. The
epoxy material material they promote will do the same thing, just slower; it
is slower because epoxy has a stronger bond than does the polyester resin
used in Bondo.
The exception is plywood and it is an exception because ply doesn't respond
to weather/humidity changes as much as solid wood.
Time was that many home built boats, usually trimarans, were built with
plywood which was then covered with layers of fiberglass all of which were
adhered with polyester resin. In fact, I have a pram I built eleven years
ago in that manner; it is still good as gold. Numerous commercial boats
were built in the same manner; the Newport 40 ketch was one.
Other than just replacing the rotted wood in the video, the guy would have
done better by cutting it out to good wood, then building it up with
On Tuesday, May 17, 2016 at 9:37:37 AM UTC-5, dadiOH wrote:
Great post. All true; Bondo has its place, although not literally as a scu
lpting material as seen in the video. I have seen it used extensively as a
filler before painting where it worked well. But like any product, extens
ive repairs require some familiarity with the product to get maximum perfor
mance. The lack of surface prep was really obvious in the video when they
peeled back the hunks of Bondo and you could see the rotted wood the covere
d. You could also see further deferred maintenance on all the surfaces as
well. It looked like an abandoned warehouse to me, so no telling when the
work was actually done on those windows, or if it was just another idiot's
On Tuesday, May 17, 2016 at 11:47:32 AM UTC-5, email@example.com wrote:
the product to get maximum performance. The lack of surface prep was reall
y obvious in the video when they peeled back the hunks of Bondo and you cou
ld see the rotted wood the covered. You could also see further deferred ma
intenance on all the surfaces as well. It looked like an abandoned warehou
se to me, so no telling when the work was actually done on those windows, o
r if it was just another idiot's repair.
Note that as pointed out numerous times in this thread that lack of prepara
tion is a great deal of the problem in the video.
What filler is completely waterproof? Solid epoxy finishes are for some ti
me, but they break down eventually.
In context of this post, water proof fillers for wood(none of which I know
actually are)the fillers are nearly irrelevant except for their ability to
hold a sealer and retain elasticity.
In the specific case of this thread, it was stipulated that the door (and i
ts fillers) would be painted, so whether or not the filler provides a super
ior water proofing on its own as a stand alone product is irrelevant.
You guys make this stuff waaaaay to hard.
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