Hi all,
I've been building a captain's bed for my son out of some old
reclaimed pine. Due to the limited amount of wood I was not able to
avoid having some knots at the edge of a face frame. One of them is
big and really shabby, with quite large voids. I'd like to fill it,
and I'm thinking epoxy would be the best choice. I really don't like
the look of wood filler when it gets any bigger than a BB.
Assuming you agree that epoxy is a good choice, how can I apply it?
At the edge of the board it's going to just run out, so I need to
block it while it sets. The blocking must not stick to the epoxy. I
don't have sheets of teflon, other than teflon plumbing tape. Is
there something else (like HDPE or polyethylene, which I didn't try it
yet) that will work instead? Alternatively, if I let the expoxy get
proud of the surface can I sand it down and hope to apply water based
Minwax Varathane and not see the sanding marks? In that case I can
block it with a few strips of wood and just plane/sand them away.
Actually, I'm inclined to think that's the best approach, so I may try
it on some scrap while I await more brilliant feedback from you guys.
If there's no other choice I can cut the offending chunk away and glue
in a replacement, but it'll lose a lot of character and just plain
won't look as good as I know it can.
I hope all this makes sense. Thanks for your advice.
- Owen -
"manyirons" wrote:
> I've been building a captain's bed for my son out of some old
> reclaimed pine. Due to the limited amount of wood I was not able to
> avoid having some knots at the edge of a face frame. One of them is
> big and really shabby, with quite large voids. I'd like to fill it,
> and I'm thinking epoxy would be the best choice. I really don't
> like
> the look of wood filler when it gets any bigger than a BB.
>
> Assuming you agree that epoxy is a good choice, how can I apply it?
------------------------------------------
Since the knot is "shabby" anyway, knock it out so you can get back to
some structurally sound wood.
You then cover the sides of the knot hole with duct tape to form a
temporary dam.
Mix up some decent epoxy and thicken it with some micro_balloons to
the consistency of mayo.
(Using Cab_O_Sil to thicken epoxy is like getting a sentence to wear a
hairshirt while sanding. You don't want to go there.)
I might add some carbon black an make the patch an accent, but that's
just me.
If the knot is much larger than about an 1-1/2" in diameter, I make
two pours to keep the heat down.
Allow to cure for 2-3 days, then remove tape and sand.
You now have a structurally sound timber.
If you want to cover the patch with a "Dutchman, go for it.
C Groh, want to jump in on this?
Lew
"dadiOH" wrote:
> I've used Cab-o-sil for 40 years, sanded a lot, nary an itch.
> Fiberglass, yes, fumed silica, no. Nothing wrong with micro baloons
> if you don't mind the color. Ditto wood dust. Ditto talc (but it's
> heavy, no big deal for a knot).
-----------------------------------------
After sending a few thousand hours on the business end of a fairing
board, to fair out a boat hull, get back to me.
Some where along the fairing process, someone is bound to mix up some
fairing putty using Cab_O_Sil.
Once you have had to fair out Cab_O_Sil.with a fairing board, you will
NEVER want to do it again.
DAMHIKT.
MIcro-ballons are white unless you are referring to pheonlic balloons
used by the race boat builders because of their very light weight.
Those are brown and VERY expensive.
Wood dust and talc for fillers?
OH FUCK.
Why waste good epoxy by using garbage fillers?
A 30# bag of Dic_A_Perl (HP-500) which is 8 cubic feet is about
$25.00.
Unless you are a boat builder, that's probably a lifetime supply.
Lew
Lots of excellent advice in this thread about epoxy, but here's another
approach: I don't know if it's because I know it's there, but I find that my
eye is always drawn to an artificially-filled knothole. It never quite
matches up to the grain around it. So -
If the knots are loose or ugly, knock them out. Walk the woods and find a
branch of a similar wood. Whittle it down to a fair fit, spot on some glue,
and hammer it into place. Trim and sand - it'll be just like Nature intended
- a knot, but a nice-looking one.
Nemo
-----------------------------------------------------------
Posted using Android Newsgroup Downloader:
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"Steve Turner" wrote:
> There have been many cases where I've worked with knotty wood and
> chose to leave the knots in place because I felt that removing them
> or plugging them would take away from the natural look. What's
> worked well for me is to saturate them with a good slow cure epoxy
> (like System Three, perhaps with some black pigment mixed in), to
> lock them in place and fill in all the voids that would compromise
> the structural integrity. This can actually wind up looking very
> nice, depending on the type of wood and what kind of finish you
> apply to it.
-------------------------------------
Same trick,using black epoxy to fill voids, as the people who work
with mesquite.
A little tip, you can thin the mixed black epoxy with denatured
alcohol (About 5% max) to get better penetration without weakening the
bond.
Lew
"Steve Turner" wrote:
> I think whether or not you can do that must depend on what brand of
> epoxy you're using. I've tried that with Bondo brand marine epoxy
> (which I really like) and wound up with a rubbery result that would
> never cure hard. I may have used more than 5% though; not sure.
------------------------------
My choices of "Good Epoxy" never included Bondo so can't comment.
System 3 has good stuff, have used thousands of gallons of it.
The alcohol add can be tricky, a little goes a long way.
------------------------------
> I've never tried it with System Three, which is the other brand I
> use most often, but it's already sufficiently thin that I haven't
> felt the need to cut it any thinner.
---------------------------
Strictly for special applications.
----------------------
> And I too have done the black epoxy on mesquite thing; I do live in
> Texas after all.
---------------------------
Black epoxy works well with several woods, not jut mesquite.
Lew
Add On:
"Steve Turner" wrote:
> I think whether or not you can do that must depend on what brand of
> epoxy you're using. I've tried that with Bondo brand marine epoxy
> (which I really like) and wound up with a rubbery result that would
> never cure hard.
---------------------------
If your alcohol had any water in it all bets off.
Rubbing alcohol won't cut (Too much water).
Lew
On 7/11/2010 9:14 AM, Steve Turner wrote:
>
> There have been many cases where I've worked with knotty wood and chose
> to leave the knots in place because I felt that removing them or
> plugging them would take away from the natural look. What's worked well
> for me is to saturate them with a good slow cure epoxy (like System
> Three, perhaps with some black pigment mixed in), to lock them in place
> and fill in all the voids that would compromise the structural
> integrity. This can actually wind up looking very nice, depending on the
> type of wood and what kind of finish you apply to it.
Most sensible advice ... David Marks had a portion of a show dedicated
to fixing/stabilizing knots that pretty well summed up the above,
including using pigments to make the stabilization look like mother
nature intended.
--
www.e-woodshop.net
Last update: 4/15/2010
KarlC@ (the obvious)
> Really? =A0I didn't know that; I promise I didn't steal the idea from him=
. :-) I just kinda
> migrated towards it; I hate throwing away good wood simply because of a l=
ittle defect here
> and there.
>
>
> - Show quoted text -
I have always loved working with wood precisely because of the
"defects", it is the varied grain, knots, wounds healed over and how
the stresses of living have given the wood it's character. Much like
people, how they have incorporated that adversity into their life is
what gives them their true character.
Can't find that kind of unknown and surprising quality so much in
metals or ceramic's etc. Some but not so much.
On 07/10/2010 11:54 PM, [email protected] wrote:
> Lots of excellent advice in this thread about epoxy, but here's another
> approach: I don't know if it's because I know it's there, but I find that my
> eye is always drawn to an artificially-filled knothole. It never quite
> matches up to the grain around it. So -
>
> If the knots are loose or ugly, knock them out. Walk the woods and find a
> branch of a similar wood. Whittle it down to a fair fit, spot on some glue,
> and hammer it into place. Trim and sand - it'll be just like Nature intended
> - a knot, but a nice-looking one.
There have been many cases where I've worked with knotty wood and chose to leave the knots
in place because I felt that removing them or plugging them would take away from the natural
look. What's worked well for me is to saturate them with a good slow cure epoxy (like
System Three, perhaps with some black pigment mixed in), to lock them in place and fill in
all the voids that would compromise the structural integrity. This can actually wind up
looking very nice, depending on the type of wood and what kind of finish you apply to it.
--
Free bad advice available here.
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On 07/11/2010 10:58 AM, Swingman wrote:
> On 7/11/2010 9:14 AM, Steve Turner wrote:
>
>>
>> There have been many cases where I've worked with knotty wood and chose
>> to leave the knots in place because I felt that removing them or
>> plugging them would take away from the natural look. What's worked well
>> for me is to saturate them with a good slow cure epoxy (like System
>> Three, perhaps with some black pigment mixed in), to lock them in place
>> and fill in all the voids that would compromise the structural
>> integrity. This can actually wind up looking very nice, depending on the
>> type of wood and what kind of finish you apply to it.
>
> Most sensible advice ... David Marks had a portion of a show dedicated
> to fixing/stabilizing knots that pretty well summed up the above,
> including using pigments to make the stabilization look like mother
> nature intended.
Really? I didn't know that; I promise I didn't steal the idea from him. :-) I just kinda
migrated towards it; I hate throwing away good wood simply because of a little defect here
and there.
--
See Nad. See Nad go. Go Nad!
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On 7/11/2010 6:44 PM, Lew Hodgett wrote:
> "Steve Turner" wrote:
>
>
>> There have been many cases where I've worked with knotty wood and
>> chose to leave the knots in place because I felt that removing them
>> or plugging them would take away from the natural look. What's
>> worked well for me is to saturate them with a good slow cure epoxy
>> (like System Three, perhaps with some black pigment mixed in), to
>> lock them in place and fill in all the voids that would compromise
>> the structural integrity. This can actually wind up looking very
>> nice, depending on the type of wood and what kind of finish you
>> apply to it.
> -------------------------------------
> Same trick,using black epoxy to fill voids, as the people who work
> with mesquite.
>
> A little tip, you can thin the mixed black epoxy with denatured
> alcohol (About 5% max) to get better penetration without weakening the
> bond.
>
> Lew
I think whether or not you can do that must depend on what brand of epoxy
you're using. I've tried that with Bondo brand marine epoxy (which I really
like) and wound up with a rubbery result that would never cure hard. I may
have used more than 5% though; not sure. I've never tried it with System
Three, which is the other brand I use most often, but it's already sufficiently
thin that I haven't felt the need to cut it any thinner.
And I too have done the black epoxy on mesquite thing; I do live in Texas after
all. :-)
--
"Our beer goes through thousands of quality Czechs every day."
(From a Shiner Bock billboard I saw in Austin some years ago)
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On 7/11/2010 10:51 PM, Lew Hodgett wrote:
> "Steve Turner" wrote:
>
>> I think whether or not you can do that must depend on what brand of
>> epoxy you're using. I've tried that with Bondo brand marine epoxy
>> (which I really like) and wound up with a rubbery result that would
>> never cure hard. I may have used more than 5% though; not sure.
> ------------------------------
> My choices of "Good Epoxy" never included Bondo so can't comment.
Yeah, with a name like "Bondo" one might conjure up the idea that it's
low-quality automotive body putty crap, but it's really quite good compared to
most locally available junk called "epoxy". This is the stuff I'm talking about:
http://www.jamestowndistributors.com/userportal/show_product.do?pid=6147
It has nice nice working qualities and excellent strength (and a nice caramel
color too, which blends very nicely with wood without the need for additional
colorants), and I was planning on buying some more when this batch ran out, but
it looks it's been discontinued...
> System 3 has good stuff, have used thousands of gallons of it.
>
> The alcohol add can be tricky, a little goes a long way.
Since you've already tested alcohol with System Three I might try it sometime
if the need arises. I'm not sure it would work with their T-88 product though;
that stuff is a bit of a different animal.
> ------------------------------
>> I've never tried it with System Three, which is the other brand I
>> use most often, but it's already sufficiently thin that I haven't
>> felt the need to cut it any thinner.
> ---------------------------
> Strictly for special applications.
> ----------------------
>> And I too have done the black epoxy on mesquite thing; I do live in
>> Texas after all.
> ---------------------------
> Black epoxy works well with several woods, not jut mesquite.
Yep. You see it a LOT with Mesquite though because it's so hard to find any
decent quantity of wood that isn't full of checks and voids.
--
Free bad advice available here.
To reply, eat the taco.
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On Jul 10, 1:50=A0pm, "Tom Dacon" <[email protected]> wrote:
> I'd suggest mixing up some epoxy in a cup and adding sawdust from the sam=
e
> kind of wood until the mixture is pretty stiff - it should stand up in pe=
aks
> and droop slowly if at all.
>
> It'll still sag some while it's curing, so all you need to do to keep it =
in
> shape is to make some of what used to called "dams": take a couple pieces=
of
> scrap wood, cover them with a strip of smooth tape, and then wipe a thin
> film of white grease on the tape so it'll release after the cure.
>
> Do the knots one at a time. Fill the voids with a spatula, tool it until
> it's a bit proud all around. Clamp a piece to the underside face and anot=
her
> to the vertical edge to keep the stuff from drooping out of the patch.
> Finally wipe off the squeezed-out mixture and tool the upper face until i=
t's
> just very slightly proud (epoxy doesn't shrink to any appreciable extent)=
.
> Work reasonably quickly.
>
> After a while, while it's still just a bit green (not yet cured rock-hard=
),
> pop off the dams, give the edge and the underside face a wipe with a smal=
l
> bit of paint thinner to remove any trace of the grease, and block-sand as
> necessary with a coarse paper like 60 or 80 grit to make it flush. Let it
> finish curing, and then go over the faces and the edge with finer grits
> until you like the look.
>
> The filler will come out darker than you expect, so do a test on a piece =
of
> scrap to see if it's to your taste. If not, there are other special-purpo=
se
> fillers for epoxy which come out white or gray, and then you can take a
> brown sharpie and just draw over the patches to try to match the grain, o=
r
> stain it to suit yourself.
>
> For something like this, I use West Epoxy. You can get different catalyst=
s
> which cure at different speeds. For this I'd use slow catalyst so that I'=
d
> have plenty of time to work the patch before it started to stiffen up.
> Hardware store epoxy might not give you that flexibility.
>
> Tom
Well I've filled all the knots now, and to my eyes they turned out
great. I pre-finished around the sites to seal the pores, and after a
few hours of drying I made dams out of small strips of wood into which
I rubbed paraffin. The epoxy was too thick to flow into every single
crevasse, but it didn't have to. It just had to hold the biggest
chunks in place. So now that's done, and the dams came off easily,
leaving behind perfectly flat and flush epoxy surfaces. I've got a
couple more dutchmans to do, and then the whole face frame will be
ready for finishing and installation. Yeehaa!
Thanks again, everyone, for all the tips!
- Owen -
> I've been building a captain's bed for my son out of some old
> reclaimed pine. =A0Due to the limited amount of wood I was not able to
> avoid having some knots at the edge of a face frame. =A0One of them is
> big and really shabby, with quite large voids. =A0I'd like to fill it,
> and I'm thinking epoxy would be the best choice. ....
Another suggestion: Cut away around the knot and patch the wood with a
scrap of the same stock. Try to match the grain as best you can. I
think that would look better than a lump of epoxy.
If your scrap pieces have knots, use those knots to fill the voids and
epoxy them into place. If you don't have knots in some scrap pieces,
maybe you could stain some scrap to "make" knots, and insert them into
the voids (epoxy into place).
I vote for the waxing suggestion, for your "framing in" of the
filler.
Sonny
> I hope all this makes sense. =A0Thanks for your advice.
>
> =A0 - Owen -
Epoxy sands out really well so you could just build up a dam using
tape and sand it all away later.
I like the concept of doing a patch using similar grained material. In
a very early job (16-17 years old) at a rustic furniture factory when
we had bad knots in Pine we would use a chisel them out and sand a
plug to fit and just yellow glue it in place. You would be amazed how
well it blends.
Another option is to just break out all the loose material and grind
and sand the edges smooth. I actually always like to have some little
hidden wild edge on any of the better furniture I build. And when it
is for me, I like it to be visible.
On 9 July, 13:33, manyirons <[email protected]> wrote:
> and I'm thinking epoxy would be the best choice.
Decent epoxy, filled with phenolic microballoons to the consistency of
peanut butter. For paler wood, silica microballoons with a dye. You
can apply this with a popsicle stick, you don't need a mould.
Microballoon filler is useful because it's easy to sand afterwards.
On Jul 9, 8:33=A0am, manyirons <[email protected]> wrote:
> Hi all,
>
> I've been building a captain's bed for my son out of some old
> reclaimed pine. =A0Due to the limited amount of wood I was not able to
> avoid having some knots at the edge of a face frame. =A0One of them is
> big and really shabby, with quite large voids. =A0I'd like to fill it,
> and I'm thinking epoxy would be the best choice. =A0I really don't like
> the look of wood filler when it gets any bigger than a BB.
>
> Assuming you agree that epoxy is a good choice, how can I apply it?
> At the edge of the board it's going to just run out, so I need to
> block it while it sets. =A0The blocking must not stick to the epoxy. =A0I
> don't have sheets of teflon, other than teflon plumbing tape. =A0Is
> there something else (like HDPE or polyethylene, which I didn't try it
> yet) that will work instead? =A0Alternatively, if I let the expoxy get
> proud of the surface can I sand it down and hope to apply water based
> Minwax Varathane and not see the sanding marks? =A0In that case I can
> block it with a few strips of wood and just plane/sand them away.
> Actually, I'm inclined to think that's the best approach, so I may try
> it on some scrap while I await more brilliant feedback from you guys.
>
> If there's no other choice I can cut the offending chunk away and glue
> in a replacement, but it'll lose a lot of character and just plain
> won't look as good as I know it can.
>
> I hope all this makes sense. =A0Thanks for your advice.
>
> =A0 - Owen -
Another way to approach this is by covering a piece of scrap with
kitchen waxed paper. This suggestion is a variation of previously
mentioned ideas.
I also like the dutchman technique. Norm has demonstrated this on
several shows and it seems to produce a satisfactory solution to the
problem.
Joe G
On Jul 9, 2:38=A0pm, "SonomaProducts.com" <[email protected]> wrote:
> > I hope all this makes sense. =A0Thanks for your advice.
>
> > =A0 - Owen -
>
> Epoxy sands out really well so you could just build up a dam using
> tape and sand it all away later.
>
> I like the concept of doing a patch using similar grained material. In
> a very early job (16-17 years old) at a rustic furniture factory when
> we had bad knots in Pine we would use a chisel them out and sand a
> plug to fit and just yellow glue it in place. You would be amazed how
> well it blends.
I actually have most of the original knots still in place, but some of
them are loose and there's wild grained gaps up to half a centimetre
across near the centre plug.
> Another option is to just break out all the loose material and grind
> and sand the edges smooth. I actually always like to have some little
> hidden wild edge on any of the better furniture I build. And when it
> is for me, I like it to be visible.
I like the wax idea. I'm going to try it on some scrap and see just
how easily it pops off. I already have a few dutchmans replacing the
ugly man-made tears the contractors made when they ripped this stuff
off the walls. The natural "defect" seems more appropriate to
preserve. But I think I'll pre-seal the wood so it takes the finish
before I embed wax into the pores.
>lots of guys here claim that for wood they never go finer than 220 but for=
epoxy I think
you're going to need at least 400 (maybe 600) or you're going to see
scratches...
I'm hoping to avoid all that by applying finish on top of the epoxy,
letting it fill in the scratches, but I've never tried that before.
Won't it work? I've seen how smooth you can make it using finer and
finer grits, but I'm hoping it's not necessary. I've got the fine
grits I need, and given the small area it's not really such a big deal
if I have to go that route. I'm also hoping to avoid a lot of
experimentation just by asking you guys for your experience, but I'll
do what I must, and learn what I will.
Thanks for the great suggestions so far. It's exactly the kind of
feedback I was hoping for!
- Owen -
manyirons wrote:
> Hi all,
>
> I've been building a captain's bed for my son out of some old
> reclaimed pine. Due to the limited amount of wood I was not able to
> avoid having some knots at the edge of a face frame. One of them is
> big and really shabby, with quite large voids. I'd like to fill it,
> and I'm thinking epoxy would be the best choice. I really don't like
> the look of wood filler when it gets any bigger than a BB.
>
> Assuming you agree that epoxy is a good choice, how can I apply it?
> At the edge of the board it's going to just run out, so I need to
> block it while it sets. The blocking must not stick to the epoxy.
Add Cab-o-sil (fumed silica) to the epoxy to thicken it. Make the mixture
about peanut butter consistency. You can get Cab-o-sil (or Air-o-sil) at
most any place that sells epoxy other than HD, Lowes, etc. Marine stores or
Surfboard shops may be a good bet. If not, internet.
You can use clear packaging tape to help shape the fill. Best to apply it
to another piece of wood, clamp that to what you are filling.
______________
> Alternatively, if I let the expoxy get
> proud of the surface can I sand it down and hope to apply water based
> Minwax Varathane and not see the sanding marks? In that case I can
> block it with a few strips of wood and just plane/sand them away.
Epoxy doesn't sand real easy. A cabinet scraper works pretty well. As far
as seeing marks, depends on how finely you sand. Just like wood.
________________
IMO, a large epoxy fill isn't going to look good...it will look like a
yellowish chunk of glass. Or dark glass, depending on how deep the fill is.
My own preference is to use wood...chips (as from a planer), coarse dust
(saw dust) and fine dust (sanding dust) mixed with glue to build up a
surface that is flat but shows irregularity because of the mix of particle
size. It may or may not be acceptable "as is"; if not use an artist's brush
with paint - any kind of paint - in varying colors to draw in a pattern and
colors that matches the surrounding wood. Then top coat. Do it right and
you'll never know the knot was there.
BTW, if the knot has a dark edge, cut that away before filling and coloring.
--
dadiOH
____________________________
dadiOH's dandies v3.06...
...a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico
On Fri, 9 Jul 2010 05:33:36 -0700 (PDT), manyirons
<[email protected]> wrote:
>If there's no other choice I can cut the offending chunk away and glue
>in a replacement, but it'll lose a lot of character and just plain
>won't look as good as I know it can.
You could remove the offending area and replace it with some scrap
material that the grain matches the affected area's grain. Repairs
like that are often invisible.
If you're concerned about losing some character why not create a
"Dutchman" patch for that area. One that would repair the area but
not attempt to conceal it's existence. That way you could have your
cake and eat it too.
Gordon Shumway
When you subsidize poverty and failure, you get more of both.
> =A0The only thing I think I
> must watch out for is over sanding, since the epoxy is much harder
> than the pine and it ends up a bit proud. =A0In this case it won't
> matter, but someday it might.
With the 5-minute epoxy there's a window of time after it has set up
firm during which you can slice it off with a sharp plane blade flush
with the surrounding wood. It's one of two uses I've found for the
Lee Valley flush-trimming plane, the other being to slice off
polyurethane glue squeeze out.
JP
On Jul 9, 9:31=A0pm, "Lew Hodgett" <[email protected]> wrote:
> "manyirons" wrote:
> > I've been building a captain's bed for my son out of some old
> > reclaimed pine. =A0Due to the limited amount of wood I was not able to
> > avoid having some knots at the edge of a face frame. =A0One of them is
> > big and really shabby, with quite large voids. =A0I'd like to fill it,
> > and I'm thinking epoxy would be the best choice. =A0I really don't
> > like
> > the look of wood filler when it gets any bigger than a BB.
>
> > Assuming you agree that epoxy is a good choice, how can I apply it?
>
> ------------------------------------------
> Since the knot is "shabby" anyway, knock it out so you can get back to
> some structurally sound wood.
>
> You then cover the sides of the knot hole with duct tape to form a
> temporary dam.
>
> Mix up some decent epoxy and thicken it with some micro_balloons to
> the consistency of mayo.
>
> (Using Cab_O_Sil to thicken epoxy is like getting a sentence to wear a
> hairshirt while sanding. You don't want to go there.)
>
> I might add some carbon black an make the patch an accent, but that's
> just me.
>
> If the knot is much larger than about an 1-1/2" in diameter, I make
> two pours to keep the heat down.
>
> Allow to cure for 2-3 days, then remove tape and sand.
>
> You now have a structurally sound timber.
>
> If you want to cover the patch with a "Dutchman, go for it.
>
> C Groh, want to jump in on this?
>
> Lew
I did a test on a scrap mortise with a peg hole in one side where I
poured in the 5-minute epoxy, and the waxed board pretty much did the
job. A little shred of it was left behind, but it was quickly sanded
away, to 320 grit. Scraper didn't seem to make any difference over
sanding, but it sure is hard to remove significant material. I
applied finish over top and it cleared right up so I'll probably stop
at 220 next time. It's drying now, and I'll see in the morning
whether it bonds and takes another coat. The only thing I think I
must watch out for is over sanding, since the epoxy is much harder
than the pine and it ends up a bit proud. In this case it won't
matter, but someday it might.
- Owen -
On Fri, 9 Jul 2010 05:33:36 -0700 (PDT), manyirons wrote:
> Hi all,
>
> I've been building a captain's bed for my son out of some old
> reclaimed pine. Due to the limited amount of wood I was not able to
> avoid having some knots at the edge of a face frame. One of them is
> big and really shabby, with quite large voids. I'd like to fill it,
> and I'm thinking epoxy would be the best choice. I really don't like
> the look of wood filler when it gets any bigger than a BB.
>
> Assuming you agree that epoxy is a good choice, how can I apply it?
> At the edge of the board it's going to just run out, so I need to
> block it while it sets. The blocking must not stick to the epoxy. I
> don't have sheets of teflon, other than teflon plumbing tape. Is
> there something else (like HDPE or polyethylene, which I didn't try it
> yet) that will work instead? Alternatively, if I let the expoxy get
> proud of the surface can I sand it down and hope to apply water based
> Minwax Varathane and not see the sanding marks? In that case I can
> block it with a few strips of wood and just plane/sand them away.
> Actually, I'm inclined to think that's the best approach, so I may try
> it on some scrap while I await more brilliant feedback from you guys.
>
> If there's no other choice I can cut the offending chunk away and glue
> in a replacement, but it'll lose a lot of character and just plain
> won't look as good as I know it can.
>
> I hope all this makes sense. Thanks for your advice.
>
> - Owen -
take a piece of scrap and rub it with wax and clamp it
over void, will pop off easily after the epoxy sets.
basilisk
On 07/09/2010 08:00 AM, basilisk wrote:
> On Fri, 9 Jul 2010 05:33:36 -0700 (PDT), manyirons wrote:
>
>> Hi all,
>>
>> I've been building a captain's bed for my son out of some old
>> reclaimed pine. Due to the limited amount of wood I was not able to
>> avoid having some knots at the edge of a face frame. One of them is
>> big and really shabby, with quite large voids. I'd like to fill it,
>> and I'm thinking epoxy would be the best choice. I really don't like
>> the look of wood filler when it gets any bigger than a BB.
>>
>> Assuming you agree that epoxy is a good choice, how can I apply it?
>> At the edge of the board it's going to just run out, so I need to
>> block it while it sets. The blocking must not stick to the epoxy. I
>> don't have sheets of teflon, other than teflon plumbing tape. Is
>> there something else (like HDPE or polyethylene, which I didn't try it
>> yet) that will work instead? Alternatively, if I let the expoxy get
>> proud of the surface can I sand it down and hope to apply water based
>> Minwax Varathane and not see the sanding marks? In that case I can
>> block it with a few strips of wood and just plane/sand them away.
>> Actually, I'm inclined to think that's the best approach, so I may try
>> it on some scrap while I await more brilliant feedback from you guys.
>>
>> If there's no other choice I can cut the offending chunk away and glue
>> in a replacement, but it'll lose a lot of character and just plain
>> won't look as good as I know it can.
>>
>> I hope all this makes sense. Thanks for your advice.
>>
>> - Owen -
>
> take a piece of scrap and rub it with wax and clamp it
> over void, will pop off easily after the epoxy sets.
>
> basilisk
That should work, but I wonder what the remaining area around the knot hole looks like
(perpendicular to the backer board). It's likely that the epoxy will "sink in" to the wood
and NOT be proud of the surface by the time it's cured, so what I like to do is build a
"dam" around the affected area with simple latex caulk, which allows you to overfill the
area with a "lake" of epoxy and plane or sand it down after it's cured. You're going to
need some pretty fine sandpaper if you don't want to see sanding marks after you're done;
lots of guys here claim that for wood they never go finer than 220 but for epoxy I think
you're going to need at least 400 (maybe 600) or you're going to see scratches...
--
"Our beer goes through thousands of quality Czechs every day."
(From a Shiner Bock billboard I saw in Austin some years ago)
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On 7/10/2010 7:17 AM, Jay Pique wrote:
>> The only thing I think I
>> must watch out for is over sanding, since the epoxy is much harder
>> than the pine and it ends up a bit proud. In this case it won't
>> matter, but someday it might.
>
> With the 5-minute epoxy there's a window of time after it has set up
> firm during which you can slice it off with a sharp plane blade flush
> with the surrounding wood. It's one of two uses I've found for the
> Lee Valley flush-trimming plane, the other being to slice off
> polyurethane glue squeeze out.
>
> JP
That's true of pretty much any epoxy, not just the 5-minute variety. BTW, most
5-minute varieties yield pretty crappy results in terms of strength and holding
power; you're better off using the slower-curing epoxies if you want the best
quality. Most commercial grade epoxies I've used that yield these kinds of
results take at least a half hour to "kick" (get thick and gooey), and about 4
to 6 hours before they can be sliced and planed (like you mentioned), and at
least 6 to 8 hours before they can be sanded, preferably overnight. Good epoxy
can't be rushed.
--
Free bad advice available here.
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
I'd suggest mixing up some epoxy in a cup and adding sawdust from the same
kind of wood until the mixture is pretty stiff - it should stand up in peaks
and droop slowly if at all.
It'll still sag some while it's curing, so all you need to do to keep it in
shape is to make some of what used to called "dams": take a couple pieces of
scrap wood, cover them with a strip of smooth tape, and then wipe a thin
film of white grease on the tape so it'll release after the cure.
Do the knots one at a time. Fill the voids with a spatula, tool it until
it's a bit proud all around. Clamp a piece to the underside face and another
to the vertical edge to keep the stuff from drooping out of the patch.
Finally wipe off the squeezed-out mixture and tool the upper face until it's
just very slightly proud (epoxy doesn't shrink to any appreciable extent).
Work reasonably quickly.
After a while, while it's still just a bit green (not yet cured rock-hard),
pop off the dams, give the edge and the underside face a wipe with a small
bit of paint thinner to remove any trace of the grease, and block-sand as
necessary with a coarse paper like 60 or 80 grit to make it flush. Let it
finish curing, and then go over the faces and the edge with finer grits
until you like the look.
The filler will come out darker than you expect, so do a test on a piece of
scrap to see if it's to your taste. If not, there are other special-purpose
fillers for epoxy which come out white or gray, and then you can take a
brown sharpie and just draw over the patches to try to match the grain, or
stain it to suit yourself.
For something like this, I use West Epoxy. You can get different catalysts
which cure at different speeds. For this I'd use slow catalyst so that I'd
have plenty of time to work the patch before it started to stiffen up.
Hardware store epoxy might not give you that flexibility.
Tom
Lew Hodgett wrote:
> Mix up some decent epoxy and thicken it with some micro_balloons to
> the consistency of mayo.
>
> (Using Cab_O_Sil to thicken epoxy is like getting a sentence to wear a
> hairshirt while sanding. You don't want to go there.)
I've used Cab-o-sil for 40 years, sanded a lot, nary an itch. Fiberglass,
yes, fumed silica, no. Nothing wrong with micro baloons if you don't mind
the color. Ditto wood dust. Ditto talc (but it's heavy, no big deal for a
knot).
--
dadiOH
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