Thanks, Rob
Hey, that's an interesting question, I never heard the term "strainer" before
although I've used plenty of them. But I have never seen anyone successfully add
tension to a stretcher by using those little corner keys. I tried it a few
times, but it just doesn't work for me, but then, I tried this using those
cheapo 1 inch stretcher bars which are pretty damn unsuitable for anything
serious. On the other hand, I have never had trouble with canvas slackening
after its stretched, but then, I stretch REALLY tightly. I once was in a
painting class, I acquired a used redwood "strainer" about 6 by 10 feet, and
stretched it really tight (it took two people to help) and then gessoed it and
went to work in another room. Someone came in about 10 minutes later saying
"hey, you should SEE what your stretcher is doing!" I went back, and the bracing
bars were bowed out 18 inches from the plane. It looked like a wooden canoe
frame with canvas on top. But it relaxed and everything was perfectly square.
Now THAT's how to stretch a canvas!
Anyway, if it was me, I'd just pull the canvas tighter rather than use expansion
keys the corners. If you work really large, you really don't have any choice
except to use strainers, because you need crossbraces. If you expanded the
corners, you'd have to expand the braces too, and that would be a lot more
trouble than just pulling up some staples or tacks and restretching the canvas a
bit at a time.
>I stretch REALLY tightly. I once was in a
>painting class, I acquired a used redwood "strainer" about 6 by 10 feet, and
>stretched it really tight (it took two people to help) and then gessoed it
>and
>went to work in another room. Someone came in about 10 minutes later saying
>"hey, you should SEE what your stretcher is doing!" I went back, and the
>bracing
>bars were bowed out 18 inches from the plane. It looked like a wooden canoe
Yeah, I know what you mean. I used to stretch tight, but now I have gotten so
that I pretty much know just how much slack to leave in the canvas before
priming. I make mistakes though. Recently I had to clamp and glue a sister
brace to an original brace that had bowed out about six inches from the back of
a too tight canvas.
The thing is, some of these still slacken after a while, so pulling up and
re-tacking is the next step.
By the way, it is possible to make expandable cross braces, too. It does
add a bit of woodworking to do it right, though...a mortise and tenon with
slots for wedges. But at this point I'm looking for less complication in the
products that I use and I want to keep prices reasonable for my customers.
>>But I have never seen anyone successfully add
>>tension to a stretcher by using those little corner keys.
>When I have used commercial stretchers, I have always used the heavy duty
>variety and it is actually possible to key them out with wedges, but it is
also
>possible to damage the canvas. Bitter experience taught me that!
I've infrequently had to use the corner wedges to tighten
a canvas after I'd finished the painting. When I do that
I try to use the plastic ones that are sold for the purpose
rather than the wooden ones that sometimes come with the
smaller cross-section stretcher bars. There are commercially
available metal corner expanders that one can purchase also
that have a threaded screw/thumbwheel arrangement.
On the other hand, my experience has taught me that if I
thoroughly soak my canvas (I use acrylic gesso exclusively
for priming) before gessoing, it is much like wetting watercolor
paper before stretching it. The canvas is "as expanded" when
soaked through as it will ever get and once stapled to the
stretcher bars it is as tight as it will ever get once it dries
out. Using this method I rarely have a problem with sagging
canvases anymore.
> >But I have never seen anyone successfully add
> >tension to a stretcher by using those little corner keys.
> When I have used commercial stretchers, I have always used the heavy duty
> variety and it is actually possible to key them out with wedges, but it
is also
> possible to damage the canvas. Bitter experience taught me that!
>
> >I stretch REALLY tightly. I once was in a
> >painting class, I acquired a used redwood "strainer" about 6 by 10 feet, and
> >stretched it really tight (it took two people to help) and then gessoed it
> >and
> >went to work in another room. Someone came in about 10 minutes later saying
> >"hey, you should SEE what your stretcher is doing!" I went back, and the
> >bracing
> >bars were bowed out 18 inches from the plane. It looked like a wooden canoe
>
> Yeah, I know what you mean. I used to stretch tight, but now I have gotten so
> that I pretty much know just how much slack to leave in the canvas before
> priming. I make mistakes though. Recently I had to clamp and glue a sister
> brace to an original brace that had bowed out about six inches from the
back of
> a too tight canvas.
It happens to the best of them. I noticed that my local museum restretched
a major Jackson Pollock work they own, its a huge mural about 20 feet wide
by about 8 feet tall. I had viewed the painting for years, but when they
did some maintenance (for a rare traveling exhibit) i noticed they did some
work on the frame. Now its on a square frame, and its obvious where the
original stretcher's top bar was severely bowed downwards. They actually
let the canvas out, and filled in the blank canvas (that used to be wrapped
over the bar) with a neutral grey color, rather than use a shorter
stretcher and lose actual painting surface. But hey, it was almost his
first large work, live and learn. Oh, BTW, that work is on display with the
Pollock retrospective right now, I think its currently at the Tate in
London, if you care to see it. Its called "Untitled" but you'll recognize
it by the 4 inch wide arc of gray at the top edge.
> The thing is, some of these still slacken after a while, so pulling up and
> re-tacking is the next step.
> By the way, it is possible to make expandable cross braces, too. It does
> add a bit of woodworking to do it right, though...a mortise and tenon with
> slots for wedges. But at this point I'm looking for less complication in the
> products that I use and I want to keep prices reasonable for my customers.
Yeah, I have a 36x48 2inch stretcher bar with expandable crossbraces, I've
reused it about 8 times now, but finally got a serious finished painting
permanently mounted on it. The thing is, to make something with expandable
bars, you're probably talking about a 2 or 3 inch bar, which are so rigid
they don't need bars until you're into huge sizes (my 36x48 didn't really
require it). And they're still a pain in the butt to expand (which I've
never needed to do).
Hell, I dunno, if people want the fancy expandable stretchers, they'll pay
big bucks for it, and it will cost a bundle if they're working large. I
bought one, but every time I used it, I would look at the finished work,
and think, "is this painting as good as the stretcher its on?" ..heh
----------------
Charles Eicher
cei...@inav.net
----------------
> In article <19990315084503...@ng94.aol.com>, beef...@aol.com
> says...
>
> >>But I have never seen anyone successfully add
> >>tension to a stretcher by using those little corner keys.
> >When I have used commercial stretchers, I have always used the heavy duty
> >variety and it is actually possible to key them out with wedges, but it is
> also
> >possible to damage the canvas. Bitter experience taught me that!
>
> I've infrequently had to use the corner wedges to tighten
> a canvas after I'd finished the painting. When I do that
> I try to use the plastic ones that are sold for the purpose
> rather than the wooden ones that sometimes come with the
> smaller cross-section stretcher bars. There are commercially
> available metal corner expanders that one can purchase also
> that have a threaded screw/thumbwheel arrangement.
>
> On the other hand, my experience has taught me that if I
> thoroughly soak my canvas (I use acrylic gesso exclusively
> for priming) before gessoing, it is much like wetting watercolor
> paper before stretching it. The canvas is "as expanded" when
> soaked through as it will ever get and once stapled to the
> stretcher bars it is as tight as it will ever get once it dries
> out. Using this method I rarely have a problem with sagging
> canvases anymore.
Some advice: Generally, a strainer will not give you problems if you are
stretching canvas (although I do not have extensive experience in drastic
climatic/humidity shifts...nor hae I used every configuration of canvas
weight). Linen, on the other hand, almost always becomes problematic on a
strainer, particularly the larger you go. I have decided to never again
use a strainer for linen, no matter how tightly stretched, no matter how
much the strainer bows and distorts when the primer is applied, it
inevitably responds more profoundly to humidity changes and ends up with
large rippling sagging movements across its surface, impossible to deal
with on a strainer other than a tedious process of restretching. Linen
demands much more attention in the tautness tuning department. YMMV.
Cheers,
-N.
--
N
To reach me, remove _xxx from my address.
> >But I have never seen anyone successfully add
> >tension to a stretcher by using those little corner keys.
> When I have used commercial stretchers, I have always used the heavy duty
> variety and it is actually possible to key them out with wedges, but it
is also
> possible to damage the canvas. Bitter experience taught me that!
>
> >I stretch REALLY tightly. I once was in a
> >painting class, I acquired a used redwood "strainer" about 6 by 10 feet, and
> >stretched it really tight (it took two people to help) and then gessoed it
> >and
> >went to work in another room. Someone came in about 10 minutes later saying
> >"hey, you should SEE what your stretcher is doing!" I went back, and the
> >bracing
> >bars were bowed out 18 inches from the plane. It looked like a wooden canoe
>
> Yeah, I know what you mean. I used to stretch tight, but now I have gotten so
> that I pretty much know just how much slack to leave in the canvas before
> priming. I make mistakes though. Recently I had to clamp and glue a sister
> brace to an original brace that had bowed out about six inches from the
back of
> a too tight canvas.
> The thing is, some of these still slacken after a while, so pulling up and
> re-tacking is the next step.
> By the way, it is possible to make expandable cross braces, too. It does
> add a bit of woodworking to do it right, though...a mortise and tenon with
> slots for wedges. But at this point I'm looking for less complication in the
> products that I use and I want to keep prices reasonable for my customers.
About 10 years ago I used to work for an artist's stretcher maker,
fabricating stretchers. Most were strainers.
I make mine differently. Recently, I have been making stretchers using
metal corner hardware instead of using wood joinery. I think it is
similiar to other corner hardware systems, although I can't be certain, as
I never really examined the construction of other systems close up (I
relished the challange of figuring out a design that would be functional).
In any case, on a very limited run (not buying massive board footage) I
can make a seriously choice 6'x 5' heavy duty poplar stretcher (grade A
wood), stunning to behold on its own, with adjustable (breakdown,
expandable) metal corner hardware...all for under $25. Buying in bulk
would drive this price down. This is about as fine a stretcher as you will
ever see. Fairly easy to construct, basically, in addition to cutting
simple miters, it amounts to drilling a few holes. I make them with
adjustable (but not expandable) crossbraces. For a few dollars more , I
could upgrade to expandable/tensioned crossbraces, with similair
hardware...it would be a cinch. If I was more foolish than I currently am,
I would go into business production here in NYC.
E-mail me for orders... :-)
Just kidding.
>Recently, I have been making stretchers using
>metal corner hardware instead of using wood joinery. I think it is
>similiar to other corner hardware systems, although I can't be certain
When I cut two-inch stretchers from larger stock I use
a corner system that uses the 45 degree miter and a
hole drilled to fit a 5/8 inch diameter dowel. I hold
the corners together in a framing jig while drilling
the holes, insert the dowel and trim it to length.
This corner holding works well for me and allows some
expansion of the corners later if I need to tighten
the canvas. My cross-braces are made with a mortise so
that they can be loosened and allowed to expand if I
do need to stretch at the corners, and then the cross
braces are refastened in the new position. Also, when
cutting the stretchers I saw a 30 degree miter into the
face that will be the fronting under the canvas so that the
canvas is in contact with the underlying stretchers only
at the thinnest of outer edges.
> In article <redirect-200...@1cust242.tnt9.nyc3.da.uu.net>,
> redi...@earthlink.net_xxx says...
>
> >Recently, I have been making stretchers using
> >metal corner hardware instead of using wood joinery. I think it is
> >similiar to other corner hardware systems, although I can't be certain
>
> When I cut two-inch stretchers from larger stock I use
> a corner system that uses the 45 degree miter and a
> hole drilled to fit a 5/8 inch diameter dowel. I hold
> the corners together in a framing jig while drilling
> the holes, insert the dowel and trim it to length.
> This corner holding works well for me and allows some
> expansion of the corners later if I need to tighten
> the canvas. My cross-braces are made with a mortise so
> that they can be loosened and allowed to expand if I
> do need to stretch at the corners, and then the cross
> braces are refastened in the new position.
I understand your design, however, how do you expand or contract the
miters using your dowel method?
My experience and research has proven to me that any stetcher system that
uses a hammer to adjust the corners (I'm not suggesting this is your
method), is not a good system...one doesn't want to be banging in wedges
(it shocks the painting, and also yields the potential for a misplaced
blow and other damage to the anvas/support material from behind). I think
the driven-wedge system to be functionally obsolete, with respect to other
designs currently availible.
> Also, when
> cutting the stretchers I saw a 30 degree miter into the
> face that will be the fronting under the canvas so that the
> canvas is in contact with the underlying stretchers only
> at the thinnest of outer edges.
If you start with thicker stock, I suppose you could make your cut and
have two indentical peices of similiar form (assuming your wood to be
stable). These days, I am using 1/4 round molding. The easiest way I have
used, is 1/4 round moulding brad-tacked with a pneumatic nailer onto a
trued up frame side cut to dimension. Fast, simple, cheap, no waste. If
you have a source for quality lumber that sells it pre-cut to a dimension
you can work, you can even forgo any planing or jointing: take delivery,
tack on a 1/4 round, cut to dimension, drill for corner hardware, jump in
jaccuzi.
>I understand your design, however, how do you expand or contract the
>miters using your dowel method?
I cut my own wedges. I have no compunction about hammering
from the back side. I'm not THAT clumsy that I'd damage the
canvas in any way. Not sure what you mean by 'shocking' it.
There is no reason one couldn't use hardware expanders if
that is what one prefers. I try to keep it simple.
>If you start with thicker stock, I suppose you could make your cut and
>have two indentical peices of similiar form (assuming your wood to be
>stable). These days, I am using 1/4 round molding.
I use either redwood or cedar for my stretchers. No problems
so far with stability. And getting rid of the need to add round
molding is exactly the reason I 'rip' on a miter of 30 degrees.
You get the same angle on both sides of the rip cut. For example,
if you begin with a 2X6, you get two stretchers and two cross
braces from the same piece of stock. A 2X4 ripped would give
two stretchers of something less than 2 inches cross section
since a 2X4 is less than 2X4 to begin with. A 2X6 will be less
than 2 inches in that direction also, but it's close enough
for my purposes.
> I cut my own wedges. I have no compunction about hammering
> from the back side. I'm not THAT clumsy that I'd damage the
> canvas in any way. Not sure what you mean by 'shocking' it.
> There is no reason one couldn't use hardware expanders if
> that is what one prefers. I try to keep it simple.
I have found many good reasons in support of going with hardware. If it is
adjustment you are after (and why bother with an adjustable stretcher if
this is not of importance?), I have found stretcher keys to be innaccurate
and more difficult to get a precise increment with. If you work with
linen, particularly large scale, this is a significant issue. To tighten
up with keys, that is, to really expand a large stetcher, you need to
apply force to the keys...on a large work this can be a substantial
undertaking, demanding much presure to expand and tighten the support.
That involves percussive force, either administered by your own hands, or
after your work is out of your controll, by someone else with their
hammer. Simply put, over the life of the stretcher frame, if and when it
needs to be adjusted, the stretcher frame is receiving x# of percussive
blows (as well as potential damage to the support from the rear during
tightening). In my point of view, using keys, there is more opportunity
for damage to the work over time, and more difficulty in adjustment.
Another thing to consider, is lost keys. This is fairly common, as over
time they can work their way loose due to the changes in the support.
Conservators often tie them with a corded leash drawn tight and attatched
to the stretcher. In the case of your own keying wedges, if they are made
to your specifications, if and when lost, it opens up an opportunity for
mishandling the maintainance of the stretcher.
All in all, if you are satisfied with your method, then there really is no
reason to stop using it.
> I use either redwood or cedar for my stretchers. No problems
> so far with stability. And getting rid of the need to add round
> molding is exactly the reason I 'rip' on a miter of 30 degrees.
> You get the same angle on both sides of the rip cut. For example,
> if you begin with a 2X6, you get two stretchers and two cross
> braces from the same piece of stock. A 2X4 ripped would give
> two stretchers of something less than 2 inches cross section
> since a 2X4 is less than 2X4 to begin with. A 2X6 will be less
> than 2 inches in that direction also, but it's close enough
> for my purposes.
I used to make stretchers like that, but personally, I found 1/4 moulding
much faster and simpler. As I fabricate now, I eliminate ALL ripping
operations: as well as the measuring plus set up that it entails. A bigger
consideration is joinery. What type of corner joinery are you using and
how long is that taking to measure, set up, and cut.
Cheers,
-N.
>A bigger
>consideration is joinery. What type of corner joinery are you using and
>how long is that taking to measure, set up, and cut.
The simplest part of the entire operation is cutting the
corners, which are simple butt joints at 45 degrees. It's
drilling the dowel holes and inserting the dowels at each
corner that takes the most time but this is simplified
as I pointed out earlier by my use of professional quality
cast iron framing jigs (vises).
OK. I think I understand...you either use a doweling jig or a miter clamp
to set up for the dowel drilling operation. However, I am unclear how you
make the joint expandable using a dowel and where the wedges are inserted.
>OK. I think I understand...you either use a doweling jig or a miter clamp
>to set up for the dowel drilling operation. However, I am unclear how you
>make the joint expandable using a dowel and where the wedges are inserted.
If you will visit a framing shop you will very likely be able
to see the kind of vise I am referring to. It allows holding
two pieces at 90 degrees to one another with the joint being
a butt joint cut on a 45 degree angle. You can purchase cheap
aluminum vises of similar design at some builder supply outlets
but the quality cast iron ones are harder to find. You need
to have access to a framing supplier catalog or source. You
can find similar devices in specialty tool catalogs such as those
published by Leichtung Handy (1-800-321-6840), Woodcraft (where
I purchased my pair for about $45.00 each) (1-800-225-1153),
and J. Cheaps & Sons (1-800-821-4142).
The wedges I use are cut by myself and when and if I use
them they are inserted into the butt joint and driven in
until the corners tighten up. I am NOT talking about huge
canvas sizes -- the largest I have ever painted are in the
5 ft and 6 ft categories. For any size in excess of 3 ft
I use this system with the 2 inch thick stretchers. Under
4 ft I use the commercially available lighter weight ones that
are also 'expandable' at the corners by use of wedges but
these differ in design from my own.
So, let me see if I am visualizing correctly. You have the miter clamps
(I'm familiar with them, own several types [the best yield generous space
to toy around with the joint] but I rarely use them anymore however) and
you are making a dowel reinforced mitered butt joint. Now, are you using
one dowel or two dowels per corner, I am assuming one? You are driving the
wedge directly into the joint from the inside corner (without any special
tooling to create a boardered channel for it...is this correct?
BeefaloeB,
I've used almost exactly the system you are describing, and still do use
it occasionally if I need a thicker sided canvas. I like using the L beam
crossection. I've also used the two-dowel method, but I am wondering if
one dowel would work just as well and be just as effective in eliminating
frame-member rotation. I've found corner hardware (can be used on
crossbraces too) for just a hair over a dollar a pop. I can do the $25
deal, including the hardware.
I started using two dowels because I wanted to keep the corners fairly strong
and eliminate any twisting, especially if I came up with a method to expand
the corners. At this point, fastening the corners with hardware anyway,
probably one dowel would do. I'm still tinkering.
Rob
>So, let me see if I am visualizing correctly. You have the miter clamps
>(I'm familiar with them, own several types [the best yield generous space
>to toy around with the joint] but I rarely use them anymore however) and
>you are making a dowel reinforced mitered butt joint. Now, are you using
>one dowel or two dowels per corner, I am assuming one? You are driving the
>wedge directly into the joint from the inside corner (without any special
>tooling to create a boardered channel for it...is this correct?
You've got it. But I reiterate. I rarely have to restretch my
canvases since learning that wetting them through and through
during the first stretching and before priming 'shrinks' the
cotton canvas that I use. I have also discovered that by
rewetting the back side of the canvas after it is painted in
acrylic will often further tension it. I have used linen on occasion but
only for smaller sizes under 3 ft or so. So I can't speak
from experience on stretching larger canvases using linen.
As for the doweling, I prefer to use one large diameter rather
than two smaller diameter. I usually use 5/8 inch. Don't know
about using two without some sort of jig that would keep the
holes paralell when drilled. Not to worry about that though
if you never use wedges or expand the corners anyway.
> Hey, you guys...are you artists or carpenters?
Both and more.
> Contact Twin Brooks
> Stretchers up in Lincolnville, Maine. Those guys will do whatever you want,
> any size you want, ship it to you, and let you get on with painting.
> I used
> to make my own. Twin Brooks is easier and better. Trust me on this.
Already seen their stuff, not impressed, stop. Would not change my
methods, as I enjoy making stretchers and working with wood in general,
and do superior work, customized work to my own specs,stop. Love working
with wood, stop. Love just being in the shop, stop. Don't feel time is
being wasted, stop. On the contrary, feel fully alive, stop. Thanks for
the advice though, stop.
Me too. I think of carpentry as an art too.
My problem is lacking proper carpentry tools at
the moment. I no longer have a shop and all my
power tools now are hand-held ones. Not conducive
to the finest workmanship but I manage. Had to
dado a garage door replacement part the other day
for a friend and managed to get it done with a
skill saw. I used to have a good shop setup and
enjoyed the availability of stand supported tools.
No longer have shop space and am lucky that I have
a good studio space in which to do my other loves.
> >I've also used the two-dowel method, but I am wondering if
> one dowel would work just as well and be just as effective in eliminating
> frame-member rotation.<
>
> I started using two dowels because I wanted to keep the corners fairly strong
> and eliminate any twisting, especially if I came up with a method to expand
> the corners. At this point, fastening the corners with hardware anyway,
> probably one dowel would do. I'm still tinkering.
Would not one dowel suffice if used on all the corners? I imagine that
there would (theoretically) no twisting because the angle of the dowels
and the fact that all four dowels are on a different axis.
Theoretically, perhaps. In practice, even corners with two dowels can twist,
depending on a number of factors, poor workmanship being one. I know because
my own workmanship has improved, but I went through a long learning phase.
Rob