Luminous Landscape Forum

Raw & Post Processing, Printing => Printing: Printers, Papers and Inks => Topic started by: philbaum on May 25, 2013, 12:41:14 pm

Title: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: philbaum on May 25, 2013, 12:41:14 pm
I'm convinced that early stretcher bars were designed for painters, not for for photographers using already printed canvas.  Sharp edges don't matter so much on painters canvas since the canvas is often primed after installation, causing shrinkage and therefore a tight installation.  

Many stretcher bars you buy often still have sharp edges.  When one stretches printed canvas, some users will blame the amount of force used as the cause of cracks.  But this is not the real problem.  When i started buying stretcher bars from French Canvas (frenchcanvas.com), i became aware that nice rounded outer edges will allow canvas to be stretched without  this tendency to crack.

When i've been forced to buy locally from an art shop, today i'm still getting getting sharp edges (they mostly cater to painters, so weren't much interested in my complaints)  So now i either use a handplane or file to round the edges before assembly.  

I can't say i get perfect quality on the stretcher bars from French Canvas because i still get an occasional warped  bar, mismachined bar, or a sharp edge or two, but i haven't found a company that produces better quaity yet.  But i am glad to hear that French Canvas is going to produce their own stretcher bars in the US using poplar wood.  I think it means better more consistent quality.  Which means less time for me to groom these bars before installation - a pain in the ass :-)

If there are better suppliers out there, please let me know.  I have to admit i have often ruled out suppliers that charge a lot more for their bars - so perhaps thats my problem :-)  Another thing that French Canvas does, is that their bars are often sized 1/8" under on their length, such that the breaks in prints occur on the side of the canvas and not on the front, where they tend to more disruptive to the viewer.  I have found this practice of making slightly undersize bars to work very well.

No, i don't have any affiliation or ownership with French Gallery, just happy to find a supplier that provides a more reliable product.  Also i should note, that their customer service has so far been excellent.

 
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: dgberg on May 25, 2013, 01:16:07 pm
Three options.
Do like I did and had my millwork firm setup and run my 1/12" and 2" stretchers with the proper radiuses.
Second option keep your present stock and run a small router with a quarter round bit over that bottom edge.
Last option is to find a supplier that offers the bars with the proper top and bottom radius.
I used Decor Moulding out of NY. In the past but the pine was inconsistent in size and needed more of that bottom radius for stretching without cracking.
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: Paul2660 on May 25, 2013, 04:25:50 pm
Larson makes a very good 1.5 inch bar which I use.  Part number 6011 sold in 9 ft lenght.  I also sand down the first edge just a bit to take some of edge out. 

Paul Caldwell
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: bill t. on May 25, 2013, 04:46:21 pm
When last I used stretchers these guys had a good product with excellent consistency and nice rounded corners.  The boxes were also sized for economical shipping.

Just remember, if you cut your own stretchers they will not be easily adjustable to re tension the canvas.

http://linenliners.com/products/stretchers/
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: philbaum on May 25, 2013, 09:21:05 pm
Thanks for the replies.  Still checking out some of the suppliers mentioned.  I'd forgotten, but i do have a trim router than i haven't used in a while.  It would make sense to use that for the occasional rounding chore, that might speed things up a bit.

Linenliners has quite the selection of bars, but i'm going to still try to minimize the amount of woodworking i do.
But some of those framing supplies might be useful jobs i occasionally have - a good source.

thanks, phil
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: darlingm on May 26, 2013, 12:24:47 am
OP, dead on.  Before I started stocking lots of mail ordered bars, and larger ones I could cut down to size, I searched every place I could find that sells stretcher bars, and they were all meant for artists with sharp edges.  I don't think many storefronts stock rounded bars.
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: chaddro on May 28, 2013, 04:05:58 pm
Dick Blik actually has a decent stretcher bar with keys so you can add tension to the stretch print after.
I've been using them for several years now. They have heavy duty bars up to 96" and also braces.

http://www.dickblick.com/products/blick-heavy-duty-stretcher-bars/

You may have some minor inconsistencies from bar to bar, so I always buy in store so I can test fit before buying.
 
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: RFPhotography on May 29, 2013, 08:55:26 am
Are you talking edges or corners?  It makes a difference.  I've never found a stretcher bar that had a sharp edge (the part of the bar that touches the print).  But every stretcher bar I've looked at does have sharp corners (where the two milled pieces join).  The latter is pretty easily taken care of, if desired, with a power sander.  That said, I've never had a problem with cracking with properly coated prints.  The spray on coatings are useless.  But there are roll on coatings that do a very nice job of sealing the print and preventing cracking. 
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: PeterAit on May 29, 2013, 11:11:42 am
I assume you don't really mean that the canvas cracks, but rather the varnish you have applied? Could that be the problem? I have stretched many prints on bars with 90 degree edges without a single instance of cracking (I use the the Breathing Color varnish). FWIW, my workflow has the stretching done within a day or at most 2 of the varnishing. If the varnished prints sat around a lot longer, perhaps the varnish gets a bit more brittle?

I would not accept bars that are not the specified length. If I want the print to wrap around the edge by a wee bit (a good idea), I will make the print that much larger.
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: philbaum on May 30, 2013, 02:35:53 am
I'm talking the edges along the length or width of the bars, not the corners.  And its not the canvas cracking, that would be really bad :-), its the pigment flaking off the creased canvas, minutely - very tiny flakes.

I've been using aqueous polyurethane varnish, exterior, clear, selling for about $20/quart which is probably much cheaper than BC.  I previously was using interior polyurethane and it cracked more frequently, the exterior is definitely better.  Self leveling, dries in less than 2 hours, brushed on coat.  Now i get only a slight amount of cracking in the corner when its folded back on itself.   

I buy my larger prints (larger than i can print that is :-)) from a company that sprays on the varnish.  I don't see cracking in even the corners on theirs, so its either due to a lighter coat or better varnish than i'm using.
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: Photopro888 on May 30, 2013, 03:27:35 am
I have tested many stretcher bars… (Including French canvas) and the best I have found are from ML Supplies (http://mlsupplies.biz/C-Stretcher-Bar_c21.htm) the edges have the perfect amount of roundness to them. The sizing is always very accurate within a 16th of an inch – the corners join so good that they are sharp so I do sand them (by hand) with a sanding block, but it only takes 60 seconds to do four corners.

It looks they may use the same stock from what Bill T recommended (http://linenliners.com/products/stretchers/) but I’m not positive on that, so if you don’t have your own chop and join equipment this place (ML Supplies) is my favorite for stretcher bars.
 
As far as canvas cracking, I would agree with Peter it’s most likely the coating (that we put on) that will pull the canvas coating (the coating that the canvas manufacture puts on) along with the ink   – the BC coating is good if you stretch in a day or two, but with ClearShield Type C I can stretch months later without issue, this has been my experience after well over a hundred Gallery Wraps.

-Darren
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: PeterAit on May 30, 2013, 08:19:20 am
I've been using aqueous polyurethane varnish, exterior, clear, selling for about $20/quart which is probably much cheaper than BC.  I previously was using interior polyurethane and it cracked more frequently, the exterior is definitely better.  Self leveling, dries in less than 2 hours, brushed on coat.  Now i get only a slight amount of cracking in the corner when its folded back on itself.   

The BC Timeless Gloss or Satin is $90 a gallon, just a little more than you are paying. For some odd reason, the matte is $120 a gallon.
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: jferrari on May 30, 2013, 09:08:15 pm
The BC Timeless Gloss or Satin is $90 a gallon, just a little more than you are paying. For some odd reason, the matte is $120 a gallon.
Or $107.95 as reported on their website...
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: bill t. on May 30, 2013, 11:57:37 pm
If anybody's interested the corner joints on those ML Supplies bars were made with a device called a thumb nailer or thumbnail joiner.  It's not as awful as it sounds, really!  I don't  recommend the technique, but it is a way to join frames without an underpinner, while enhancing your pleasure at generating an even bigger sawdust mess than your saw.  If you are interested in that technique, you should search thegrumble.com where you will get an earful of widely varying opinions.  The best ones aren't cheap and they are as persnickety as you could hope for.
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: dgberg on May 31, 2013, 06:27:59 am
Although I have an underpinner my tool of choice has been my hand held v nailer.
Especially with the larger frames. A spot of glue,pinch the joint together with your fingers and shoot 3 nails per joint.
Flip the frame over and another 3 vnails per joint. lightly sand the corners and done.
The vnails pull the joint together so no clamps required. You start with square miters you get a square frame.
I just completed a 30"x40" frame and it took 3 minutes to cut up the 10' lengths on my dual mitersaw and another 5 minutes to staple and sand.Just under 10 minutes from start to finish.
And the reason to make these yourself? The frame was actually 30 1/16" x 40 1/8" the exact face size of the canvas after stretching requires that little difference in frame sizing.

Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: mg73 on May 31, 2013, 09:26:08 am
Dan,

Which V nailer are you using?  How do I get one?
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: dgberg on May 31, 2013, 06:17:24 pm
It is a Woodtek, available at Woodworkers Supply.
$229.99
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: Kanvas Keepsakes on June 01, 2013, 03:09:01 pm
Hey Dan, I saw the image of the V nailer you posted.  I didn't know they sold these.  I'm going to purchase one ASAP.  Quick question.  The wooden stretcher bars you are nailing in the picture.  I like the little lip on top.  Where do you get these made? 
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: petermfiore on June 01, 2013, 03:13:30 pm
rgvsdigitalpimp,

The lip is pretty standard on Artist stretcher strips. It is there to prevent a brush from striking against the stretcher bar, leaving a phantom mark. Search on Artist stretcher strips , and you should have a good choice.

Peter
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: dgberg on June 01, 2013, 04:55:45 pm
rgvsdigitalpimp,

The lip is pretty standard on Artist stretcher strips. It is there to prevent a brush from striking against the stretcher bar, leaving a phantom mark. Search on Artist stretcher strips , and you should have a good choice.

Peter
Their are other good reasons for that top lip w/radius. All manufactured bars have it.(Or they should.)  
I have my millwork shop do custom runs twice a year to my specifications. All the proper radiuses 1 1/2" and 2" deep bars in 10' lengths in Poplar. It is called taking charge of your quality control. Just too many defects coming from my suppliers.
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: RFPhotography on June 01, 2013, 07:23:58 pm
I'm talking the edges along the length or width of the bars, not the corners.  And its not the canvas cracking, that would be really bad :-), its the pigment flaking off the creased canvas, minutely - very tiny flakes.

I've been using aqueous polyurethane varnish, exterior, clear, selling for about $20/quart which is probably much cheaper than BC.  I previously was using interior polyurethane and it cracked more frequently, the exterior is definitely better.  Self leveling, dries in less than 2 hours, brushed on coat.  Now i get only a slight amount of cracking in the corner when its folded back on itself.   

I buy my larger prints (larger than i can print that is :-)) from a company that sprays on the varnish.  I don't see cracking in even the corners on theirs, so its either due to a lighter coat or better varnish than i'm using.

I've been using Premier Eco for a few years now with no problems.  It's not inexpensive, but it works.  A quart is about $38 here in Toronto.

When I said the spray on coatings, I was referring to things like the Hahnemule or Moab that come in a spray can.  Of course the Eco and similar coatings can be sprayed or rolled on.
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: Mike Guilbault on June 02, 2013, 05:30:49 pm
Hey Dan... just wanted to confirm what you wrote earlier when you said 3 v-nails per corner, but then flip it over and add another three v-nails per corner?  So that's 6 v-nails per joint?  Seems like you'd increase the chances of splitting with that many, no?
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: dgberg on June 02, 2013, 06:28:26 pm
No splitting. These are 1 1/2" and 2" poplar and will not split with those nails.
The sharpness of the nail along with the power that they are driven in with makes splitting a non issue.
Maybe with other materials like 3/4" thick pine but I doubt it.
You of course could use just 2 per side.
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: John Nollendorfs on June 02, 2013, 08:34:58 pm
While I can see getting one of those expensive "V" guns if you are doing custom wood framing too, I think it's a bit overkill just for stretchers. I've been just driving 3 heavy duty 3/8" staples on both sides of each corner. (same staples I use to fasten canvas in my $30 pneumatic stapler from Harbor Freight.) Have not had any trouble in 3 years even with 3' x 5' frames.

The frame is basically held together by the stretched canvas.
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: dgberg on June 03, 2013, 08:26:28 am
I also used my canvas stapler in earlier days. Worked just fine but nothing like a vnailer.
Just like using a standard chop saw to cut joints works just fine until you start using a dual mitersaw. Big difference.
Their is a high and low cost/quality tool made for about every process you can imagine.

Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: StuNY on June 03, 2013, 11:49:24 am
Lots of great info in this thread thanks! Inspired me to start making my own gallery wrap frames after endless using/experimenting with purchased parts and kits that I was never quite satisfied with. Picked up an upholstery stapler and had everything else already. Home Depot select pine 1x2's (once you find a few straight ones!) seem to be the right size (nothing larger than 13"x24" for me) and easy to work with. They make 1.5 inch deep frames. Just finished mounting my first 4 canvas' last night and am very happy!
I put an 1/8 inch round on the edges the canvas touches with my table mounted router, cut a 15 degree bevel on the front and back sides, and used miter saw for cutting the angles. Sounds more complicated than it is, I made 8 small frames in an hour or two. Adds a little bit of pride knowing I did everything from take the shot/process/print/mount.
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: Kanvas Keepsakes on June 03, 2013, 03:30:22 pm
Stuny, I'd love to see your finished stick after you do those cuts.  I use 1x1.5" poplar sticks.  I use a nail gun to add a .5" quarter round moulding to edge.  Makes a 1.5" stretcher with raised bevel as well.  If I can eliminate the nailing quarter round moulding to poplar stick using router table that would be awesome.  I just don't get quite the picture on exactly how to do what your describing. 
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: StuNY on June 03, 2013, 03:57:55 pm
I will take a picture and post later. I was originally intending to do it the way you describe, but when I saw the price for the molding decided to just make the whole piece in one shot!
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: Kanvas Keepsakes on June 03, 2013, 04:47:53 pm
Stuny, at the local cabinet supply shop about a block down the road from me I get the 1.5" x 1" poplar sticks plus the .5" quarter round moulding for a total of .74 cents a linear foot.  Super cheap
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: dgberg on June 03, 2013, 05:28:05 pm
You should be able to do better then that.
My custom 1 1/2"  x 1 1/2" poplar run me .45 a Lin. Foot.
Perfectly profiled all you do is miter and assemble.
The 2" x 11/2" are a little more at .58 a foot.
You can buy them already profiled for the size you are doing for under .50 a foot.
Decor moulding out of New York has 3 different sizes and they are ready to miter and assemble.
No millwork shops in your area that could set up their molder and do a run for you?
You really should not have to go through what you are going through unless you just enjoy it.
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: Kanvas Keepsakes on June 03, 2013, 05:33:26 pm
Dan I had two places quote me a couple hundred just to cut the blade to make the bars.  Then they wanted $1.25 a foot AFTER that.  Insane.  I really dont enjoy doing this.  Luckily I have a retired father in law that loves doing it.  I place my order with him he brings the frames ready.  I wish I had a local shop that could cut that for me
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: dgberg on June 03, 2013, 05:50:48 pm
We are really spoiled here in the amish mecca of southeastern Pennsylvania.
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: StuNY on June 03, 2013, 06:39:23 pm
Stuny, I'd love to see your finished stick after you do those cuts.  I use 1x1.5" poplar sticks.  I use a nail gun to add a .5" quarter round moulding to edge.  Makes a 1.5" stretcher with raised bevel as well.  If I can eliminate the nailing quarter round moulding to poplar stick using router table that would be awesome.  I just don't get quite the picture on exactly how to do what your describing. 
Ok, the picture is below. I like the angle on the back that I staple too as it looks a little cleaner against the wall from the sides than when I had a flat back side.
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: Kanvas Keepsakes on June 03, 2013, 09:48:37 pm
Thanks for the photo! Now to try and reproduce it :) I know nothing about woodwork so I'll be consulting with an uncle of mine with your instructions.
Title: Re: Sharp Edges on Stretcher Bars cause cracking on canvas prints...
Post by: John Nollendorfs on June 04, 2013, 01:26:37 pm
Something to consider is using brick moulding, available for around $1.10 per foot, primed with white paint, and very sturdy for large framing sizes. 1 1/4" deep.