Do any of you cut your own strainer bar stock

Larry Peterson

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I'm considering cutting my own strainer bars from 10' length stock so I don't have to keep various sizes in stock. I have a full woodworking shop so the tools aren't a problem.

If I cut them the same way as the pre-cut ones are sold, most of the cuts (except for the key slot cut - haven't decided how I am going to do that one yet) are straight forward. In other posts I have read about just cutting them like a frame and glueing/joining them. I think you lose to much strength this way. Or.... do you cut them some other way.

Does anyone know of any jigs/techniques/tips for this. Since LJ and others sell length stretcher bars, someone must be using them. Or are they????
 
people who are purchasing either chops or length strainer stock are making just that strainers. Bars that are glued and nailed.

Stretchers have the speciality lap joined corners. I have never seen a consumer jig dedicated to making these speciality joints.
 
Larry, I am using the strainer stock, but only for odd-sized canvases. I made one just yesterday.

I used Wally Fay's turnbuckle scheme, which was posted (with a drawing) a while back to make the strainer adjustable. It becomes, in effect, stretcher bars instead of a strainer and can be "keyed out" by adjusting the turnbuckles.

It's a very elegant system and I recommend it - at least for those odd sizes.

If you take the strainer stock and just glue and nail (or underpin) it like a frame, you can get a nice, strong corner, but if the canvas relaxes with time, there's no way to adjust it to take out the wrinkles.
 
Larry, if you can't find it in the archives, email me and I can fax you a diagram. With a full woodworking shop, you might want to investigate the "Lebron" stretcher, also in the archives (in the same thread, I think).
 
I use strainers exclusively.

I like the way they stay square after you join them. You can cut them to any size and not have to rely on standard sizes.

My feeling is that if you’ve got to key in a stretcher after the fact, you just may run out of frame.

It takes a bit of practice to be able to get the right amount of tension on the canvas without distorting the strainer.
 
We use strainer stock exclusively also.

Ditto Bill's comments.

I've heard that using the keys to adjust a canvas on a stretcher does not increase the force on the canvas linearly, thus putting uneven force on the canvas and has the potential to cause problems down the road.
 
Thanks for the info. I did a search on Lebron and found the diagram that you referred to. The method used, and hardware, is identical to what I have used before for joining sections of countertop, albeit with larger turnbuckle hardware. I built a 24' bar in my last house and the turnbuckle method for joining countertop is straight out of Countertop 101. My favorite hardware site, rockler.com has connectors at http://www.rockler.com/ecom7/product_details.cfm?&offerings_id=349, but these are too large for strainers. They have another one that is very interesting at http://www.rockler.com/ecom7/product_details.cfm?&offerings_id=10770 but this one looks to large also. The driver on this one is interesting. If any of you know a source for the small turnbuckles, let me know.

With my drill press, it should be easy to setup a jig for drilling the dowel holes and connecting holes for the turnbuckle. I may setup a jig that will drill the dowel holes through both pieces at the same time to ensure alignment. Plan B would be to use a doweling type jig out of Doweling 101 where the two sides are clamped together side-by-side and drilled in parallel to ensure alignment. That method would be needed anyway for drilling the connecting holes for the turnbuckle. I'm going to give some thought to which method I will use. Once I can find smaller turnbuckles, the setup for that on the drill press using a forstner bit will be easy also.

Although I've done this before for countertops, I've never gave it a thought for strainers.

Thanks, guys.
 
I agree with Bill. I only use strainer/stretcher stock. A properly stretched canvas will not require tightening for years, if at all. If needed there are other ways of tightening a canvas without using the plastic wedges or other devices incorporated in the strainer/stretcher frame.


FYI: Webster's definition of strainer is: "any of various devices for stretching or tightening something"

So a strainer frame is stretcher frame and visa-versa.

There are several different ways of cutting and joining the strainer/stretcher frame.
 
I'd be interested in hearing more opinions about strainers vs. stretchers - not the definitions (I think that's been established) but the pros and cons of each.

I have heard that you shouldn't need to key stretcher bars immediately after stretching a canvas, but that it might be needed at some future date. I have also heard that traditional 'keys' are an imperfect way to tighten canvases. I think Wally's turnbuckle system is superior because of the increased control. Tapping on keys with a hammer cannot be good for a canvas.

I've probably stretched a few hundred canvases in all these years - at most - and it's not my area of expertise,* so I'm really interested in hearing more.

*In case you're wondering, that would be bunny rabbit mats.
 
I use strainers, I also have several artists that I make them for and they say that with the newer canvas, if properly stretched, there isn't a problem with the canvas relaxing. I've spent more time fixing stretcher canvas because of squareness than I've ever had with square strainers. Ever try to frame some of the inexpensive tourist originals that are more than 1/4" off square?
 
Now you have got me wondering. If you stretch a stretcher by tapping the keysaren't you just stretching the canvas that is between the corner and the first staple? Then don't you get a pucker in the canvas at that point? Or are you supposed to remove the staples stretch the stretcher and then restaple the canvas?

Obviously I have never tightened a stretched canvas but I have put canvasses onto strainer (and stretcher) stock. Personally I've liked using strainer stock because it stays square when you pull on it while the stretcher seems to want to collapse on itself.
 
We like to make our own strainers.
One thing we use is "primed brick mold" for larger canvas. It is heavy duty and has a lip to hold the canvas up. We also brace the corners with 1/4 inch plywood or masonite as well as braces in the middle and sides.
 
I use only strainer stock. Glue it...vice it...it's perfect every time. I add a 1x2 support brace up the middle before I stretch.

When I stretch my canvases, I take my time, I won't tolerate even the slightest pucker or wave with every staple, and the stretches are always wrapped. I've never had one come back, even as big as 35 x 70 inches.

On most canvases, a loose canvas can be greatly improved by spraying a fine, light mist of hot water(not from the tap) on the verso side.
 
Larry, The Lebron stock material is 3" wide X 1" thick and is beveled on the face (Wedge cross section) so it can accept the larger knock-down hardware. The design also calls for crossbars with tensioning hardware on larger paintings.

Empirical study has shown...Tensioning of the canvas isn't necessary if the canvas never stretches under the original tension, and/or it is never exposed to climatic changes. I have stretched paintings on joined strainer stock as tight as a drum only to have to re stretch the painting a couple of days later because it is sagging.

It seems curious to me that folks went to all the trouble over the years to build tensionable frames for stretching canvas when a simple strainer would have sufficed. Perhaps one of the resident C/P gurus could enlighten.

I have also heard of continuous tension stretchers that incorporate spring tensioners in the hardware. As I understand it, the springs are held in a compressed state while the canvas is stretched and then the spring's retainers are removed allowing the springs to provide additional tension. As the canvas reacts to climatic changes, and as it ages and stretches naturally, the springs keep the tension on the canvas constant.

Snafu, If you try to apply Webster to the framing lexicon you will drive yourself crazy. There are a lot of words and phrases in framerlingo that have evolved from their original English and French roots. How to pronounce fillet, is it rabbet or rebate, when is a mat not a mat, and when is a mount a mat?
Strainer is typically used to describe a fixed sub-frame used to reinforce the primary frame, and in the instances mentioned in this thread to serve as a support for fabric. Stretcher is similar in use for fabric support, but has the feature of being tensionable after the fabric is attached.
 
ditto wally...we refer to strainers as those that are a subframe(eg, for a weak frame) which is square stock, and stretcher material has a "lip" to lift the canvas away from the bar. whee chap n joyn'm jes lak ah reglar framm!
 
Interesting topic. What is the cost difference? We use Fredrix stretcher bars unless the piece is odd-sized. From where are you getting your strainer stock? Does it warp over time if you buy in bulk? I don't have a complete measuring system on my saw (I do chop almost exclusively and use the saw mostly for "recovering" frames), so would I perhaps be eating up any profit by the time taken to cut strainers?

Do you discern a quality difference in the use of strainers vs. stretcher bars? We do a lot of canvases and I've been considering strainer stock for the future so would love some input on the above questions.
 
I buy strainer stock from L-J and from Evald Moulding. Both deliver and both have 2-3 sizes. I rarely order more than 20-40 feet, so warping hasn't been a problem. It's all finger-jointed wood and seems stable.

I stretched an imported canvas a few weeks ago and had to re-tension it 24 hours later. People are saying here that a good canvas, properly stretched, should not need keying later.

I guess most of the canvases I stretch are just no **** good.

This is a perfect example of why we need to talk about this stuff. There are people I respect on opposite side of this issue (on this thread.) Who wants to step up as the Canvas God (or Goddess) and tell us what's what?
 
The only pertinent written reference I can put my hands on at the moment is Decor's Framing Art on Canvas in which Vivian Kistler says,

Keying-out was once a common practice, it is now considered unwise to place the canvas under such restriction. If a painting is already "keyed," the keys should be left in place, but it is probably best for framers to avoid the use of keys on newly-stretched canvases.
She also talks about the problems with uneven stretching with keys and the possibility of keys coming loose and migrating around in the frame package.
 
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