B I G canvas stretch help

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OK - we've got a couple of big canvas panels to make. Two sided.
4'x10'
Two sided is not biggie, we've got that part figured out. Does anyone have any ideas on easily stretching such a big piece and getting it tight? It's primed blank canvas that will be painted at a later date.
First run was a real pain - getting it tight was tough so we're looking for suggestions on efficiently and easily (as possible) to do this. No, we aren't buying a stretching machine ;-)
Thanks in advance
 
I've done lots of huge canvases, some so big I had to splice the stretcher bars. I'm not sure about the 2 sided part but I usually tack them in the middle, stand them up, and get on a ladder or on top of the work table with a stretching pliers and have at it.
 
When working on a large canvas, I like to work on the floor or place the stretcher frame on saw horses. I use the standard chrome plated stretcher pliers and work slowly.

When its done, I take two Aleve®.
 
Well if you started with unprimed canvas that would be the biggest advantage to getting a desired result. Stretching......... then priming will make the canvas tight as a drum.
 
I find that sometimes if I try to work on a large canvas flat the weight of the loose canvas causes it to sag in the middle and it's harder to overcome the sagging. When I stretch it standing up, I don't have that problem. But then after 40 years I do have arthritis in both thumbs. And I recommend 2 Aleve and a Gin + Tonic. Or 2 Gin + Tonics and 1 Aleve.
 
It's got to be flat since the ceiling is only 8 1/2 feet and they're 10' tall. We stretched the first today laying sideways but there is too much sag....maybe we'll try laying it flat on the floor and see how it goes.
 
The ceiling height is a factor. I had 14 foot ceilings to work with. You might be able to tack the centers and lean them against the worktable on an angle to try and use gravity as a help against the sag even if you can't stand it straight up. Possibly 3 Gin + Tonics and no Aleve. Even with the 14 foot ceiling I had to frame an African antique quilt one time in a 9 foot wide by 10 foot high plex box and the shop lights which hang on chains had to be raised in the area where I worked on it so I could stand it up. One day I will frame something so large I won't be able to get it out of the shop, or it won't fit in the front door of the clients house.
 
The obvious answer is to use stretcher bars and not strainers. Then you can key the bars to achieve tension and re-key if necessary. For bars that size, I would use a mechanical stretcher.

Another suggestion is to pin the canvas prior to stapling, so if you do get sag, all you have to do is unpin and re-tension. Use aluminum headed push pins. ALL canvases we do are pinned prior to stapling and often stay on the stretchers overnight or for a day prior to stapling.

How many cross supports are on your stretcher (or is it a strainer?) Over a 10' length we would have two and depending on the width of the stretcher/strainer material, probably one over the 4' as well if the bar stock was less than 3" wide. Our rule of thumb is anything over 36" needs a cross support. It is possible your sag is coming from the bar stock bowing. Also, what steps have you taken to keep everything square? A stretcher/strainer that size cannot rely on v-nailed corners to stay square while stretching, and unless it is a mechanical stretcher drawn taught, a keyable bar is also too flexible to stay sqaure.
 
As I said, I've stretched many canvases that size and larger without major problems. I put in center bars and diagonal 45 degree braces in the corners. I don't know where you're going to get 120" stretcher bars if you don't use length stock, but good luck on your project.
 
I`ve made lots of BIG(4x6 to 8x10 foot) canvases. We used 2x2`s cross braced at the corners,AND, with metal L brackets on the INSIDE of the corner. Works great! As for the canvas, get the fabric damp,staple the canvas along one side..now..find a partner and have him/her pull the canvas tight while you staple.This works wonderfully,but only on un painted canvas, of course.Tight as a drum! L.
 
Luddite said:
I`ve made lots of BIG(4x6 to 8x10 foot) canvases. We used 2x2`s cross braced at the corners,AND, with metal L brackets on the INSIDE of the corner. Works great! As for the canvas, get the fabric damp,staple the canvas along one side..now..find a partner and have him/her pull the canvas tight while you staple.This works wonderfully,but only on un painted canvas, of course.Tight as a drum! L.
Click to expand...

I've also done it in that manner on the floor. My previous shop had low ceilings, too. Making the canvas damp just prior to stapling works great!

BTW, forget the Aleve and gin - just do two Cosmo's! They are prettier to look at and have the same effect as Aleve without the stomach upset. LOL

:thumbsup:
 
We've got 2 cross braces and 45 degree corner braces - they're tight and square. I think the issue is simply pulling it tight against the sag (weight) of 10' of canvas. We sprayed it prior to stapling but I'm not sure if that didn't make it worse (strange, I know. we usually spray small stuff to be sure it's drum tight)
Tomorrow we'll try them face down flat on the floor - no sag/weight and we'll get a better pull without having to support and pull tight. Definitely a 2 man effort but I'm confident.
These have to be a perfect as we can get them - they'll be a backdrop for a new HD TV studio at the local FOX affiliate and flaws will show. #### I hate when things don't go as planned.
 
Oh WOW! Forgot to mention strainer bars on the bigger canvases.But you already know that here :)...L.
 
Rob Markoff said:
The obvious answer is to use stretcher bars and not strainers. Then you can key the bars to achieve tension and re-key if necessary. For bars that size, I would use a mechanical stretcher.

Another suggestion is to pin the canvas prior to stapling, so if you do get sag, all you have to do is unpin and re-tension. Use aluminum headed push pins. ALL canvases we do are pinned prior to stapling and often stay on the stretchers overnight or for a day prior to stapling.

How many cross supports are on your stretcher (or is it a strainer?) Over a 10' length we would have two and depending on the width of the stretcher/strainer material, probably one over the 4' as well if the bar stock was less than 3" wide. Our rule of thumb is anything over 36" needs a cross support. It is possible your sag is coming from the bar stock bowing. Also, what steps have you taken to keep everything square? A stretcher/strainer that size cannot rely on v-nailed corners to stay square while stretching, and unless it is a mechanical stretcher drawn taught, a keyable bar is also too flexible to stay sqaure.
Click to expand...


Searched some threads and found this one.
I hope I haven't jumped in over my head.

The piece I am stretching is 61 by 107 inches and they need it stretched. The don't want to lose much around the edge of the piece and I showed them a painted African sheet that I had to use beva on to get enough material to stretch. They asked if I could do it all the way around to lose as little as possible of the painting. I showed them this to do the one side where the sig is close. So I guess I will be calling you for some more beva.....

I have always used strainer bar in the past and don't have experience with keyable or mechanically adjustable stretcher bar.

I always use 45ed braces on the corners for larger strainer mounts. And a cross brace is necessary. Even with the beva extension they don't want deeper than a 1.5 inch bar.

And.......



they need it in about 10 days.
I don't think I can get UPs or fedex shipping on anything 10 feet anyway, so I might be limited to what there is at my regular drop next week.

Did I hose myself here?
I know I can keep it square and pretty sure I can get a good stretch on it if I do a good job on the beva.

Thoughts?
Ideas?
Gun?
To shoot myself.

Thanks
 
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