Canvas Stretching Machines

By David Weaver

Co-creator of the Gallery Stretcher

Canvas stretching machines can certainly increase productivity and eliminate the need for skilled personnel capable of stretching canvas. But what machine should you buy?

I have been asked many times what makes our machine our machine better than other canvas stretchers on the market. My first thought is how do I describe the features of our machine without denigrating our competitors. Some competitors are not very delicate when it comes to comparing their machine to others. The most frequent comparison is to overstate their products throughput, or to suggest that a pneumatic machine is over kill and a mechanical machine will last longer.

This article is an effort to dispel any false claims, inflated or misleading production rates and other inaccurate comparisons you may have heard. It is not intended to single out a competitor specifically by name so I will group them based on functionality and design.

Most of the canvas stretching machines on the market will produce a descent stretch, some are easier to operate, some are better suited for high-production, some are affordable and others are quite expensive to own and operate. The following is an honest assessment based on 11 years of interacting with our customers.

Production Rates

Perhaps one of the most misleading claims is the number of stretches a machine can produce in one hour. Many large print-on-demand facilities produce 10’s of thousands of stretched art on canvas each month. The brutal truth is that no single machine currently on the market can operate at that level, including ours.

There are a couple of manufacturers that claim to produce 50-60 stretches per hour. In order to achieve these numbers they would have to produce about one a minute, not taking in to consideration breaks, misalignment, running out of staples, errors and changes in set-up between sizes. If you were able to justify spending $130,000 on a single machine to produce 50-60 stretches an hour, would you be willing to let an unskilled worker operate this machine? Production rates are not much different than miles per gallon when buying a car; you’re driving habits, traffic and condition of the car will determine what you will actually realize.

The Gallery Stretcher can produce a conservative 30-45 stretches an hour. This production rate is actually understated because some of our larger facilities produce more than that.

Who Should Own a Machine?

Canvas stretching machines are ideal for anyone that stretches art on canvas. Artists, small custom frames shops, Photographers and especially large print-on demand facilities would benefit from having such a machine if their production levels warrant one. If you stretch less than 50 canvases a month it might not be feasible or cost effective to purchase a machine just yet.

We have found that a lot of small custom frame shops elected to purchase a 36″ model for no other reason than to expedite the process and reduce hand fatigue. What they quickly realized was other custom frame shops, artists and photographers started sending them work because they lowered price based on the reduced labor cost. This actually resulted in more business. In some cases they even offered to stretch canvas while they wait.

Gallery Stretcher-60 with production bench

What Should I Buy?

The answer to this question is not quite that simple. This depends on your budget, production level, number of personnel and available space. There are several canvas stretching machines that can get the job done. So, in all fairness, I will describe and compare a few machines based on their mode of operation without mentioning the manufacturers. The following quotations describe the design features of the Gallery Stretcher, or other amplifying information provided by some of our larger customers.

We have several customers with as many as 10 machines operating in 12 hour shifts that produce over 4000 stretches, by unskilled laborers.

Staged Stretcher Bars

Mechanical Stretchers – No Air or Electricity

Some canvas stretching machines operate mechanically without any compressed air or electricity. This method is effective and they can produce a tight uniform stretch. How they achieve a stretch varies slightly between manufacturers.

Tension

A mechanical canvas-stretching machine provides no accurate feedback to the operator given there is no pressure gauge. The tension on the canvas is determined by the amount of force an operator exerts on the lever. The tension is not easily repeatable between operators. Some manufacturers provide a means of adjusting but that is based on travel and not an exact pressure.

The Gallery Stretcher uses a two-stage system with two pre-set pressure points so that everyone, at any skill level, will produce repeatable results at the same pressure every time. Our two-stage system was actually a recommendation from one of our customers when I was touring their facility.

Compressed Air

One claim is that a mechanical machine does not require the use of a compressor and that mechanical components are more reliable than pneumatics. This is incorrect. Modern pneumatic cylinders are incredibly reliable. Pneumatic controls are used onboard ships and industrial facilities because they are very reliable. Modern pneumatic cylinders rarely fail, if at all provided the source of compressed air is clean and free of dirt, oil and moisture. This easily remedied by adding a moisture trap. We have never had to replace a single cylinder in the last 11 years.

If you are not using compressed air than you would need a manual or electric staple gun, neither of them are effective.

Gripping

Some mechanical canvas stretching machines use metal teeth to grip the artwork during the clamping process. Other manufacturers rely on an abrasive surface to grip the canvas. Both of these methods work but tend to leave marks on the back of the canvas. This may not be a concern for some shop owners, but Artists and large print shops may have an issue with it especially if their customers reject it. Some customers send inspectors to evaluate the finished product. Many of the large jobs that facilities bid on require that the work be inspected by their own staff, they are graded on staple spacing, consistent tension, under/over stretching, wrinkles, alignment, folds and scuffing.

The Gallery Stretcher uses a soft rubber grip that does not mar the back of the artwork.

Pneumatic Stretching Machines

A machine that relies on pneumatics without any external electrical or electronic sensing or control is by far the most reliable and cost effective method. Pneumatic cylinders are infinitely more reliable than they were 50 years ago and because pneumatic staple guns are by far the best choice for applying staples it makes perfect sense to use pneumatics.

Our cylinders are rated for 1400 miles of shaft travel and they are oil less, meaning that they do not require any oil to be added to the airline.

Vertically Oriented Machines

Some machines operate on a vertical plane and the artwork is moved from a staging area to the machine. This may seem like a fairly easy task but it actually is quite awkward to feed a larger piece of art into the clap or to move it to the machine while staying aligned. Some of the vertical models require the artwork to be aligned at a separate staging area and then moved into position to be stretched. This might be a little easier on a small piece but it is incredibly awkward on larger pieces.

Alignment

Having the artwork perfectly aligned is critical to a good stretch. Gallery wraps have well defined edges and can easily shift when moved. Rarely will you see a video or live demonstration where they stretch anything larger than a 30” x 30”.

Gallery Stretchers use a Starter Bar to align the artwork. One end of the canvas is stapled to the back before it is moved into position to be stretched.

Gripping

Most of the vertically oriented machines use a rubber-grip that does not mar the artwork like some of the more aggressive manual machines do.

Excess Canvas

Another concern for large print-on-demand facilities is the amount of excess canvas that is needed past the image. When you print art on a continuous roll it can save a lot of money by limiting the space between prints. Most of the vertical oriented machines are designed to slip and to allow for this it requires a bit more excess canvas past the image, around 2.5-3.5”.

The Gallery Stretcher requires 1.5” of excess canvas, as measured from the bottom of the stretcher bar.

Stapling

Some of the vertical machines require the operator to staple from behind the machine or to reach behind and staple, this is awkward and unsafe.

Stapling is safely done in the front of the Gallery Stretcher and is far more ergonomic than reaching behind to shoot staples.

Horizontally Oriented Machines

Working on this plane is the most effective way to stretch a canvas. The artwork is easily handled, can be rotated between stretches and provides the operator feedback if the artwork is misaligned. In this position the workbench is an extension of the machine and can easily be maneuvered into position without scuffing the art.

Stapling

All of the stapling is done from the front on horizontal machines. Stapling from the front is safer and is more ergonomic.

Stapling is done in the front of the Gallery Stretcher.

Mounting

Some of the horizontal machines simply set on top of the workbench, others mount to the face of the bench extending the work surface. In this position the artwork can easily be rotated between stretches.

The Gallery Stretcher not only mounts to the front it comes with a universal bench mount.

Adjustable Pressure

Some of the vertical machines allow the operator to adjust the stretching pressure and provide a gauge for feedback. This allows the operator to change the pressure based on the weight of the canvas.

The Gallery Stretcher Pro has 2 pre-set pressure settings that are adjustable by the operator.

Over-sized Art

Some manufacturers offer a 96” model to handle over-sized art. The challenge with large art is maneuvering the canvas into the clamp. The other challenge is taking the slack out of the canvas before stretching. This is made easier when the machine is mounted to the face of a workbench extending the work surface. Now the artwork can simply be rotated between stretches.

Automated Machines – Pneumatics & Electronics

There are a few semi-automated machines on the market, they are intended for very large print-on-demand facilities with enough space to accommodate them. They are also more expensive than the manual or straight pneumatic machines but they do appear to perform well.

For those of us that like flashy things, automation would appear to be the ideal solution if we could afford it. Another thing to consider is the actual throughput of this machine and the true cost to operate. This is not a machine that you would want an unskilled laborer running.

Design vs. Function

All of these machines still require someone to place the artwork and an assembled stretcher frame in-place; it also must be properly aligned so this is really a semi-automatic machine. All of these machines require somme set-up change between sizes and that is down time.

The Gallery Stretcher does not require a set-up between sizes as long as you are using the same wood profile.

Proprietary

These machines have certain proprietary components to take into consideration. First, one machine requires an incredibly unique staple gun with proprietary staple cartridges. Another machine uses a multitude of fairly common staple guns in an array to affix the staples. Another proprietary item is a platen that must be changed out to accommodate different sized art. Consider for a moment the multitude of different sizes and there are no half sizes.

Production

One manufacturer claims to produce 80 canvas an hour, an impressive number but not entirely accurate unless the production run is for one size, no breaks, no jambs, no replacing staple cartridges etc. Even if this was a sustainable throughput your facility would never produce more than 960 stretches in a 12-hour shift and at $130K you might need to wait a little while for your 2^ndor 3^rdmachine so that you can start bidding on large jobs.

Ten Gallery Stretchers in a 12-hour shift produce more than 4000 stretches. The key to production is how you arrange multiple machines and personnel.

Skill Level

When a facility makes such a purchase they are going to want to assign someone with a working knowledge of the machine. This requires a person that can identify a problem quickly and correct it before there is further damage. If a facility is working in shifts it would require hiring more than one person to perform this task.

We have several facilities that operate as many as (10) machines in efficient work groups called “PODS”.

It stands to reason that (10) machines operated by (10) day workers is more efficient and cost effective than one unique machine with one skilled operator; even with the additional labor cost.

Reliability

A purchase of this magnitude should include a maintenance program. A machine working around the clock is bound to encounter excessive heat, vibration, moisture, metal fatigue, electronic failure, pneumatic leaks and any number of issues that would require a technician. Also, your production comes to a halt if you have only one of these machines.

Summary

I have installed, demonstrated and toured several of our larger customers and I am comfortable making these statements. Some of these same customers had already owned other manufacturers machines before purchasing from us. They gave me their honest assessment of those machines and they explained why they still purchased our machines.

Canvas Stretching Machine, LLC is the sole manufacturer of the Gallery Stretcher. If you should decide to purchase one of our machines then please consider purchasing the Pro model. These models are designed for high-production and they are available in a 60” and 96” version.

If you follow this link to our products page and enter DAW2019 in the coupon code you will receive $50 off your order for any Gallery Stretcher.