How to make a Bellows

When it comes to large format cameras, the bellows is by far the most challenging and most rewarding part to make. If you haven’t made one before, it will likely take more than one attempt. There are two common ways that bellows are made. Flat on a table, and around some sort of form. Since it is rare to find information on bellows making with a form, we will be showing this strategy. You are free to make your bellows any way you like. Make sure that it more or less matches the specifications below. Keep in mind that there are a lot of competing opinions on how exactly to make a bellows. Treat this as another option, not the best one. Use whatever strategy works best for you.

Make sure you have enough resources to make multiple attempts, and read carefully. Bellows making is a complicated process. You can always purchase a ready-to-go bellows from us here: Standard 4x5 Bellows

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Specifications for The Standard 4×5 Bellows

If you already know how to make a bellows, you can use the following guidelines to make one. When you’re done you can scroll below where we show how to mount the bellows to the camera.

  • Front Standard Opening: 96 x 96 mm
  • Rear Standard Opening: 145 x 145 mm
  • Recommended Stiffener Size: 12 mm with 2.5 mm gaps
  • Max Bellows Thickness: 0.4 mm
  • Recommended Bellows Draw: Minimum: 35 mm, Maximum: 300 mm

Make sure you have at least 3 or 4 cm of additional material on each end of the bellows for mounting it to the camera.

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Step 1 – Materials Selection

Material selection is incredibly important for making a functional, lasting bellows. There are four things you will need to shop for. First, the inner layer of the bellows – this needs to be light-tight. Second, the stiffeners – these define the folds of the bellows. Third, the outer layer of the bellows – this can be (nearly) anything as long as it is thin and flexible. Finally, you will need a glue to hold everything together. If you are making your bellows for The Standard 4×5, make sure that the inner and outer layers combined are not thicker than 0.5 mm. Any more and they will not fit inside the Bellows Frames later.

Inner Layer Suggestions

At minumum, the inner layer must be light tight. This is by far the most critical detail.

  • Duvetyne
    • Also sometimes called Molton or Rokel. Duvetyne is easy to find online, but you may have trouble finding some that is thin enough for our application here.
  • The company ThorLabs makes a product called “BK5” which is very thin and light tight. We have used it in some test cameras with good results.
    • They do recommend using two layers for ‘very sensitive applications.’
  • Check the last link at the bottom of this page for a few more ideas/suggestions.

Stiffener Suggestions

The stiffeners should be about 120 – 180 gsm in thickness. This will vary based on what kind of material you use for them – some vinyl type materials might be stiffer and much thinner than some papers. Ideally it should also be waterproof, but this is entirely optional. The exact requirements for stiffeners will depend on your preferences.

Manila Folders are a great baseline for the approximate thickness needed for Stiffeners. They aren’t the best answer for a long-lasting bellows though. If possible, look for some kind of synthetic material that does not tear easily. We have even used inkjet paper in a pinch for tests.

It is also good to try and find a paper/material that is large enough to cut each set of stiffeners in one pass. More info on this in “Cutting The Stiffeners.”

Outer Layer Suggestions

If you aren’t going to double up your light-tight material, this can be anything you like. We like to use waterproof materials for an added bonus to the bellows. You will probably be able to find something you like at the local hobby/fabric shop. Make sure the material is not too thick.

  • Ripstop Nylon
    • This is what we use on all of our cameras. We use a water resistant variant that keeps water from soaking into the material. Check out Ripstop By The Roll for high quality options.
  • Taffeta Fabric
    • Taffeta is made from silk or rayons. It can be made quite thin, so it is potentially a great option.
  • Make a trip to your local fabric store
    • Shopping around might give you some alternate ideas. Black material is always the best answer, but if you trust your inner layer you can always get creative.

Glue Suggestions

Strong glue is a must for keeping a bellows from falling apart over time. Make sure that the glue you choose works on the materials you have chosen for the Inner/Outer Layers and the Stiffeners.

  • 3M 90
    • 3M 90 is a great industrial strength contact adhesive. You will need to spray both surfaces for it to work properly. This is what we will use in step 5 below.
  • Weldwood Contact Cement
    • Similar to 3M 90, Weldwood comes as a spreadable glue, and a spray adhesive. This is common to find at the local hardware store.
  • Loctite Bonding Adhesive
    • This is also a spray adhesive. We have not tested it for bellows making, but it does work nicely for other applications

There are a ton of adhesive options. The best recommendation we can make is to buy a few and test which is best for your specific application.

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Step 2 – Making the Bellows Form

There is more prep work involved with making a bellows with a form, but in the end you may find that the process is made much easier. The form can take some of the guess work out of the process if used correctly. In general, the form’s shape is achieved by taking the two end dimensions if the desired bellows, and creating the shape from those dimensions. To help you along, we will be using the dimensions for The Standard 4×5 bellows provided above to explain the process.

Use the above image as a reference for this paragraph. As stated above, the bellows should have a max draw of about 300 mm. With this we can estimate how large the form should be. Multiply the desired max draw (300 mm) by 1.2.  300 x 1.2 = 360 mm.  Now draw 360 mm between the Front Standard Opening (96 mm) and the Rear Standard Opening (145 mm). To allow extra material for the bellows to be mounted later, we will add 40 mm on each end. Then, draw a line from the end point of the Front and Rear Openings, beyond the 40 mm extensions. The image above is the result. Take some time to read and understand the image above. Below, it has been cleaned up to only show the final required dimensions. We rounded 150.444 to 150.5 and 90.556 to 90.5.

The dimensions above can be used to make a template for the faces of the form. Keep in mind that 440 mm is 90 degrees from the two end lines, not the length of the line at an angle. We recommend making the form with wood, but you can also 3D model and print the form you need. This same process can be used to find dimensions for any bellows form you need to make. The image at the beginning of the section shows two different Bellows Forms made using this process.

When making a form out of wood, you will need to compensate for the thickness of the material. For this example, we will use 1/2″ MDF because it is quite common at hardware stores and has a smooth, clean surface. Measure the thickness of the material. Often times raw materials will not be the exact dimensions advertised. In our case, the 1/2″ MDF we’re using is actually 12 mm thick. This will need to be compensated for. To do so, we will need to make a second template. Template #1 will use the measurements from before: 150.5 mm, 440 mm, and 90.5 mm. Template #2 will use these same dimensions, but account for the material thickness by subtracting 2x the material thickness from the two end dimensions. Template #2‘s dimensions will be: 126.5 mm, 440 mm, and 66.5 mm.

The form has four faces, so we will need a piece of MDF for each one. Make two pieces using Template #1, and two pieces using Template #2. The shorter two pieces will be glued inside or nested in the two longer pieces. You can see this in the image below.

It is good to lightly sand the form when you’re finished putting it together with a fine sandpaper to remove any rough edges or burrs. The form needs to be smooth and clean enough that it won’t snag or damage the materials you will be draping over it later.

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Step 3 – Material Cutting Template

The same measurements found in the previous step will be used here – 150.5 mm, 440 mm, and 90.5 mm. Above they have been drawn in again in the center. The shape is then copied and aligned on the edges. The image above shows the shape of the cut of material needed to make the bellows.

The template has been drawn in the center, and then copied once to the left and once to the right. So there are three full templates. Then, on either side, the template has been cut in half and added to each side. These are the four faces of the bellows. There needs to be overlapping material so it can be glued together. The extra 20 mm (highlighted green) on each end is this extra material. In total, the bellows will overlap 40 mm since we added 20 to each side. Once the cutting template has been completely drawn up, cut it out of a large piece of paper or cardboard. This way you can trace it onto the bellows materials you’re using. Below you can see a cardboard form made using this technique.

 

Use this to cut one Inner Layer of material for the bellows, and one Outer Layer of material. The Stiffeners will be cut separately in the next step. Having the cardboard or paper template (rather than drawing the layout directly onto your materials) is ideal. If you make any mistakes you can cut more materials without remeasuring.

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Step 4 – Cutting The Stiffeners

You will need the measurements found in Step 2. If we review the initial image, the area that stiffeners will need to be used is highlighted blue below:

Since the 96 mm and 145 mm measurements represent the opening of the Front and Rear Standards, the stiffeners should not go outside this area. So we can use these measurements to determine the stiffener design. Many bellows tutorials suggest that the stiffeners come to a point (click here for an example – they call the stiffeners ‘ribs’), but we will not be doing this. Instead, we will leave space around the corners. This means that the folds will need to be creased more manually. We will touch on that in Step 5.

Leave space to fold the bellows – make this value approximately the thickness of each stiffener + the space between each stiffener. In this example case, we suggest 12 mm stiffeners, and 2.5 mm gaps. So we will use 15mm in the example below. So the largest stiffener should not be wider than 115 mm and the smallest should not be wider than 66 mm.

Now, we can use a little math to determine how many stiffeners we will need. (14.5 * X) + 12 = ~360

(14.5 * X) + 12 = 360

What we have is the width of one stiffener and one gap (14.5 mm) multiplied by X, plus one additional stiffener. 360 is the value determined in Step 2 to create the correct amount of bellows draw. The goal is to find a whole number value for X that equals 360 or just less than it. In this case, 24 is the magic number. 14.5 * 24 = 348. Add the 12 to arrive at 360 even. You must add 1 to the value you find for X to find the correct number of stiffeners. So this bellows has 25 Stiffeners. Each stiffener will be 12 mm thick, and there will be a 2.5 mm gap between each one.

One of the key details to a quality bellows is even spacing between the stiffeners. To ensure this, add two tabs between each stiffener. The location is up to you, but keep them near the ends, and no thicker than 2mm each. These will save you the effort of manually measuring and placing each individual stiffener (friendly reminder that for this bellows that would be 100 individual stiffeners!).

Depending on how you’ll be cutting the stiffeners (laser cutter, cutting tool, manually) you might choose to add the tabs differently. If cutting by hand, it may be easier to have them run along the edge (click here for an example of this).

If possible, draw up the stiffener design you need in CAD, photoshop, or whatever you have access to. If you will be cutting them by hand, you can print them out to scale and save having to measure and cut four sets of stiffeners.

Make sure you cut four sets of stiffeners before proceeding.

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Step 5 – Make The Bellows (Finally!)

Before proceeding, make sure you have:

  • One Bellows Form
  • One Inner Material cut down to size
  • One Outer Material cut down to size
  • Four sets of stiffeners
  • Glue

First, take the Bellows Form and the Inner Material. Drape the Inner Material over the form similar to the next image. Try to remove most of the slack from the material so it sits tightly over the form. Take note of how much the material overlaps itself. To help remember how much, you can make a mark on the material on the ends. We have used a white marker in this image.

Then, using straight pieces of paper or cardboard cover all of the material, except for the overlapping areas. Spray these sections with glue. You should be spraying the inside on one end, and the outside on the other as seen here. If you are using a contact adhesive, make sure to allow the appropriate amount of time for the glue to set. Make sure you use an even coat of glue.

Once again, return the material onto the form, carefully pressing the overlapping area together to glue it together, onto the form.

*Before proceeding, drape the Outer Material over the form and make note of how much material overlaps. We will do a similar gluing for the Outer Material later. Since the form will be covered in glue, this is the last chance to do this cleanly.

Apply an even coat of glue to all four stiffeners, and all four sides of the Inner Material on the Form. Measure from the top of the form the 40mm (or whatever measurement you used) we added to the design earlier. This is where the top of the stiffeners should lay. So in our case, there is 40mm above and below the stiffeners. Carefully apply each stiffener.

The stiffeners should all be perfectly in line with each other. To help this, you can draw a line where they go on each side. Also, it helps to mount them out of order. Apply one set of stiffeners, then apply the stiffeners that share a corner with that side, then apply the back set last. This is a better solution than doing it in a clockwise fashion.

If using contact adhesive, make sure to apply some pressure to the stiffeners to help them set in place.

Next, you will glue the Outer Material to the Inner Material and Stiffeners.

First, apply glue to the strip of material that will overlap so that it will glue properly. The red highlighted area is glued on the backside. Then flip the material and apply an even coat over the entire surface as seen here.

Then, apply an even coat of glue to all four sides of the Inner Material and Stiffeners on the Form.

It helps to make two passes on the material to help achieve a sufficient, even amount of glue.

With the layer of glue on the Outer Material facing up (like in the last two images), carefully place the Form on the center of the material. The first face you place down should be the side with the Inner Material seam. It helps to place one corner, then one edge, and then slowly press the entire form onto the material.

Carefully pick up the form – the Outer Material will be dangling from just the one side that is glued. Press the Outer Material onto this first surface fully.

Locate the dangling half that has the glue on the outside. Slowly going from face to face, press this half onto the form until it is fully attached as seen here.

From there, do the same thing for the remaining half. Press the glued surfaces together. Once it is fully pressed in place, and the Outer Material has been pressed onto itself, make several passes over each surface pressing them together. You can simply rub them together, applying a decent amount of force. You can apply extra pressure to areas where small creases have occurred to remove them as much as possible.

When the three layers have been fully glued and pressed together, you can remove the Bellows from the Form.

Now begins the hard part of folding the bellows. In general, each face will fold opposite of the adjacent faces. We find starting at the small end is easiest. Starting at one end, make the first crease, between the two stiffeners. Manually form each fold – make sure you crease the fold carefully in the correct position. Then rotate the bellows in your hands and make the next adjacent fold. Again, this fold should be the opposite of the previous fold.

Continue this procedure, slowly spiraling down the bellows.

You will need to manually form the corner folds to create clean corners. As the bellows takes shape, it’s best to form each fold from the inside and outside.

Keeping one hand inside the form helps to control the material as you fold along.

Take your time, and don’t worry if you have to re-fold some of the seams as you rotate along. Folding bellows is a time consuming process.

If you are having trouble, using bulldog clips or weaker alternatives are helpful. They can be used to hold the bellows folded while you work on other sides or further along.

Once the bellows has been fully folded, place something flat on top of it, and apply some weight. We recommend letting the bellows sit folded for at least an hour or two before using it. This gives the glue more time to set in position, and for the folds to fully form.

If this takes your more than one try to get right, that’s normal. Don’t become discouraged! Give it another shot and take your time. Especially with contact adhesive, there is no need to rush materials together.

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Step 6 – Mount the Bellows to the Bellows Frames

Parts Required:

➤ Bellows

➤ #4 Black Oxide ⅜” Screw   (x16)

➤ Rear Standard Bellows Frames

➤ Front Standard Bellows Frames

Take note of the bellows frames shape. The flat sides (facing down in the image) should face each other in the assembly.

First, take the Bellows (not pictured), the Front Standard Bellows Frames, and 8 of the Screws.

Take the smaller Frame, and position it inside the bellows. The edge nearest the stiffeners should have 1 or 2 mm of clearance before the first stiffener. Make sure the frame is square with the four sides of the bellows. This will help the bellows fold properly when the frames are mounted.

Slide the larger frame onto the outside of the bellows material. Line up the inner frame with the outer frame by pinching them together. It should be a snug fit with the bellows in between the two.

Make sure the two frames are properly lined up. If they are not you risk damaging one of them or the bellows. Also double check that the frames are in the position you want them. Then, using two of the screws, first fix them on the RED side. Do not over tighten the screws, but make sure they have pulled the frame flush with the bellows. Then repeat the same steps with the YELLOW side, then the GREEN side, and finally the BLUE side.

You may find it helpful to use an Awl to pre-puncture holes in the bellows before using the screws. If you do this, just be careful the bellows does not shift after puncturing it.

Next, take the Rear Standard Bellows frames and remaining 8 screws.

Place the bellows with the Front Standard facing downward. Insert the inner frame, leaving a 1-2 mm gap between it and the last stiffeners. Try to mount it as square with the Front Standard Frames as possible.

Once the inner frame is in position, slip the outer frame over the assembly. It must go on from the front. If you simply place the bellows on top of the outer frame (similar to in this image), it will slide on in the correct position. You may need to unfold the bellows to get it all the way on.

When both Rear Standard Bellows Frames are in position, place the assembly flat on a table as seen here. double check that the Front and Rear frames are square with each other. If they aren’t, slightly rotate the Rear frames until it is correct. You may need to remove the outer frame to do this.

Do not screw the Rear frames to the bellows until this is correct. If you don’t, the bellows will not sit properly on the camera once complete.

Follow the same order as the Front Standard Frames. Fasten both Screws on one face of the bellows, then the opposite side. Then do the two remaining faces one at a time. Do not over tighten the frames, but make sure they are flush with the bellows material.

Once complete, you will need to trim the excess material from each end. You want the material to end flush with the frames, as seen here. If they stick out too much, they may impact your ability to mount the bellows properly to the camera during assembly.

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We put together a few resources about bellows making. If you’re looking for more information or ideas, these are a good place to start.