By Chris Wantuck
In Parts 1 & 2 of this series, we showed you the basics for sewing machine selection & set up, three basic seams, and some common attachments used when doing automotive upholstery. Now it's time to tackle a simple project, making a Tonneau cover for a pick up truck. Many general purpose upholstery courses would have you making a smaller project like a simple pillow or stadium cushion. These are valuable projects and do test your skills, but we want to focus on specifically on automotive upholstery. Keep in mind that many of these techniques, as well as materials and supplies, are suitable for both automotive and marine upholstery applications.
As with many of the steps involved in car restoration projects, for our Tonneau cover project we recommend creating a plan. This plan needs to include information on all the details necessary to create the project. It doesn't matter whether you're copying a project from a previous job or creating something from scratch, you need to start with making a plan (Photos 1 & 2). You can draw your plan or use a computer ... use whatever method you're most comfortable with. We used Power Point to make our simple plan, primarily to make the plan clearer for our readers. We could have just as easily used pencil sketches. What is important is to document all the dimensions and details about your project. One unusual feature of this project is that the frame this cover must fit is tapered front to rear. That taper requires many more dimensions than might have otherwise been needed. You should be meticulous in your planning. The plan should include all details that need to be addressed. This is a relatively easy project, but following the series of steps we outline here can be applied to this as well as more complicated projects.
Photo 1 — Pictured is a simple plan for our project created using Power Point. The idea is to create a drawing that accounts for all dimensions and features. You can see by the dimensions that this particular cover is tapered. Plans such as these go a long way in creating a final layout and cutting diagram, as well as indicating the quantity of materials needed.
Photo 2 — Rear view of the plan in Photo 1. Again we want you to account for all dimensions — including the one inch height of the frame and some extra material allowing for the curved bows. You have to be sure to look at all three dimensions.
Plan Design & Sizes — Include all key dimensions where possible. Be precise when taking the measurements; remember the old woodworking adage: measure twice, cut once. Take into account fabric stretch and form as well. This particular cover uses both sharp bends (front corners) and gentle radius corners in the rear. We will discuss forming corners using multiple layers later in this article.
Availability of Materials — Most upholstery projects use materials such as vinyl, canvas, wool, cotton, etc. that typically are available in rolls. Most rolls are 58-64 inches wide. We know this is an exterior cover, and as such, size of the material is important. The best design for us is to avoid seams down the middle of our Tonneau. Looking into materials specifically for Tonneau covers, we found that some are available at 78 inches wide, allowing us to avoid that seam. For our Tonneau cover project, we're going to use material from Haartz that is acrylic cloth on one side and vinyl coated on the other side. The manufacturer advertises it as useable on either side. There are less expensive vinyl materials available and the decision is yours to decide which is best for your application. The choice of binding along the edge should be easy, but nonetheless must be included in the plan/materials (See reference section at end of this article). Also see binding photos from Part 2 of this series.
Layout and Cutting Pattern — When developing your Layout and Cutting Pattern, you want to focus on using your materials in the most economic way with as little waste as possible. This is especially true for this Tonneau cover project; the width being the most critical dimension because we will barely have 1/4 inch of material left after cutting. Preparing a layout pattern before ordering materials ensures that you order enough. We ordered 3-1/2 yards for our Tonneau project. We ordered an extra 1/2 yard for some of the edges. Keep in mind that some vendors will only sell by the full yard. Sample layout and cutting diagrams are shown at Photos 3 & 4. As we mentioned before, this particular project is tapered and has to be cut as such. Straight panels are cut first followed by the taper cuts to the main panel. Your design will most likely by different; adjust accordingly. Once you are comfortable with the layout and cutting plans and you are sure you have accounted for all panels in your project, you may begin cutting. Long heavy duty scissors work well as does the rotary cutter in Photo 5 (please note the warning on the sharpness of rotary cutters). Cutting panels square is as important as their dimensions. Photo 6 shows the use of a large right triangle as a guide for perpendicular cuts.
Photo 3 — A Layout diagram is useful when accounting for where all material will be used in your project. Note that a single 6 inch piece is used at the front which addresses the two front corner reinforcements and the front edge in a single reinforcing panel. The same could be said of the rear corners and edge, but that would require more material. Create this in conjunction with the cutting diagram in Photo 4.
Photo 4 — The cutting diagram is used to guide you in the most efficient way to cut the material and reducing waste. Since this Tonneau material will arrive in a long roll, having this diagram helps when unrolling it and indicates what and where to cut it. Note that this project cuts 2 inch strips off the sides.
Photo 5 — We used a 60 mm diameter cutting wheel to cut the material. Be very careful using these tools. The wheels are sharp and can easily veer off track. Cut against a straight edge whenever possible. There are times when it maybe necessary to cut curves in material, but this not one of them. Strongly suggest practicing on scrap material. An alternative is to use long scissors.
Photo 6 — Cutting panels straight is important. We used a large drafting triangle to mark panels. The white square piece in the picture is tailors chalk.
Sewing Corner Patches — Our cover project includes reinforcing material in each corner to make the cover more durable. Most of the corners are easy to include by top stitching them, but extra consideration is needed when forming outside corners.
Sew Strips — Sewing on reinforcing strips is simple and they provide extra material where the cover comes into contact with the metal frame. This extra material provides additional thickness and durability necessary for attaching snaps snaps as well as for added durability for the corners. Photos 7 - 9 provide additional tips on joining panels together and Photos 10 — 13 highlight topstitching the panels together.
Photo 7 — Panel reinforcement strips and corners are glued together, using Loctite #200 spray adhesive, vinyl sides facing each other. To control where the spray adhesive is applied, scrap card board is laid against the main vinyl piece and a second card board protects the work table. Ensure the edges line up as best as possible.
Photo 8 — Similar to Photo 7, wide masking tape is applied to the material to limit the spray adhesive. Panels are glued enough to keep them together till they are sewn together.
Photo 9 — Glued panels should look like this, even though the cover is larger than the table, work in sections to keep panels flat.
Photo 10 — Working in small spaces will present many challenges. Here the cover is folded in half and presented at the machine for top stitching. The white chalk line is the guide for this step. Check to be sure you're starting with a full bobbin.
Photo 11 — As the cover is top stitched and makes its way through the machine, it does get easier to manage on the table.
Photo 12 — In Part 2 of this series, we introduced you to the magnetic edge guide. Here both the guide and masking tape are employed to guide the top stitching for the side strips.
Photo 13 — Also in Part 2 we introduced on top stitching (making) corners, keeping the needle down and lifting the presser foot while turning the material. Use chalk marks to accurately position your stitches.
Sewing Corners — This Tonneau cover uses reinforcing panels at the corners and the radius of the bend determines the sewing order. The intent here is to be as weather-tight as possible. We suggest practicing on scrap material to ensure proper fit before attempt on the real cover. The procedure we suggest is shown in Photos 14- 16.
Photo 14 — Stitching corners begins with a diagonal cut through each layer. Refer to our plan in Photo 2, the frame is one inch high which is the dimension of the edge.
Photo 15 — Tools for the upholstery trade come in many forms. Here a medical hemostat holds the cut layers together. Interleave the layers by alternating one over the other to make the corner more weather resistant. Turn the cut edges gently to make a more round corner. Hand stitch the corner along the diagonal (red line).
Photo 16 — Similar to Photo 15, hold the cut edges together overlapping each layer. Notice the amount of material that overlaps and the orientation to make a tight corner. Hand stitch along the red line.
A Word About Bindings Bindings come in different sizes and styles. In Part 2 we introduced the Two Edge Turned (TET) and One Edge Turned (OET) binding terminology. You must use the correct size binding attachment for the desired binding. The 3/4 inch TET binding is the most common and you need to use a 3/4 inch TET binding attachment to fold and sew it in place. If you use 3/4 TET binding in a 1 inch TET attachment, the binding will fold sloppy and sew unevenly. You cannot use TET binding of any size in a OET attachment under any circumstance.
There is no standard for attaching attachments. Many attachments use 6-32 screws. Our machine is set up for 8-32 screws, and we modified our machine's adapter to by drilling and tapping 6-32 holes.
The binding material itself can come in many different styles and patterns. There is cloth binding that can be used with cloth applications like awnings, vinyl binding that can be used in marine or automotive applications, and leather used for automotive. The wrong binding can ruin the look of a project. Using vinyl binding on a cloth application like an awning could be pass as acceptable, but using a cloth binding on a marine or automotive project will not be durable enough for marine use and will look totally out of place.
OET binding has one side folded and is used for thick applications like trimming carpet. The top is folded nicely and the bottom folds under and is not seen. We'll cover that in a subsequent article.
Test the Folder (binding attachment) — Attach the binding folder to the machine and adjust as needed to present the folded binding in front of the needle. The presser foot should not interfere with the folder attachment. Do a short test stitch to ensure the stitching is in the proper place on the binding (Photo 17). It is important to make sure the test material is pushed well into the folded binding as its stitched. Photos 18 & 19 shows the test binding.
Photo 17 — The binding folder is fastened to the sewing machine table. Suggest running some short sample test strips. Don't forget to use a full bobbin, once you start with the real binding — our binding is about 25 feet long and you can't stop until you're done.
Photo 18 — Sample binding. What do you notice about this photo? The stitch tension needs adjustment. Other wise the placement of the stitch is correct.
Photo 19 — Cross section of the test binding. Notice the material is pushed in all the way which is correct.
Apply Binding — Apply the binding beginning at the center front — this is where the two binding edges will be least seen (Photo 20). Constantly push the material into the binding as the machine stitches it into place. It is easy to veer off (note the problem in photos 37 - 40). When stitching around the corners push the material as flat as possible into the folder and use the hand wheel to "walk" the stitch around the curve (Photo 21). Did you remember to start with a full bobbin?
Photo 20 — Rear view of the sewing machine as the binding is sewn onto the cover. The binding was started on the front edge in the center, the least noticeable part of this cover. Notice the extra thread at the beginning which will be needed for hand stitching later.
Photo 21 — Sewing the binding around the corners requires careful maneuvering, pushing the material into the binding while manually rotating the machine's hand wheel. The important point here is to keep turning the material during each stitch.
Hand Sewing — Hand sew the final few stitches where the end of the binding meets the beginning. Always leave extra thread to perform hand sewing. Knot stitches on the bottom (Photo 22).
Photo 22 — As you reach the end of the binding procedure, cut off from the roll and hand stitch those few stitches onto the starting point. Don't forget to leave a generous amount of thread for hand stitching. Use of pliers is recommended. Tie threads on the bottom side.
Fit on Frame — Apply a nice chalk line down the center of the cover. This will ensure the cover is centered. This chalk line could have been applied when we first started or after the binding is sewn in place. (Photos 23 & 24)
Photo 23 — Shown is the completed cover loosely laid out on the frame and adjusted using the white chalk line for center.
Photo 24 — Rear view of the loosely fitted cover. Note the importance of the chalk center line which is a guide between the center snaps. The chalk will easily wash off upon completion.
Snaps — The final choice in this project is the selection of fasteners or snaps. This cover could be attached using Velcro which comes in many styles such as plain (which can be sewn) and rolls with and without adhesive. Since the frame of this project already used the snap method and that sixty male snaps were riveted onto the frame the decision to remain with snaps was easy. However, not all snaps are alike. The button heads in the world of snaps come in a variety of colors and materials. Ones known are 1) Vinyl (Delrin plastic) cap over metal, 2) Button heads dipped in enamel paint, 3) brass natural finish, 4) high luster nickel plated, 5) unpolished nickel plated, 6) stainless steel and 7) powder coated in numerous colors. To giver you an idea of the variety of snaps available, have a look at Perfect Fit's offerings. We chose the Fasnap brand Button Head and the Fasnap socket in black Matte finish for this project. Familiarize yourself with the different brands. Notice the differences between brands not just in appearance but also in size and ease of separation. Have a look at other types of fasteners such as Common Sense Turn Fasteners and Pull-the-Dot brands. These maybe appropriate in future upholstery projects. Black matte buttons and black matte sockets were selected because they blend well with the fabric. Stainless heads could have been an option. They, of course, would appear as shiny heads along the edge. As always, the final choice is up to you. One other consideration when selecting snaps is the crimping tool to attach the socket between the head and fabric. Buying this tool is a one time expense, but quickly pays for itself in future projects. Photos 25 & 26 show a well-known crimping tool from Hoover Products. Photos 27 - 30 provide some examples of snaps that are available. Become familiar with them — there are many. Another tool in attaching snaps is a hole punch shown in Photo 31. Do a few test crimps and holes to familiarize yourself with these tools (Photos 32 — 34).
Photo 25 — This is the crimping tool for button head snaps manufactured by Hoover Products. It is a good investment to properly crimp button heads against sockets. Other anvil and press-punch accessories are available for other types of snaps and grommets. This tool is available through select distributors.
Photo 26 — Shown are three different types of anvil and press accessories for the Hoover Crimping Tool. The top set are for setting snap bases, the middle set are for button heads (this project) and the lower set are used for crimping grommets. Pictured with the middle set is a button head and a socket that correspond with the crimping anvil.
Photo 27 — Here are various button head snap hardware. On the top row are unpolished stainless steel button heads, brass button heads dipped in dark blue enamel paint, and brass button heads dipped in flat black enamel. On the bottom row are sockets from two different vendors, and flat black sockets (for use with the flat black button heads).
Photo 28 — This shows a close up view of the flat black button head and socket set. The material would be sandwiched between them before the head is crimped (center brass dowel is forced down against the socket).
Photo 29 — Close up view of a stainless steel button head and socket set.
Photo 30 — Not all snap hardware are equal. The genuine DOT socket on the left provides a better snap fit to the snap base than the generic version on the right. When ordering, chose your hardware carefully.
Photo 31 — This is an upholstery fabric punch. The head offers six different hole sizes, selected by rotating the wheel. Holes are punched against a brass base and makes surprisingly clean holes in even the thickest materials. This is one tool that should be in each upholsters tool kit. They are available from many internet sources and from tool vendors at flea markets.
Photo 32 — Shown is the Hoover crimping tool setting a button head and socket into some scrap vinyl material. The crimps hand lever provides an abundance of leverage against the button head stud. Consider applying a layer of tape on the anvil side to avoid marring the button head.
Photo 33 — Close up view of the socket side of the snap set in picture 32 above. Notice the even crimp in the center barrel, the sign of a good crimp. When you achieve results such as this you'll understand the significance of acquiring the right tool for the job.
Photo 34 — Close up view of the button head of the snap set in picture 32 above.
Attaching Snaps — Begin the process of marking and crimping the snaps at the center front of the cover (Photo 35). Do just the center snap for now and repeat at the rear center to begin stretching the cover. Continue setting the snaps on the front edge keeping the cover centered on the frame. Once the front ones are set, set the rear snaps, again maintaining equal tension between snaps. Once completed, the cover should be evenly stretched front to back. Attach the side snaps beginning at the front first. Do one or two at a time, alternating from side to side (Photo 36).
Photo 35 — Looking down at the front of the cover, the first snap is carefully marked using a white chalk pencil. Punch a small hole using the hand punch and set the first button & socket. Now place one snap at the center rear. This will begin stretching the cover. Refer to Photo 24.
Photo 36 — Continue marking and setting the snaps in the front only. Do this in a symmetrical fashion to ensure the cover doesn't veer off center and maintains equal overhang on the sides). Set snaps with equal distance between them. Now apply snaps on the rear, again working from the center out to the edges. Now that the cover is stretched front to back and held with snaps, start setting snaps on the sides beginning at the front. Do one or two at a time on each side, alternating on each side. This is where you have to be careful to avoid going off center. Continue to the rear.
Binding Problem — A problem was noticed about a section of binding and was corrected by hand sewing the problem segment. Photos 37 through 40 show how this was handled.
Photo 37 — As the cover is test fitted, this problem with the binding was noticed. The binding veered off the cover's edge (must not have been pushed into the folder enough). This is where your hand sewing skills will come in good use.
Photo 38 — Cut the thread in the middle of the problem area and use a dental pick to pull back the thread to a suitable distance where the binding is firmly attached and tie knots in the bottom.
Photo 39 — Adjust the binding to fit over the edge of the material and hold it in place with small clamps.
Photo 40 — This is a good use of the thread left over from a bobbin. Hand sew the binding back onto the cover. Use small & sturdy needle nose pliers to push and pull the needle.
Finished Cover — Photos 41 and 42 show side and overhead views of the completed cover. It fits well onto the frame at the front and along the sides. Our only criticism is the roundness of the rear corners, but not bad for a first time project.
Photo 41 — Side view of the completed Tonneau cover just after a brief rain shower. The binding repair mentioned in the above photois not even noticeable.
Photo 42 — The completed cover with all snaps crimped in place. The bows offer a slight arc and the cover's nice tight fit make rain water to roll off.
— This Tonneau cover project is not the first time one was made for this truck, a 2003 Ford F-350. A previous version used a blue vinyl with a woven base. After more than five years in direct sunlight, the vinyl became brittle and shrunk. We wanted to avoid a similar outcome, so we decided to use the material from Haartz. The Haartz material is acrylic woven cloth on one side and vinyl coating on the other side and is advertised as reversible (can be used either side up). While more costly per yard, the result provided the appearance we were looking for, and hopefully it will last longer than generic vinyl.
— Tonneau cover material is wider than other materials, 77-78 inches in most cases and in only a few colors. Due to this wide width and what seems to be low demand, the color availability seems to be limited. Haartz material is available in black, bright white, and maybe grey. If your project design demands a vehicle color compliment or match, a seam may be required. This is why we suggest considering the materials available during the planning stage.
— Keep a notebook list of various vendors and the products they offer for future reference. Expect some vendors to change or discontinue brands and sizes previously offered. Doing this for all your materials will help when tracking down materials for future projects.
— Know and understand available bindings and their attachments to help you decide on the best types of binding to use. It maybe worth ordering some short lengths to familiarize yourself with a certain vendor's product line. When acquiring attachments, make sure you know the method and screw sizes for mounting to the machine. Experience has shown to be a mixture of metric and English machine threads.
— We mentioned Velcro as a fastening method. There is an industrial grade version known in the trade as mushroom heads (each side has blunt rounded heads that interlock but can be pulled apart when needed). While a Velcro type fastener could be used, experience has shown that rain or snow can collect onto the cover and that extra weight can pull Velcro apart.
— This project uses two layers of material crimped on the snaps. Your design could include another layer (between the two) along the perimeter to offer additional durability when pulling the snap off the frame.
Santa Barbara Upholstery Supplies Source for the Haartz Tonneau material
PerfectFit Upholstery Supplies
Sail Rite for Tonneau material
Sail Rite for polyester fabric binding
Superior Threads for UV resistant thread
Hoover Products Manufacturer of crimping tool for snaps and grommets.