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Chapter 16: Upholstery - Interior Panels​

Like the chapter on painting, the sections on upholstery and interior work are not intended as tutorials or "how-to" guides for upholstering a hot rod. This is the first full interior ever attempted by the builder, so there are far better sources to rely upon if you want the nitty-gritty for stitching up your interior.

The fact is that some of the techniques and materials you will see in this particular chapter might even be scoffed at by purists and high-end upholstery shops. But, this is hot rodding, and hot rodders tend to bend the rules here and there to get the results they want at a price they can afford. That's what this book is all about.

The techniques and materials used here worked for the builder. However, no claim is made that they are perfect or that they should be substituted for more tried-and-true alternatives; they are presented only to stimulate your own thinking and ideas.

Backer panels[edit]

Flat panels[edit]
Wall Room Floor Tile 16-1 Backer boards such as this are cut for all the flat interior panels. Photo attribution
The interior "skin" of the car can be considered much like the exterior skin. And like the exterior, the interior consists of a number of large, flat panels connected together by a series of curved panels, which hopefully provide an aesthetically pleasing transition from one flat panel to the next.

The flat panels are relatively easy to fabricate. Most can be cut simply by measuring the width and length of the area to be covered. Others, like this oddly-shaped side panel, are made by first creating a paper pattern and then tracing it onto the backer board (Photo 16-1).

Photo 16-2 shows all of the flat panels cut and installed in the car.
Red Room Ceiling House Door 16-2 All of the flat panel backer boards installed. Photo attribution

Panel material[edit]

The panels shown here are cut from 1/8" Masonite. Later during the interior fabrication, some of the panels were done over to repair some damaged foam. The newer panels were made using 1/8" Luan-type plywood. Backer panels can also be made using waterproof panelboard (available through upholstery shops and on the internet), ABS plastic, and PVC foam board. Each panel material has its pros and cons and each builder should do his own research on all of them before selecting which material he wants to use.

Panel attachment[edit]

There are many ways to attach your panels to the body structure. Most often, hidden clips are used, which slip onto the panel and then friction-fit into holes drilled in the body substructure. Some of these clips are metal and some are the plastic "Christmas tree" type of fasteners.

For this particular interior, a different type of attachment method is used: the "button head stud screw". Unlike clips, button head screws are visible once the interior is done. Photo 16-3 shows how button head screws appear on another interior, the roof panel of my '32 pickup.

The stud screws are capped with the male portion of a snap (Photo 16-4). If longer screws are required, they can be made up by using a common screw inserted through a snap head as shown in Photo 16-5.

Ceiling Wood Line Beige Peach 16-3 Button head stud screws look like this on a finished interior. Photo attribution
Screw Fastener Metal Brass Nut 16-4 The snap head of a stud screw. Photo attribution
Screw Fastener Metal Fashion accessory Washer 16-5 An alternative is to use common screws with a snap head. Photo attribution
Wood woodworking Tool Metal 16-6 A button press will cost around $140. Photo attribution
The button heads themselves are made using the same upholstery material as used elsewhere in the interior (or an accent color if desired). A hand-operated press (Photo 16-6) is used to cut small circles in the upholstery (Photo 16-7).The circle is placed over a plastic button form (Photo 16-8) and a plastic snap ring (Photo 16-9) is placed in the press, where the pieces are joined together to form a button, as shown in Photo 16-10.
Floor Wood Circle Placemat Wood stain 16-7 The press cuts perfect circles from your fabric. Photo attribution
Button Fashion accessory Metal Jewellery Wood 16-8 The circle of fabric is placed over a plastic button shell and loaded in the press. Photo attribution
Brown Yellow Tan Wood Leather 16-9 A plastic snap ring is also loaded in the press. Photo attribution
Yellow Wood Button Circle 16-10 A quick pump on the press handle and a button like this is formed. Photo attribution
Button Wood Metal Circle Fastener 16-11 This view of the button bottom shows the plastic ring that snaps onto the stud screw head. Photo attribution
Photo 16-11 shows the underside of the button, which snaps onto the head of the screw stud. If the panel needs to be removed, the button head can be popped off and the stud unscrewed. Photo 16-12 shows just some of the button heads made for this project.
Food Plant Cuisine Dish Legume 16-12 Dozens of button heads were required for this interior. Photo attribution
Curved panels[edit]

After trying and rejecting a number of different ideas for building the curved backer panels, an article from an old issue of Rod and Custom provided the solution. The piece showed how Carson tops were formed using 1/2" square hardware cloth (wire mesh screen). A lightbulb went off immediately, and after a bit of experimentation, the panel building was under way.

Photo 16-13 shows a close-up of how the wire screen is formed to fit into the corner curve, and Photo 16-14 shows the full corner with wire backing in place. The wire is folded over the body skeleton, and screws are used to hold the sections in place (Photo 16-15).

Harp String instrument Konghou Plucked string instruments Musical instrument 16-13 "Hardware cloth" is shaped to fit the corner curves. Photo attribution
Red Motor vehicle Vehicle Automotive exterior Car 16-14 The wire screen is fitted to the rear corner curve. Photo attribution
Net Tile 16-15 The screen is held in place with self-tapping screws. Photo attribution

After all of the curved wire pieces are formed and in place, the flat panels are all re-installed (Photo 16-16).

Obviously, we cannot apply upholstery directly over the wire mesh; we need to create a smooth and solid surface for our base. To do this, we use a fiberglass mesh material...commonly known as "drywall tape" (a roll of it is on the left in Photo 16-17). This is the fine mesh perforated tape that is sticky on one side. Drywall tape is available at any hardware store. Do NOT use paper tape; the fiberglass mesh tape is designed to prevent any potential cracking or flaking of the backer once it is cured.

To do this job, you need to get a little messy, since the best way to apply the drywall compound is by just using your hands. The fiberglass tape is cut to manageable lengths and held against the wire mesh with one hand, while smearing drywall compound with the other. The drywall compound is lightly pressed through the mesh tape and through the wire screen. The compound has a natural tendency to wrap itself around the back side of the wire screen, which holds it firmly in place once dry. Gently smooth this first layer using your hands or a Bondo applicator ( Photo 16-18).

Ceiling 16-16 The flat panels are re-installed. Photo attribution
Paint Joint compound 16-17 Fiberglass drywall tape is used to build the surface of the panel. Photo attribution
Wall Brown Line Material property Tints and shades 16-18 The first layer of fiberglass and compound is applied to the wire mesh. Photo attribution

To make them removable and easier to handle, the wire mesh and drywall tape are separated into individual panels. To keep the sections separated, 1/8" plastic welting cord (Photo 16-19) is inserted between all the "joints" (arrows) where the backer sections will be separated (Photo 16-20). When the entire backer panel is finished and dry, the welting cord is pulled away, and the backer sections will separate from one another. The welting cord will also create a 1/8" space between all of the panel sections. This space is necessary so that the upholstery material can be wrapped around to cover the edge of each panel. When competed, the panels should butt up to each other without any gaps showing.

When the first layer of mesh and compound has dried (which usually takes overnight), it is sanded to knock off any big lumps or imperfections, and a second layer of fiberglass mesh is laid on in the opposite direction of the first layer. Drywall compound is once again forced into the mesh, bonding the second layer of mesh to the first.

This process is repeated for a total of four layers of fiberglass mesh, allowing each layer to dry before going on to the next. After the final layer is completely dry, the welting cords are pulled out, all the flat panels are removed, and the curved panels are sanded smooth. After blowing the panels clean and wiping them down, two coats of water-based polyurethane are applied to seal the joint compound and to reduce any future effects from humidity (Photo16-21).

Wire Thread Electrical wiring Textile Lighting accessory 16-19 Welting cord is used to keep the curved panels separate while the fiberglass is laid up. Photo attribution
Red Yellow Wall Design Room 16-20 Welting cord inserted between the panels. Photo attribution
Yellow Ceiling Wall Room Architecture 16-21 Water-based polyurethane is used to seal the surface of the curved panels. Photo attribution
Table Wood Flooring Furniture Floor 16-22 Closed-cell foam must be sanded wherever it will be glued to another material. Photo attribution
All the panels, whether curved or flat, are covered with 1/4" closed-cell foam. The foam is glued on with an adhesive, which is sprayed with an inexpensive paint gun or sprayer made for this specific purpose. DAP Landau Top and Trim Contact Adhesive was used for this project.

When spraying glue on foam or panels, it is advantageous to have lots and lots of paper (or newspaper) on hand to cover your work table. Spraying adhesive can get messy, and glue can get into some very unwanted places. So, change your paper often and keep your work table as clean as possible.

A second general rule is that all foam must be sanded wherever adhesive is going to be applied (Photo 16-22). This opens up the "cells" of the foam so that the adhesive can gain a grip. A Scotch-Brite pad can be used for the sanding.

Inserts and accents[edit]

Most panels seen on custom cars will have some sort of insert or accent. The accent might be done with different-colored upholstery, a different texture, such as rolls and pleats, or a different material such as metal or plastic. These accents are often created with a separate "backer", and then the foam on the base panel is cut away so that the accent panel can be "inserted" into the base panel. The following roof panel fabrication will be shown in some detail here, since it includes nearly every step used during production of all the other panels on this car.

The roof panel[edit]

The roof panel fabrication will be shown in full detail, since it demonstrates almost all of the techniques used during fabrication of the other interior panels on this project. This panel will have two rectangular rolled and pleated "inserts" surrounded by a plain fabric border.

The inserts[edit]

After deciding on the approximate size for the inserts, the rectangles are cut from black waterproof backer board. To round the corners of the backer board, simply trace around any appropriately-sized circle and make the cuts (Photo 16-23). Clamp the two backer boards together, use an air sander to clean up the edges, and make sure the two backers match one another (Photo 16-24). The finished backer boards are shown in Photo 16-25.

Design Hand Drawing Table Writing instrument accessory 16-23 Corner curves are traced around any round object of a suitable size. Photo attribution 16-24 Backer boards are clamped together, and the edges cleaned up with an air sander. Photo attribution
Table Furniture Technology Electronic device Hood 16-25 The finished backer boards. Photo attribution

A piece of sew foam is cut to the exact width of the backer board, but two inches are added to the length to allow for shrinkage when the pleats are sewn (Photo 16-26 ). Also note in this photo that holes have been drilled in the backer board to accommodate #10789 panel clips. The holes and clips can be seen more clearly in later photos. The fabric is cut with an excess of 2" on all sides (Photo 16-27).

The fabric is marked on the face side with lines 2" apart to guide the sewing of the pleats. The fabric is then glued to the sew foam with the centerline of the foam matching the centerline of the fabric (Photo 16-28).

Floor Wood Flooring Brown Beige 16-26 Sew foam is cut for making the pleated insert. Photo attribution
Floor Wood Flooring Wood stain Plywood 16-27 Fabric is cut with a 2" allowance on each side. Photo attribution
Wood stain Table Wood Floor Furniture 16-28 The sew foam is lightly glued to the fabric, to keep it positioned while sewing the pleats. Photo attribution

Starting from the center and moving toward each end, the pleats are sewn following the lines drawn on the fabric (Photo 16-29). Photo 16-30 shows how the panel now looks from the back side.

Yellow Roof Paper Floor Paper product 16-29 The pleats are sewn beginning in the center and moving toward the ends of the panel. Photo attribution
Paper Paper product Beige Envelope 16-30 The backside view of the pleats. Photo attribution
Gadget Technology Table Electronic device Smartphone 16-31 The backer panel is used as a pattern to trim the excess foam from each end. Photo attribution

The backer panel is laid on the sew foam and lines are drawn to trace each end of the backer onto the foam (Photo 16-31). The excess foam is then trimmed away so that the panel now looks like this (Photo 16-32). This photo shows more clearly the holes drilled for mounting the insert to the roof panel. The clips used are shown in Photo 16-33.

The fabric is then pulled firmly over the edges of the backer board and glued to the back side using DAP adhesive sprayed on both the backer board and the fabric. The finished insert is shown in Photo 16-34. The second insert is made following the same steps.

Table Floor Furniture Metal 16-32 The panel after excess foam is trimmed. Photo attribution
Metal 16-33 Example of clip used to hold the accent panel to the roof panel. Photo attribution
Mattress pad Furniture Mattress Linens Floor 16-34 The completed insert. Photo attribution
The flat surround[edit]

The roof panel "surround" is cut to fit the entire flat section of the headliner. The position of the two "inserts" is marked on the panel, and stick-on shelf liner is cut to the exact size of the insert panels and attached to the roof panel (Photo 16-35). When the foam is glued to the panel, we do not want the foam to stick in the area of the inserts. This would require a good deal of work to remove the foam residue from the panel. The shelf liner basically acts as masking paper, which can be easily pulled off when the foam sections are cut and removed to allow for placement of the inserts.

To "foam" the roof panel, a piece of 1/4" closed-cell foam is cut with about an inch of excess on each side. The foam is sanded on both sides (since both sides will eventually be glued) and then positioned on the roof panel. Clamps are used to hold one end of the foam in position (16-36).The "loose" end of the foam is lifted up, and DAP adhesive is sprayed on both the panel and the foam (16-37).

Table Rectangle Furniture 16-35 The roof panel with the insert sections covered with adhesive paper to mask it from glue. Photo attribution
Table Textile Linens Floor Tablecloth 16-36 One end of the foam is held with clamps to keep it correctly positioned. Photo attribution
Table Wood Flooring Floor Art 16-37 Contact adhesive is sprayed on the panel and the foam. Photo attribution
Machine 16-38 After gluing one end, the clamps are removed and the other end is glued. Photo attribution
After the adhesive has been allowed to tack up, the foam is slowly and carefully laid back on the panel, working from the center to the outside edges of the panel. Panel adhesive is a "contact" glue. Once the two surfaces make contact, it may be difficult to separate or move them without damaging the foam. With the foam glued on one end, you can then move to the other end of the panel to lift the foam and apply the adhesive in the same way (16-38).With the foam glued to the panel, mark off the location of the inserts, and then lay the insert backer boards in position and trace around the perimeter of each (Photo 16-39). Before cutting the foam, however, we must take into consideration the width of the upholstery material which we will be wrapping around the edges of the insert and around the edge of the surrounding foam. This material takes up space. We want the insert to fit within its opening without distorting the fabric or creating wrinkles or creases, and we also don't want huge gaps between the insert and the surround. So, this part is a little bit of guesswork.
Table Tile 16-39 The foam is marked for cutting out the areas for the inserts. Photo attribution
Floor Table Wood Flooring Tile 16-40 A straightedge and razor knife are used to cut the four sides of each insert section. Photo attribution
Based on some practice panels that were created, a margin of about 1/8" all around the insert was found to work out well. To create that margin on our foam, a slightly blunted (used) Sharpie felt-tip pen was used to trace around the backer boards. The blunt Sharpie makes a line approximately 1/8" wide. By always cutting on the outside of that line, we will create our 1/8" margin.A straightedge is positioned along the outside edge of the Sharpie line and clamped in place. A razor knife is used to make the straight cuts on all four sides of the insert (Photo 16-40). The curved corners are carefully cut freehand (Photo 16-41).
Leaf Wood Drawing Hand Design 16-41 The corner curves are cut freehand. Photo attribution
Audio equipment Electronics Technology Electronic device Subwoofer 16-42 The foam and the adhesive shelf paper are removed together, leaving a clean, unglued surface for mounting the insert. Photo attribution
The foam covering the insert areas can then be removed by slipping a razor knife under one corner and peeling up the shelf paper "masking" below the foam. This leaves a nice clean area of the roof panel where the inserts will be installed (Photo 16-42). Photo 16-43 shows the insert backer panel laid in the opening to demonstrate the 1/8" gap around the edge of the insert.
Floor Leather 16-43 The backer panel demonstrates the extra 1/8" of space needed for the fabric to wrap around the insert. Photo attribution
Wood Yellow Plywood Floor Hardwood 16-44 The fabric is carefully glued to create a sharp edge around the insert opening. Photo attribution
The fabric is cut to overlap the roof panel on all sides and the holes for the inserts are cut out, leaving ample material to ensure that all of the edges will be covered. The fabric is glued to the foam in the same way the foam was glued to the backer board, securing it first on one end with clamps and then gluing the other end. Once the first end of the fabric is glued, the clamps are removed and the other end is glued. The outside edges of the fabric are pulled over the edges of the backer panel, and are glued to the back side of the panel. The insert areas are "notched" around each corner so that the material will lay down without creasing. The backer and the underside of the fabric are sprayed with adhesive, and the fabric is carefully positioned so that a nice tight edge is created around the entire perimeter of the insert opening. There should be no air bubbles between the fabric and the foam. (Photos 16-44 and 16-45).
Wood Plywood Table Furniture Wood stain 16-45 The panel being prepared for the inserts. Photo attribution

Clips are then installed on the back of the pleated insert panels and the panels are snapped into place. The finished roof panel is shown in Photos 16-46 to 16-48.

The other panels[edit]

Polished aluminum insert panels[edit]

The door panels and rear side panels have polished aluminum inserts. The backer panels are made in the exact same way as the roof panel, except that aluminum inserts are screwed to the panel rather than using pleated fabric inserts.

The aluminum accent pieces were cut from a large sheet of 1/8" aluminum and were then sanded, polished and buffed (16-49). The slotted panels (Photo 16-50) were made by first cutting the panel to shape, and then drawing slots on the panel. Holes were then drilled at each end of each slot (Photo 16-51) and the material between the holes was cut out with an abrasive cutting wheel (Photo 16-52).

Hood Table Automotive exterior Bumper Auto part 16-49 The aluminum insert pieces after polishing. Photo attribution
Wood 16-50 This slotted accent is for the rear side panel. Photo attribution
Bumper Table Auto part Metal 16-51 The slots are made by first drilling holes. Photo attribution

The Ford "ovals" on the door panels were created in the same way as the other inserts (Photo 16-53). The ovals were then dressed out with a vinyl graphic of the finished car (Photo 16-54).

Bumper Automotive exterior Hood Auto part Metal 16-52 The material between the holes is then cut away. Photo attribution
Table Sport venue Glass Metal 16-53 The Ford "oval" for the door panel. Photo attribution
Motor vehicle Vehicle Car Transport Wheel 16-54 A vinyl graphic of the finished car is applied to the panel. Photo attribution
The back panel[edit]
Table Furniture Wood Desk Plywood 16-55 The panel for the back curve and rear window area of the car. Photo attribution
The back panel and insert are made using the same steps as the roof panel (Photo 16-55 and 16-56)
Yellow Floor Table 16-56 The panel for the back curve and rear window area of the car. Photo attribution

Curved panels[edit]
Pattern Paper Pattern 16-57 Foam being glued into the rear corner curve. Photo attribution
All of the curved panels are also covered with foam and fabric. Photo 16-57 shows how sections of foam were cut and fitted into the compound-complex rear corner panel. Photo 16-58 shows the fabric being coaxed to fit the panel, and Photo 16-59 shows the completed corner panel. The rear top curve was also covered with foam and fabric (Photo 16-60).
Yellow Footwear Textile Floor Shoe 16-58 Working the fabric into the rear corner curve. Photo attribution
Yellow Design Wood Pattern Wing 16-59 The completed rear corner panel. Photo attribution
Yellow Table Wood Automotive exterior Plywood 16-60 The completed rear top curve. Photo attribution
Stud screw supports[edit]

In certain areas of the interior, the panels must be bent to conform to the curvature of the body structure. In these areas, the stud screws must be tightened down quite firmly to bend and hold the panels in place. For these "stressed" areas, special support plugs are made to reinforce the fabric and foam. Without a plug, the stud screw head would make a deep indentation in the foam and fabric, and might even cause rips or damage.

Fortunately, there is an effective and inexpensive tool for not only creating the plugs but for cutting out the foam where the plug is inserted. This tool is a 1/2" hollow punch (Photo 16-61).

The punch is handheld to cut out the foam. It is placed over the screw hole and twisted (spun) back and forth to "drill" through the foam (Photo 16-62). These punches are very sharp, so is quite easy to cut and remove the foam (16-63).

Pen 16-61 A "hollow punch" is used to make screw support plugs. Photo attribution
Floor Hardwood Tile Flooring Table 16-62 The punch removes a cylinder of foam from around the screw hole. Photo attribution
Sink Beige Bathroom sink Ceiling Rectangle 16-63 The hole made for the support plug. Photo attribution
Machine Sewing machine 16-64 The hollow punch cuts chipboard disks to make the plugs. Photo attribution
To make the plugs, we use the same tool. The punch is mounted in a drill press, and plugs are cut from chipboard (a heavy cardboard about the thickness of the backing on a yellow legal pad) (Photo 16-64). Chipboard can be purchased in quantity from a number of internet sources, including It takes 4 chipboard disks to fill each hole and complete the plug, but 80-100 disks can be cut out in under 5 minutes (Photo 16-65).
Coin Money Currency Metal Dime 16-65 Using the drill press, disks can be cut out very rapidly. Photo attribution
Sink Beige Plumbing fixture Ceiling Bathroom sink 16-66 The disks are wiped with glue and inserted into the hole. Four disks are required for each hole in 1/4" foam. Photo attribution
Before being installed, each plug disk is given a quick swipe with Elmer's glue, and inserted into the hole (Photo 16-66). Photo 16-67 shows a series of plugs installed in the rear panel foam. Once the glue is dry, a hole is drilled through the center using the screw hole in the backer panel as our guide.
Wood Table Plywood Furniture Metal 16-67 Plugs installed in the rear panels. Photo attribution

Insulation and sound deadener[edit]
Window Room Architecture Glass Wood 16-68 Foil-faced bubble pack is glued to the sheet metal for insulation. Photo attribution
Before doing a final installation of the finished panels, your preferred insulation and/or sound deadener should be installed. Foil-faced bubble pack is being used on this project as the insulation material. The pieces are cut so that they fit between the sections of skeleton tubing. Outdoor carpet glue is applied to the underside of the sheet metal, and the insulation pieces are pressed into place (Photo 16-68).After the glue has had sufficient time to dry, the sound deadener (in this case, carpet padding) is added. The vertical panels of padding can be friction-fit, while the overhead panels are glued with the same DAP adhesive used for gluing the interior panels (Photo 16-69).
Red Wall Door Antique Metal 16-69 Carpet padding is installed as a sound deadener. Photo attribution

The completed panels[edit]

Photos 16-70 to 16-75 show the completed interior panels installed in the car.

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