Antique or Classic Layered Fiberglass Headliner Repair - Resin + Fiberglass Reinforcement

When I decided to tackle the repair of my headliner on my new 1985 Fiero, I expected it to be an easy task. A quick Google search told me that I could have it done in a few hours. Instead, I ended up spending somewhere around 20 hours on this repair, and now I want to share with the world all the research I did to make this possible, in case someone else ever wants to tackle this task like I did!

Some important terms I will use here:

The Fabric: This is the outermost visible layer; in my photos, it's the greyish beige color you see.

The Foam: This is the cushion layer behind the fabric. This is usually the layer that decomposes or unadheres, causing the headliner to drop.

The Backing: In general terms, this is the layer behind the foam that is rigid. Its job is to give the headliner its correct shape and keep it there when it's installed in the vehicle.

The real trick for me here is dealing with the backing. For the modern car (and some older cars), headliner backings are made from some form of ABS plastic, or other hard material. The usual recommendation I saw for replacing headliners mounted on ABS backings was to use some form of wire wheel, strip away any foam from the headliner that stayed stuck to the backing, and then proceed with the normal gluing steps. For me, the backing was composed of many layers of fiberglass batting pressed into shape. A gun brush was pulling it to shreds, so I needed a new solution.

I decided to use resin and fiberglass tape to support the backing, as well as to give the adhesive a nice firm surface to adhere to. I also used these materials to fix a tear/crack in the backing material. This Instructable will take you through the steps I followed along the way, and hopefully be a guide on how you can do this yourself!

Materials

1. JB Weld Fiberglass Resin
2. 0.13 mm Fiberglass Tape
3. Acetone
4. Duct Tape

Tools

1. Putty Knife
2. Battery-powered sanding wheel
3. 60 grit sanding pads [I went through about 6]
4. Disposable chip brushes
5. Various drill bits
6. Utility knife
7. Mixing sticks
8. Disposable measuring containers (I used paint mixing containers)

Protective Gear

1. Respirator
2. Safety glasses
3. Gloves
4. Full-coverage clothing (preferably a shop jumper or other outerwear)

The first step (after removing the headliner, of course) is to get the backing ready for all the new materials we will be adding. In my case, I pulled away the outer fabric layer first, then pulled off the topmost layer of fiberglass to remove any remaining foam that didn't come off with the fabric. The fiberglass will try to pull off more layers than you really want to remove, so be sure to keep an eye on what is peeling off when you take off the top layer. One of the things that made pulling one layer easier was using a putty knife. It felt like it gave me more control, especially over the flatter areas.

Being careful here pays off in regards to time and materials later, but if you accidentally peel too much you should still be alright. Any delamination between the layers will be taken care of by the resin later if you're thorough, so if you accidentally peel too much, you can readhere it to where it belongs in later steps.

My own backing ended up pretty fuzzy and uneven since I was learning as I went, but it all looked good in the end, so peel at your own discretion!

Note: Check how your old headliner was stuck down, especially how it was wrapped. It's important to get yours looking like the original so it fits well. Take pictures of edges (and of course, some pictures for that great before and after)!

This was one of the hardest parts of the process for me. Resin is complicated, and searching the internet for recommendations leads to dozens of different results. If you want to read a bunch of detailed information about the kinds of fiberglass, resin, and tools, I found this link super helpful in my research: Fiberglass Warehouse Link

The main conclusion I came to was that my two choices were either epoxy resin or polyester resin. Epoxy resin is more expensive than polyester resin, and the difference in strength between the two was unimportant to me, so I went with polyester.

Once that was decided, I learned that there was laminating resin and finishing resin. The basics of each is that laminating resin dries with a tacky finish to promote adhesion between layers, and finishing resin contains wax which causes the final finish to be hard, sandable, and paintable. Since I didn't want to buy two different kinds of resin, I opted for a brand that I was familiar with that claimed to be able to do layering with fiberglass but also hardened to a sandable, paintable finish. We want something that we can build up, but also will let the adhesive for the foam stick well.

If you decide to go with a different resin, be sure to check what kind it is, and make sure it's designed to do what you're expecting it to!

In my own attempt, I tried immediately laying fiberglass. However, I found that the fiberglass didn't adhere very well, since the backing would soak up a lot of the resin before I could lay the fiberglass tape.

To fix this, I mixed up a batch of resin to pour over the front face of the backing first. I found that having two people to do this was very helpful. One would pour the resin in lines over the backing, while the other used a chip brush to spread the resin as soon as it was poured. If the resin sat too long, it would only soak in where it was poured, so it needed to be spread pretty quickly to cover the most area.

Be sure to mix your resin to the correct ratios given on the packaging, and stir thoroughly. I mixed mine in batches of 16 oz, which worked well, and added 128 drops of hardener for each batch. Be careful when spreading the resin. Try your best to make the surface of the backing flat; the wisps of fiberglass will want to stick to your chip brush, and might pull away. Again, the smoother you make the backing now, the less work you have to do in the future.

Safety Note: Be sure to use resin in a well-ventilated area and wear gloves. I'd also recommend wearing a respirator.

In my case, I didn't do a good job soaking the fiberglass in a way that made it dry to a flat surface. While this isn't super important right now, I did take the time to sand off some of the spots I noticed were high. If you choose to do the same, this will mean you have to sand through less fiberglass tape later. Since the resin wears through sandpaper slower than fiberglass does, sanding now will help you use less sandpaper on your wheel throughout the project.

The surface doesn't have to be perfect, just close to flat.

Safety Note: Sanding will make some dust from the resin. Use gloves, a respirator, and safety glasses. Consider wearing long-sleeved clothing to protect your skin.

This step varies a lot depending on the shape of and any damage to your specific backing.

General Application:

First, clean the surface with acetone. It's a good idea to do this between every layer to promote adhesion. Next, pour a thick line of resin out on the backing and spread it just beyond the width of the tape. Lay the tape over the resin, and aggressively tap the brush against the tape to encourage the resin to soak through. If you brush across the tape to spread the resin, be aware that you may displace the tape. Just push it back into the right position. You can also pour more resin on top of the tape if it doesn't seem like there is enough to soak through it. You want it to become somewhat see-through, with as few bubbles between the backing and the tape as possible. Finish one strip before moving to the next.

Make sure that when you lay the tape, you are overlapping each strip a little bit to provide stability.

Repairing Tears:

In my case, I had a tear along the large hole for the overhead light which needed extra support. Use some duct tape on the backside to align any breaks, which also helps to prevent any excess resin from dripping out from the other side of the backing. Lay fiberglass sideways across the break first, then lay fiberglass on top of that in a perpendicular direction to support it. For any tears, it's best to cross the fiberglass tape in opposite directions to support it. I'll reinforce some of this more later on the rear of the backing.

Note:

When cutting the fiberglass tape, you may wish to use an old pair of scissors. The fiberglass will dull the cutting edge of your scissors. Remember; just because it feels like fabric doesn't mean it is. You are cutting strands of glass.

When you overlapped the fiberglass tape, it probably resulted in high ridges. Use your sander and knock down those high edges until the surface feels smooth. If needed, mix more resin to pour in excessively low areas, or apply more fiberglass tape to add bulk or strength. If you have any areas you will need to mount hardware (i.e., visors, clothes hooks, or handles) that need more support, fill in areas as necessary with patches of tape layered with resin. On my backing, I did this on the holes in the two uppermost corners.

For any edges of the fiberglass tape that overhang the backing, you can gently run the sander along the outside edge of the backing to wear through it and break it off. If the tape doesn't have resin on it, you could also optionally cut it with scissors.

Repeat the layering and sanding steps on problem areas as much as necessary to produce a relatively smooth surface to adhere your foam layer to.

Note: When sanding, be aware that the hardness of the sandpaper is less than the hardness of the fiberglass. Replace your sandpaper as soon as you notice wear to help prevent any damage from friction or heat to your sander.

Safety Note: Sanding makes a lot of fine fiberglass dust. Wear gloves, safety glasses, a respirator, and long sleeves while sanding. The fiberglass will embed itself in your outer layer of clothing and make you itch, so I'd recommend using the same outerwear every time you need to sand the fiberglass. I used straps to cinch sleeves so the sander couldn't send dust up my arms. When washing your skin after contact with fiberglass, it is best to use cold water first to close pores and remove fibers, then warm water if desired after the skin is well-cleaned.

I forgot to take photos of this step, however, you can see it in the photo above. For any cracks or holes that you know may be subject to force, it's a good idea to support the backing on the rear side. It's also important to harden the edges to allow for good adhesion of the foam layer.

Be sure to soak the backside in resin anywhere you expect to lay down fiberglass tape or eventually lay down the foam layer. For cracks, if there is a gap you want to fill, a good way to do so is to roll up a small segment of fiberglass tape and shove it in the crack. Cover the crack with a new strip of fiberglass tape to seal in the roll, then cover it in resin. This helps you not to accidentally pull out the roll of fiberglass tape when filling the void with resin.

Don't worry about sanding this side unless you make major ridges.

Note: Avoid covering the rear of your backing entirely in fiberglass like we did to the front. While it may seem good for strength, it may compromise your headliner's ability to fit properly back in the vehicle.

Now is a really good time to make sure everything lines up, especially if you had to make holes in your headliner for fittings. I'd recommend putting the headliner back up in place with some help and making sure all clips, screws, or other attachment points can actually catch before you continue on. There's no worse feeling than getting something looking pretty, then realizing you have to start over because you didn't take the time to double check!

Now this is just like any other headliner replacement! In my case, I bought material that had the foam and the fabric fused together for me. For some, they may desire to glue down foam first, then attach a layer of fabric.

From here on out, you may be better off looking up headliner replacement videos for your own vehicle, to cover specific details that may apply to your headliner. The visual can really help you understand the best ways to press the lining into place, and on a job like this, it's good to come prepared. I'll include a couple important things that I learned when applying my own material.

1. Contact adhesive is what is typically recommended when replacing a headliner. Be sure to spray adhesive on the backside of the foam and the front of the hard backing, but don't apply too much! It can be hard to tell how much glue is going onto the headliner due to a lack of color contrast. Try applying your adhesive spray to the foam layer first so you can easily see spray pattern and density.
2. Once it sticks, it's stuck! Assume that anything that touches after the contact glue is applied will be permanently adhered. To help prevent this, have lots of people there to assist! It took 3 people to adhere my headliner.
3. Work in sections. Glue a small portion first, then progress to the next segment. It's less to fight to keep from sticking if you don't glue it all at once.
4. The foam doesn't stretch well. Don't glue the outer edges of the foam layer first and expect to be able to stretch the foam into the divots of the backing. It stretches just well enough to work from either side to side or front to back; stick to one of those directions instead!
5. Cut out openings last. Don't make your cuts before you glue the backing; it'll make alignment impossible. Just wait until it's all stuck down, then you can flip the whole headliner over, cut out the holes, and fold over edges nicely.

Good job, it's all done! Now reinstall it in your car, truck, or other automobile and show off to all your friends that you did that! It's a great feeling to get a project all done. And hey, if in another 20 years or so this vehicle needs a new headliner again, it should be just as easy as any other hard-backed liner to replace; peel, stick, and go. Nice work!