Reinforcing MazdaSpeed bumper

[MrMazda92]

I've seen a few people mention reinforcing the fiberglass on the lower lip of the bumper, and wanted to know if anybody actually followed through so far.

By my thinking, a few well placed strips of fiberglass cloth in the corner areas(curves, if you will) of the lower lip would help to reduce the risk of breakage. After adding these strips, I intend to go over the entire lower lip surface with a single(longer) strip to reinforce the entire edge.

While I have the resin and cloth available, I'll be installing a mesh of sorts. I have yet to decide exactly what I will use for the mesh unfortunately. I'll probably fiberglass around the edges to permanently mount the mesh, when I do find the right material.

[Nd4SpdSe]

Well reinforcing has both it's strengths and draw backs. I'd scraped my MS bumper before; on curbs, car lifts and tow truck beds. I want to say what may have saved it was that it flexed. Reinforcing it would help against inpact, but there's no way that you could reinforce it to survive the weight of the car on low clearance ramps and entrances.

I think I remember having the idea to pack behind the lip with fibreglass mat, mat being stronger than cloth. I would revise that and contemplate using something flexible but help keep it to together while it flexes. Maybe something like a rubber strip rather than fiberglass cloth, or the rubber strip covered with a layer of fiberglass just to hold it in place. Keeping fiberglass layers at a minimum since fiberglass doesn't really like to flex.

[MrMazda92]

Indeed, I had feared exactly that as well... One of the benefits of my near stock ride height(I don't like low-low cars), is that I won't contact curbs or driveways with the bumper. My only real concerns are animals crossing the road, and damaging it while working on the car(removal/re-install), as that was the cause of my original crack.

I'll look into a different backing material, and consider fiberglass behind that as you suggested. From what I've read on fiberglass mat, it's not any more or less flexible than cloth(of equal thickness), and the determining factor for flexibility is your choice of resin... Which gets you into product longevity, and how often you will need to touch it up.

At least fiberglass is relatively easy to repair, if nothing else.

[Nd4SpdSe]

Indeed, I had feared exactly that as well... One of the benefits of my near stock ride height(I don't like low-low cars), is that I won't contact curbs or driveways with the bumper. My only real concerns are animals crossing the road, and damaging it while working on the car(removal/re-install), as that was the cause of my original crack.

I'll look into a different backing material, and consider fiberglass behind that as you suggested. From what I've read on fiberglass mat, it's not any more or less flexible than cloth(of equal thickness), and the determining factor for flexibility is your choice of resin... Which gets you into product longevity, and how often you will need to touch it up.

At least fiberglass is relatively easy to repair, if nothing else.

I know how you feel. My cars setup was just high enough there only a few times that it touched/dragged, but not enough to cause it to break. Drover over a huge dead racoon once (at night on a back road, going pretty fast), just had some hairs on the gas tank, but I was deathly affraid for my bumper and had pulled over right away.

Fiiberglass mat is suppose to be stronger because of the various directions that the fibers go in, rather than the weave of the cloth version. I haven't worked with fiberglass for many years sadly. Like boat hulls being injected/shot mat.

That's interesting, I didn't know there was different flexibilities of Fiberglass resin.

[MrMazda92]

Yeah, I've not tagged anything but the front lip on the stock bumper, and since removing it never once touched.
I'm not looking forward to that awful, grating sound of my car dragging on the driveway again, ever!

Honestly, I've never hit an animal, alive or dead... I've had a few near misses with daredevil cats, but never hit anything to my knowledge, which is a shock living in Eugene!

The mat is supposed to be significantly heavier as well, but again it's determined by thickness. Most boat hulls are made using mat, but oddly enough are repaired with cloth quite often. I believe it's due to the weave of the cloth being angled to reinforce the hull where it is strained the most. I know that for bulkheads we always used cloth, and seldom touched mat for anything smaller than 6"x6", and never on a loadbearing surface, only the underside of the deck for the most part(boats with less freeboard tend to be hard to see on a crowded multi-class starting line, and decks are damaged more than hulls in most instances).

I hadn't seen mention of that before either, but it does make sense... The cloth/mat isn't extremely rigid in thin layers, but it does make sense when I think about it.

[Josh]

I have purchased all my materials and will begin this process this week. I am going with matte material as it is stronger by thickness and more rigid. I am only going to use it on the lower half of the cover however. I am only applying one layer as that is all it needs then I am rolling it flat. It will be thick enough to not fracture apart and or break when if i bump a curb and pliable enough that it will still bend and twist. I am using a Polly based resign as well.

Most use fabric for repairs because it is easy to work with over matte material.

[MrMazda92]

Please take pictures!