Prevost XLII Skin Delamination Repair

[davidbrady]

(04-30-2017 08:06)CC_Guy Wrote:  I once read that this problem was corrected in 2010. Does anyone know of a 2011 or nearer with delamination?

There was a guy on PC who said he saw delam on an X3 at a show in Indio, but who knows??? Certainly far from a confirmed case.

If you go to http://www.scholar.google.com and google for "adhesive steel frp fatigue" you'll get a feel for the current state of the research and testing. Methyl Methacrylate (MMA) is often cited when structurally gluing FRP, steel, and concrete. Loctite H8000 is an MMA. An interesting side note is that MMA is often used to glue bone, dental caps and veneers. You can imagine the service life expected in medical applications.

One of the interesting things about MMA is it requires very little, if any, surface prep. However, the researchers in the attached paper got much better adhesive performance if they first sandblasted or grinded steel surfaces. Perhaps Prevost bought into the manufacturers' hype and they didn't prep the stainless steel. I would have expected Prevost to run their own strength tests given what's a stake.

One thing's clear, there's no way bus manufacturers are going back to rivets. There are just too many advantages of a glued on panel: it simplifies manufacturing, reduces time and cost, simplifies paint prep, cleaner look, waterproof interface, stresses are evenly distributed - no stress concentrations at the rivets, etc. Panels provide chassis stiffening; adhesives provide damping. Once they settle on the right adhesive, and the correct prep (even if in addition to the adhesive manufacturers' recommendations), and if they can keep stresses in check, bonded panels should last 30+ years.

Even with rivets, it's fairly common to see busnuts reskin their old buses.