Re: trunk floor pan repair/replacement

Posted by BH On 2013/11/1 13:48:30

Their PowerMesh product appears to be some sort of thin, pressed random mat; sold in small, single sheets, it doesn't seem very cost effective.

For years now, the supplier has suggested using a small piece of fiberglass, soaked with POR-15 to repair small holes. I recently tried it, but didn't like the results. The fibers didn't want to maintain contour with the surrounding metal - kept popping up. Part of that may have been due to my use of random mat, when the supplier recommended woven mat, but I think POR-15's cure time is just as much of a problem.

In contrast, I've often used the random mat with regular epoxy polyester resin - even backed by pieces of wire mesh to span a void - and had no problem, as the resin kicks off incomparatively short order. However, to achieve maximum strength, you need to laminate the steel with fiberglass mat from both sides; and having several holes through the steel to allow both layers of fiberglass to bond to each other (much better than they bond to steel) - helps lock it all together. I find fiberglass and resin much easier to work with in this type of repair.

Yet, I suspect that POR-15 bonds better (with proper surface preparation) to rusted metal than the resin does. In fact, in constructing the Avanti body, Studebaker attached fiberglass bonding strips to metal parts, with pop rivets, and then bonded the strip to the fiberglass part. Also, when cured POR-15 remains somewhat flexible. If the metal isn't full of holes and doesn't shatter from a hammer blow, a couple of coats of POR-15 may be all it needs.

However, why not just cut out the weak spot and replace with good metal? If welding is not an option, pop rivets may be another option - depending on your preferences/tolerance. A body man once told me that, properly sized/placed, pop rivets are as strong as spot welds.