Time to work on the rear door, and its mounting. I take extra time to engineer areas of high stress. I normally build it in the panel in this case when I construct it (them) but as this is made up by non specific pieces I did not have this luxury. As my fellow adventurer pointed out above there ate a host of different hinges and they each serve a different purpose but do well within that purpose, and Peter brings up a good point. "Point loads" is something that you always need to pay attention on in composites. Specially as your using alloy fasteners and composites. A fatal flaw, if not addressed with Carbon is that its abrasive resistance properties is like a pencil lead. Sorta.... So once a screw or alloy fastener vibrates loose it will relatively fast "file" through its hole and could simply fall out, leaving the joint exposed. It can happen to all of us. If you are following the XO- Africa expedition you will see what I mean as they are battling the worst roads they have ever seen, things are coming apart. There are a few things you can do to mitigate this. If you screw in alloy fastener directly into fiber, add a layer of epoxy. Sorta like a Danish Layered cake. The epoxy, after it has cured, has this amazing capability to kinda "grap" hold of whatever it is next to. A bit like fly paper but obviously not that sticky. Remember above when I created several layers inside the door flange to bolt the stainless hinge on? That was done in order for the screws to stay. Like a lock nut. On the camper side it is a different problem as we are drilling on a 90 deg through fiber, foam and then fiber. This is why a bonded hinge would not work well in this application and premature failure would be expected. If you bond a hinge to the outer skin on any FRP panel, you are only utilizing the outer composite layer. As that door or window will work, vibrate, call it whatever you'd like, there is a high properbility that it will yank the outer composite layer off the foam and you are now delaminated. It is not the debonding of the epoxy from foam, but simply the foam splitting. In order to achieve the maximum strength in a FRP or any sammich panel really, you need to engage both fiber layers, but that i itself presents an issue. Ya cant torque on foam. I'tl squish. Trying many different solutions over the last many years, I find that if you replace the foam around each fastener with epoxy, you can now torque, while engaging both sides on the panel. It is a time consuming application but this is why it is so cool to do it yaself, as you can do whatever ya want.
All that said, it is time. The rear doos corners was filled with THIX.....and is now curing.
Then after a small hole was drilled to line up the holes for the hinge on the camper side...... they were taped off to prevent any drip through of epoxy.
Shell was then sat down on the aft part in order for me to be able to work the holes. Each hole was enlarged with a dremel tool.
Then sanded in order for the Carbon Fiber tape to get the best bonding surface.
Then a strip of unidirectional Carbon Fiber tape was cut.
Each hole was then filled with Thixotropic and the carbon fiber tape was laid on top. The strip was saturated with Max Bond 1618 but THIX was below and above it.
This will now cure and I have 21 M4x25mm stainless hardware due in the next few days. Until tomorrow.....