Thanks to some help from Jenny today we've more or less finished sealing up the bottom of the hovercraft.
There's two small joints that I'd like to fiberglass over. However, my epoxy level reached a critically low level such that the pump for the resin started sucking air. So I had to use my estimate for the right ratio to mix the epoxy.
We started off the day by sanding down a the previous epoxy work. And we got the hovercraft balanced back on it's other side. With the skirt attachment point it's actually semi-balanced not quite on it's side. So I tied it in place to the rafters.
The hovercraft propped on it's starboard side.Ready for work.
We cut a few more strips. I switched back to using scissors from the razor blade. It cuts with less pulling stress, and allows me to follow the weave better. This leaves the edges much more square with less dangling fibers.
Marking the fiberglass with a pen prior to cutting for better weave cutting.
We finished up the side with the last of the epoxy. Here's the full timelapse.
One oddity when flipping the vehicle was that I had a little bit of oil leak from the front engine on the port side. But on the starboard side fuel started coming out of the primer pump. And there was a bit of a leak from the thrust engine but turning off the fuel cutoff helped that a lot. ;-)
And here's the results as it's drying. I found just enough epoxy to seal up the small side joint too.
With great help from Jenny and Jennifer L we made a lot of progress today!
It was super hot today which both made things uncomfortable as well as challenging with the epoxy.
We started off sanding down the corners and surfaces we planned to glue. While preparing the fiberglass strips.
The challenges started early when the resin didn't look right when I pumped it and it came out much whiter than it should with particles from 1/4" downward. And the pump didn't refil correctly. After some investigation it appears that the resin has sat too long in the pump and has partially reacted somehow.
White precipitate in the resin pump. Unfortunately the focus in this picture is on the wrong part.
I pumped it a bunch and tried to clear as much as possible and we got back to relatively clear fluid flow. But new pumps are in order. And we're almost through with this batch of epoxy so that's not too bad.
As I noted in the last post there was quite a bit of gap in the front edge. So we started by trying out the silica thickener that I got to fill the gap. Since this was less critical I used the large pool of leftovers and tried to mix the hardener in in the right ratio and put the thickened epoxy into the gap.
Using the thickener in the epoxy
It seemed to work quite well.
After inserting that, we applied the glass down the outside, and then clamped the surface down. Hopefully with the epoxy squeezing everywhere it will come back apart ... ;-)
The clamped front end.
We moved onto doing the lower part of the lift duct. And ended up clamping it too for a small section of lifted plywood.
Duct post epoxy/fiber pre clamp
Duct clamp top size
Duct clamp bottom side
The clamps being attachable/detachable was quite convenient for sneaking the rod through the fan housing.
We continued from the front edge to the starboard side, and the rear. However we stopped doing the port side since it's fighting gravity and figured we'd wait until this hardened and do that side separately.
The end result was 3 sides done. And with a little extra time we also did the center joint between the plywood.
Edges done from the rear
Edges done from the front
And I had a little extra epoxy so I used the thickener again and filled in under the skid boards that I'd identified as having broken away previously.
Starboard skid board aft end
Port skid board aft end
Here's a timelapse. Unfortunately it's pretty long, but missing a good portion of the epoxy application due to poor batter management/tending.... Once the epoxy is flowing there's not much extra time for anything like thinking about the camera.
I finally bit the bullet and decided to take the skirt off and fix up the bottom of the hovercraft.
I'll also use this time to change the skirts from the plastic drop cloth to the proper rubber surfaces. I still have some experimentation but I found that the plastic had failed in several places already.
Tears in the front port interior corner. These were clearly from rubbing back on the skid bars.
Tears in the front starboard interior corner.
A little bit of the wear and tear can be seen on the skirts here. With roughing going on down the sides.
Here's a full timelapse of removing the skirt.
I also made some interesting discoveries inside the bag. With non-trivial amounts of dirt of non-trivial size. I guess the smaller stuff blew out at some point.
There was also a surprising amount of dirt inside the skirt
After removing the skirt my next step is to clean up and seal the bottom of the hull. The top of the hull has been fiberglass reinfored at the joints but not the bottom yet. This is both putting the full load on the foam, as well as providing surfaces for water intrusion.
So with a bunch of help from Jenny I've tipped the hovercraft up on it's side. Here's a video it was a good anount of effort.
Here's the final result
Here it is resting on the fan housing, it makes a nice roll bar...
And the bottom you can see the blemishes clearly in the streaking sunlight.
There's a bunch of work to do down here. For example the corners especially the front and rear need some reinforcing.
And one of the skid boards, is only attached in the front half.
I can fit my whole finger behind the skid board.
However the skid boards appear to be doing their job well. There was no noticable damage to the skirt attachments and there was clearly some wear and tear on the skid boards themselves.
An example of the wear on the skid boards up close.
Here's some closeups of the joints that need reinforcement. Clearly glue on foam w/o vacuum application doesn't really work too well. I'll make up for it with some good fiber/epoxy corners.
The bottom edge of the bow.
Bubbling along the bottom of the boat.
The dolly mechanism does appear to have left some wear and tear on the transom.
