Second, thrid plywood gluing and second side cutting.

I'm making good progress on the hovercraft.  With the help of Michael I filled in the center of the plywood on the first side. The biggest update to the process was to do it not in full sunlight and use more boards for holding down the plywood. The 12-18" gaps between weights was enough for the 1/8th inch plywood to flex noteably.



The following night I had some time to finish up the side. I tried sawing on the saw horses since the hovercraft was in the way of the pallet. I used the angle iron to make a fence to run the saw along instead of drawing the line. However the flexible board bowed enough that the saw couldn't follow the fence(it drifted under the fence). So the cut was not exactly straight. You'll see the door close. As it was late at night I closed the door when sawing so that I wouldn't be too loud for the neighbors.



The next round of work encompassed cutting all the plywood for the second side. Again I was cutting with the door closed, but I moved back to cutting on the pallet. The plywood still twisted enough to jam the saw once I was 6' into the 8' cut so I finished the cut coming from the other side. I need to prop up the outside edge too. I was going to glue it all down too, but on inspection I noticed that I was getting close to the bottom of my epoxy supply so i decided not to continue and find out that I was half way through gluing and didn't have enough epoxy. More's on order and should be here soon.


I'm going to need to rip plywood edges to go around the perimeter which will be pretty narrow. This will definitely require a proper fence as they will be narrow strips. Or a table saw would be optimal.

I also have ordered a furniture dolly to help me manuver the hovercraft around the garage. It's now heavy enough i had to get help moving it by myself. I could lift it, but it's so awkwardly big that it's impossible to move without dragging or skuffing. And the foam is still quite exposed.

First plywood gluing

So now that we have the core of the hull formed out of foam. The next step is to attach plywood to the exterior. It has two major functions. The first is to be a tensile element making the whole hull an effective box beam.  Secondly it also protects the foam from impacts and denting.

Here's another timelapse of the process.



Thanks to Michael G for the help. And Wim provided some good comments at the end.

To cut the plywood the cordless Makita circular saw was

Weighted plywood for curing epoxy. 

You'll note that the weighting is much denser. This is due to the flexibility of the plywood. I will need to inspect more closely, however even with this density I believe there are still pockets where the plywood is separated from the foam.

Also an issue we identifed was that working in the full sun the epoxy seemed to almost dry out on the foam before we flipped the wood on top. Even though we were well within the expected 30 minute setup time. We rewetted the area but I'll need to do some inspection, and I will avoid full sun in the future.

In the timelapse you can see the fan ducts for the lift fan was placed on the hull as we discussed mounting options for the front motor. This needs to be addressed at this point so that we make sure to cut the plywood for the front end correctly.

Here it is parked inside:

The craft back inside the garage

Even with 3 layers and the plywood. It's still trivially liftable by two people.

Foam layer 3 of 3

I've completed layer 3 of the foam for the hull. Here's a view of it curing.

Foam layer 3 completed

Here's another timelapse of the process.

This required cutting out one last sheet of foam. One whole sheet of foam. And you'll see that on the far side I used several small left over pieces of foam to fill in the rest of the area since I cannot easily find more large foam boards.  (See previous post)

The other update you'll see here is me filling in my new weight objects. I felt that the available heavy objects was risking having pockets of uneven attachment so I invested in 12 Home Depot buckets with tops and filled them about half way with water to provide a good uniform weighting, but be easily moveable.  I looked for 3 gallon buckets but they cost noteably more than the 5 gallon ones.