24 April 2011

Construction begins...

As we figured out what the workspace was going to look like, I proudly posted the plans in the garage.  Using the sheets of 2" Styrofoam that we acquired, we started placing the sheets on the garage floor and got them ready to cut into a general hull shape.

We used a chalk-line to mark the center down the length of the hull and marked the dimensions as set forth in the plans with a permanent marker.  What lay before us, was a giant rectangle of blue Styrofoam, 20' long and 8' wide and 6" thick, with marks all over it.  We screwed all the pieces together using 5 1/2" deck screws and got busy putting the assembly on sawhorses in order to cut the rough shape of the hull.  We initially started cutting the Styrofoam with a fine tooth hand saw.  This makes a giant mess and required a lot of clean-up after the fact.  This changed after we adopted the hot wire foam cutter idea.

Once the rough shape was cut, we lined the garage floor with painters plastic (which I highly recommend so that you don't glue the hull to the floor) and took everything apart.   Now, for vacuum bagging...

The difficult part about the vacuum bagging process is that you need several people to do a variety of different jobs.  Here's how I delegated the jobs:

  • Epoxy mixer
  • Epoxy spreader
  • Styrofoam stacker
  • another person insuring no gaps between joints,
  • and the last person screwing the pieces onto each other.  

 We used some of the 2:1 epoxy provided by Universal Hovercraft (which didn't last very long, by the way) and later on in the project started using 5:1 marine epoxy from a local company called Fiberglass Hawaii.  Last thing on epoxy: An accurate delivery system is crucial; there should be no time wasted on measuring this stuff!  I recommend the WES delivery system.  There's no thinking involved.  It automatically does the work and delivers 5 parts of resin with one pump and then 1 part of hardener with another pump.  Easy Peasy!  Once the epoxy had been spread and all the pieces were in place, the race was on to set up the vacuum bag system.

We used some pretty thick painters plastic (5 mil) as our boundaries so that nothing would rip seeing as we are a bunch of clumsy asses in a confined area.  Also, good quality duck tape or Gorilla tape is essential.  This ensures minimal leaks between the plastic and the garage floor.  The clock officially starts as soon as you mix that first cup of epoxy, so make sure that everything is in place to drag over the entire assembly. And for Pete's sake, do a couple practice runs before you even think about mixing epoxy.  Ensure that everyone is familiar with exactly what they will be doing if you're bringing in some outside help.  Your goal should be to have everything epoxied and the vacuum bag set up within 25 minutes of having mixed that first cup of epoxy.  We worked with some intense background music in order to motivate us!

Here's how the specifics go, as far as the vacuum bagging is concerned.  You will need: a layer of plastic for the garage floor; a layer of plastic to go on top of the hull; a layer of blankets; a garden hose and vacuum hose; a scale and finally, one last layer of plastic on top of it all, the edges of which you will tape to the garage floor.

On the garage floor, you should start with a layer of painters plastic.  Then, you should have the actual body; or hull, or whatever you're going to bag.  Then, you'll have another piece of plastic on top of the hull in order to protect the next few things from the epoxy.  On top of that sheet of plastic goes the blankets.  We used 3 blankets that were about 8' x 8'.  This ensured plenty of coverage over the entire hull.  The purpose of the blanket is to protect the last outer layer of plastic from being sucked up by the vacuum hose.   For uniform vacuum pressure throughout the bag, we actually used a cheap garden hose (about 40') and drilled a bunch of 1/2" holes in it.  These holes prevent you from having one vacuum point that will probably squeeze really hard and make the epoxy too thin at that particular point and it wouldn't bond correctly at other points.  We ran the hose around the perimeter and then started a little spiral toward the center after we made it all the way around the first time.  After laying the hose down, scrunch the blanket up over the hose without losing too much coverage from the edges of the hull.  The blanket provides a barrier so that the plastic won't get sucked into the hose and rip.

The vacuum bag is almost complete at this point.  The last step is the most important.  Lay the top-most layer of plastic on and ensure that it conforms to the shape of the hull.  Make sure to account for the actual contour of the hull so that when the vacuum is turned on the plastic will hug the Styrofoam and not stretch over that stair-step shape between the edge of the hull and the floor.  You'll also need to cut a hole in that top-most layer in order to connect the modified garden hose to your vacuum hose.  Tape the hole shut around the hose once it's all connected so that it won't leak any air.  Cut the hole before-hand so that there is no time wasted while the epoxy is curing.  I put a small scale under the plastic somewhere near the edge of the hull so that we could see it without stepping on the craft. I recommend finding a cheap one that is approximately 1' x 1'.  This makes it easy to see how many pounds per square foot of pressure you have once the vacuum is on.  At this point, tape the top-most layer to the garage floor.  Every inch of plastic has to be taped down so that there are no leaks whatsoever.  Lastly, turn the vacuum on and check for leaks.  I recommend having beer on hand at this point because it will take a little while for the epoxy to cure and after all that, I sure needed one. 

So, hopefully, you didn't go cross-eyed in that long-winded explanation of how to vacuum-bag.  Seeing as how the hull is the attach-point for everything, it's crucial that it is constructed correctly.  Some of the later steps in the process can be fixed with minimal time and effort, but this one is not easily fixable and if done incorrectly can be very costly, both time and cost-wise.

This was our first big hurdle!  It took several nights of planning and another additional night to actually execute this.  Take the time to actually plan this out.  Don't get in a rush.  This is a big step.  

Additionally, here are a few tips that I learned along the way:
  • Using a fine tooth hand-saw to cut the rough shape of the hull is not a bad idea.  However, a hot-wire saves a lot of time and patience (and arm fatigue) if you choose to go that route.  Go to Hot Wire Foam Cutter Info on the web to get some advice.  This guy seriously knows what he's talking about.  Try practicing on some scrap before you start cutting the real deal though.
  • Vacuum bagging ensures even adhesion of the epoxy along the flat surfaces of the Styrofoam.  There is not a more efficient way to do this business.  However painful and time-consuming it is, make sure you do it when it is called for.  Universal Hovercraft actually got this one right.
  • Epoxy does not stick to painters plastic after it has cured.
  • Use gloves and work in a well-ventilated area when handling epoxy.  Floor or standing fans help a lot here.  Epoxy stinks and sticks to everything!
  • Having enough people is crucial.  Make sure you don't try to Superman some of these steps solo. You might find yourself stuck and having wasted a lot of time and money.  However, if it comes down to having too many chiefs and not enough Indians, know when to tell people to stand by and watch!

15 April 2011


Hey guys,
This is a test from my phone. Thanks for reading. More to follow soon!
Sent from my iPhone

12 April 2011


"Trying to convince the men in the garage to help me with this blog has been like pulling teeth."
I understand that I am the writing brains in this outfit, but they have all the technical knowledge. I believe that the technical information they can give is vital to this blog. That being said, I have to find an easy way to get them involved.

My plan is to set up "mobile blogging" for Mike so that he can post short snippets of what is happening out there in the man  cave. Hopefully, if he gets the hang of "mobile blogging," I can get him working on a hovercraft twitter account that would also feed directly to the blog. We'll see how that goes.

In the mean time, I am busy uploading pictures and videos to sites that can be linked to easily. I hope to have all our hovercraft media accessible to you from this page in the next few days.

My next post will be somewhat of a historical piece. The idea of building a hovercraft began a very long time ago and with much less money! I think you will all enjoy seeing the comparison between the original craft and the one we are currently working on. Look for the post before the end of the week. Til then, Adios!

11 April 2011

Step 1... of more than we care to count...

Preview the Plans.

We moved to Hawaii in late October, 2010. Mike's only conditions on renting a home were (A) home allows pets and (B) a two car garage in which to build his hovercraft. So there we were, searching and searching for a home that met those expectations. Come to find out, that is much easier said than done in Hawaii. Between single wall construction and advertisements of open carports trying to pass for garages, we were in a pickle. But, at the last minute, base housing came through for us. Before our furniture had even arrived, the order was placed for the UH-18SPW plans from Universal Hovercraft.

November, 2010. I've never seen a more anxious man as my dear husband awaited the arrival of those plans. When they did arrive, he was mid-nap and probably dreaming about that very craft. After rubbing the sleep out of his eyes and realizing his plans were here, he tore into the envelope like a kid opening a Nintendo 64 on Christmas morning. He read through the plans in about an hour and then headed into the garage. He measured the area to ensure the craft would actually fit while being constructed and began copying down the longest supply list I've ever seen.

For potential hovercraft builders, here are some things Mike encourages you to consider:
  •  Be prepared to lay painter's plastic on every square inch of your workspace floor.
  • Twenty feet (the length of the hull) does not mean that you only need 20 feet of workspace.
  • For those of us with limited workspace, a strategy and order in which to build is crucial.
  • Vacuum bagging requires extra space around the craft and a smooth, level workspace floor.
  • The estimated time of completion is for the mechanically inclined and properly equipped. Be prepared to improvise when necessary.
By the time Thanksgiving had come and gone, we were ready to purchase supplies. We placed an order with Universal Hovercraft for the basic hovercraft construction kit. We purchased the Styrofoam required to construct the hull from the local Home Depot and began waiting patiently, or not so patiently if you were my husband, for the kit to arrive.

Around that time, our friend Ryan moved to island. He and another gentleman, who prefers to remain nameless, have been invaluable to Mike in this construction process. At this point, I had three men in my garage prepping for phase one of hovercraft construction.

Coming soon: Step 2... Construction begins...

Introducing... The Woot'n Care!

Welcome to the Wooten family hovercraft blog! The project is well underway and we'd like to share our progress. We'll have pictures, video and written commentary of the trials and tribulations of building this machine. Check back soon for more updates!