Vacuum Bagging - Test 1

 I am building my own rear seats - but very similar to how Glasair does it.

In their design, the rear seat backs and bottoms are fiberglass / foam.

Having never done this before, I did some small test pieces, and laying it up is easy, its getting nice edges.

Talked to some fellow builders, and their solution is vacuum bagging.  A whole new skill to learn...

Here is a really good write up on vacuum bagging.

I purchased a vacuum bagging starter kit from Aircraft Spruce.

My first test piece was pretty small - about 4" x 6", 1/2" foam.

This is where I made my first mistake...  I lined my 'mold' with vacuum bag material, then a layer of breather material, then perforated film, then peel ply, then the fiberglass, then the foam.  Then more fiberglass, peel ply, perforated film, breather and bag material.  Essentially I had no mold.

Here is what the layup looked like before applying any vacuum.

After

A fellow builder loaned me a pump.  I bought the valve from Aircraft Spruce.

So I need to try again.  This time using only half the material.

Here is what came out of the first attempt.  Because I put peel ply down on top and bottom, it is stuck to itself along with the perforated film.

Definitely learned something from this...

2nd test

Slightly larger foam (6" x 8").  Used Aluminum tape on the mold, and waxed the area where the part will be laid down.

This time no bag material on the bottom.  Lay up (from bottom to top):

Aluminum tape

Wax (4 coats)

Peel ply

2 layers of glass

Foam

2 layers of glass

Peel ply

Perforated sheet

Bleeder

Bag

Finished part

I need to pull a bit more vacuum (and need a vacuum gauge), especially when trying to do the seat back that is roughly 3' by 3'.  More vacuum, more CFM.  Also, I have been told I am putting the bag on too tight.  It should be really loose.

But definitely going in the right direction.