More of the Same

There has been slow steady progress.  Most of the work has been on the akas and mainsheet beams and I have posted about those before.

This is the 16th and final pultrusion glue up on the beams.  Nice to have that done.



Here is a quick vid of the outer sleeve going on the second mainsheet beam.

The wet-out went on for a while to force epoxy through the sleeve.

Task time: 40 hours

Total project time: 402 hours 

Last Carbon on Mainsheet Beam

After a bit of fairing to level any previous layup seams, I have applied the final layer of carbon.

This is a 300gm/sqm bidirectional sleeve. The sleeve went on before wet out.  It looked pretty hard to wet it out and then slide the slimy, slick tube over the beam.  I rolled and squeegeed multiple coats on the beam, as I was a bit worried about full saturation of cloth this heavy. 

There was some creative clamping going on.  I skipped vacuum bagging to avoid wrinkling.  The sleeve can be stretched pretty tight by hand.

Finishing will require fill coats of epoxy and sanding smooth.  The worst of the process will be sanding the gathered ends to blend them into the end shapes.  

Task time: 12 hours

Total project time: 346 hours

Mainsheet Beam Carbon Layups

Each side of the mainsheet beam gets about 12 layers of carbon.  These include uni, bi-directional and plain weave cloth.  It seems quite easy to wrinkle the cloth as it goes around the compound curves in the vacuum bag. As I learn, I tend to get less of this.  It is definitely not good since to get a smooth layer a wrinkle must be sanded a little bit, causing a small area of reduced strength.

A pattern for cutting cloth.

A typical layup applied to the beam before going into the vacuum bag.

I had to cleanup the nubbins with a router after a few layers that did not lay well into the groove.

Above, I am putting a few layers of scrap carbon back into the groove.  The dowel matches the size of the router and is used a clamp to compress the carbon.  I lashed the ends of the dowel around the beam to pull it tightly into the groove.

The dowel was removed after cure. I used packing tape to keep most of the new material off the surrounding beam. 

The  excess cloth has been trimmed and sanded.  This beam needs three more layers all the way around.

Each layup has quite a few steps including cutting the cloth, peel ply and breather, setting up a vacuum bag, wetting out and applying the cloth, peel ply and breather and getting it into the bag.

I have been wetting out the cloth on a piece of plastic.  I spread the epoxy over a layer and squeegee it back and forth.  Another layer of cloth goes on top and more epoxy.  At about three layers maximum, I  stop.  The plastic gets folded over the cloth.  I then squeegee the whole stack very firmly on both sides of the plastic envelope.  This forces air out and epoxy in.   The stack is then peeled off the plastic and laid on the beam where it is smoothed down tightly before the peel ply is smoothed over the top.  I tend to error on the side of too much epoxy.  The bag squeezes out the excess and you really want the carbon well wet out.

I am getting to the last layer which will be a bidirectional woven sleeve.  The sleeve should conform well and leave no seams.

Task time: 20 hours

Total project time: 331 hours

Finishing Up Stay Bulkheads

I needed to seal the exposed "endgrain" of all the laminated layers.  I decided to try using a slit section of carbon sleeve.  The knit sleeves tend to wrap nicely around corners.

Here is a shot of the wet-out carbon which took the shape pretty well.

I then layed the final covering layer of cloth over the edge of the sleeve.

These pictures show the final coat after un-bagging.  There is a little bit of print through from the sleeve edge.  Those two laminations should probably be done separately, so that the fringe of sleeve can be sanded flush.

These bulkheads are about done, though they will need urethane coating for UV protection where they are exposed above the deck.

Task time: 5 hours

Total project time: 309 hours