Sunday, February 26, 2012

So on my last post I said that I would give details on what went wrong on the last top mast. This is the end of it. Not sure what caused this. Keep in mind that there were plenty of times that it was wet and still in that aluminum tube on hot sunny days and it took two years for this stress to show. Clearly the wood is separating form all epoxy joints.
I did try to shave it down and glass it to try to save it. That did not help it was a nice end of season temporary fix but not a long term one.
My second epoxy failure was on the rudder box. My fix for this is to double up on ply wood rather than the popular strips shown here. I had enough left over plywood material from the original build to make a second box again. I care fully made two more skins then got some high quality 4mm ply at the local Low's then care glued them over size then cut the final shape after glue set. More pics of that are on the way. My second attempt at a strong box is on its way I will continue to keep the updates coming.
Here is my final fix for the top mast. Yes that is just PVC 2" as i said on the last post just shaved the .040 thousands off with a chisel shown below.
Here is the end view. Make note that I made the PVC a 1/16" longer that the wood material. For the reason and purpose of enough room to finish off the end grain with a good coat of thickened epoxy then a second coat of regular epoxy. My home made epoxy is simple mix a regular batch of epoxy then use left over sanding dust from sanding all that cedar and use that to thicken it up right in. Then let it dry fully cured out. Second coat is just regular epoxy.
Here is how I shave .040 off the outside diameter of the PVC. If you think that .040 is a lot it is not. I carefully shaved .020 each side and was careful to keep it's circumference accurate. PVC is a easy material to work with it does require a little patience, tlc and stinks when you shave it like this.

Wednesday, February 15, 2012

Note the Finished mast in background. Sorry there is no shaping pics it is a very detailed and long processed to get all 16' in. Here we are waiting on good weather for varnish. It is the same as the one at the bottom of this set of pics. The aluminum sleeve is fit in the same way as the PVC receptacle.
Here is one of the new top mast with cerf cuts put in by hand.
Hand saw set up = two 1/8 popular strips clamped precisely. I use a pair of dial calipers do care full math let this dept strong and then shave, and sand to EXACT inside diameter size for the PVC in this case. Aluminum in the main mast case. Why do this well after only two years of use I had my original top mast split out in major ways. More pics on that later. There is also a complete engineering solution to this issue that will post in a short while.
PVC for top mast. This to is over size to fit into the aluminum sleeve. The out side diameter is .040 thousands larger than the inside diameter of that aluminum sleeve on the main mast. Simple fix is to CAREFULLY take back side of a chisel and shave that material off. A little sanding in between to keep the circumference accurate.
My bad on the rest of these they are from the winter of 2011. This is my set up for a accurate scarf joint for main mast joints.
Yep with a little math and patience I got it. Note the SMALL brads on the foot of the angle. The door has a line on it that the templates get set on. A clamp on the back side and well the rest is history.

The finish of the scarf joints were good and very accurate. Much better than trying to sand them as Dix makes hint at.
Well here we are in a winter of record snow fall making a extra large epoxy run. First I want to note that the original main mast had some struggles in my original set up of the off sets of the scarf joints. Some of them were week at the end of two years of sailing. So I went with a different set up that ended up much stronger. I ran 12's - 4' opposite of each other, then the opposite side was 11' and 5' opposite of each other, next was 10' and 6' lastly 12' and with a 2' on each end opposite of each other. The last scarf with the 12' with a 2' on each end doubled my scarf joints yet my hope is to gain strength and straightness. Get the drift. No pun intended.
So here we are note the careful lay out I am working by myself running 128' of epoxy and that usually calls for six batches and a whole lot of scrambling even with the below freezing weather to help delay the kick off of the epoxy.

Note the careful lay all the way down to the zip ties and pliers are ready to go because fingers can not handle all that pulling alone!
Here we are back safe and sound in the house. Note the extended popular birds mouth hanging out the end. I give the mast about two hours then make a second run down all zip ties pulling all slack out making sure it adheres well.
Well I am back. Its been a long run but had a bit of a life change spent some time deployed and missed the entire summer of sailing and lots of paper jet 14 up dates are on the way. First this little jewlery box another heritage project. Above the walnut and cedar for the box.
All dado's are in and everthing is to legth. Why blue painters tape? That is all drawer material all get cross grain dado's and it prevents chip out and if it does it come off when you take the tape off and just glue it back in and that is how you can easily hide any sin.
Book match top was split in half with thin table saw blade, the olive cross precisely fit then glued back together with pins to keep it from ever warping because of its size.
Remember the blue tape well all work is done and as always it was the perfect trick for the need no chip outs at all and no need to hide any sin.
All cedar is cut and ready for drawer assembly
The asembly went well and well on the way to a finish project!
Looks good could be better had some mistakes here and ther yet I believe over all it went well.

Final top outcome. I did cheat a little the original size was over size both in leagth and in width. This helps with any error on the centering of that cross. The scrap from the width was perfect for the feet on the bottom of the case.
Here is the internal view. Popular runners make it a easy go for any adjustments in expansion and contraction of the seasons.
Ohh the finish. Its a new one to me from Dept. To volatile and really sets fast to fast in fact. I used a 2'' precision horse hair bursh and tried my best to keep up with it and still failed every time. Persistance paid off once you start a finish you finish with the finish cant go back unless you want to sand the entire thing down.

The new finish does have a nice shine!





The result of many days trying to deal with that crazy finish. Infact it took me two solid weeks to get this top to come out like this. Still spent plenty of time polishing it off.

Final project just in time for a special valentine.