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sábado, 28 de fevereiro de 2015
domingo, 15 de fevereiro de 2015
Somehow I can´t find what was left from the 1 meter long G10 tube after I used a couple of cm on the rudder mount. I nearly turned the whole shop upside down but no success. I think I paid around $98 for that tube! No way I was going to order another one! So I took on the task of making one by rapping 68 cm of 120gsm BD glass on a 16mm OD steel tube after laying down 6 coats of wax. I used the metric version on the rudder mount ( 16x19mm) so had to make the same bore. Was a bit sceptic about the outcome but with the help of some searches on the net it came out way better than I could imagine. It looks almost like a factory product although it did put on a fight jacking it out of the mandrel. I’m only sorry about the precious time I lost trying to find a supplier close by.
Also made flat table to have better control when cutting the rudder case flange molds. Using the jigsaw in this way avoids any angle in the cut out which can be very annoying. By using a remote control on the power main I didn’t need to bend under to turn on and off the tool. It also allowed to use the blade almost like a router to refine the surface. It took some time but after some filing and sanding it worked out just fine.
The moldes are now in place ready for the carbon fiber. Here I used some vinyl I had around to create the desired thickness and then used plastic tape as mold release. The angled molds are locked in place with hot glue on the outside and wax on the inside to fill in any voids so resin doesn’t get under. As for the fillets I may just use putty and then sand it back to the carbon to get the desired fillet radius after the part has cured. I did buy some plastecene but was not satisfied with how it handled and how it was releasing from the laminate on a small test I made. Now I'm just waiting for drier weather to lay down the carbon.
By the way the rudder came out super light! At this stage (only need to prime and paint it) it weighs 1575 gr which is incredible! It took me 3 vacuum bagging processes to do it and it was visible the amount of excess epoxy that was soaked up by the breather every time. I started with a 825gr foam core with central re enforcement and used full carbon all the way trough.
Here is a side view of the daggerboard after 1st layer of BD carbon and unidirectional carbon. At this point it weighs around 5500 gr which is not bad for such a large part, I think. The perspective of the photo shows how reasonably straight it is.Those who have followed the blog may remember that at the routing stage I ended up with a serious warp due to uneven heat distribution as I was shaping the foil. For a moment I thought the whole thing was ruined beyond repair. I’m very happy the way it is as in fact I can’t find any visible foil misalignment .
As if I didn’t have enough thorns on my feet already I ended up with a friend’s Vaurien to work on ( so I believed!) some minor repairs. Oh man, what a nightmare! Once we inspected the inside it looked like as someone who came out of a car crash,alive but with every single rib broken in several places! Now I'm stuck with the thing and have to get rid of it to make space for the floats. Always learning! There's always a worse time for something to come up.