GrantL wrote:No job. Just meticulous and well researched.
Amazing what you can achieve
So there is another stage yet to come . . .
How do you put the two halves together?
I always thought that these masts were made up by the two halves of the mold being clamped together after each half had been laid up . . . but both sides still wet. Obviously not the case when infusion is involved.
Have I missed something here . . . ?
Once the infusion is complete and cured for 24 hours , remove all the bagging , peel ply etc. When I lay up the carbon I always over lay the laminate , but what tends to happen is you end up with a slightly thickened edge. It is almost impossible to cut the laminate exactly the correct length and width. With multiple layers you get this thickening affect. What is important is that you make sure the laminate is slightly proud in the center of the mould.
What I do now is not sand the laminate as I don't want to damage my mould flanges. I use a Carbide scraper to carefully shave the excess down to the flanges. Using a 50mm carbide scraper it is easy to monitor how much you are shaving and how flat the laminate is. Use a straight edge to keep the carbon face FLAT. If you tape around the flanges you can get right down to the flange tape without damaging the flange.
I can get down to the thickness of the tape (0.2mm) Now carefully pop the carbon part out of the mould and block sand with 60 grit to remove that last 0.2mm. Keep putting the carbon part back into the mould to check the height with a straight edge. Spot sand finally to remove any high spots. Repeat this process for the other half of your mast. If you assemble the carbon halves in their moulds and assemble together all should fit nicely. Double check with a light for any gap on the flanges. This method will give you a perfect fit together with no clearance.
As my mast is solid and extremely stiff. I will give you the bend/torsion test results later I know that the shear between the 2 halves is not to great. This being the case I choose to glue the 2 halves together. But I could of laminated the 2 halves together with 1 layer of 150gsm carbon Twill laminate just as well. Both will work as well. But if you DON'T have a solid mast layup I would recommend laminating the two halves together only.
I use a special high bond glue specifically for this type of application. It is important to prepare the faces of the part halves for the glue. There must be a glue gap (0.1 -0.2mm max) To achieve this I now carefully hand scrape the center out of the carbon faces around 0.1mm per side. I finally hand scrap and sand the perimeter of the part down to the -0.1mm. This is the ideal situation , which sound difficult but is not using a scraper.
Rewax the mould (carbon halves removed) BEFORE applying glue to carbon halves. Place 1 half in mould and spread the glue with a straight edge just filling. repeat the same for the other half out of the mould. Assemble on 1st haft and press down by hand and remove excess glue. Your cavity should be full of glue. Position other mould on top and clamp down in multiple places. The mould should clamp together tightly and aligned. Leave to cure and remove from mould.
Mast will be dimensionally as you intended , but more importantly you know that the fiber you laid is all intact , no sanding of fiber weakening the mast.