Hello all, I am new to this forum but not new to composites. I have been building plugs, molds and parts for very large RC sailplanes for many years.

I now have a project that requires me to create a pylon from carbon that is shown in the pictures (part-1, part-2 and parts-1n2 (combined)). There are two parts which will be screwed together as shown in picture parts-1n2. This implies that the inner dimension of part2 is critical as is the outer dimension of part1 (so that part 2 slides over part 1). The layup will be done by hand with a combination of 1K light carbon fabric and a 3K 8.7oz carbon fabric for bulk to a thickness of about 1.5mm.

My current strategy is to build a bathtub type mold for part-1 (picture p1-mold) and a male plug for part-2 (picture p2-plug) and use a vacuum system as the matrix cures. I will then use a CNC machine with appropriate tooling to machine all the holes and slots and in the case of part-2, the profile shape. The mold and plug will contain steel pins for reference purposes for the milling step after cure.

I have a couple areas that I'd like to get feedback on if possible.

1). Is this strategy, molding shells and then CNC machining the holes and slots the optimum strategy? If not, what would be better?, why and how?

2). What is the best way to create a vacuum -based molded part from the female mold? I see this particular part as being troublesome when using standard vacuum processes (I only own a simple vacuum pump and some mylar vac bags, peel ply and breather cloth). Is there a more reliable method of vacuum forming this part that does not include infusion processes which I do not intend to invest in at this time. Part-1 is generally the structural element.

From a dimensional perspective, the structure is about 18.5" long, 2.45" wide and about 1.3" deep.

Looking for pointers on strategy. Thanks in advance. Tony