HINGING (PART I)
I split the hinging in half on this build. I didn’t want to permanently hinge the control surfaces for the control horn installation process, so I did most of the leg work ahead of time. The only materials you’ll need for this are a fresh bottle of thin CA (very important!), covering iron, and perhaps a fresh #11 blade. This is another area of the build that requires patience. Contrary to most people, I embrace the hinging process and actually look forward to it. There is something about it that is very therapeutic for me, and there is a huge benefit from doing a good job.
The first thing that you’ll want to do is to verify that the hinge slots are truly in the center of both surfaces. To check this, you’ll dry install all of the hinges and slide the control surfaces on their respective mating surface. Looking squarely from the trailing edge forward, you’ll sight down the entire surface from root to tip and verify that there is an even “reveal” from the control surface to its mate. If any of the hinge slots are off, adjust the slot as required. The flying surfaces on my airplane were perfect, but the bottom of the rudder was off about 1/32” on the fuselage side on my model. I adjusted the bottom two hinges accordingly and had no more issues. This may seem like an unnecessary step, however I can assure you that “knots” in the control surface hinging can cause you a lot of grief when trimming a model.
Next, take your covering iron, and carefully go over the hinge lines to remove any wrinkles and to ensure that the covering is well-adhered to the wood. Reinsert your hinges into the control surfaces halfway, and in open center of the hinge, carefully saturate the hinge with thin CA to lock it into that half of the control surface. There is a fine balance between “too much” and “not enough” glue. Because you are effectively sealing off the hinge from accepting more CA when you attach the control surface to its mate, it’s necessary to saturate that half of the hinge completely without having any CA seep outside of the control surface and wick into the rest of the hinge. This is where the fresh bottle of CA comes into play. I highly recommend buying a ½ oz bottle of thin for each build as it doesn’t take long for CA to thicken considerably after the bottle has been opened. It’s shocking to see how fast a fresh bottle of thin CA wicks into a hinge compared to a bottle that’s been open for even a week.