I recently completed a Venture 60 Kit and I'm a little worried about the gaps in some of my control surfaces. (see pics). That's a penny to give some scale. I used a Easy Hinge machine to cut the slots and pushed the surfaces together as closely as I could, but the gap remained. The gap is about half the thickness of a dime.

Should I cover the gap with monokote? Or should this be ok to fly with? It doesn't seem like the Monokote would adhere very well with the amount of movement it will be subjected to. I didn't hear any flutter over the weekend, but I haven't flown the plane really hard yet.

For smaller planes... blenderm tape works well and comes in several widths
for larger planes Clear monokote also works well just put it on with the surface fully flexed and use one of those small sealing (trim) irons to get it adhered. Best to put it on the underside of the elevators and ailerons and hide it as well as you can on the rudder.
Sealing reduces drag, reduces the possibility of flutter and increases the effectiveness of the surface

Sealing the hinge gaps is always a good idea, and for what it's worth your hinge gaps look pretty good. You can use clear monokote if you want to be really thorough, but box tape will work just as well.

In either case, just put the control surface at maximum deflection before sealing so there is enough slack for the surface to move. Full "up" when sealing the bottom side of the control surface, full "down" when sealing the top. The slack will make it look bad in any case, so you may as well just use box tape.

Sealing the gaps is pretty easy to do. I've discussed how to do it with monokote in my Pay it forward built thread. You can find the post where I discuss how to do it here: [link]http://www.rcuniverse.com/forum/fb.asp?m=5589251[/link]

Hope this helps

Ken