Hi there!

I just glued the vert. and horiz. stabs onto the fuse of my US40+. I would think that a neat, small fillet in the joints would make finishing these areas allot nicer. How do I go about this? I was thinking of using 30 min. epoxy and micro balloons, but once you have it all mixed up, how do you lay a bead in the joint? How would you shape it? Would you use something else? I will be applying Monokote over the joint.

Thanks for your help!

I know there are many ways to do this but the method I've used for the past 15 years or so is SIG Epoxolite Putty. Get yourself a SIG catalog and check this stuff out. They usually devote a page on how to work with the stuff and how to make wing fillets, etc.

I also make small molded parts with it. One of my favorite tricks is to make ADF antennas. I cut out a profile from light ply, then form the shape with Epoxolite.

David
I try to avoid using anything that requires a lot of sanding around joints/seams such as fins and stabs. No matter how careful you are your sand paper will hit the exposed balsa around your fillet and leave low spots. I use lite balsa filler that I thin to a thick creamy consistency. Put a little on your finger tip and press it down into the seam and pull along the seam, the contour of your finger will leave a nice fillet between the two pieces. After the filler has dried a damp paper towel can be used to clean up any filler that got onto the surrounding area and can further shape your fillet. A couple light skim coats should leave you with the effect you are after. When your happy with your fillet put a few small drops of thin CA on the filler and it will set up like a rock. Although not really necessary, as a final coat you can put a skim coat of auto body putty, don't try the acrylic it is darn near impossible to sand, then sand very lightly with 300 wet and dry (dry of course).

I use an automotive product called Evercoat 400. It is a polyester glaze putty that you mix with an activator. It smooths out easily with your finger, and sands very easily. Of course you should use a protective glove.

Vince

I should have mentioned that the surfaces and the fuse are already covered so sanding etc. in the area won't be possible.

Try a little Elmers Wood Putty for Light Woods available at Wally World.

Mike, I was thinking of using some of the balsa filler I have, but there is only a very small area where it would be able to get into the joint for "mechanical" grip. I have to get this done before I can put the last bits of trim on so I can post pics!

Sounds like you're doing this a little back *****wards. This should have been done before the covering started, and the thin covering strips should have been applied first, and then the tail feather covering. I wouldn't worry too much about it at this point. Use filler if you think it will hold, otherwise, forget it, you'll never see it at 500 ft.

Nope, not backwards...you are supposed to cover the surfaces before you install them onto the fuse according to the manual and everything I' ve read on RCU. I had just left off the last piece of trim that lies along thejoint between the stabs and the fuse because this piece of trim is the same colour as the fuse and I could overlap the joint a bit with it.

What I ended up doing was mixing up some 30 min. epoxy and micro-ballons and putting it in a freezer bag. Snip of the corner and you can extrude a nice even bead. I laid this in the corners then hit it with a low heat gun... this seemed to make the mixture settle into the joint and left me with a nice even fillet. When I say fillet, I mean a bead of material that is perhaps 2mm wide.

Uhh.. I think when people have said to cover the control surfaces before attaching them, they (or at least I) refer to the ailerons, rudder, and elevators. Not the Vertical Fin and Stab. Those should be attached first, filleted in, strips added to the corners, and then covered.

Whoops! Would seem to make sense doin it that way, but it would have made doing the trim sceme almost impossible. The manual for my kit says to do the fin and stab and to cut the covering away from the stab where it is going to be joining the fuse before glueing it up.

Nex time I will definitley use the method you describe, I'm sure it would give a nicer result.