Estes Colonial Viper #1310, Part 11, Tube Fillets

Mentioned earlier, the instructions have you set a line of glue down the top engine tube. Slide the glued tube through the alignment guide, then turn the tube and line of glue to make contact with the interior tube.

I used very little glue to adhere the outside BT-52 tube, deciding to make fillets only on the top side in the area that will be covered by the card stock rectangular strips.

Why not fillet on all sides? Fillets in deep, tight corners are difficult to get smooth. You always end up with bubbles.  

Here's the bottom of the model.

I'm not doing fillets here in the tube joints, just on the top where they will be covered by the card stock strips.

  

I went through this many Q-tips while applying glue and smoothing out the fillets!