RCU Forums - V-Tail Layup Schedule

I've had a couple requests to see my mold layup schedule, but when I tried to find them, they were missing. I put this together this morning, but haven't had a chance to physically lay one up, going step by step through the way I did it in my head. So if something looks incorrect or out of order, please let me know and I can fix. Thanks.

Seeker V-Tail Layup schedule

Prep

- Clean molds (Clear 2” packing tape works well for removing PVA residue)
- Wax molds with Dolphin Wax from H&M Racing or good molding wax
- Spray watered down (50/50) PVA into molds, 3 mist coats with 10 minutes drying between coats
- Light coat Primer or Paint in molds
- Apply small piece of Electricians tape over torque rod holes

Layup order (I prefer Ez Lam 60 laminating epoxy from Aerospace Composites)

- Create cutting templates for both the glass and the balsa sandwich material and hinge cutout, I use 1/8” light ply
- 4 pieces 1.4 oz glass cut 1” larger than molded piece for each tail half
- 2 pieces 1.4 oz glass 1” wide to double up on the center section seams
- 1/32” contest balsa cut 1/8” smaller than mold. Cut out 1” wide by 7” long rectangle for hinge material. Bevel all edges
- Fit hinge .005 fiberglass sheet (cut on bias) into rectangle cut-out, lightly scuff the sheet with sand paper. Use a tiny piece of masking tape on both ends to hold in place to balsa (tape will be inside the piece)
- 4 pieces .75 oz glass cut 1” larger than molded piece for each tail half
- 2 pieces .75 oz glass 1” wide to double up on the center section seams
- Perforated peal ply 1” larger than the molded piece. A piece for each tail half (4 total) and a small piece about 1” wide at the center of the mold
- Heavy Duty paper towels, I use two, connected for each mold half (I like Viva)
- Layer of breather cloth
- Put in the vacuum bag (I use a separate bag for each mold half with a splitter off the pump) and pull as much as you can. My pump will pull about 23” if the bag is good, 25” would be better.
- Let sit for 24 hours at 70 degrees

Joining

- Pull molds out of bag, remove breather, paper towel, peal ply. Be careful pulling off so you don’t pop the piece out of the mold
- Do not remove excess glass, just leave that for now
- Fit ¼” balsa spar (center of mold) Use depth gauge on each half to measure take about 4 readings on both halves (you can write them right on the piece with a sharpie, it will be on the inside and never seen) Undersize the spar by .025” to leave a little room for glue
- Glue spar to one half of the mold with medium CA, I normally glue to the bottom
- From bottom, drill up through your torque rod holes carefully
- Bend and fit torque rods, I use 4/40 rod with thread on one end with aluminum sleeve bearing. Bend the tang so about 2” of rod extends past where the inboard elevator surface begins. The sleeve should end about 1/8” before the elevator surface begins. Scuff the sleeve with rough sandpaper. I cut all but 1/8” of the threads off and clean up on a sanding wheel. You don’t want your torque rod bend on the threads, and you don’t want them too long.
- Fit 1/8” balsa or aluminum tubing rear spar, about 1/8” behind the hinge line. You will have two pieces for each half as there will be a break where the tang of the torque rod goes out towards the TE, glue to piece with CA. 1/8” material works for my molds, different molds may need a different size, measure with depth gauge again
- Mix Laminating epoxy with equal parts cab-o-sil and micro balloons to the consistency of tooth paste. Scoop into cake decorating bag and cut off tip of bag with scissors
- Squeeze out glue mixture on top of both spars, on top of aluminum torque rod sleeve, torque rod tang, and all around the perimeter of both halves (less is more here)
- Carefully align and join mold halves, bolt together and let sit for 24 hours

Final clean up

- Unbolt mold halves
- Carefully insert plastic bondo scraper between halves, I use several and slowly go around the edges until it “pops”
- Gently remove piece
- Take to laundry sink and wet sand entire piece with 600 grit under warm soapy water to remove all PVA residue
- Remove glass flashing with a combination of scissors and/or xacto
- Gently sand edges of tail with 220 grit sanding block, take off just the flash, be careful not to sand part
- Mark and cut your elevator ends with Zona saw, if you don’t want to mark the piece, you can apply masking tape where you will cut, mark that, cut, and remove when done
- Use an Xacto and remove a little material around the two torque rods coming out of the tail, not much is needed for proper movement
- Flip tail over, I like to place it on a soft towel at the edge of the table, mark and cut your gap from one edge to the other of the elevator. Use an xacto blade angled at about a 45 degrees. Pull from the inboard end to the outboard, I do this freehand, just be careful
- The elevator half should now be free, gently flex both ways, insert a piece of 220 grit sandpaper and sand the edges at the ends and also the angled cut on the bottom. You should be able to get a smooth ¼” of throw each way
- Attach Dubro ball links with blue or red loctite to the extended torque rods, some people use JB weld, which would be fine also
- Mount to fuse and enjoy