Estes Cosmic Interceptor Build, Part 29, I Gotta' Paint!

I'm tired of rain! I went outside to spray about 1:30 p.m. Humidity was probably a little high, there was some bluing of the glossy paint. I'll probably polish out any dull areas. 

Not the perfect scenario, but I've got to get moving on this one!

   

The side "shield" fins were painted off the model.

This is a big rocket with lots of inside areas. I felt it would be easier to mask these shields and the wings separately. 

They'll be glued on after the masks are complete.

With the nose cone in place, the model is longer than I can comfortably spray in a long, one arm sweep.

A cardstock "handle" was rolled and taped to the nose cone shoulder.

The engine mount ring got the final gloss black spray.

On the left is the first coat sanded with 400 grit.

The light sanding paid off, you can see the gloss in the right side picture.

Once in a while I run into balsa that shows grain even after filling.

The sanded paint helps fill them a bit, but this wood required more CWF. 

The final black will cover the bit of sanded beige filler. 
 

Estes Cosmic Interceptor Build, Part 28, Small Things

The engine mount ring and intake vanes are painted black. It's easier to pre-paint then glue them in place. It would be nearly impossible to mask the intake vanes if they were glued into the tapered body tube.

The engine ring was taped to a painting wand (dowel) and sprayed gloss black. The paint will require light sanding and another coat.

Only the exposed front of the vanes need paint.

These also will require some sanding and another coat of paint.

The tri-fold mount was glued up and formed into a curve while the glue was still wet. I pre-form the mount so I can glue it in the tube later.

Here the mount is pressed into some of the leftover intake tubing.

It's been a frustrating weather week. I usually spray at about 2:30 p.m. when the humidity is low. Most all afternoons have been raining!

Estes Mini Scale Combo Pak, #0874, Tomahawk & Exocet, Build, Part 8, Covering The Shock Cord

It's easier to use tweezers to grab the end of the shock cord.

Pull the cord through the slit until 1/4" sticks outside the body tube.

I traced around the paper shock cord anchor, then scraped off the gray primer for a better glue bond.

Apply glue to the back of the exposed shock cord and press the cord down onto the body tube until the glue sets up.

Glue the paper anchor over the shock cord and body tube area.

Use the center marks to line it up. Shape with a burnisher.

When the anchor is still wet with glue, you can shape and mold the paper cover.

I won't know how good this will look until paint is applied.

Estes Mini Scale Combo Pak, #0874, Tomahawk & Exocet, Build, Part 7, Slitting For The Shock Cord

The shock cord install reminds me of the oldest kits. You made two slits in the body tube and laced the shock cord through them. You were left with unsightly cuts and a bulge after the paint was applied.

Maybe this simpler single slit and paper cover will look better.

The shock cord "anchors" are cut form the instruction sheet.

A 1/8" wide slit is made 3/4" down from the top of the body tube.

Notice I pencil marked the 1/8" wide slit position before cutting with a knife.

The nose cone shoulder is only about 1/4" long so you will have enough clearance.

Cut the slit - 

Fish the shock cord end into the slit using the tip of your hobby knife. This ended up being easier than I initially thought.

Estes Mini Arcas, #2441, Part 13, Shock Cord & Streamer

When forming a paper shock cord mount, I like to form the glued up mount to fit the inside of the body tube.

Estes has developed new plastic, self-adhesive shock cord mounts for the BT-50, BT-55 and BT-60 tubes. The BT-20 and BT-5 tubes are too small. 

Note the pencil mark on the rubber cord to be used as a depth gauge, 1" down inside the tube.

I use tweezers to insert the paper mount to the 1" depth before pressing the glued mount to the inside of the tube.

The chromed mylar streamer had rough cut ends. 

For easier placement of the clear tape, the upper end of the streamer was lightly taped down to my work surface.

Estes Time Warp Build, #7321, Part 8, Scattered Steps

I'm always apprehensive about using pre-made parachute shroud lines.

These broke with a good tug!

I cut them off the chute and replaced them with #10 embroidery thread.

Plastic nose cones and adapters take longer to dry between paint coats.

I waited three days before spraying the yellow and the paint wrinkled!

Sand smooth, wait four days and spray again!

Here's the new Estes self-adhesive shock cord mount.

It's a simple knot, I left a loose tail for some extra insurance.

I'll be checking the adhesion of the mount after a few flights.

Older rocketeers might remember the problems with the Centuri self adhesive mounts - 

Initially claimed to be "permanent", they did loosen and pull loose over time. Later kits would include an addendum to the instructions reminding you to burnish the fastener between launches.

Granted - in 1971 we didn't have the 3M tape that is on the back of the new Estes shock cord mounts. Time will tell . . .  

I Wish Manufacturers Wouldn't Do This, Part 5 . . .

TRI-FOLD MOUNTS ON SMALL DIAMETER BODY TUBES -

Tri-fold shock cord mounts can block the ejection of a parachute.

On BT-5, BT-20 and BT-50 sized models, drop the tri-fold mounts and go with Kevlar tied to the engine mount.

BT-5 models with this type of mount are especially problematic. This was more common years back when mini-motor kits were introduced.

New Estes Shock Cord Anchors

Estes has just released new Shock Cord Anchors 

for BT-50, 55 and 60 tubes: CLICK HERE

These are certainly an upgrade from the paper tri-fold anchors.

Still, no improvement for BT-5 and 20 sized tubes.

These are adhered with 3M peel and stick tape.

Centuri developed a self-adhesive shock cord mount in 1971.

Initially claimed to be "permanent", they did loosen and pull loose over time. Later kits would include an addendum to the instructions reminding you to burnish the fastener between launches.

The 3M tape in the new Estes mounts should hold better!

Not A Tri-Fold Mount - Tip

This type of shock cord mount feels stronger than a thin paper ti-fold mount. It can be used on BT-55 and larger tubes. I wouldn't recommend using this in a BT-20 or BT-50. In smaller diameter tubes, the shock cord knot might block the ejection of a parachute.

Cut a rectangular piece of body tube, from the same diameter as your main airframe tube.

Tie your shock cord around the rectangular piece.

 

Glue into the body tube with the tail of the shock cord pointing up. The rectangle mount is already rounded to match the inside curve of the main airframe tube.

Be sure to recess the mount deep enough to clear the nose cone shoulder.

This shock cord mount design was used in some Centuri kits.

Estes Star Seeker BT-50 Upscale (Tri-Pack) Kit #0866, Part 8, Nose Cone and Shock Cord Mount

On the Apogee plastic nose cones, 

there is sometimes a raised lip on the shoulder edge.

Sand this down a bit.

The nose cones can have a slight bulge at the tip.

You can sand the tip so it follows the contour of the nose cone sides.

The shoulder cap was glued in using Beacon Fabri-Tac glue.

If you can't find a good plastic glue (most don't contain Acetone to "weld" the plastic pieces) Fabri-Tac is a good substitute.

Run a ring inside the nose cone, slide in the base and turn to even the glue bead and get better coverage.

I don't normally use a tri-fold mount, 

I didn't feel good about a Kevlar loop under the upper (homemade) centering ring. They're probably strong enough to handle an ejection pull, but I played it safe with a folded mount and elastic.

A 12" Odd'l chute was tied onto the shock cord.

Estes Black Star Voyager Build, Part 26, General Assemblies

In the shock cord mount instructions, note where the glue is placed. You fold the mount into a pool of glue.

TIP: You'll make a cleaner mount if you apply a thin coat of glue on the section to the right and fold onto the dry section on the left. It doesn't take much glue (a thin skin) when gluing paper to paper.

 

With the backside of the mount dry, press and form the still wet mount into the inside tube wall to form the curvature of the tube.

This kit was bagged in 2014 or so, when many kit shroud lines were weak. 

A quick, easy pull and the string breaks!

The shroud lines were cut off the parachute.

I used a plastic Avery reinforcement disks to strengthen the tie off points.

New #10 cotton embroidery thread was cut. 

It's easy to re-tie knots using long tweezers.

New Estes Mini Alpha Instructions - Shock Cord Mount

The new Estes Mini Alpha kit instructions have been posted online: CLICK HERE

Most instructions tend to say tie a "double knot".

This implies tying two overhand knots which gives you a "granny" knot. They are prone to slip and open up. Unless you were a Boy Scout, a first time builder probably doesn't know the difference between the two knots. 

At the arrow point in the illustration, look how short the free end of the shock cord line is! If you've tied a "granny" or "false knot" that short end could easily pull through. Tie so the free end is longer, maybe 3/8" to 1/2".

You can use fancier knots, but a "square knot" is easy and shouldn't come undone when tightened.

In the third picture below, note how both ends come out side by side. Both lines come out under the turned line on one side and over on the other side.

Instruction once said to use a drop of glue to "set" knots.

If you tie and tighten a knot correctly it shouldn't need the glue.

TIP: NEVER, no, no NEVER apply super glues (CA glue) to a knot!

CA dries hard and makes the shroud line or shock cord brittle. 

If you want, you could apply a small bit of white or wood glue to a knot. Again, if you tied a good knot correctly, it won't need the glue.

I tie parachute shroud lines using square knots. In the past, some shroud lines found in Quest kits would come undone by themselves! Those Quest lines did require a small drop of white glue to help hold them closed.

Estes Condor #0807 Build, Part 9, Tri-Fold Mount TIPS

I usually don't like using tri-fold mounts in smaller tubes like a BT-5, 20 or 50. But on this older kit I'll (almost) follow the instructions 

Here's how the instructions show how to glue up a tri-fold mount. 

Three folds and three bends of the shock cord.

Older kits included a mount printed on 65 lb. cardstock.

Current kits have the mount printed on the 20 lb. stock instruction sheet.

Over the years tri-folds have evolved to two folds of rubber.

The original tri-fold mount had you glue the shock cord at an angle. This makes a flatter finished mount inside the body tube.

I run a light line of glue at an angle down the cardstock. The elastic shock cord is pressed into the glue and allowed to dry. 

Apply a skin of glue over Section 1. Note I wrote "skin" of glue. When gluing paper to paper you don't need a heavy glue coat. Be sure the glue coat covers all of the section area - side to side.

On the left I'm burnishing the first section. 

On the right you can see how much glue is placed before folding it over onto section 3.

Shape the mount into an arc to better fit the inside curve of  the body tube.

On the right - you can see how the angled shock cord ends up in the folds. The finished mount is flatter than it might have been otherwise.

 

Estes Great Goblin, #9724 Build, Part 16, Shock Cord Mount

The fold lines on the tri-fold shock cord mount can be "pre-creased" using the dull tip of a butter knife.

I glue the rubber to the mount before gluing the flat fold areas. Notice the angle of the shock cord. This makes a flatter mount, important for easier ejections in smaller diameter tubes.

On the left is how much glue is applied. This is a cardstock mount, paper doesn't need much glue to adhere well.

On the right is how much glue is left after smoothing and removing the excess.

Before the two glued sections dry,

Shape the mount by pressing it into the inside curvature of the body tube. No glue on the back yet.

The mount is to be glued 3 1/2" below the top lip of the body tube.

Mark the rubber cord with pencil using a ruler at the 3 1/2" length. Use the pencil mark as a depth gauge. Drop the glued mount into the tube until the pencil line is at the tube edge.
 

MPC Lambda Payloader Build, Part 13, Stine Shock Lock

Here's how the instructions show the lacing of the round elastic shock cord. 

They suggest gluing the mount down 1" from the top of the tube.

The next illustration shows the mount in place - but not recessed a full inch.

Here's the kit enclosed shock cord mount. It's 110 lb. cardstock with three holes punched in line down the center.

I pre-curl the cardstock to better fit the inside of the body tube.

The round elastic is laced through the mount

On the right, the back gets a thin coat of wood glue.

TIP: Set the elastic line beside the other exposed line to keep the mount as flat as possible.

The glued mount is pressed against the inside wall with a dowel.

Lightly pull on the elastic to pick up any slack and to tighten the laced line.

Estes BOSS Kit #7316, Build, Part 21, Recessing The Shock Cord Mount

The Tri-Fold shock cord mount is glued up.

Note that I've already got the mount formed into a curve, ready to be glued into the body tube.

The mount is recessed 1 1/2" inside the tube.

Mark with pencil on both sides of the cord. This will be your depth guide.

An even coat of wood glue is spread on the tri-fold mount. 

Drop in the mount without touching the inside wall of the body tube. 

Stop when the pencil mark is at the edge of the tube.

It's hard to see in the picture, but the mount is hanging inside the tube, not touching the tube walls yet.

Now you can press the mount into the inside of the tube.

I use a rounded dowel to lightly press the mount into the tube over the entire mount -  from side to side and top to bottom. Don't press too hard with the dowel, you don't want to dent the body tube.

The parachute and shock cord are tied to the small loop on the shoulder of the nose cone.

Estes BOSS Kit #7316, Build, Part 11, Fins, Shock Cord & Windows

The motor tube standoffs are glued 1/4" from the rear of the main BT-50 tube.

Shock cord is a standard tri fold. 

Sometimes I glue the mount in later after the model is painted.

The tri fold mount is molded into a curve to fit the inside of the body tube while the glue in the mount is still wet.

Press it into the body tube (dry) and insert the nose cone to mold the mount into a curve.

The little round windows (Part AA) can be painted black off the model and glued on after the gloss white is sprayed.

The dots were taped down for black spray.

I made a window positioning template out of the upper tube marking guide.