Estes Black Brant XII, Kit # 9723 Build, Part 23, Assembly

I wouldn't recommend applying epoxy to the fin tab then sliding it into the slot. That would squeeze epoxy out into the fillet area. It'd be a mess to clean up.

I applied epoxy into the fin slot using a toothpick, then slid the fin into it.

A rubber band was used to apply pressure on the fin pushing it into the fin slot for a tighter fit.

You do have to check the alignment before the epoxy sets up. The rubber band can pull the fin to one side.

Glue in the fins one at a time only after the epoxy has set up.

The launch lugs are centered between two fins.

Looking from the lower lug - 

The upper lug segment has the balsa standoff. 

The Kevlar cord is slipped through the back end before gluing on the second stage orange tube.

You can see the epoxy glue inside the body tube right before it was slid in place.

Estes Black Brant XII, Kit # 9723 Build, Part 22, Rear Ring & Retainer

With the fins in place, 

The third centering ring is dropped in and pressed down onto the rear of the fins tabs.

I applied some wood glue to the fin tabs before sliding the ring in place.

A wood glue fillet was applied to the tube/ring joint using a Q-tip.

The inside ring of the two-piece engine retainer is roughed up with 220 grit sandpaper for a stronger Epoxy bond.

Epoxy is applied to the outside of the engine tube and the retainer ring is slid over, down to the inside raised stop.

Turn the ring to spread and even out the epoxy.

Estes Black Brant XII, Kit # 9723 Build, Part 21, Attaching First Stage Fins

This illustration (second stage) implies that both parts of the epoxy mixture are squeezed our of the tubes onto the fin tabs. MIX the two part Epoxy before applying to the model. Wear gloves! You might have an Epoxy allergy or could develop one from exposure over time.

TIP: I didn't apply epoxy to the fin tab, then slide in the fin. That would squeeze out epoxy onto the outside surface of the model. You might end up with a strong fillet, but it would be a mess to clean up. 

I neatly applied epoxy into the slot, then slid in the fin tab. 

I had to sand a little bit on the TTW tabs for a easier fit.

Yellow glue was used for fillets where there was a wood to Kraft tube joint. The glue was applied using a Q-tip. 

Epoxy was used inside where the fin tab contacted the plastic outer fin can tube.

 

Here's the finished lowest fin can. Notice the gap between the upper end of the root edge.

Estes Black Brant XII, Kit # 9723 Build, Part 20, Tunnels & Hatches

The upper body got the tunnel and hatches glued on after being painted off the model.

I used my aluminum angle to mark straight lines and scrape off the black paint inside the gluing area.

The angle was again used to make sure the tunnel was straight after gluing in place.  

Masking tape was wrapped for a position refernce when gluing the hatches in place.

Look close, you can see a scraped line at the side of the hatch. This is a border for scraping off the black paint. The scraped glue "box" is smaller than the actual hatch.

The hatches are glued on opposite each other.

 

Here's how the upper section looked when finished.

Estes Black Brant XII, Kit # 9723 Build, Part 19, Third Stage Paint

The "Rocket Finishing" photograph at the bottom of Page 10 doesn't give any measurements for the third stage painting lines. I checked the picture on the kit box to figure out where the silver paint should start and stop.

On the Kraft tube, the 3.24" measurement is the top of the tunnel (Part V) and the beginning of the silver paint. The angled top of the hatch (Part U) overhangs the start point of the silver paint.

This picture might explain it better.

On the left is the plastic body and nose cone. 

There is a molded recess line, marked with a piece of tape for clarity.

Silver is sprayed above the recess line around the tube.

On the right is the Kraft tube that slides in beneath the plastic section on the left.

The tape is placed at 3.24" from the top of the tube. Silver is sprayed above the 3.24" mark.

Many people insist that silver paint is more vibrant with black paint underneath. Silver is one of those rare paints that you can spray over a dark color.

Estes Black Brant XII, Kit # 9723 Build, Part 18, Scattered Build Pics

This blog build probably hasn't followed the instructions order. Many of the parts were painted before gluing the model together.

Here's two of the first stage fins.

GOTCHA: The Finishing Picture on Page 10 of the instructions says to paint all four of the 1st stage fins yellow. Actually, there are three yellow fins and one red fin.

The second stage fins are three red and one yellow.

The single first stage red fin lines up with the single yellow fin on the second stage.

The area under the third stage fins is flattened for a better fit of the plastic fins.

The instructions show a sanding block being used. I used a flat diamond file for more control. The block is too big, with a file I could see what I was sanding.

Here's all the black parts ready for paint.

On the largest adapter shown at the right - 

The orange was sprayed first. A straight line mask went around the bottom of the orange. Another white under coat was sprayed before the silver was added.

Silver was sprayed and allowed to dry. 

Sometimes it's hard to get a clean mask line in a recessed area.

TIP: I used a ultra fine point Sharpie for an easier, sharper mask. The black pen ink filled the recess area. Masking followed, then spray black paint.

Estes Black Brant XII, Kit # 9723 Build, Part 17, Filling & Filler/Primer

I'm brushing on a single coat of CWF or Carpenter's Wood Filler.

Be careful to keep the filler off the root edge. I brush on the CWF but stop at the edge without lapping over on the root.

Use a fingernail to remove any filler and square up the edges.

The CWF was sanded to surface. 

A follow up spray of filler/primer followed.

After sanding down the filler/primer - 

Notice the high point at the center of the fins. If carefully sanded, the filler/primer can help define that line one last time.

Here's how I taped the pieces down for the filler/primer and white undercoats. 

If you spray from the angle in the picture, you shouldn't get any spray paint on the fin root edges.