Semroc (Centuri) Taurus Finished

I wish all the builds turned out as well! This one could end up being a display only model.

On the right you can see the slight ridge from the Contact paper blackboard trim piece.

I also added some chrome trim around the motor mount tube that extended out the back.

TIP: The colors follow a good design practice - Three colors in descending order of coverage area.
The major color being WHITE. A secondary color, BLACK. The third color is ORANGE.
The decals round out the finer details.
This might be why so many of the Centuri catalog pictures caught your attention. Check out their sport designs in the 1972 catalog: CLICK HERE

Semroc (Centuri) Taurus Build, Part 15, Gluing On The Conduits

This shows some vertical bands cut from the Contact paper blackboard cover material. You could mask it, but this is cleaner and much easier. I had to mask the fins, the peel and stick vinyl wouldn't work there.

The kit has supplied three tunnels, the face card seems to show two. With all the decals I decided to go with just two. I didn't want to crowd any of the detail and there are plenty.

TIP: When surface gluing pieces like this, use a white glue that dries clear. If you were to use wood glue you might see some dried yellow glue along the edges.

The tube has been scraped just inside the width and length of the conduit piece. Notice the contour sanded in the back of the conduit to fit the curve of the body tube. Glue just the back, here no fillets are needed.

Semroc (Centuri) Taurus Build, Part 14, More Decals & Pod Trim

The kit has some trim pieces for the pods but they were not as shiny as the chrome trim I had.







GOTCHA: The kit supplied decal didn't fit around the nose cone as shown on the face card. I ended up placing it around the body tube, below the nose cone.

At the base is the shinier Monokote chrome trim.





The lower adapter was painted metallic silver.
I tried a strip of white decal paper but didn't like the contrast. I went with a strip of the Contact paper.




Before gluing onto the standoffs, the pod paint gluing line was sanded to the tube surface with a sanding block.

TIP: Shown in the second picture, the upper bar decal didn't make it all the way around the tube. I started and finished the decal wrap on the inside where the gap won't be seen.

Semroc (Centuri) Taurus Build, Part 13, Ends, Edges, Upper Trim & Decals

There are two blue conduits shown on the face card picture.
The old Centuri catalog page showed these pieces glued lower on the adapter.









I didn't have blue paint, purple should work.




The nose cone and smaller pod cones were sprayed before gluing in their tubes.

TIPS: I used a strip of chrome trim Monokote around the base of the nose cone. A little bit of chrome really adds a lot to the looks of some designs.
The black vinyl is my old standby - Contact Paper Blackboard material.






You have some freedom with some hatch decals, place them where you want.

TIP: Cut out the inside middle of the canopy decal so it will conform to the curvature of the nose cone.

Semroc (Centuri) Taurus Build, Part 12, Where'd That Tube Go?

All the balsa is filled, all the tube seams are filled.
Everything is painted and pretty much ready for assembly and decals. Well, almost . . .

I can't find the center ST-8 tube!
It was filled and painted white, ready for the tunnels and decals.
We've all misplaced launch lugs, but I've never lost a tube. I thought about putting in an order for a replacement, but you know what will happen. A day after the order is made, I'll find the original.

Another problem - I don't know what the tube length was. The kit height is 23.5" tall. I can measure the assemblies, subtract that total from 23.5" and I'll have the ST-8 tube length.

The Semroc instructions say the tube is a ST-857. Using Centuri lingo, that might mean it's a ST-8 tube, 5 3/4" long.

The Semroc Classic Kit parts list (CLICK HERE) says the length is 5.75" long.  Under the "Original Part No." listing it says: ST-8?

Then I went to a new Centuri list being compiled by Jay Goemmer. To see the Centuri kit parts list: CLICK HERE
This list also gave me a length of 5.75" long.


To get the model to 23.5" tall, on my model that ST-8 tube ended up at 6" long. Some Semroc reissued kits aren't always exact clones.
I was lucky enough to find an 8" length of ST-8 tubing. My OOP Odd'l Rockets Pipeline kit used ST-8 tubing, a lucky break. Keep your extra rocket parts - You never know!
The new piece of tubing was cut to size, seam filled, filler/primered and shot with gloss white.

The way it always goes - That original tube will show up in a day or so - 

Semroc (Centuri) Taurus Build, Part 11, Masking The Lower Fins

The lower half of the fins are masked to leave them white.
Enlarge the picture to see the two layers of tape - the knife blade is sitting on the brown masking tape, the Scotch tape is below that.

This is after the flat black was sprayed and the tape is ready to be lifted.

I did have a little bit of bleed under the tape.
The top picture is the before,


This is after a little "push up" against the black paint to clean up the line. I don't scrape the paint off, it is pushed back while it is still a bit sticky.

Here's the finished low end mask.

Notice there is a thin strip of brown tape keeping the paint off the gluing edge of the pylon standoff.

Semroc (Centuri) Taurus Build, Part 10, Paint Problems & A Fix

I don't know what happened here -

One adapter came out fine after the first white undercoat, the other adapter still showed rough balsa under the paint!
I had to go back and hit it again with filler/primer, sanding and then more gloss white.

This picture shows some sanding of the fillet areas, a normal rough spot. The paint has been sanded down and the gray primer is seen.

Note there is a thin strip of masking tape down the pod support gluing outside (pod root) edge.

More rough edges were found on the leading and trailing edges of the pod supports. Filler/primer was sprayed into a cup. A Q-tip dipped in and the paint rolled just over the leading edges.  

Dry, sand and spray with more gloss white after 48 hours.

Semroc (Centuri) Taurus Build, Part 9, Engine Mount & Balsa Pod Mounts

I was concerned about the old-school black coupler between the engine mount centering rings. There is a lot of surface area on the sides to get stuck while gluing.
On the left you can see the white showing through on the lower centering ring after sanding for a sliding fit.
On the right is the position of the engine mount with the rear ring being recessed by 1/16".

The trick is to use enough glue so it slides in, but not too much glue that you get a shrink line (Coke Bottle effect). You sometimes see these on the outside of the tube at the coupler top location.

The mount went in without incident - Whew!
The lower ring is recessed 1/16" allowing a rear fillet around the inside tube joint.

The tube was marked for three fins and the three pod mounts.

On the left, the tube has been scraped for gluing the root edges of the fins. One line is wider for gluing on the launch lug.

On the right the pod mounts are glued on. With six fins total I thought it might be easier to glue and fillet these first.

TIP: The longer the rocket, the harder it will be to get an even spray paint coverage. On tall rockets (when you can) spray the model in segments. Picture trying to paint an assembled Estes Mean Machine.
Mask off the exposed adapter shoulders to keep off the paint.

Semroc (Centuri) Taurus Build, Part 8, Filler/Primer

TIP: Here's something new I'm experimenting with.
These fins were laser cut from soft balsa. After the CWF and sanding, I wiped some medium CA glue down the leading edge with a Q-tip "brush". Go light and smooth, this will have to be lightly sanded after it dries.
This could help reinforce the leading edge of the soft balsa fins. Years ago I tried gluing on half-found dowels to get a strong round, leading edge. This could give me almost the same result. 
This end treatment could end up with a leading edge that is harder than the surrounding soft balsa. When sanding and smoothing be careful not to sand into the softer wood down the sides.

Three fins, three tube standoffs and three tunnels were stuck down to a piece of cardboard for a shot of filler/primer.







The kit included a 12' old-style Semroc parachute.
I was never a big fan of the shroud line attachment disks. You had to weave the shroud lines through two small holes, tie the line then stick the disk onto the chute material. It's do-able, but requires some long tweezers and time.

Semroc (Centuri) Taurus Build, Part 7, Fin Sanding TIP

TIP: To insure a flat, even fin surface, use a sanding block. I sand fins in a "circle". I'm not sanding small circles, I rotate the fin under the block while sanding. On my block is 220 grit sandpaper.

1. First, sand the fin side with up and down strokes with the grain, parallel to the leading edge.

2. After the first sanding, turn the fin clockwise, on quarter turn. Sand the side again.
EDIT: The arrow is turning the wrong way - I'm actually rotating the fin face clockwise.

3. Turn the fin again one quarter turn. Sand the side.

4. Rotate the fin one last quarter turn and sand.

After all the 220 grit sanding smooth the surface with 400 grit. Smooth the flat surface and remove any scratches.

Now the fins are ready for one fairly heavy coat of Duplicolor Filler/Primer, #FP101.
If you don't already use the Duplicolor Filler/Primer I recommend it. I've tried them all, some sand like rubber. The Duplicolor F/P is made for car finishes. When sanded to surface it will fill any remaining scratches and tube seams.

Semroc (Centuri) Taurus Build, Part 6, Adapters and Joints

The balsa adapters were slid into the body tubes and the sides sanded even with the body tubes.

TIP: That pencil line lets me know the starting point as I sand around the tube. I don't want to over sand down into the wood itself.

The circled area on the left is a spot that needs a little more CWF.



The nose cone was set in the upper tube, almost up to the tube end. There is a open gap just wide enough to allow a folded piece of 400 grit sandpaper.
Carefully rotate and sand with the folded sandpaper in the open joint to square up the nose cone shoulder edge. The inset picture shows a good fit.





The body tubes and nose cones were assembled, no glue yet.

On the left is the sanded CWF, on the right is after the filler/primer was sanded.

Semroc (Centuri) Taurus Build, Part 5, Dressing the Nose Cones

The adapter shoulders weren't flat.
This next step isn't necessary, it's just something I do.

That extended "nub" was cut down with a fine razor saw. The rough edge was sanded with 220 grit.
400 grit was set over my index finger tip and the edge rounded for an easier fit into the body tubes. This end clean was done on all five nose cones and two adapters.

The smaller inside shoulder edges weren't very sharp.
The body tube end was "roughed up" with 220 grit. The tube is slid down to the edge and the body tube turned and pressed into the balsa. The rough tube edge "sands" the inside corner of the shoulder, sharpening up the balsa edge. The picture on the right shows the "after".

The small BT-5 sized nose cone shoulders weren't sharp.
TIP: I brushed some CWF filler over the edge and onto about 1/8" of the recess shoulder. Leave the filler off the top off the nose cone so you have something to grab onto with your fingers.
Press the nose cone down onto the body tube and turn the nose cone forcing the filler into and over the shoulder edge.

Partially pull the nose cone out of the tube and let dry. Notice the new raised ridge around the shoulder lip.

After the CWF filler dries, sand off the ridge so the nose cone sides are even with the sides of the tube. You should now have a nose cone that is the same diameter as the body tube with a smooth seam between the two parts.

Semroc (Centuri) Taurus Build, Part 4, Tunnels Detail Shaping

The original Centuri kit had one tunnel on the upper narrower tube. The catalog picture must have been a prototype, the tunnel overlaps the lower adapter and up the tube. When the kit was released there was on tunnel, glued on the tube.

This Semroc reissue has three tunnels.
You first sand a taper on the ends. Set them side by side to make sure the angle is consistent. In the first picture, the third tunnel angle isn't wide enough. The second picture shows the fix.

The bottom face of the tunnel should be contoured to match the curve of the body tube.
TIP: You could sand it over the body tube, but I like to sand these contours over a smaller diameter tube. Here I'm using an engine casing. I get a better fit when sanded over a smaller diameter.

The lower picture shows a pretty good fit on the model. Fillets will cover up any gaps.

Check the ends to see if you got a good arc across the top.

The curve was evened out with a few passes over the used engine casing.







Here's the top after shaping - good to go for filling the balsa grain.

Semroc (Centuri) Taurus Build, Part 3, Engine Mount

TIP: The coupler ends are always cut at a slight angle. To get a flatter, slightly wider edge gluing joint, sand the ends flat.

TIP: Along with glue on the flat edge, roll some glue on the inside so you will get an interior fillet.

Press the disks into the glue and turn the disk to even out the inside fillet.

Before the glue sets up, roll the glued disk and coupler on a flat surface to even up the edges. I'm not sanding here, I'm just rolling the the coupler and disk on the flat side of the sanding block to even out the edges.

I was surprised there wasn't a laser cut notch for the engine hook.
TIP: Notice the line down the black coupler. Notches are cut on both disks, the pencil line helps keep both notches in line.





Here's the finished engine mount.

With 1" space at the bottom, the upper ring goes right over the upper bend of the engine hook. The Kevlar tied line loop went under that upper bend.
TIP: When Kevlar is tied under the hook, try to glue the centering over the upper bend of the hook - much stronger.