Semroc Sam 3 Build, Decals and Finished

This Centuri designed "Strike Force" missile is sport scale at best. When you compare the model to the actual missile pictures there are major compromises.

I learned a few things - On a smaller model with too many close fins - don't bother masking! You'll spend too much time cleaning it all up.
I drew up decals to make it more interesting but got some of the Russian spelling wrong. The decals ended up being about 10% too large, but they still look better than the Dr. Seuss art.

Semroc Sam 3 Build, Part 12, Touch-up and Red Paint

I sprayed some of the Winter Gray into a small mixing cup and touched up the bad mask lift with a clean brush.
Certainly not perfect. I had a feeling this mask was not going to work out.

I did something different on this model.
With the launch lug glued into the fin/tube joint you never know where to put the mask line. This time I masked down the middle of the launch lug to (maybe) camouflage it. This really only works at this angle. Oh well, worth a try.

In this picture, the narrowed scalloped decal wrap is already placed between the upper two sets of fins.

That red band was masked and sprayed. This really sets off the model.

The tunnels should have been masked and left white. I didn't bother with the narrow mask.

Semroc Sam 3 Build, Part 11, The Mask . . .

This was going to be a difficult mask, I never should have attempted it!

On the left is just the Scotch tape mask. The rounded root edges required a few pieces to get the tight arc.






I also knock off just the sharp corners on the squared edges.







Regular masking tape is used to mask out the middles.

Rustoleum Winter Gray was used for all the fins and nose cone, like the picture posted earlier.

Ah, crap!
The white was probably too smooth for the gray paint to hold. Some edges lifted when the tape was lifted.
This doesn't happen often, most colors hold just fine - this Winter Gray didn't.

Luckily, Rustoleum paint touch-ups brush on easily and "meld" into the earlier coats. I'll be doing a LOT of touch-ups on this model.

Semroc Sam 3 Build, Part 10, Kit Differences and Decals

The old Centuri instructions have you glue the upper (3 piece) fin assembly with the rear edge 1/4" from the end of the ST-7 tube.









The Semroc instructions have you glue the 3 piece upper fin assemblies 1/8" above the exposed end of the upper tube.

That throws things off when you go to redraw some decals.
There is a black scalloped wrap decal that should fit in that 1/4" space.

There are some white decals, I'll only be able to print up some black accent pieces.

I drew the scalloped wrap much thinner, but will probably still have to trim it to fit.

Semroc Sam 3 Build, Part 9, Paint Plan

I did some searching and found a few pictures of the Russian Sam-3.

It's always interesting to see an actual missile and the design compromises made to produce a sport scale model.








This looks to be the inspiration behind the Semroc kit paint scheme.
This is a smaller model and masking will be a chore.








These missiles with the upper red band are much more interesting. I'm going with this, or something close to it!
With the additional decals it should be a good look.

Semroc Sam 3 Build, Part 8, Launch Lug, Tunnels & Decals

The launch lug is glued into the root edge of a lower fin, even with the front of the fin.

Tunnels are glued on opposite sides between two fins.

Four tiny fins are glued onto the base of the nose cone in line with the lower fins.

Here's where we are at. Now to figure out a paint scheme.
The original Centuri kit was painted in camouflage. I have no experience painting camo and no airbrush to do it with. Time to do some searches for alternative paint.

There is a scalloped decal separating the first and second stages of the missile.
I wrapped a paper strip around the tube and divided it into fourths.

The original Centuri decals had Russian wording on it. Many of the decals were printed in white.
My decor will be a compromise, just black ink and not as many decals.
I had to make up some Russian lettering under the 19-2C5T decal line. Circles and hatches were added.

Semroc Sam 3 Build, Part 7, Fin Gluing and Alignment

The large, square rear fins are glued on even with the end of the body tube.








Before gluing on the upper fins, the body tube edge got a quick wipe with CA glue. The edge was a bit rough. With the CA glue on it could be sanded smooth.







The upper fins were aligned with the help of  clothes pins. This works well if the balsa is hard. Soft balsa might be scarred by the clamps.






On the clothes pins I used -  The wood halves are removed and flipped on the center springs so you clamp with the back, longer flatter end.

Semroc Sam 3 Build, Part 6, Fins!

The small nose cone canard fins were cut from basswood. I made a few extras and will pick the best four.

The launch lug seams were filled before gluing on the model.

Along with the nose cone canards, there are many pieces to fill!

For reference, the small fins at the top should be shown in the middle position.

I ended up using the balsa tunnels provided in the kit.
The ends and sides are rounded. This is tough to do, the thin balsa stick is easily broken.









Here's the four nose cone canards in place, spaced at 90 degrees like the fins below.

Semroc Sam 3 Build, Part 5, Joining The Tubes

The upper centering ring goes right over the the tubes joint.

The lower ring is glued 1/4" up from the low end.A bead of glue is set around the upper ring and more glue is applied the outside bottom edge.

Slide the lower tube on until the upper ring is even with the top of the tube.

A glue fillet is added to the lower ring joint. A drop of glue is applied and spread around the joint using a Q-tip. It may take four drop applications to get the glue ring all the way around.









Here's the main body assembly.
Fin gluing is next.

Semroc Sam 3 Build, Part 4, Small Forward Fins

The small, upper fins are made up of three pieces. I cut new forward strakes from basswood, the large middle piece is the kit supplied 3/32" balsa, the upper antenna was also cut from  basswood.

The older Centuri instructions have you glue the individual pieces together on the model. The new Semroc instructions have you assemble the three pieces off the model then glue onto the body tube.

Set and glue them together in a line on a straightedge.

Here's all four fins, the flat sides were sanded with 400 grit on a block.






CWF is brushed on and sanded off.

The fins will get a good shot of filler/primer and more sanding before gluing onto the upper body tube.

Semroc Sam 3 Build, Part 3, Engine Mount

The engine hook slot was a small punch made with an X-Acto knife tip.
Rather than just punching the engine hook through the tube, I enlarged the slot and cleaned it up.

This is typical of some Centuri engine mounts from the late 1970s. The lower ST-7 tube is 3" long.
No engine block, a coupler butts up against the upper bend of the engine hook. The coupler also connects the longer top tube.

A Kevlar line is tied through a small hole in the coupler.
Instead of masking tape I used a wrap of electrical tape to hold down the center of the engine hook.

Semroc Sam 3 Build, Part 2, Parts Prep Before Building The Kit

The upper fin tip pieces felt weak to me in the kit supplied balsa. The burnt edges were lightly sanded clean.
Four new pieces were cut from basswood using the balsa piece as a template.

I used a single edge razor blade to cut out the new fin tips.
On the left is the initial cut.
On the right is the same angle after sanding and truing up the end.

The nose cone shoulder end could use some sanding.
On the right is the flat sanded end. The shoulder was re-rounded with some 400 grit rolled over a fingertip. The rounded shoulder makes for a better slip fit in the body tube end.

The center is marked before screwing in the screw eye. Mark a center dot with a pencil, roll the nose cone to check the center and mark again if needed.

TIP: The upper end of the tube is sanded flat with 220 grit on a block. This slightly roughens up the end of the tube.
Slide in the nose cone and turn it against the rough end of the tube. The rough edge will "sand" and form the shoulder lip, sharpening up the stepped edge.

Semroc Sam 3 Build, Part 1, Parts

All parts were good, Centuri thick ST tubing.
This model has a Dr. Seuss decor with a Green Eggs and Ham, "Sam I Am" decal.
Lots of small 3/32" balsa pieces! The original Centuri kit had basswood tunnels. In this kit they are cut on the balsa sheet.
A washer weight is included for better stability.
I won't be using the Dr. Seuss style decal.

Semroc Sam 3 Background

All the copy below is from the Semroc website.

"The Centuri Russian SAM-3 was first advertised in the Centuri 1878 catalog with an availability date of May 15, 1978. It was one of the four models in the new Strike Force line. It was loosely based on the actual Russian SA-3 surface-to-air missile of the Cold War era. Photos of early prototypes were closer to scale than the final released version. It was released as Catalog No. 5332 and retailed for $3.75."

To see the Centuri Strike Force catalog page: CLICK HERE
To see the original Centuri instructions: CLICK HERE









"The Semroc Retro-Repro™ SAM-3™ is very faithful to the released version. It is a semi-scale model that preserves the flavor of the Strike Force series. We released it as a special kit for our SAM members. The decals do not reflect either the original Russian or Centuri version, but feature the SAM mascot. Added nose weight is provided for better stability."

The Semroc SAM-3 was released to SAM (Semroc Aerospace Modelers) members only. I'm finally getting around to building it.

The only other Strike Force kit I built was the Centuri Israeli Gabriel and Cruise Missile. The Gabriel was one of the few models that survived in my old bedroom until 39 years later.