Semroc Baby Orion FINISHED

This one finished out shorter than I thought it would.
A great downscale by Semroc.

I probably spent more time building the Semroc Baby than I did the original larger Centuri Orion back in the 1970s.

Semroc Baby Orion Build Part 22 Decals

There were a lot of decals crammed on a small decal sheet. Take your time when cutting them out.
I didn't like the word "Baby" at the top left of the name Orion.






It was cut off and the Centuri logo put in it's place.

Near and up the nose cone, the thin blue vertical stripes are hard to place. Wet the tube before setting them down so they can be easily moved.






Because I added some card stock trim tunnels, a few decals wouldn't go where the face card showed their position.
The vertical "Orion" was placed under the blue stripe, it wouldn't fit with that card stock tunnel in the way.







The round vent decal was moved above the tunnel.

Semroc Baby Orion Build Part 21 Masking The Nose Cone

I used the Tamiya tape for this mask.

Two overlapping pieces were set on my patio door glass.
With direct sun, you should have enough light to make this work like a cheap light table.
The printed transition was taped over the Tamiya tape with overlap on all sides.
Carefully cut around the lower arc and through the tape below the print.



Carefully remove the tape from the glass.

Set it around the nose cone getting it as straight as possible. Take your time, make small adjustments getting all ends to match.







This is the nose cone completely masked.
Lightly seal all the edges before spraying. Press lightly on the edges, you don't want to crease the soft balsa.







After spraying, here's the red after removing the mask.
Considering it's a smaller nose cone, the end results come out well.

Semroc Baby Orion Build Part 20 Masking The Nose Cone

Originally I was going to paint the model like the facecard art. I don't have a can of light blue paint for the small nose cones.
So I decided to go with red for the six small nose cones and the tip of the larger main cone. There was already red in the Centuri logo and red stripes on the tank decals.



Just the upper third of the large front cone is painted. I used a scrap BT-20 to get an idea of how far down the red was going to be from the tip.

You have to cut the masking tape on a curve to get it to conform and go around the nose cone in a straight line.




The BT-20 was still a little too big at .736" diameter. I figured to go smaller at .740"
Back to Payloadbay.com and the transition tool.
I plugged in .740" dia. X 2.0"dia. X 2.0" long.

I'll only be using the lower .740" small arc to cut the nose cone mask.

Semroc Baby Orion Build Part 19 Yellow Tank Bands

I waited to glue on the three BT-3 tanks. I never would have been able to get paint coverage on the standoffs if the tubes were glued in place.

These were sprayed off the model, a thin strip of masking tape went down one side to keep the tube clean for gluing.


A 1/16" thick band of yellow Monokote trim was cut and applied to the top and bottom ends of the tubes. Sure, you could mask and paint the yellow, but why bother if the Monokote was handy.

The tube on the left shows the unpainted gluing strip with the masking tape removed. The trim material was cut to allow it to cover edge to edge when glued on the balsa standoff.




The six small balsa cones will be painted off the model as soon as I decide which color to paint them. The white and yellow trim colors are used on the face card art.

Semroc Baby Orion Build Part 18 Gluing Wrap Details

All the small detail pieces had been sprayed yellow.
The wider pieces had their back sanded to a round contour to better fit the body tube.







Any area that had a glued detail was lightly scraped to remove a little of the clear coat.

















Now the real fun starts, when you get to see all the small work in place. I knew where most of them should go, the others I just guessed.

Semroc Baby Orion Build Part 17 Wrap Install

I'd drawn the wraps wide with plenty of overlap.
The thickness of the paint probably widened the circumference of the tube.
A long strip of 110 lb cardstock was wrapped around the tube and the overlap point marked.




The cut length of the strip wrap was transferred to the printed wrap.



The back of the wrap sprayed with adhesive.
For a guide, the strip was wrapped 2 1/8" from the top. 2 1/8" is where the top edge of the wrap will go.
As usual, the spray adhesive held well except at the seam.
After it raised up, some white glue was slid underneath on one side of a razor blade.
Being careful not to smear any excess glue, the seam was burnished down.

Semroc Baby Orion Build Part 16 Decal Wrap Plan?

Sometimes the plan doesn't turn out right.
I was going to use the decal wrap supplied in the kit then glue all the small pieces I'd made to it.

I'd left the decal out when working on another project.
Somehow, two drops of thin CA had dried on the decal. The CA had ruined the fine line detail on the wrap.

Sure, I should've taken the easy way out ordered another decal from Semroc for $1.20.
Instead, I redrew both wraps.

In one way, this made the model a closer "scale" downsize. The original Centuri Saturn 1B wrap was a vacuform wrap on the Orion kit. If this small wrap was printed on 110 lb. card stock, it would raise the wrap surface more like the original vacuform.

It turned out to be a good learning exercise on the Corel Draw software.

1,000th Blog Post! Semroc Baby Orion Build Part 15 Engine Mount Fix

The centering rings were too loose in the ST-10 body tube. I had to build up the diameter slightly.

I cut some strips from 110 lb. card stock.
Three were glued on and between the centering rings.
To make it easier to start in the tube, the front end of the overhanging card stock was bent down to the center for a ramp.




A test fit was done in the front of the ST-10 tube. The fit is much better.




Here's the mask for the black paint on the nozzle. A 13mm engine casing was slid inside to keep out the paint over spray.

Masking tape was set on the edges of the lower centering ring. Paper was wrapped around the forward end of the mount.

Semroc Baby Orion Build Part 14 Fin Gluing

There was nothing out of the ordinary in regards to gluing on the fins. Except, there is six fin positions. Three large fins and three tank standoffs.

In the picture I tried a dry fit of the engine mount and nozzle assembly. The original Centuri instructions have the nozzle extending 1" out the back beyond the tube end.
This model is half size, so this nozzle will extend out 1/2".

Without all the tanks and detail wraps, this model is pretty plain.

Here the back end is masked to keep paint out of the tube. The nozzle cone will be sprayed black separate from the model then glued in the rear of the tube.
Look close and you can see masking tape strips down the outside edges of the tank standoffs.
The tanks will be painted off the model and glued on afterwards.
I can remember the painting the larger Orion and how hard it was to get spray paint in all the tight corners and backside of the tanks.

Because the model is small and light I'm using a dowel in the launch lug for a painting wand.

Semroc Baby Orion Build Part 13 Primer

If I'm building a model that is getting an overall color (like the Orion, which is white overall) I would normally glue on the fins before painting.

This model is small, with lots of tight spaces, especially at the tanks and tank standoffs. So everything will be primed before gluing to the body tube.

Where I could, I butted the root edges (gluing surfaces) together to keep primer out.

These are all the small wrap detail pieces before spraying the white undercoat.
These were not hit with the gray primer. They've already been sealed with two coats of varnish, sanding after each coat.

Semroc Baby Orion Build Part 12 Small Nose Cone Shoulders

Looking ahead, I started thinking about the paint pattern.

The nose cones would be painted blue before gluing to the tank tubes. The tube edge would give a good color separation.

After sanding down the filler on the small tank nose cones, I noticed the gaps around the shoulder. On smaller cones these shoulders are hard to keep sharp being made from soft balsa.
These shoulders should be built up for a better color separation line.



The nose cones were slightly pulled out of the body tubes.

A dull X-Acto blade was dipped into thinned CWF and dragged around the open joint.






The nose cone was pushed back into the tube and twisted, forcing the filler into the shoulder and making a raised lip to be sanded off after it dries.

Semroc Baby Orion Build Part 11 Details and Filling

This is all fourteen wrap trim pieces cut and shaped. These are not glued on yet.

I'll seal all with varnish, two coats sanding between coats.



All the parts needing filling are shown on the right.
Seven nose cones, three fins, three standoffs, four body tube seams and a launch lug.
The three BT-3 tank tubes are stacked on a dowel to have thinned CWF brushed on.
The launch lug is on two toothpicks for a brushing handle.

Semroc Baby Orion Build Part 10 Wrap Details

A couple more half rounds were needed on the lower wrap.






The front was marked and sanded at the correct (or close) angle.

The bottom is marked for cutting.
I'll usually cut a little long and sand it to the right length.






Here's the tunnel ready for sealing and sanding.

Semroc Baby Orion Build Part 9 Wrap Details

These little nozzles were the hardest to make.
The front end of a toothpick was cut and sanded at an angle.
I guessed at the pencil mark for the next cut.





After getting a good shape on the first nozzle, the angles were drawn on card stock and three more toothpicks were cut using it as a template.






Here's the nozzles set dry on the decal wrap.
Cut with this angle on the root edge, they stand up on their own.

Semroc Baby Orion Build Part 8 Wrap Details

On the lower wrap is a two piece detail.
The lower piece was a thinned down Popsicle stick. The upper round is a toothpick with the bottom sanded flat.





After gluing the toothpick with CA, the front angle was made with 220 grit on a block.







I matched the angle of the cut against the angle in the wrap picture.
The front was rounded using a sanding block.







The second on the right is ready for rounding.
As before, the longer pieces are shaped then the back end is cut off to the length needed. It's just easier when you have more of the back end to hold onto.

Semroc Baby Orion Build Part 7 Wrap Details

First up are the half-rounds at the top of the upper wrap.
As is my usual practice, keep the dowels long while shaping the front, then cut the back to the correct length.

Here I'm sharpening the dowel tip chucked in a drill against a sanding block.






Sand off the back half of the dowel.








Cut to the length needed on the Semroc decal wrap.



TIP: Anytime you do small details like this, it's easier to make them from a harder dowel or basswood. Typically, rocket instructions have you make them out of balsa scraps.
The balsa is grainy and hard to fill smooth on pieces this small.
Dowels and basswood have no real grain and will finish smoother with just a couple coats of clear dope or varnish and light sanding.