Centuri Skylab Build, #KB-4, Part 14, Fitting The Shroud, Gluing The Fin Supports

The first dry fit of the shroud fit showed a gap.

Turns out the glue fillet on the tube and centering ring joint wouldn't allow the shroud to seat all the way down. The fillet was sanded and the centering ring hole slightly enlarged.

I got a better fit but one side was slightly high. The high side was sanded using a block.

Here's a better fit of the shroud on the lower body tube.

Line up the shroud seam with one of the large, square fins.

The solar panel (fin support) gluing area had the filler/primer scraped off for a better glue bond.

After placing on the tube, they were held down with rubber bands as the glue dried.

Centuri Skylab Build, #KB-4, Part 7, Fitting The "Super" Shroud

Mentioned in the previous post - 

Here's the smaller end showing the inside stepped shrouds.

This gives a better fit and adhesion area onto the smaller tube.

One of the previously made centering rings is glued into the doubled shroud. 

After the glue dries, the edge should be stiff enough to sand off, even with the face of the centering ring. 

The fit is good -

Even if the low end were a hair wider than the larger tube, the 3nd printed instrument wrap would cover any shroud lip.

In the next post:

Now that all the parts are almost ready, the actual build can start. 

Centuri Skylab Build, #KB-4, Part 6, Making A "Super" Shroud

Cardstock shrouds have always felt like the weakest part of a LPR build. You can make a stronger two layer "nested" or super shroud.

For a complete explanation of the technique, I wrote an article for the Apogee Peak Of Flight: CLICK HERE
 

Go to payloadbay.com and click on "Tools", then to "Transition Tool".

Enter your tube diameters and length of the transition.

I printed the transition on 110 lb. cardstock.

The unused lower half of the page is cut off and taped behind the printed transition. Two layers are cut out at the same time. 

Note the glue tab in the upper right, added it with a pencil line.

I don't pull the shroud under a straightedge or pull it over a table edge.

Form the shroud in the heel of your hand with a smooth dowel. Press the dowel in an arc matching the curve of the shroud. 

Your shroud should be formed until it can stand on its own.

I don't put glue on the outside glue tab,

the glue stick goes on the inside where the tab will touch.

This makes the glue area easier to handle and prevents any glue getting on the outside of the shroud.

Burnish the glue tab area over a dowel set on the inside.

Repeat with the second shroud.

Pick the best shroud to go on the outside.

 Apply glue to the outside of the central shroud and press the two together placing the seam joints on opposite sides. 

After drying you'll notice how much stronger a nested shroud is. It almost feels like sheet plastic.

Inside the smaller end  the tow shrouds are "stepped" making a better joint over the upper tube. 

Look at the bottom and you can see the inner shroud overhanging the outside shroud. This will be sanded off in the next post.

Centuri Quasar Clone Build, Kit #KC-7, Part 9, The Shroud

I went to payloadbay.com for the shroud pattern. Click on "Tools", then click on "Transition Tool". 

I entered the dimensions 1.637" (BT-60) by .976" (BT-50) by 2.44" length.

    

The shroud was cut out with a separate glue tab so the edges could be butted up without much of a raised joint. 

Run a fingertip down the curved sides - you might feel some slight bumps and dips. You can smooth these out to a degree with 400 grit sandpaper rolled around a fingertip.

Here's the glue tab. 

I set the glue closer to the center line, not any on the outside edge.

This keeps any glue shrinkage distortion to a minimum.

The right side picture shows the tab half glued. Joining Cardstock shrouds takes very little glue.

Joining the two sides - 

I set the shroud over a dowel for backing.

With the two sides tightly together, a burnisher is pressed and rolled up and down the seam.

Do some dry fits before gluing on the shroud.

The engine mount is already glued in place with a bit of the lower centering ring exposed. 

Glue rings were set at the top of the centering ring and bottom position on the engine mount tube. The shroud was slid into the glue.

While the glue is still wet, roll over the upper joint with a burnisher. The wet glue shroud edge can be molded to better fit the larger tube.

I had a decent fit of the shroud but did a CWF fill anyway.

Here I'm using a single edge razor blade to smooth and level out the wet filler.

Estes Super Orbital Transport Build, Kit #7314, Part 12, Glider Nozzle Shroud Gluing

I don't put glue on area marked TAB - 

TIP: Instead I place the glue inside the other straight edge. shown by the shaded area in the left side picture.

If just a skin of glue is spread out to the flat edge you shouldn't find any glue squeezed outside the finished shroud.

Have two clean dowels ready.

Set and align the tab. Place the shroud over the larger dowel. Press and roll the second dowel over the tab area.

Check the roundness of the nozzle and use the dowels to shape if needed.

A narrow line of glue is set along the inside of the 20/50 ring. 

Center and lightly press onto the nozzle shroud.

Estes Super Orbital Transport Build, Kit #7314, Part 11, Glider Nozzle Shroud Forming

The flat outside face of this 20/50 nozzle support ring will visible on the finished model, even with the end of the BT-50 Orbiter body.

Sand the outside face smooth with 400 grit on a block.

TIP: You can "seal" the ring face with a light coat of wood glue and lightly sand again when dry. Sealing a rough surface like this gives you a more even paint coverage. The paint won't soak in if the surface is sealed.

TIP: As I always recommend, scan and make a few practice copies of the shroud. Form a few and pick the best one for the build.

Cut the flat sides with a straightedge and knife. Cut the rounded sides with scissors for a smoother arc.

TIP: Run a fingertip over the curved sides and you'll probably reel some high and low spots. Run some 400 grit over the sides to smooth them out.

Pre-form the shroud in the heel of your hand with a clean dowel.

Press into the shroud with the dowel in an "arc" shape shown by the arrows.

You might need a little more pressure forming at the ends to get a complete full circle shape.

New Way Mars Snooper II, Build, Part 10, Positioning The Lower Shroud

The centering ring was a little tight. 

TIP: To get a smoother shroud edge with no bulge, sand a slight angle on the ring edge to fit the angle of the shroud.

On the right, I used my flat sanding block to press the ring into the shroud, no glue yet.

The ring and shroud are slid up over the end of the BT-50 until the small end of the shroud is even with the tube end.

   

Mark the ring position with a pencil.

Remove from the tube and pull out the centering ring.

Slide the ring up to the pencil lines and glue onto the tube.

After the ring glue dries, Apply glue lightly (seen on the right) and slide the shroud up and onto the glue and ring.

TIP: For easier positioning of the vanes,

Extend the alignment lines onto the centering ring. You can also do this on the bottom of the BT-50 tube edge.

Why? When the vanes are glued on, the alignment lines are covered by their root edge. You might end up gluing the vanes at a slight angle.

New Way Mars Snooper II, Build, Part 9, Doubled Super Shrouds

The kit supplied shrouds were a little big, loose on the BT-50 tube. Kit supplied shrouds don't always fit. There can be slight differences in different production lots of the "same" body tubes.

The supplied shrouds looked to be copies of the original Estes art. There can be changes in sizes when second generation scans or copies are made.

I went to Payloadbay.com and printed off new shrouds. These were loaded into CorelDraw and the vane and fins lines added.

I wrote an article for the Apogee Peak Of Flight Newsletter on SUPER SHROUDS. For a better explanation: CLICK HERE

    

"Super Shrouds" are simply a double "nested" shroud. Two layers of 65lb. cardstock. They are so much stronger than a single layer card stock. When the glue dries, they feel like hard plastic.

TIP: I don't put wet glue on the glue tab. Instead, I rub a glue stick onto the opposite side of the shroud. This gives me more control over where the glue goes and ends up when the shroud is formed.

This is the lower "Vanes" shroud. 

On the left - I don't use much glue, I don't want to oversaturate the card stock. The picture shows the applied glue before it was smoothed out with a fingertip. 

YOU'VE GOT TO WORK FAST - smooth the glue and press the glued shroud into the outside shroud before the glue starts to set up.

There will be some overhang of the inside shroud.

This is cut off AFTER the glue has dried using a single edge razor blade. Cut carefully along the bottom edge of the outside shroud.

Sand and clean up the doubled cut edge with a block.

You don't have to worry about the inside of the narrow end of the shroud. The doubled shroud lip is "stepped" giving you a second edge to better fit around the body tube.

Estes Skylab #001973, Build, Part 8, Third Stage Adapter Shroud

Here I haven't glued the cardstock shroud in place yet. It is taped to hold and "form" it to the tube diameters.

TIP: Before laying down any tape - reduce the tackiness by pressing the tape on your pantleg. Press and lift, press and lift. Do this a few times so there is less chance of the tape tearing the card stock when the tape is lifted.

On the right side picture - Note the overlap of the card stock shoulder. This edge will be much thicker when the vacu-form wrap is in place. 

Try to fit the shroud edge evenly over the adapter tube top.

Even though the tape is not very sticky, carefully lift the tape.

Don't glue the shroud in place yet - see the next step.

Here's how the instructions show the shroud gluing.

The gray bands imply more glue than is needed.

I would only apply glue to the upper edge of the adapter - just to the left of the arrowheads in the above drawing. 

Make the glue bead small.

Slide the shroud down and seat the edge on the line of glue.

Then - apply a small bead over the joint, 1" at a time and remove excess with a finger.

This will all be covered with the vacu-form body wrap reduction piece.

Semroc Point, KV-58 Build, Part 9, Fitting the Shroud?

With the inside taped down, the outside edge of the shroud is still open.

I set a small drop of white glue on my knife. 

Work the glue as a thin film covering all the glue tab from top to bottom.

Close the end and burnish to set the tab.

Here's when I realized something was wrong.

On the left - 

This is as far as the internal engine/fin assembly would go, up inside the shroud.

On the right - 

You can see light at the top of the outside fin edges. Fin contact with the shroud is only at the bottom.  

I figured I could fix it by sanding down the low end of the fins. I don't remember doing any adjustments like this on my two previous Point builds.

This is where I stopped the build -

I guess I could have finished it, but the trimmed bottom support ring was so short the shock cord tie point was removed to get it to fit. I was concerned about the strength of the cone. 

I wrote to Semroc and explained the problems.

The email responses are in the next post.

Why do build posts on a kit that wasn't finished?

Hopefully there are some ideas shown that might help on a different design.

Semroc Point, KV-58 Build, Part 8, Support Ring & Main Shroud

The vertical ring is glued inside the base ring.

Apply glue lightly. Set the ring in place.

Let dry with a wide, light weight on top.

Apply glue fillets afterwards. Go light on the fillets, too much glue can pucker the cardstock.

Keep forming the dowel until it is near closed without any pressure on the outside.

I did my usual pre-forming by pressing a dowel around the shroud while it was sitting in the soft heel of my left hand.

Scotch tape is set down the edge with the sticky side out.

Use the tape to line up the edge lines. Press the tape in place to hold the shroud closed.

Semroc Point, KV-58 Build, Part 7, Shroud & Support Rings

The shroud is cut out using scissors on the curves.

Cut the straight lines with a knife and straightedge.

Run your finger around the curves and you can feel some high spots.

Curl some 400 grit sandpaper around your finger and lightly sand around the inside curve top.

You can sand the outside (larger bottom) curve with a block.

TIP: Instead of cutting corners in the square on the inside ring, try using the rotary punch.

A round punch will be much stronger than sharp corners that can tear.

Go slow when cutting out the support ring.

Again, use fine sandpaper to smooth out any rough edge cuts.

After a dry fit, I realized the ring I formed was too tight.

I pulled apart the glue joint (it was still wet) and slightly spaced out the glue tab contact area.  

This moved the alignment of the previously punched shock cord tie holes. I re-punched the hole through both layers.

Maybe I should have punched the hole once, after the red ring ends were glued together.

Estes Super Mars Snooper #7309, Build Part 15, Glue & Trim Launch Lug

I rolled a clean dowel over the raised glue tab area. 

A fin will go over this cardstock step. I'll get a better glue bond if the seam were more flat.

A rubber band was wrapped around the low end to keep the launch lug in the glue at low half circle cut in the shroud and ring.

Here's the top end of the lug.

This will take some careful trimming.

Use a new, sharp single edge razor blade to cut off the launch lug.

Don't cut to the surface of the shroud yet. Cut a bit high then trim the lug closer afterwards. You'll be better able to see the lug edge after the initial cut is removed.

The top of the lug will probably be long after the first cut.

Estes Super Mars Snooper #7309, Build Part 11, Gluing (Almost) All The Shrouds

Two 50/55 rings are glued onto the top and bottom of the internal BT-50 tube.

On the right is a dry fit of the BT-55 tube. The tube slides over the lower ring.

The marks on the BT-55 tube must align with the cut lines on the centering ring.

I marked a glue application dowel for a internal ring of glue inside the BT-55 tube. The dowel was set beside the shroud assembly and marked with a pencil for a glue depth mark.

The BT-55 tube is slid down and over the lower centering ring.

A glue fillet is then applied around the base of the tube/centering ring joint.

Here the BT-55 tube has been glued on.

Three internal support balsa triangles are glued on the centering ring cut and pencil marks on the tube.

I didn't want to use much glue on the outside edges of the support pieces. Too much glue could distort the cardstock shroud and show on the finished model.

Glue was applied, then the excess removed and smoothed with a Q-tip.

Note the small line of glue around the outside edge on the right side picture.

Continued next post -