MX-774 Kitbash Part 9 Filling Fins

I brushed Carpenter's Wood Filler onto the fins earlier today.

My filler is starting to dry out a bit and get thick.

You'll learn the proper consistency after a few tries. After applying, most of the brush lines will disappear when dries. You should let it dry overnight before sanding.

Here's a fin after sanding.

Ideally, with the CWF you want to leave a thin yellow coating overall.

In this picture you can see the pink balsa showing through in the center.

I'll have to go back, reapply and sand again.

In this last picture you can see two different layers of filler.

On the top is the dried filler before sanding. You can still see the brush strokes.

Below is the sanded surface. There is a thin overall coating of the sealer above the surface of the balsa.

Use a bright light when sanding to be sure you are removing all the brush lines and getting to the surface.

Downscale MMX Galaxy Guppy GooneyBird

Here's another in the downscale series I've been working on.
This time it's the Galaxy Guppy based on the old Estes GooneyBird #0852.These are actually easy to build, there is no painting involved except for the nose cone. The blue match isn't perfect, but close enough for me.

Drawing the mouth with a Sharpie pen takes a steady hand, but came out okay.
If you are a Patreon supporter, email me at: oddlrockets@bellsouth.net and request the MMX Galaxy Guppy PDF. 
I'll send a PDF plan for you to print out.

Old Range Box Part 2

Check out the old stickers on the inside lid!

Those go back to NARAM 17 and 18.

The upper shelf holds (clockwise from the upper left)

1. Engine mount adapters and heavy twine.

2. Igniters from Estes and Quest and a roll of masking tape (not in the box)

3. In front is clay weight, smaller launch rods for monocopters and MMX rod adapters.

4. In the center left are tools. I always carry disposable knives, sandpaper, small tubes of CA and needle nosed pliers.

On the second level are the engines (from left to right)

Slot 1. Micro Maxx and T engines

all moving up in power through

Slot 8. D Engines.

Years back when I was flying FSI and Enerjet Es and Fs, they had their own place in slot 7 and 8.

At present I carry up to D engines in this box.

I didn't have a labelmaker back then, I typed up engine designations, cut them out and taped them to the front of the tray.

The bottom of the box holds a small launcher, controller, too much wadding, a bag of spare parachutes/streamers and smaller rockets.

Two rockets that never leave the box are an Odd'l Rockets Birdie and the Art Applewhite Monocopter. The Birdie is always a good first flight of the day to check the system and for wind. The Monocopter is for the days when you want to get in just one more quick, easy flight.

This Range Box carries too many memories. It still does it's job well, I wouldn't trade it for a new one.

Old Range Box Part 1

This is my first Range Box, going back to 1969.

I still use it today.

I originally got it with by trading in 3 full books of S & H Green Stamps.

A few years back, stores would give out trading stamps, one for every dime spent.

You'd fill a up a book with stamps and could either trade it in for merchandise or get $3.00 in cash per book.

This range box was 3 books, probably close to $10.00 retail back then.

It was bigger than the Estes Range Box sold in their catalog.

When I was away from rocketry, this box held all my leatherwork supplies.

I thought of removing all the rocketry stickers then, but I'm now glad I kept them.

MX-774 Kitbash Part 9 Rounding Fins

I don't know if the Centuri MX-774 kit used 1/16" balsa, I would assume it did. Mr. Wilfong's kitbash instructions suggested using 1/16" balsa. I decided to go with 3/32" thick stock.

The trailing edges are behind the body and would be prone to breaking on landing. I felt 1/16" balsa would be too thin.

Mr. Wilfong also suggests airfoiling the fins. Again for strength, I simply rounded the edges.

Here I'm removing most of the edge by rolling the edge over a block with 220 grit sandpaper.

That block is a Great Planes Easy Touch Hand Sander, a great tool. You buy the sandpaper in a roll, the paper has a sticky back to hold it on the flat side. Their 220 grit paper isn't a real 220. It's more like 320 so it's perfect for this kind of work. That roll of sandpaper is a little pricey.

I use a block for the initial rounding of the edges. It helps keep an even roundness across the entire length of the edge. Most younger modeler's tend to take off some of the corners when using too rough a grit held in their fingers.

After using the block I go back and knock off any small edges with a piece of 400 grit held over my index finger.

Tools - Long Tweezers

Regular cosmetic size tweezers can help in a build, but you should get something much longer.

These tweezers are 6" to 7" long, leftovers from my model ship building days. They were used in tying rigging lines.

If you hate making parachutes, these will quickly become a favorite tool.

It's much easier to grab and tie shroud lines with long tweezers instead of your fingers. I also use them to pull Kevlar through a long body tube.

Sometimes you never know the difference until you use the right tool.

A six piece tweezers set is available from Harbor Freight for $5.99 at:

http://wwwharborfreight.com/

Search for item # 93598

MX-774 Kitbash Part 8 Sanding Tube Seams

Here I'm sanding down the filler already dried in the body tube seams.

Sand down the length of the tube, up and down, against the seam direction.

Don't sand in a circle or along with the seam, you could knock the filler right out of the tube.

The sanding block is holding 400 grit sandpaper. Carpenter's Wood Filler will not load up sandpaper the way sanding sealer used to.

Look close at the next picture to the left. You can see the filler has been knocked out of the seam. This will require me to go back and fill again.

While some hate the white tubes, it is easier to see the tan filler in the white tube seams.

MX-774 Kitbash Part 7 Fin Trailing Edges

The MX-774 has four flat bottomed fins that stand flat and square.

Sometimes you won't know if the trailing fin sides are square until the model is finished. You stand your finished rocket on a table and the bottom edges aren't flat!

Here's one way to check them before gluing to the body.

Stand your straight edge up on a flat surface. You could use anything long enough that has a true square bottom. Set the fin's root edge against the vertcal side, keeping the bottom flat against the surface. Your fin is now standing straight. (I used a wooden ruler just for the example. It didn't reflect light in the picture.)

Check out the light coming through the right side of the trailing edge!

I'll have to sand the left side of the trailing edge to square it up.

Better to fix it now than see the rocket wobble when standing up after it's finished.

MX-774 Kitbash Part 6 Seam Filling

Some builder is going to read this and say: "He's doing what?"

I've gone back and forth over the years on the best way to fill body tube seams.
Thirty years ago I used white wall spackle, back when it was real wet and gritty. It was too wet and gritty for the kraft paper tubing.

More recently I've been using Elmer's Carpenter's Wood Filler mixed at the same consistency you'd use on to fill balsa.

I first used small brushes, painting over the seams. Then I'd lightly "squeegee" off the excess with a razor blade, leaving as much as I could in the seam.

For now I use a old, dull X-Acto blade to apply it. I dip just the tip of the blade into the filler, leaving a drop on the blade tip. Wipe off the back side of the blade on the filler jar lip. You won't need all of it.
The bead of filler is set into the seam. I can drag and spread the drop of filler down the seam. The Blade edge easily stays in the seam trench as I push the filler forward and back, in a sawing motion.
You are doing about an inch at a time, then going back for another drop of filler.

Because the filler will shrink when it dries, I don't "Squeegee" off the excess. I simply sand the raised ridge down to the surface. Tube seam widths will differ between tubes, a smaller width seam will hold the filler better than a wider width seam. Let the filler dry thoroughly before sanding.
I use 400 grit on a block to sand off the dried filler. Sand lightly, you don't want to knock the filler out of the seam. Using Carpenter's Wood Filler will usually fill 3/4 of the seam depth. The last 1/4 will fill with spray primer.

MX-774 Kitbash Part 5 Engine Mount Install

After a couple of dry fits I found the upper centering ring would be about 2 1/4" from the rear of the main body tube.

To insure the ring would have glue around it, a dowel was marked at 2", 1/4" below it's final resting point. You can see the pencil mark in the picture at the right.

A bead of glue was applied to the dowel top. It was set inside the tube up to the 2" mark on the dowel. The glue bead was spread evenly around the inside of the tube, using the mark to keep it around the 2" distance from the end.

The tail cone was used to push in the mount against the lower centering ring. When the tailcone was about 1/4" from the end of the body tube I removed it and twisted the engine mount to spread the glue evenly around the top centering ring. The tailcone was replaced and pushed in the final 1/4" against the body tube. With the tailcone butted up against the body tube, the mount is in the correct position.

The picture above is taken from the top looking in. You can see how the upper glue bead is even from twisting the mount and evening out the glue bead.

With every engine mount installation, you are working against the clock. This install had three distinct movements. Partial install slide in, twist of the mount to spread the glue evenly and final push into position.

I know some are thinking: "Why bother? Nobody will see the inside anyway." I try to get both - good, clean internal and external construction.

Here's the dry fit of the tail cone, both engine mount tube and the end of the tailcone are even.

MX-774 Kitbash Part 4 Fin Profiling

Here's technique loosely borrowed from guitar repairmen when they level frets on a fingerboard.

They'll mark over the tops of all the frets with a Sharpie pen before leveling them flat. When sanding over the fret tops, the remaining dark marker will show them the low spots on the fret. The low areas remain black.

Here I've marked the master (already fitted fin) with the Sharpie around the edges. Go light with the marker, you might need that fin later.

Four more fins were cut slightly oversize for this demo. All were pinned together making sure all the edges were overhanging the master, blackened fin.

Here's two edges sanded down to match the master template fin. You can see where the sanding was just starting to go into the blackened edges of the master.

I worked off a master fin this time because I didn't want to have to sand and match up three other fins to the angles of the body tube and tail cone.

That first master fin took too much time to get the correct fit.

New Saucer Design - Model Profile

Occasionally I'll post some pictures of something I've worked on from the past.

Here's my version of a Saucer, very loosely based on the old Centuri design without the blind embossed surface. It's 7 1/2" in diameter and 3 1/4 inches high.

The top was drawn on my laptop and printed to cardstock. that print was glued to thin foamboard making it light and very strong.
The "Landing Lights" were printed in yellow, but I alternated with some Monokote Chrome Trim dots, punched out with my rotary punch tool.

The four underside fairings were tough. Even though they are the same width from side to side, they would pull in when glued giving it a scalloped effect.

To correct this, the fairings would be drawn to "bow out" a bit in the middle. Next time, the outside edges of the internal fins will be cut shorter.

It'll fly again on a C6-0 at the N.E.F.A.R. launch in Bunnell, Florida on August 14.

Lone Wolf Launch July 26, 2010

I flew my new MMX Missile Toe and Sky Shriek this morning.

Both were stable and landed close to the launcher.

These little Goonies fly as well (and about as high) as their original full-sized versions did with an A3-4T.

They were fun to draw up and build. I may do the entire series, except for the Zoom Boom which was already well executed by Greg Poehlein.

Also flown was the Cherokee T with a 35 year old 1/2A3-2t and the MMX Sky Writer. The 35 year old engine worked fine, except for the original Astron igniter. It burned it's blue coating without starting the engine. The old was replaced with a new style Estes igniter and off it went.

MX-774 Kitbash Part 3 Fin Fitting

I know - enough with the Micro Maxx rockets -

let's build something with a little more power!

I decided to go with 3/32" thick fins. 1/16" balsa seemed a little thin.

This is a sport scale model so I'm going for a little more strength.

The fin pattern on Mr.Wilfong's drawings were very close. Matching the angle of the boat tail only took a little sanding with a block to get a good joint.

There is a 1/8" step from the end of the body tube to where the tail cone starts to angle in. This'll require a little filling. I'll probably end up just filling the small hole in balsa root edge instead of filling the entire tailcone step.

MMX Sky Shriek Build Tips Part 2

On most of my carded rockets, you can see a triple ply laminate at the edges of the fins. This little rocket has overall black fins.

Simply take a Sharpie pen and blacken in the edges. Any white overhang on the underside (strut side) can be touched up now.

I recommended punching the tops of the more visible "labeled" side of the fins for a reason. The inside strut sides of the fins are not seen as easily. Any Sharpie marker touch up won't be as noticeable on the inside fin surfaces.

The backside of the Sharpie pen is a great smooth burnisher.

On carded fins you can smooth out and slightly round the fins by simply running it over the outside edges. Not the root edge! - Leave that square.

MMX Sky Shriek Build Tips Part 1

Getting those fin halves to match up can be tough.

I only cut out the root and leading edges of the (outside) printed plys. the other edges can overhang for now.
In the picture you can see where I cut sharp "Vs" in the leading edge of the cardboard.

By lining up the intersection point of the root and leading edges of both outside laminate prints, you can get it very close.

I used my rotary hole punch to cut the inside curves of the scalloped trailing edges. These small curves would be too hard to cut with scissors or a knife. The convex side of the curves were cut with the tip of a razor blade.

Punch on the sides that have the "labels" on them, don't worry about the strut sides yet.

You can be as careful as you want when doing a laminate like this, but there will be a little misalignment.

See the next post for how to clean up any white edges.

MMX Sky Shriek Goonybird Downscale

This was today's "Day off" project.
I thought this would be a good challenge. Six scalloped fins, joined in pairs with wing struts.
The old Sky Shriek instructions show slots through the fins. The struts were longer than needed. You slid the struts through slots, glued and sanded off the excess.

On this smaller version, I had to join them flush with the face of the fins.
Patreon members: If you would like a PDF of the plans, it's available. Email me and I'll send it right out: oddlrockets@bellsouth.net
Ask for the MMX Sky Shriek PDF

OOP Quest Nike Smoke Build Part 13

Here's the dry fit, awaiting the stenciled "UNITED STATES" decal.

The decal has been drawn up on Corel Draw. I'm waiting on another project so I can print for two rockets on one decal sheet.

After the decal is applied, I have to decide whether to spray a flat coat or gloss coat overall. Flat finishes get dirty quickly and white can really show the dirt.

OOP Quest Nike Smoke Build Part 12

Here's the complete mask, ready for the fluorescent Red/Orange.

As I mentioned before, this is a complex mask. It required twenty pieces of Scotch tape just around the fin root edges. On top of that, masking tape holds the piece of plastic over the already painted yellow fin.

I went over all the edges with a smooth, rounded dowel twice to make sure the edges were down and secure.

After removing all that tape, here's the finished fin can.

Those thick molded-in "fillets" took a little bit of guesswork, but in the end I'm happy with the results.

MX-774 Kitbash Part 2 Engine Mount

This is the finished engine mount built as directed in the Estes instructions from Step 1.

Mr. Wilfong's Kitbash instruction drawing shows the BT-20 engine mount tube as 4 3/4" long, but he doesn't mention using a longer tube in his version of the instructions. I went with the supplied length from the Bull Pup kit at 3 1/2".

You can see there is a notch for the engine hook in the lower ring. There is no no engine hook supplied in the Bull Pup kit. While the Estes instruction drawings don't show the notch, I would assume Estes just went with a generic ring set that can work with or without hooks.

I don't use Estes "Tea-Bag" shock cord mounts. Kevlar was tied around the upper centering ring. A small hole was drilled for the Kevlar to pass through. I should have put the notched ring at the top and feed the Kevlar through the notch!

That brown lip on the end of the BT-20 tube is CA glue. To increase strength, I always run a bead of thin Super Glue around the ends of body tubes and lightly sand smooth.

MX-774 Kitbash Part 1 Parts

At present, Michael's Craft Store is clearing out the Estes kits and engines.

I'd already built a Estes Bull Pup 12D, but it was a little tough to pass up the clearance price.

The plans for a sport scale MX-774 by A. Roger Wilfong are at:

www.spacemodeling.org/JimZ/mx-774.htm

It's a kit-bash of the Estes Bull Pup 12D kit using the engine mount, nose cone and tailcone. You supply a longer BT-55 and some 1/16" balsa.

I always wanted one, but never built the old Centuri kit. This version will be a bigger at around 16 1/2" tall. The Centuri kit was a short 11" tall.

To the left in the picture are the extras going into my spare parts box.The white body tube and everything to the right are the parts I will use for the build. I still have to find a 1/12" diameter dowel.

Missile Toe Goony MMX Downscale

Here's how to use your last plastic BT-5 sized nose cone.
This is a cardstock downscale of the the Estes (Classic?) Missile Toe Goonybird.

John's EMRR Photo Contest Entry

My friend John Bishop has been a Odd'l Rockets supporter and flyer since I started the company. We get together to trade rocketry stories at the monthly Bunnell, Florida N.E.F.A.R. launches.

John had an interest in competiton and I suggested the online EMRR Challenge. The Challenge is a great way to expand and try a few things you wouldn't normally do in a weekend launch. I think these pictures are his way of getting even for my suggestion.

Here's entry #6 in the EMRR Double Vision Photo Contest:









"Chris and I are prepping the twin Squatty Body rockets for their moment in glory. A moment of robot dancing overcomes us both. Note the finely applied details and paint, similar in color yet diverse in effect."
"Chris Capturing the moment. If one ever wondered what 30+ years of rocketry do to someone . . . check out the hair. Next time he needs to back up when he hears the countdown!"

Well, John - it was windy that day! I started in rocketry in 1969, off and on I've been doing this for 41 years. You'd think I would have figured it out by now!

You can vote (for John's entry) at:
http://www.rocketreviews.com.contests/photo_contest22.shtml

MMX Igniter Installation

Our local NAR Section president, Brian Coyle, first showed me how to use toothpicks to hold MMX igniters in place.

They fit easily into the small MMX nozzles and also ended up being a convenient stand-off, raising the model above the blast deflector.

Another plus - with the toothpick tip resting on the deflector, the down weight of the model (and connected clips) kept the igniter in.

By accident, I bought some square toothpicks when I meant to get the round ones. I was stuck using the square toothpicks when prepping some MMX engines.

You would think round toothpicks would be a better fit against the sidewalls of a round nozzle. But, the four sides of a square toothpick actually gets a tighter friction fit. The square edges have just a little more "tooth".

The only disadvantage, the square toothpicks can break if you were to press too hard into the nozzle. Just take it easy, just enough to hold the igniter wire in place.

Some of my best rocketry "finds" have been by accident.

Who said: "You can't put a square peg in a round hole?"

Replacing A Screw Eye In Balsa Part 2

After the glue has dried, cut off the toothpicks close to the base of the nose cone. A little sanding brought them down even with the flat surface.

You can see the small hole in the center where the screw eye will fit.

The toothpicks will give the screw eye a much stronger grip in the nose cone.

Here's the new, larger screw eye and washer weight ready for the next (hopefully) stable flight.

Replacing A Screw Eye In Balsa Part 1

After two unstable B6-4 flights on my Groove Tube, I knew I had to add some nose weight.

But, the old screw eye was glued in place into the bottom of a balsa nose cone.

Here's the base of the cone after pulling out the old, smaller screw eye.

The hole is still too big for the larger eye and weight.

After squirting in some white glue, I pushed three toothpicks into the old hole. Try to keep the toothpicks sticking straight out of the hole.

Let the glue dry before cutting them off.

Spray Paint Tips

Years back, when I built a scale model rocket, I'd have to go the extra and buy a can of flat spray paint. I had cans of flat white and gloss white, flat black and gloss black.

When I re-joined the hobby I had a revelation.

I was stuck buying new spray paint and it hit me.

Why bother buying two different cans of the same color?

I ended up buying gloss in the colors I use most - White, Black, Yellow, Orange and Red. I don't paint my rockets green or blue (unless it's dark blue) for obvious reasons. I finished up my shopping with one can of flat clear.

When I build scale, I finish the rocket with gloss. If the actual rocket had a flat finish, I follow up with the flat clear.

NOTE: As of 2021, I am now recommending ACE Hardware Premium Enamels for model rocket painting. The Ace Gloss White does not spray out a random, spattering "cottage cheese". The Ace bran paint is much better for touchups. Spray some paint into a small cup and touch-up using a brush.  

The paint in the picture is my old spray of choice - Rustoleum Painter's Touch - Ultra Coverage, 2X. I had to find a new paint after Krylon changed (and screwed up) it's formulation.

TIP! Water slide decals adhere better to a smooth, gloss finish. If a decal is placed on a flat finish, the edges won't stay down and the clear areas will "silver". So on scale models, apply decals over a gloss finish, let dry, then apply the flat clear coat.

ANOTHER TIP! Krylon Gloss Clear Coat is garbage! It'll turn your shiny finish to satin with one pass of the can. (Unless you buy the flat coat to purposely dull a gloss coat like I did!)

OOP Quest Nike Smoke Build Part 11

This is a complicated fin mask.

With all the angled tapering at the root edge and the ends, there is eight masking lines on each fin. Or to put it another way, each fin will have eight pieces of tape around it's base.

It's a little hard to see in the picture, but there is Scotch tape right at the mask lines. Brown masking tape outside of that taped to a bag covering the entire fin can. The engine mount is not glued in place yet.

To make it a little harder, at the root edge there is a very clean rounded joint or fillet. You almost have to guess where the tape edge goes.

Here's the fluorescent yellow fin after removing the tape. The mask came out very well.

I'd mask and paint the fluorescent red/orange but I got pink (or Pank) by mistake. My daughter was with me at Home Dept and told me there was no such thing as fluorescent red: "They don't make fluorescent red in fingernail polish, the closest you'll find is pink."

I returned the pink and will search for the red.

What's Wrong With This Engine - ANSWER!

Axe figured it out yesterday.
There's a pretty surprising misprint on the engine.
It's a 1/2 A3-2T, printed in Green ink overall.
Check the top of the casing - UPPER STAGE?
Someone at the Estes factory obviously didn't reset that printed area at the top when this single stage engine was printed.
Pretty easy to spot when you look twice, I wish I'd double checked the engine before I used it!

OOP Quest Nike Smoke Build Part 10

Here's the nose cone sprayed white and finished. One of the filled seams is facing the camera, right above and next to the light relection.

Filling the seams was a more work than I would have liked from a kit, But the end results were worth it.

Before anyone comments about the gloss finish, it will get a coat of clear flat after all is done.