Tips and Technique of the Day Thread (Twice a week).

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Vacuforming Nose Cones

Contributor: @georgegassaway

Ok, this is a blast from the past. I found a link to this on the Apogee site. The original post was from 1985 and centered on how to use your vacuum former machine to make lightweight nose cones for model rockets.

https://web.archive.org/web/20050115005642/http://members.aol.com/GCGassaway/vacuform.htm

 

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Centuri Guidebook:

Contributor: @cwbullet and the Wayback Engine

This manual is a blast from the past also and chocked full of great tips.

https://web.archive.org/web/20030403164356/http://www.dars.org/jimz/manuals/cmrdm.pdf

 

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An anchor can be a weak link:

Contributor: @cwbullet

Your shock cord and its link to the body tube are probably the weakest part of the typical Estes-style kit. Many other kits, including Quest, are light years ahead in this area. Other kit designers use a Kevlar line for their shock cord anchor. I have also seen some use a metal leader. It is good if the anchor is tied around the engine block or attached firmly to a solid bulkhead. The elastic or nylon cord is then tied to the kevlar anchor.

These stronger shock cords can fail if the attachment point is weaker than needed. I have seen eye screws pull out balsa and eye bolts that have straightened out.

No matter whether it is a heavy or light rocket, the concept is the same, A sturdy anchor is key to recovery success.

 

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Lengthen your shock cord:

Contributor: @cwbullet

In the prior post, I discussed the need for a good anchor. It is also essential to have enough length. The longer the shock cord (within reason), the more shock it can absorb and the less likely a line will be zippered. The extended size is especially needed with more rigid shock cords like Kevlar. The shock cord supplied with most Estes kits is way too short. I use 2 - 3 times the length of the body tube as a way to estimate the required length.

 

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Cheap adaptor:

Contributor: @slickwilly

Another blast from the past:

https://www.rocketryforum.com/threads/cheap-29mm-to-24mm-adapter.8129/

 

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Consider Reusable Bowls:

Contributor: @cwbullet

Do you tire of throwing away all those disposable cups you use to mix epoxy? My wife hooked me on these little boogers. I use small silicone mixing bowls to mix epoxy and my igniters. The stuff dries, and then I flex the bowl, and the stuff cracks up and falls out. The best part is you can get 16 for about $16.99. I get about 10-20 uses per bowl.

 

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Cracked Fillet Repair:

Contributor: @cwbullet

This repair will work for low-power to smaller high-power rockets. Pack the crack with baking soda and wick in a little CA. When it is set, sand the fillet lightly, trying not to scuff anywhere else. Touch up the paint with a brush - if you used rattle can paint, you can spray some onto a pallet like a pie pan and use that to touch it up with a brush.

Or the Crazy Jim Repair - Use pure CA to fix cracked fillets. They tape both sides of the cracked fillet with the easy-remove blue masking tape to keep the mess to a minimum. You then have to force the crack open, then apply the CA. When you release the fin, the excess will come out. Having an extra set of hands nearby, with a Q-tip or corner of a paper towel to sop up the excess, will make for a neater repair.

 

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Fiberglass hotbox:

Contributor: @cwbullet

Another blast from the past and I am sure they have other options. I have noticed a few threads that offered DIY plans for a box to cure fiberglass.

https://www.rocketryforum.com/threads/fiberglass-hot-box.18001/
https://www.rocketryforum.com/threads/diy-composite-curing-oven.150939/
https://www.rocketryforum.com/threads/curing-oven-as-if-it-isnt-hot-enough.65484/
Hopefully, this will help you come up with your own plan.

 

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Don't Stretch Electrical Tape

Contributor: @John Kemker
When wrapping anything with electrical tape, it's tempting to stretch it to tear it or stretch it as you wrap. You can stretch it while wrapping it on the intended target, but at the end, do not stretch it. If you stretch it when laying the last inch or two down, it will pull and unwrap.

As you say, keep at least the last couple of inches unstretched.

Agreed, and, if you want the taped joint to last, go ahead and buy good stuff. 3M/Scotch Super88 or something, not generic Harbor freight/Walmart stuff, that seems to just spread sticky, poorly.

 

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Micro-Sponges for Touch-Up:

Contributor: @neil_w

Testors Micro Sponges are excellent for very fine paint touch-up work:

If you want to save a few bucks, you can buy these under micro and dental applicators. The also can double as a disposible glue applicator. Every dollar saved is more you can spend on motors.

 

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This is index #8 for the tip-of-the-day thread.

List of Techniques (Index 8)
�
�

Page 1		Link to page 1 index
Page 2		Link to page 2 Index
Page 3		Link to page 3 index
Page 4		Link to page 4 index
Page 5		Link to page 5 index
Page 6		Link to Page 6 Index
211	30 August 2023	Consider Using Spray Can Handles
212	31 August 2023	Let the fillet material cure a little
213	5 September 2023	Inexpensive Burnishing Tool for Decals
214	7 September 2023	Another Burnishing Tool
215	12 September 2023	Dispensing Powders
216	14 September 2023	Mask when spraying paint
217	19 September 2023	How to flush mount a motor retainer
218	21 September 2023	Tooth Pick or Cotton Tip Applicators
219	26 September 2023	Twist those wires
220	28 September 2023	Finely Ground Powder
221	3 October 2023	CONSIDER A SWIVEL
222	5 October 2023	Removing masking early
223	10 October 2023	Papering fins with label paper?
224	12 October 2023	Sharp Lines Masking
Page 9		Link to the next index

If you have an idea, could you each please help me post tips? Send me any ideas, and I will add them to the list.

Comments or suggestions should be posted here:

TRF Tips and Techniques Comments Thread.​

Guys, we will use this thread for comments and suggestions against the Tip of Day thread in the Techniques forum. This goal is the maximum value and limited side chatter. If you have a comment, post it here and add a link to the post you are commenting about.

 

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Consider using Spray Can Handles:

Contributor: @cwbullet

Old hands can have difficulty pushing down the nozzle on a spray can. I have found that spray can handles that allow you to redirect the pressure from a push to a grasp can be very helpful and prevent hand fatigue. The link above is to the Rustoleum model but there are other versions available.

 

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Let your fillet cure a little:

Contributor: @cwbullet

The knee-jerk reaction is to apply your fillets quickly. Unless you use 5-minute epoxy, I recommend a lower, more deliberate approach. I use the methodology in tip 12 that Crazy Jim taught me. He also told me to let the epoxy mixture cure just a tad before applying it.

A simple measure I make is that if it runs when tilting your applicator, it is too thin and has not cured enough.

 

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Inexpensive Burnishing Tools for Decals

Contributor: @John Kemker

Auto parts stores often carry "Body Filler Spreaders" for spreading bondo, glazing spot putty, etc., onto vehicles. In addition to making great spreaders to even out epoxy, etc., they can be used to burnish decals onto your rocket. Apply the decal as usual, but before removing the paper on the top of the decal, use the body filler spreader to burnish the decal onto the surface of your rocket. It can squeeze or squeegee out air bubbles and give good, even pressure to the decal for best adhesion.

 

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Another Burnishing Tool:

Contributor: @OverTheTop

Another good tool for burnishing is a regular teaspoon. Push your thumb in the spoon's bowl and let the back do the burnishing.

Don't use your significant other's good silver or dinnerware. The couch can be lonely.

 

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Dispensing powders:

Contributor: @prfesser

A tip when dispensing pigments, fillers, thickeners, micro balloons, and chemicals of any sort including fertilizer and foodstuffs in the home. Most people tend to shake or jiggle the container to help the solid come out. Which usually leads to solid flooping out and into the desired container. And everywhere else as well. The finer the powder, the greater the floop and the larger "everywhere else" becomes.

Instead, tilt the container slightly and rotate it gently back and forth on its axis. You'll have much better control. Bigger back-and-forth arcs to dump larger quantities. If practical, place a wide "powder funnel" (e.g., gallon milk jug with the bottom cut off; wide exit needed for solids) on the receiving vessel, to minimize escape of solids.

 

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Wear a mask when Spraying Paint.

Contributor: @John Kemker

All spray paints require a mask. I use waterborne Createx for most of my paint jobs. It still requires a mask that can handle VOCs (volatile organic compounds), as there are acrylics, polyurethanes, acetone, and other nasties in the paints, the reducer I use (humidity issues in Georgia), etc.

Good satefy tip to prevent inadvertently huffing paint.

 

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How to install a flanged motor retainer to a flush-mount MMT

Contributor: @John Kemker

Installing a motor retainer, like the Aeropak, can make it challenging to get the retainer ID to match the MMT ID smoothly. If you have an adapter to let you use a smaller diameter motor in the MMT you're trying to mate to, tape up below the flange of the adapter so it matches the ID of the MMT. Then, you can fit the adapter into the retainer and the MMT and mark and drill the holes for the flanged retainer.



After the flanged retainer is installed, you can remove the tape.

 

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Toothpicks and Cotton Tip Applicator:

Contributor: @cwbullet

Sometimes, you need to add a little glue to a smaller area. Toothpicks can be the perfect tool for small, tight spaces. Do you need a slightly larger applicator? Use the wood end or cotton end of a cotton tip applicator.

Need a huge applicator? Use a fox swab? Those suckers come in 8 and 16 inch versions.

 

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Twist with a drill:

Contributor: @cwbullet

If need to keep wires together, give them a gentle twist with a drill.




If done right, it will stay together and help organize that rat nest.

 

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Finely Ground Powder:

Contributors: @cwbullet @jsdemar @prfesser

Need to grind up a powder such as potassium nitrate? There are lots options.

1. You can grind it up in a ball mill or rock tumbler.
2. You can use a mortar and pestle.
3. Coffee grinder.
4. If you don't have a number 1, 2, or 3 handy, the back of an old spoon rubbed against the material to be ground on an unglazed quarry tile or similar (Jimmy Yawn's method). Only good for very small amounts like the amount would use for a pyrogen, but it works.

WARNING!: Strongly recommend you not grind magnesium or metals.

 

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Consider adding a swivel:

Contributor: @cwbullet

Adding a swivel to your parachute can help prevent tangled lines. Be careful because cheap swivels can break.

For examples:

https://www.rocketryforum.com/threads/sampo-falconry-ball-bearing-swivels.182420/

 

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Remove masking early:

Contributor: @cwbullet

The longer you wait, the more time the paint has to creep, and the more likely you will peel off your paint with the tape. I remove all masking and tapes as soon as possible, often when the paint is still wet.

 

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Papering fins with label paper?

Contributor: @cwbullet with a blast from the past.

I have never done this, but I found while digging through the basement:

https://www.rocketryforum.com/threads/label-paper-lamination.7696/

 

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Shape Lines Masking:

Contributor: @Pinetree

As an addition to:

https://www.rocketryforum.com/threa...hread-twice-a-week.177679/page-8#post-2496004
To add to your last tip, 3M makes a tape called "sharp lines" for clean edges. I bought it by mistake, but man, does it work nice.

 

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Another one to add to the list:

https://www.rocketryforum.com/threads/how-to-attach-e-bay-to-body-tube.172045/#post-2560531