TRF Tips and Techniques Comments Thread.

[John Kemker]

Don't know if this counts or not:

Two 3D printing tips:

1) Clean your nozzle and hotend on a regular basis. You'll get less messy prints in the long run.

2) To store filaments without having to buy a dry box, Zwilling makes a hand-held vacuum bag system with reusable zip-lock bags. Toss your spool into the bag with a dessicant packet and seal. Use the wand to evacuate all the air and you're done. The pump costs about $70 USD on Amazon and you can get three reusable bags for under $7 USD.

 

[prfesser]

Can you take a camera photo of the end result? I would just like a photo of this addition.

This shroud is slightly larger than on my other batch of ematches. Press the edge of the shroud against a hard surface and rotate it before inserting. The straw will stretch just a bit.

After filling with BP, a wrap of masking tape and pinch closed.

 

[cwbullet]

This shroud is slightly larger than on my other batch of ematches. Press the edge of the shroud against a hard surface and rotate it before inserting. The straw will stretch just a bit.
View attachment 588263
After filling with BP, a wrap of masking tape and pinch closed.
View attachment 588269

I love this concept. I added it today. It is cheap and easy.

 

[prfesser]

Staying cool at summer launches

This is a phase change cooling vest. The inserts are filled with a liquid that freezes at about 60F. Toss the packets in the fridge, freezer, or a cooler of ice. Once frozen they stay at that temperature until essentially all the solid melts, which takes 1-4 hours depending on outside temperature and level of exertion. Increases comfort level significantly.

I just came back from a 40-minute walk at 90 degrees and most of the solid was still there. It probably would have lasted at least another hour and a half.

If possible get a second set of inserts so that one is in the cooler, freezing, while you're wearing the other.

They aren't cheap, around $150-200 with one set of inserts. But if you're outside a lot in summer heat they're well worth it IMHO. (Boo, the scaredy-cat, is not included)

 

[jqavins]

That's very cool, but I have a much cheaper way to take advantage of phase changes to keep cool. You should have a hat to keep the sun off you're head already, and I just put a small handful of ice cubes inside it. In winter, folks will warn you about how much body heat is lost through the top of the head, but in summer that's a good thing. Of course it does make you look like your head is sweating buckets, but if that keeps evaporating then it's another phase change working for you (like sweat is meant to do).

 

[Donnager]

Staying cool at summer launches

This is a phase change cooling vest. The inserts are filled with a liquid that freezes at about 60F. Toss the packets in the fridge, freezer, or a cooler of ice. Once frozen they stay at that temperature until essentially all the solid melts, which takes 1-4 hours depending on outside temperature and level of exertion. Increases comfort level significantly.

I just came back from a 40-minute walk at 90 degrees and most of the solid was still there. It probably would have lasted at least another hour and a half.

If possible get a second set of inserts so that one is in the cooler, freezing, while you're wearing the other.

They aren't cheap, around $150-200 with one set of inserts. But if you're outside a lot in summer heat they're well worth it IMHO. (Boo, the scaredy-cat, is not included)

View attachment 589012

When I drag raced, this would have been an awesome thing to use. In July, in Florida, putting on a multilayer nomex suit, with helmet, and boots for only a few minutes in a closed vehicle in the 4pm sun was not one of my favorite things.

I've used vests that just had ice packs, some cellulose "coolers", and some neck coolers. They worked... a little. This has potential.

 

[OverTheTop]

I just added a post detailing how I heatshrink eMatches so they don't short out on metal charge canisters.
https://www.rocketryforum.com/threads/heatshrinking-ematches.180719/Worth adding to the Tips thread?

 

[cwbullet]

Staying cool at summer launches

This is a phase change cooling vest. The inserts are filled with a liquid that freezes at about 60F. Toss the packets in the fridge, freezer, or a cooler of ice. Once frozen they stay at that temperature until essentially all the solid melts, which takes 1-4 hours depending on outside temperature and level of exertion. Increases comfort level significantly.

I just came back from a 40-minute walk at 90 degrees and most of the solid was still there. It probably would have lasted at least another hour and a half.

If possible get a second set of inserts so that one is in the cooler, freezing, while you're wearing the other.

They aren't cheap, around $150-200 with one set of inserts. But if you're outside a lot in summer heat they're well worth it IMHO. (Boo, the scaredy-cat, is not included)

View attachment 589012

Added for Tuesday.

 

[T-Rex]

If one is prone to possibly become larger, buy a size larger than you need (mine is velcro adjustable). Too expensive to take a chance not being able to use it......
I got one a few years back and wear it mowing the lawn. I can still wear it, but cannot zip it up in the front. (Must have shrunk, I couldn't possibly have gained weight surfing the couch stuffing my face)

 

[jqavins]

(I promise not to go any further along this tangent.) There was one time that I had to do an emergency brake job on my car, in a black paved parking lot, on a sunny 95°, humid day. I not only put ice under my hat, I also soaked a white, long sleeve, all cotton shirt in cold water and wore that. Yes, I finished the brake job with zero (heat related) distress.

 

[kjhambrick]

This shroud is slightly larger than on my other batch of ematches. Press the edge of the shroud against a hard surface and rotate it before inserting. The straw will stretch just a bit.

see pic on post #242: https://www.rocketryforum.com/threads/trf-tips-and-techniques-comments-thread.177678/post-2451409 )

After filling with BP, a wrap of masking tape and pinch closed.

see pic on post #242: https://www.rocketryforum.com/threads/trf-tips-and-techniques-comments-thread.177678/post-2451409

prfessor --

Pure-D genius !

Thanks for the tip !!

I'll be trying this REAL soon now.

-- kjh

p.s. and I've already got some plastic straws in my rocket box.

 

[cwbullet]

prfessor --

Pure-D genius !

Thanks for the tip !!

I'll be trying this REAL soon now.

-- kjh

p.s. and I've already got some plastic straws in my rocket box.

And cheap.

 

[augendoc]

Measure epoxy on a postal scale. Most epoxy I use is a 50/50 mix. This also helps keep the 2 bottles level/equally used. I mix more than I need to make sure I do not run out, and to help rotate supplies. This 15-minute epoxy is over a year old. The mighty toothpick is one of my favorite mixer and applicator tool!

View attachment 564426

Bob Smith epoxy is a 50:50 mix based on volume, not weight. You can weigh brand new bottles or look at the Bob Smith FAQs but the weight ratio is something like 1.19:1 I’ll have go check my notes as to whether is is hardener:resin or resin:hardener.

as for the scale, most of the time you are mixing up small volumes, so consider a scale reading in 100ths of a gram.

 

[jqavins]

Hundredths of a gram is surely more precision than needed, not that it hurts. But don't make yourself crazy trying to get 1.19 rather than 1.17 or 1.21.

 

[augendoc]

Hundredths of a gram is surely more precision than needed, not that it hurts. But don't make yourself crazy trying to get 1.19 rather than 1.17 or 1.21.

I agree on the 1.17-1.21. Ballpark is close and Bob Smith says as much in their FAQs. if you’re going to measure say an ounce of epoxy the 100ths of a gram is overkill. But I’ve found that my 100ths of a gram scale is really reading in 10ths +/- 0.05g. For my boatbuilding I use metered pumps, which is quicker than weighing, but that’s in batches that are greater than an ounce or so. If I’m doing a tiny mix like to fillet a LPR Imight be using only 2-3 grams and my 1/0th g scale doesnt even register until I’v put a gram in the cup. Maybe I should spring for a better scale, but it’s hard to tell the beans from the rat **** with the generic scales on eBay and anything with Ohaus on it is likely to be counterfeit unless I buy from a reputable scientific supply house.

 

[John Kemker]

Plumb fin lines on larger size body tubes.

When drawing lines to cut fin slots or fin attachment points, take a tip from Amos 7:8
“And the LORD said unto me, Amos, what seest thou? And I said, A plumbline.”

Set the body tube on the end away from the fin lines where it hangs off the edge of a table just a bit. Make sure the top of the tube is level. Then, tape a plumbline over your mark where the line is supposed to go. Wait for the plumb bob to stop its oscillations. If you've chalked the line, lightly snap it to transfer the line to the tube. If not, as in my picture below, make a mark along the line so you can line a ruler up between the two marks and get a straight line.

 

[John Kemker]

Flatten Those Warped Fins!

My LOC Warlock has a warped fin. Also, I managed to warp the 1/16" plywood fins for the Dyna Soar Titan booster. Quick search on Google turned up this video:

 

[jqavins]

Necessity is truly the mother of invention, and I invented this today.

I was using the edge of my cutting matt to make layout marks. The problem is, with the piece of cereal box up just enough to see the ruler divisions, you cant see the numbers.

So, I added a strip of masking tape, numbered every inch, and tick marked the half inches.

 

[cwbullet]

Bob Smith epoxy is a 50:50 mix based on volume, not weight. You can weigh brand new bottles or look at the Bob Smith FAQs but the weight ratio is something like 1.19:1 I’ll have go check my notes as to whether is is hardener:resin or resin:hardener.

as for the scale, most of the time you are mixing up small volumes, so consider a scale reading in 100ths of a gram.

added today.

 

[cwbullet]

I did have an idea for packing recovery equipment and organizing it on the field. Use one of these shoe organizers. It will hang from your canopy, and you can roll it up during transportation.

 

[OverTheTop]

I did have an idea for packing recovery equipment and organizing it on the field. Use one of these shoe organizers. It will hang from your canopy, and you can roll it up during transportation.

I think my wife said they use those shoe organisers for organising stuff in some of their crash carts in nursing. They unroll quickly for visibility and access.

 

[cwbullet]

What do you all think of this? Does anyone have another better one?
https://www.rocketryforum.com/threads/cheap-fin-hardening-techniques.84384/
Anyone wanting to know why I do this? I like reviewing old threads and facilitating the conversation.

 

[jqavins]

It looks to me like a mixed bag of partially contradictory, rambling advice. In other words, a typical TRF techniques thread. I think if you want fin treatment tips for hardness, stiffening, and/or strengthening, you could draw from that thread, but you'd have to do some weeding and editing.

 

[cwbullet]

Necessity is truly the mother of invention, and I invented this today.

I was using the edge of my cutting matt to make layout marks. The problem is, with the piece of cereal box up just enough to see the ruler divisions, you cant see the numbers.
View attachment 592279
So, I added a strip of masking tape, numbered every inch, and tick marked the half inches.
View attachment 592281

Add today. thanks.

 

[cwbullet]

Flatten Those Warped Fins!

My LOC Warlock has a warped fin. Also, I managed to warp the 1/16" plywood fins for the Dyna Soar Titan booster. Quick search on Google turned up this video:

added today.

 

[John Kemker]

Can't remember if this has been posted or not:

Aeropoxy PR2032 Laminating Resin with PH3060, PH3660, PH3665, or PH3670 Hardeners

These four resin/hardener combos can be measured volumetrically at a 3:1 ratio, according to the PTM&W website. The one exception hardener, PH3663, must be mixed by weight at a 4:1 (100:25) ratio. Mixing volumetrically for the other four makes it a lot easier to get the ratios correct, especially when glassing an entire airframe.

 

[John Kemker]

Save Your Reload Packaging!

Loki 38mm reloads come in tubes that are perfect for 38mm motor mounts. Save them after you've used the reload.

 

[jqavins]

Others have mentioned putting the top from a white glue bottle onto a yellow glue bottle to use the smaller tip. Note that an Elmer's top fits a Titebond bottle.

 

[OverTheTop]

https://www.rocketryforum.com/threads/tips-and-technique-of-the-day-thread.177679/post-2466800
I'll make a comment that tinning wires that go into terminal blocks is not recommended. The solder creeps under pressure and can lose contact with the terminal over time. The wire also flexes where the solder stops and if the wire is moved or suffers vibration it can break at that point.

If you do tin the ends, support the wire and check that they haven't failed at the bend points, and tweak the screw on the terminal block occasionally.

Ferrules are the preferred method, with just twisting the wires the second. You can pick up a set of ferrules and a crimper for about $20 on eBay.

 

[OverTheTop]

Consider Where You Want Your Excess Glue to Go

When gluing two parts together, there is usually an inside part (eg coupler) and an outside part (eg airframe). Carefully consider where you apply the glue before mating.

• If you apply the glue to the inside of the outer part then the excess glue goes inside the assembly when you mate them.
• If you apply the glue to the outside of the inner part then the excess glue stays on the outside of the assembly.

Think about this up front, in regards to how you want the joint finished, cleanup, and any other requirements you may have.