TRF Tips and Techniques Comments Thread.

[neil_w]

I remove the flat slot nozzle and screw on a nozzle from an Elmer's Glue All bottle.
Both glue bottles have matching threads.

TIP: Better Nozzle for Titebond Molding & Trim Glue

Here's a tip suggested by Jeff Roberts (Luke Strawwalker or OL JR) on the Rocketry Forum: "... Grab a few of the regular "school glue" type ...

modelrocketbuilding.blogspot.com

I have found that works fine for TBII but not for Quick and Thick, which clogs up the nozzle pretty quickly.

 

[cwbullet]

Thank everyone. Keep em coming.

 

[KenECoyote]

For keeping shock cords bundled nicely and quickly, I use the small rubber bands used to make bracelets. You can get a pack of 600 for about $5.



It fits well over small and large bundles, it's quicker than tape or crochet and it provides some shock absorption too.

Double it up on small cords. For big cords, it stretches plenty enough for bundles; however, you can double it on smaller bundles to keep it tighter and for more shock absorption.

 

[SolarYellow]

You can also use dental rubber bands (smaller version of the above) for thinner aramid lines with your LPR & MPR recovery rigging.

Knots:
I've been using the "Perfection Loop" (posted a thread around here somewhere with a better method for tying it than illustrated at animatedknots.com) in place of a bowline, but have been thinking I should take another look at the figure 8.

At what point in flatness of cord do you transition from other knots to the "tape knot?" The heavier weights of aramid cord, as seen in the previous post, tend to get oval. Is there a threshold like 1.5:1, 2:1, etc?

Gluing prints:
Having digested the "Properly bonding composites and what your government doesn't want you to know" thread again earlier this week, I wonder whether there might be value in sanding prints in order to "activate" the surfaces and promote chemical adhesion of the glue. Also, I would be amazed if it didn't make a big difference to match adhesive to printing polymer, at least for some materials. For instance, it seems logical that more hygroscopic materials might interact and attain optimum bond strength with different types of adhesives than less hygroscopic materials.

I suspect resin printing is likely to be a whole different situation, since it's thermoset and not thermoplastic. Mechanical activation of the surface may make a bigger difference due to the lower porosity, and the different types of resins may work quite differently with different adhesive types. As well as how well cured the parts are in the first place, etc. I've seen some discussion of leaving resin printed parts without final cure, "gluing" them together with raw resin, and UV-curing the whole assembly at once. Might be worth looking into whether that approach could be used to adhere prints to other materials.

 

[OverTheTop]

I have tried surface-activating ABS prints using flame treatment. I found it to be very process dependent so I abandoned using that method. When it worked it was good, but too hit and miss.

 

[cwbullet]

For keeping shock cords bundled nicely and quickly, I use the small rubber bands used to make bracelets. You can get a pack of 600 for about $5.

View attachment 581464

It fits well over small and large bundles, it's quicker than tape or crochet and it provides some shock absorption too.

Double it up on small cords. For big cords, it stretches plenty enough for bundles; however, you can double it on smaller bundles to keep it tighter and for more shock absorption.
View attachment 581466

Added today.

 

[John Kemker]

Instead of buying Rapid Tac for cut vinyl decal application, you can make a less-expensive solution yourself by mixing distilled water with a surfacant, such as Ilfotol, Jet-Dry, etc. You only need a few drops per liter of water in order to be effective. If you'd like to add cleaning power, add some 90% Isopropyl Alcohol, about 10% by volume.

I use this solution to clean vinyl records with my vacuum system and to apply decals:

LJC home recipe for vacuum record cleaning machines

Last Updated: January 28, 2020 The record cleaning mix muddle Tired of paying £20 for a litre for record cleaning fluid for your Moth, VPI or other vacuum machine and waiting weeks for the postman …

londonjazzcollector.wordpress.com

 

[SolarYellow]

@cwbullet,

Thanks for the mention. You might add a link to my post on an alternative method of tying it.

Perfection Loop knot - another way to tie it

From a discussion of what knot to use in your Kevlar several months ago, I got turned onto the Perfection loop knot as a more secure alternative to the bowline. https://www.animatedknots.com/perfection-loop-knot The problem is, it's substantially more complicated to tie, and there isn't an...

www.rocketryforum.com

The advantage of my method is you can end up with the loop actually passing through something without having to pass that thing through other portions of the knot.

 

[cwbullet]

I missed a few days due to illness. I am trying to get caught up.

 

[neil_w]

Use the reflection from your overhead light as an alignment tool. Here I used it to assist with decal positioning, to keep things aligned with the vertical stabilizer at left (you have to adjust your head position to make sure you keep the reflection in the correct spot; it's a little bit off in this picture, slightly above the vertical stab.)

 

[cwbullet]

Added for today. Thanks, we are up to date.

Use the reflection from your overhead light as an alignment tool. Here I used it to assist with decal positioning, to keep things aligned with the vertical stabilizer at left (you have to adjust your head position to make sure you keep the reflection in the correct spot; it's a little bit off in this picture, slightly above the vertical stab.)
View attachment 583647

 

[SolarYellow]

Paint with a brush.

I did my routine of white primer, grey filler-primer sanded, then white primer, then sanded. There were several little spots scattered around the rocket that needed a bit more filling, but smaller than anything you'd use "filler" or putty on. I really didn't want to sand off another full layer of filler-primer, so I decanted some into a red plastic cup and painted it onto the small spots that needed it with an old hobby/model brush.

It made for a LOT less sanding to knock those spots down to level after it dried overnight and will need to add less white primer (weight and cost - I need to reorder white primer) to cover the grey and get a uniform base for a light color coat.

 

[cwbullet]

Paint with a brush.

I did my routine of white primer, grey filler-primer sanded, then white primer, then sanded. There were several little spots scattered around the rocket that needed a bit more filling, but smaller than anything you'd use "filler" or putty on. I really didn't want to sand off another full layer of filler-primer, so I decanted some into a red plastic cup and painted it onto the small spots that needed it with an old hobby/model brush.

It made for a LOT less sanding to knock those spots down to level after it dried overnight and will need to add less white primer (weight and cost - I need to reorder white primer) to cover the grey and get a uniform base for a light color coat.

Thanks - I added it today

 

[prfesser]

Cutting body tubes:

Holding the knife at a fairly high angle, so that the tip does the work, seems to work much better for me than a low angle, where the body of the blade cuts. It may make a slightly rougher cut but that's why the Flying Spaghetti Monster created sandpaper.

Also, I use those big advertising cardstock "postcards" (junk mail) wrapped around the tube as a guide. With several turns around a body tube they provide a thick edge against which the blade can rest. With my shaky hands I need all the help I can get...

 

[Cape Byron]

Also, I use those big advertising cardstock "postcards" (junk mail) wrapped around the tube as a guide. With several turns around a body tube they provide a thick edge against which the blade can rest. With my shaky hands I need all the help I can get...

I use the Estes tube cutting guides. One of their best products, IMHO.