Painting 3D printed rail guides: Yes or no?

[overklock]

Hey everyone, here with another question.

Anyone ever have any issues painting their 3D printed rail guides? Would it cause any issues during launch?

I've always painted my launch lugs on both low and mid power rockets and never had an issue, but obviously the friction fit on rail guides is going to be a bit different.

 

[Hobie1dog]

being plastic, I'd use an adhesion promoter first.

 

[overklock]

being plastic, I'd use an adhesion promoter first.

Would painting it contribute to any kind of additional friction when leaving the rail?

 

[Hobie1dog]

with all those ridges on the one pictured, paint would be the least of the problems.

 

[overklock]

with all those ridges on the one pictured, paint would be the least of the problems.

Hah - was honestly thinking the same but wasn’t sure. I’m sure the paint will chip off over time but that’s fine

 

[Hobie1dog]

Hah - was honestly thinking the same but wasn’t sure. I’m sure the paint will chip off over time but that’s fine

I'd use some files or something to smooth the contact surfaces

 

[teepot]

I have painted rail guides without issues. Paint the rail buttons too.

 

[reddrock]

Careful where you use 3D printed rail guides. With a high speed liftoff they can warp.

 

[overklock]

Careful where you use 3D printed rail guides. With a high speed liftoff they can warp.
View attachment 548213

No kidding. That’s quite the warp. Makes sense considering PLA had a relatively low melting point. I’ll have to keep that in mind… maybe just buy some 1010 rail buttons next time

 

[ThirstyBarbarian]

I have one set of 3D printed rail guides on one rocket that I painted and have not had any problems, but I don’t know what the plastic is. It’s a product I bought, so presumably it’s made of something that can stand up to that use.

I own another set of printed guides that I’ve decided I probably won’t use. I don’t know what the plastic is, but it’s not the same as the other set, and it just feels like it’s not ideal for the application. Those I got from a friend, and I’ll check with him before I chuck them.

Usually I use aluminum rail guides. I always paint them. They work great. Here’s where I get them. https://giantleaprocketry.com/products/acme-rail-guide-3-00in

 

[mbeels]

I've used Wildman's 3d printed conformal rail guides, and they've worked fine for me. I like the hole for a screw.

https://wildmanrocketry.com/products/conformal-rail-guides-2pk?_pos=7&_sid=79d03f691&_ss=r

 

[cwbullet]

with all those ridges on the one pictured, paint would be the least of the problems.

Not an Issue. I have flown this design many times. They fly well. Any ridges in the way wear off in the first 2 feet of the rail.

 

[BigMacDaddy]

Is there a big benefit to having them slotted / open inside? I just make my lugs solid.

 

[cwbullet]

Is there a big benefit to having them slotted / open inside? I just make my lugs solid.

No, outside of less filament. I have tested both.

 

[Hobie1dog]

If we're micro-analyzing them for the lowest friction, then making them out of Teflon is the way to go. Can you make them out of that with a 3D printer?

 

[Banzai88]

If we're micro-analyzing them for the lowest friction, then making them out of Teflon is the way to go. Can you make them out of that with a 3D printer?

Yes, but it takes some highly tuned near- or industrial level equipment with high power extruders (hot end) and tightly temp controlled chambers to do successfully and reliably. Even though PTFE has a glass transition temp of about 115C, consumer PTFE filament temp is usually spec'd somewhere around 285C+ and bed temps are 100C+ and is really a blend of PTFE and PC (Polycarbonate). Essentially, an order of magnitude higher temps than the usual range of the home printer, and about $60ish for 500g rolls of filament.

My work has some in the print shop, and even with the best of set ups and all top end equipment, the engineer there almost never gets a successful print. Thankfully, most of the teflon parts that we need are faster and easier to produce in the machine shop across the hall.

But if you look up true industrial pure PTFE 3D printing, it's usually only offered as a service because to do it with true dimensional stability, it is a multi step print process and a multi step post production cure that takes up to a week to equal the equivalent material properties of a homogenized block of Teflon.

 

[KenECoyote]

Is there a big benefit to having them slotted / open inside? I just make my lugs solid.

A bit of benefit from drag reduction from what I read. See page 17.

https://www.apogeerockets.com/downloads/PDFs/launch-lug-drag.pdf

 

[KenECoyote]

Careful where you use 3D printed rail guides. With a high speed liftoff they can warp.
View attachment 548213

Is that PLA or ABS? I would generally use ABS for buttons and guides for the higher melting point and better durability.

Disclaimer: I haven't printed nor used 3d printed ones yet, but plan to do so soon.

 

[Banzai88]

Is that PLA or ABS? I would generally use ABS for buttons and guides for the higher melting point and better durability.

Disclaimer: I haven't printed nor used 3d printed ones yet, but plan to do so soon.

One of the benefits of 3D printing anything is that it doesn't really matter what you print it from, as long as it lasts as long as you want it to. I mean, you can print them for pennies, and can do it with machine time overnight when you're sleeping. Who cares if you change them every season, at the rate that most people launch any single rocket, when it's 10 minutes of machine time per button and $.0345 of filament, seasonal changes to have 'perfect rail buttons every season' become a realistic option.

That said, I print mine in PLA+ or PETG, and a build plate worth of them once a year is nearly a lifetime supply. I literally hand them out like Tik Taks at my launches (along with free dog barf in plastic containers that used to hold 40 ounces of dog treats).

 

[KenECoyote]

One of the benefits of 3D printing anything is that it doesn't really matter what you print it from, as long as it lasts as long as you want it to. I mean, you can print them for pennies, and can do it with machine time overnight when you're sleeping. Who cares if you change them every season, at the rate that most people launch any single rocket, when it's 10 minutes of machine time per button and $.0345 of filament, seasonal changes to have 'perfect rail buttons every season' become a realistic option.

That said, I print mine in PLA+ or PETG, and a build plate worth of them once a year is nearly a lifetime supply. I literally hand them out like Tik Taks at my launches (along with free dog barf in plastic containers that used to hold 40 ounces of dog treats).

Thanks for that insight! Since I haven't had experience with this, I was defaulting to what would be strongest for an extra measure of safety, but actual experience is better.

So do you print them for HP and would you mind providing or directing me to the file(s) you use?

Thanks!

 

[Banzai88]

Thanks for that insight! Since I haven't had experience with this, I was defaulting to what would be strongest for an extra measure of safety, but actual experience is better.

So do you print them for HP and would you mind providing or directing me to the file(s) you use?

Thanks!

Yes, for HP, no issues. I replace them as necessary, never had one fail on a launch. I consider them consumables, just like batteries, igniters, and DD initiators.

I use the Jack Hydrazine files for a lot of things, dozens of permutations in his library on Thingiverse:Click here for the rocket part library of Jack Hydrazine

Click here for basic rail buttons

 

[BigMacDaddy]

A bit of benefit from drag reduction from what I read. See page 17.

https://www.apogeerockets.com/downloads/PDFs/launch-lug-drag.pdf

A bit of benefit from drag reduction from what I read. See page 17.

https://www.apogeerockets.com/downloads/PDFs/launch-lug-drag.pdf

Thanks for sharing that -- I am unclear on why the coefficient of drag is lower but the force is higher for the flat top rail guide.

I would take the durability / strength gain over that tiny increase in drag (bet the solid ones are much less likely to distort or melt -- also suspect the melting shared in that picture might be as much the slotted lug being bent /distorted and then being partly forced into the slot in the rail as it is melting due to friction).

 

[jmasterj]

One of the benefits of 3D printing anything is that it doesn't really matter what you print it from, as long as it lasts as long as you want it to. I mean, you can print them for pennies, and can do it with machine time overnight when you're sleeping. Who cares if you change them every season, at the rate that most people launch any single rocket, when it's 10 minutes of machine time per button and $.0345 of filament, seasonal changes to have 'perfect rail buttons every season' become a realistic option.

That said, I print mine in PLA+ or PETG, and a build plate worth of them once a year is nearly a lifetime supply. I literally hand them out like Tik Taks at my launches (along with free dog barf in plastic containers that used to hold 40 ounces of dog treats).

Do you attach yours with screws? I want even my 3D printed rail guides to last a while because I epoxy them on. I print everything in ABS, though, because we have fancy printers at work that are easy to use.