3D Printing I ... may have made a mistake.

[dhurstell]

So I have an beautiful OOP Estes Vagabond (the Mid Power one from the early 2010s), but had some crushed body tubes when I opened it.

Instead of trying to build it as a mid-power flier, I decided she needs to be a minimum diameter 38mm machbuster... I hit up ole Soller Composites for a CF/FG weave sock and wrapped the body tube

... but in a moment of genius, I thought to 3D print out an internal liner/stiffener that would provide some friction for the RDS Id like to use and keep the BT in full roundness for the glassing operation.

Pulled out my brand new flashforge 5m 3d printer and made myself the part as described. Stuffed it up the backside and liberally applied some JBweld to hold it in place.

So, after about 3 weeks of having this amazing machine, I learn that there are different filaments... and they have different mechanical properties including the temperature ranges where they fail... and THEN I remembered that rocket motors get hot... like VERY HOT... like TOO HOT TO TOUCH after lying in a field for 20 minutes while you hike to collect it hot.

Now I am VERY concerned about regular ole PLA being used as essentially a motor-mount tube on a 38mm "I" motor.

This leaves me in dire need of feedback dear forums... Is my project totally screwed? If its ok on the heat.. GREAT! If its NOT ok on the heat.. is there ANYTHING anyone can imagine I can do about getting it OUT of my body tube?

 

[OzHybrid]

DO NOT USE PLA FOR A MOTOR MOUNT.!!
PLA is easy to print, unfortunately, the melting point is below the temperature a motor casing will get to.
You could use a holesaw and cut out the core.
Make a sketch of what you've printed with sizes for a more accurate guess.

 

[ShadowSpire48]

Sorry but you are gonna need a new Vagabond. PLA won’t hold up and you will never get the JB Weld out of there without damaging something badly. Nothing really in terms of filament will hold up to a high power motor for heat when used as a motor tube aside from like PC or nylon and even then.

 

[OzHybrid]

The sim that's on Rocketreviews doesn't look right. Should the fins be more angled at the rear?
https://www.rocketreviews.com/estes-estes---vagabond-1682.html

 

[dhurstell]

The sim that's on Rocketreviews doesn't look right. Should the fins be more angled at the rear?
https://www.rocketreviews.com/estes-estes---vagabond-1682.html
View attachment 675414

This is more what I have in mind, and I have a more accurate (not not perfectly accurate, fin design)

 

[K'Tesh]

Have you tried my sims of the Vagabond?

 

[OzHybrid]

This is more what I have in mind, and I have a more accurate (not not perfectly accurate, fin design)
View attachment 675416

Are the fins on this through the wall to the motor mount or surface mounted?

 

[dhurstell]

A death sentence and a blow to the heart...

I LOVE this rocket, and these kits a UBER hard to find... the nosecone is pretty non-standard... even the OR files above dont seem to have the correct NC.

Maybe I can get some centering rings and a 29mm MMT. Then maybe use some foam as insulation from the motor heat.

 

[OzHybrid]

Have you tried my sims of the Vagabond?

View attachment 675419

View attachment 675418

That looks better....

 

[OzHybrid]

A death sentence and a blow to the heart...

I LOVE this rocket, and these kits a UBER hard to find... the nosecone is pretty non-standard... even the OR files above dont seem to have the correct NC.

Maybe I can get some centering rings and a 29mm MMT. Then maybe use some foam as insulation from the motor heat.

I've got an Arreaux. One of the reasons I started 3D printing was the unobtabium nature of 1.6" parts.....
Do a hand sketch of what you've done. Doesn't need to be pretty or straight lines, just understandable.
Hopefully there will be a solution to your problem.

 

[dhurstell]

Are the fins on this through the wall to the motor mount or surface mounted?

They will be surface mounted.

 

[bad_idea]

Assuming you can't knock the mount out, just buy some replacement BT-60 from BMS, and if you plan to fly it with 38mm motors, buy some BT-60 coupler too. The ID of BT-60 coupler is nearly identical to that of 38mm motor mount, and BMS sells it in 34" lengths.

 

[dhurstell]

A death sentence and a blow to the heart...

I LOVE this rocket, and these kits a UBER hard to find... the nosecone is pretty non-standard... even the OR files above dont seem to have the correct NC.

Maybe I can get some centering rings and a 29mm MMT. Then maybe use some foam as insulation from the motor heat.

NAY! Not a death sentence.

I forget which jedi master or whoever said it.. but change your perspective!

I have one whole virgin end of tube to work with!

A SIGNIFICANT amount of effort already went into this tube... so I dont want to lose it, or chop it up and rearrange it if I can avoid it.

The Motor end can just become the DUAL DEPLOY AV bay.

The JB weld was only applied several inches into the tube, so I SHOULD be able to remove some of the PLA, and might not even have to redesign my AV bay to fit a smaller diameter.

So, my gentle experts... do we have any ideas for the fitup in this tube if I cannot use ANY filaments? (This may be straying off topic now).

 

[dhurstell]

Assuming you can't knock the mount out, just buy some replacement BT-60 from BMS, and if you plan to fly it with 38mm motors, buy some BT-60 coupler too. The ID of BT-60 coupler is nearly identical to that of 38mm motor mount, and BMS sells it in 34" lengths.

Just what I was asking for... thanks!

 

[Glasspack]

Edited: Oops ...... Need to reverify my inventory

 

[dhurstell]

DO NOT USE PLA FOR A MOTOR MOUNT.!!
PLA is easy to print, unfortunately, the melting point is below the temperature a motor casing will get to.
You could use a holesaw and cut out the core.
Make a sketch of what you've printed with sizes for a more accurate guess.

Any chance you think I could use a heat gun to melt out the PLA???

 

[OzHybrid]

Any chance you think I could use a heat gun to melt out the PLA???

Put it in the oven and take it up to the glass temperature for PLA and you should be able to pull it out. 80decC should do it.

 

[DocSeuss]

Have you tried my sims of the Vagabond?

View attachment 675419

View attachment 675418

Is the newer one using the PNC-60RL? Does anyone sell that cone anymore?

 

[K'Tesh]

Is the newer one using the PNC-60RL? Does anyone sell that cone anymore?

Yes. And unless Estes has changed the NC Assortment recently... Yes.

 

[dhurstell]

Put it in the oven and take it up to the glass temperature for PLA and you should be able to pull it out. 80decC should do it.

THANKS!!!

 

[cwbullet]

Is the newer one using the PNC-60RL? Does anyone sell that cone anymore?

Google reveals:

https://www.siriusrocketry.biz/isho...ETXtKyGL_TclVkgIbSrq5NL2BsniU_TEYty65dFCyUNKH

But you can get it from the multipack:

https://estesrockets.com/products/nc-60-long-nose-cone-asst-3-pk?_pos=4&_sid=b21191e49&_ss=r

 

[cwbullet]

Very nice laminating work.

 

[dhurstell]

Google reveals:

https://www.siriusrocketry.biz/isho...ETXtKyGL_TclVkgIbSrq5NL2BsniU_TEYty65dFCyUNKH

Thanks!

 

[dhurstell]

Got the PLA out, now back to our regularly scheduled build. I'll have another thread related to printing and lamination of fins.

 

[cwbullet]

Got the PLA out, now back to our regularly scheduled build. I'll have another thread related to printing and lamination of fins.

Good call. In general, for beginners, ABS and PETG are better for rocketry. You might also be able to get away fro PLA+ or Pro in northern climates.

 

[bad_idea]

Assuming you can't knock the mount out, just buy some replacement BT-60 from BMS, and if you plan to fly it with 38mm motors, buy some BT-60 coupler too. The ID of BT-60 coupler is nearly identical to that of 38mm motor mount, and BMS sells it in 34" lengths.

Just what I was asking for... thanks!

Someday I plan to build one of the Star Orbiters from the Estes bonanza two years ago, probably shortened to a single tube, for shorter 38mm motors. This is what I'll do, probably running the coupler all the way to the nose cone shoulder.

Edit to remove my possibly incorrect speculation on the interactions between supersonic shock waves and leading edges; definitely a subject I need to study.

Good call. In general, for beginners, ABS and PETG are better for rocketry. You might also be able to get away fro PLA+ or Pro in northern climates.

This is true, but for a motor mount where a cardboard part is available, I'd still opt for cardboard, and BT-60 coupler is perfect for this in a BT-60 body.

 

[dhurstell]

Someday I plan to build one of the Star Orbiters from the Estes bonanza two years ago, probably shortened to a single tube, for shorter 38mm motors (for I doubt that even with some heavy fiberglassing I'm brave to challenge Mach 1.4, at which speed the shockwave angle crosses over the 45° angle of the leading edge of the fins). This is what I'll do, probably running the coupler all the way to the nose cone shoulder.

This is true, but for a motor mount where a cardboard part is available, I'd still opt for cardboard, and BT-60 coupler is perfect for this in a BT-60 body.

Already put in my BMS order

 

[OzHybrid]

THANKS!!!

I didn't want to say use a heat gun as they can get pretty hot. At 80 degC you were above the glass temperature for PLA but below the glass temp for the fiberglass resin( about 120-150C depending on how long it had been curing and the resin brand.
Good luck with your rebuild.

 

[ZeroGPrints]

Because you do not have an enclosed printer I recommend trying PETG. It is easy to print once you tune it. You should still, if possible, use a cardboard tube for the motor mount.

 

[dhurstell]

Because you do not have an enclosed printer I recommend trying PETG. It is easy to print once you tune it. You should still, if possible, use a cardboard tube for the motor mount.

Thanks. I did print an enclosure for my printer now... Unsure what other upgrades are necessary for ABS or ABA