Issus
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- Aug 27, 2012
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I've been wanting to do a 2 stage black powder rocket for awhile now, both minimum diameter and with the coupler/transition, nosecone and fins all 3d printed from ABS treated with acetone vapour to make it smooth and glossy. Seeing as the rocket sims to a little over 1000m (3000ft) I figured it would pull a disappearing act, hence the name.
This is the design in SolidWorks:
I started by printing the transition/coupler. This is probably the most critical part - and due to ABS shrinkage, one of the trickiest. The coupler obviously needs to fit in the 24mm body tube snugly, but also hold the 18mm motor without too much slop as well.
It's printed mostly hollow to reduce weight at the back.
About 1.5hrs later, the part is finished, printed in 0.1mm layers.
I ended up needing to reprint this part 2% larger due to the shrinked I mentioned previously.
The tape is to stop the acetone from ruining my nice ribbed finish for optimal gluing. The wires are 0.2mm solder for lowering the part into the acetone vapour.
Next up, Nosecone:
I needed nose weight to get stability, so I'm using much higher infil on the nose:
You can see the shiny coupler at the back in this shot. I've got it sitting next to the heated bed to assist the acetone vapour remaining in the top layer of ABS to gas off. After about 2 minutes the part is about the equivalent of "touch dry" depending on how long it was immersed in vapour - after a day or so the part is free enough of solvent to be considered hardened. You can think of it like painting the part as far as the finish is concerned.
I'm still tuning the settings after upgrading my heated bed and fixing up my fan setup, so the top 5mm or so of the nosecone came out a bit squishy. Nosecone took about 3hrs at 0.1mm/layer.
I filed this smooth before giving it a vapour bath. Once it's treated, you can't tell any work has been done on it.
Next up is the fins. I was a bit worried about these, as they are 1.8mm wide, or just over 4 wall thicknesses total. These are printed with 100% fill:
You can see the layers clearly on the leading edge
Once it's finished with solvent however, it's completely smoothed out. All the fins take about 15-20mins each.
Booster fins:
The step is an artefact of going to one wall thickness, this "feature" is on the final rocket and makes it look like a control surface.
I was bored so I took 1.5hrs out to print a tube cutting tool for 18mm
I also printed a fin alignment guide
And finally the rocket is finished (with the alignment guide holding the fins in place
With the booster
The rocket took about a day to print, including the "tools" and reprints.
Finished rocket on the launch rod at todays launch
And the last time I ever saw it:
We found the booster motor, but neither the booster or the rocket.
This is the design in SolidWorks:
I started by printing the transition/coupler. This is probably the most critical part - and due to ABS shrinkage, one of the trickiest. The coupler obviously needs to fit in the 24mm body tube snugly, but also hold the 18mm motor without too much slop as well.
It's printed mostly hollow to reduce weight at the back.
About 1.5hrs later, the part is finished, printed in 0.1mm layers.
I ended up needing to reprint this part 2% larger due to the shrinked I mentioned previously.
The tape is to stop the acetone from ruining my nice ribbed finish for optimal gluing. The wires are 0.2mm solder for lowering the part into the acetone vapour.
Next up, Nosecone:
I needed nose weight to get stability, so I'm using much higher infil on the nose:
You can see the shiny coupler at the back in this shot. I've got it sitting next to the heated bed to assist the acetone vapour remaining in the top layer of ABS to gas off. After about 2 minutes the part is about the equivalent of "touch dry" depending on how long it was immersed in vapour - after a day or so the part is free enough of solvent to be considered hardened. You can think of it like painting the part as far as the finish is concerned.
I'm still tuning the settings after upgrading my heated bed and fixing up my fan setup, so the top 5mm or so of the nosecone came out a bit squishy. Nosecone took about 3hrs at 0.1mm/layer.
I filed this smooth before giving it a vapour bath. Once it's treated, you can't tell any work has been done on it.
Next up is the fins. I was a bit worried about these, as they are 1.8mm wide, or just over 4 wall thicknesses total. These are printed with 100% fill:
You can see the layers clearly on the leading edge
Once it's finished with solvent however, it's completely smoothed out. All the fins take about 15-20mins each.
Booster fins:
The step is an artefact of going to one wall thickness, this "feature" is on the final rocket and makes it look like a control surface.
I was bored so I took 1.5hrs out to print a tube cutting tool for 18mm
I also printed a fin alignment guide
And finally the rocket is finished (with the alignment guide holding the fins in place
With the booster
The rocket took about a day to print, including the "tools" and reprints.
Finished rocket on the launch rod at todays launch
And the last time I ever saw it:
We found the booster motor, but neither the booster or the rocket.
