3D Printing Back into 3D printing with a 4" Fat Boy

[RCBrust]

I've always wanted a 4" Fat Boy so I recently pulled out the old Lulzbot Mini, dusted it off and started experimenting. I have a couple different projects in mind that require threads so I started playing around with that in PLA and tweaked things until I had those working well. Then I printed a threaded nose cone in PLA and that came out quite nicely. I know that PLA is pushing it for outdoor use in the heat so I sat one out in the sun on a 90 degree day and it did start to get soft. I tried some prints in PETG and they also came out nicely but between the flexibility of the prints and the stories that I've heard about getting paint to stick to it, I decided to bite the bullet and go right to ABS. I've printed ABS in the past but nothing sizable where warping would be an issue.

The two pics below are my first attempt at a full nose cone in Polymaker PolyLite ABS. The print chamber is not fully enclosed but I did prop up some cardboard around the printer to help stop any drafts. I want to eventually have an adjustable nose weight system so that's the reason behind the screw-on coupler. The next steps are to add that nose weight system to the model, and to put together a better enclosure out of cardboard or foam board so that I can get the print chamber up to 40-50C.

I've also been keeping my eye on recent printer developments to try and find my next printer. With all of the offerings out there, it's easy for analysis paralysis to set in. Right now, the Voron and RatRig machines appear to offer pro-level components and performance at a reasonable price. I'm in no rush though, still having fun with the old Lulzbot.

Randy

 

[cwbullet]

Very nice. Thought about uploading the stl files?

 

[RCBrust]

Very nice. Thought about uploading the stl files?

It's still a work in progress. I'll post them when it's completed.

Randy

 

[Zyzzyva1000]

I know this thread is a couple months old, just curious if you made any further progress with this, I have fond memories of my old Estes fat boy when I was in middle/high school.

 

[RCBrust]

I'm still playing around with it, and putting time into researching a new printer.

Randy

 

[RCBrust]

Here is my latest iteration. This version has the U-bolt inset to give more room for recovery gear. The top of the coupler also has a well so that nose weight (epoxy and BBs) can easily be added. The well has serrated sides to lock the epoxy in. You'll notice that around the U-bolt the surface is rough from the supports. That will have to be sanded to pretty it up. That's the only area in the whole print that requires supports.

The first pic shows a cross section of the CAD model. Note that the shape is not a simple ellipse. This is a true Fat Boy nose cone shape. The STLs are attached. The print in the pics is gray Polymaker ABS.

Randy

 

[RCBrust]

Sanded down with 100 grit paper. A little micro-balloons and CA on the tip to fill in a blemish. Ready for primer.

Randy

 

[Jeremy Sim]

Lovely

 

[RCBrust]

A coat of white primer, some spot putty, then sanded down. The Dupli-Color White Sandable Primer (DAP1689) dries pretty hard. It was sandable, but I wouldn't say easily sandable. I'm going to try a coat of the Dupli-Color red filler primer (FP102) next. The white primer will make a good final primer coat before paint.

Randy

 

[RCBrust]

Here it is with the red filler primer (FP102). This stuff is really nice. Excellent coverage. I got nice thick coverage with just two coats. The majority of this will get wet sanded off with 400 grit paper, then a coat of the white sandable primer (DAP1689) and it should be ready for the color coats.

Randy