The only thing PP sticks to is PP. I.e. you need a bed with PP film or a PP
sheet on it.

On Sat, 3 Jul 2021 at 21:09, Gene Heskett gheskett@shentel.net wrote:

Am Sa., 3. Juli 2021 um 22:22 Uhr schrieb nop head nop.head@gmail.com:

definitely! There is NO comparison to PETG! It is  c.o.m.p.l.e.t.e.l.y
different. Additionally PP has stronger warping. I have very good
experience with PP adhesive film
https://smile.amazon.de/gp/product/B001AVL0Y8
Look at this Foto: it warped like crazy but still sticked to the bed and
the print could be ended and I can use this master spool.
[image: 55FD34D8-7A7B-451B-A879-479F036EDDA1_1_105_c.jpeg]

On Saturday 03 July 2021 16:21:43 nop head wrote:

But Magigoo is supposed to work with PP.

But I'm now back to PETG, which was working great with a 50C bed
thursday. Now, after all the treatment, even sanding with 320 grit to
recover from that $100 debacle, nothing sticks.  At any bed temp.

But I am slowly developing a theory, and it looks like I have composed in
OpenSCAD, an object cura cannot print. This spline ring code:

module innerspline()
{// PETG now on printer, PolyProp (PP?) has arrived. And its a disaster,
went back to PETG
// and the nozzle troubles started, plugged up whole damned hotend. 3
times so far
//  Magicgoo for PP must be very caustic warnings galore
// new example, low ratio 30/1 harmonic drive floating splined belt.
teeth = 60; // define number  of teeth
arcx = ( 360 / teeth ); // arc of circle per tooth
$fr = 0.000000;
// adjust this to just barely get an overlap at inner corners of spline
triangle
toothdia = arcx/1.60;
// adjust this for outer teeth fit in internal spline
toothrad=53.5 / 2.000;// make radius was 53.0, reduce backlash but dont
compress it either
// adjust this to thin or thicken flex valleys
linerdia=51.7; // thins web at bottom of spline, helps flex if larger,
was 52.2
height=12;
tranz=height / 2.000;
echo (177,teeth,arcx,toothrad,linerdia) ;
difference()
{ // inside smoother
// make splines first
for($fr=[ 0: 6 : 359 ])
{ //can't pass $fd to this for, why?
rotate([0, 0, $fr]) // works, finally
translate([toothrad, 0, tranz])  // mv x=[$lr + $r1] y,z=0
cylinder(d=toothdia, h=height, $fn=3, center=true);
};// made triangle
// above is first of difference now subtract a smoothing inner liner
translate([0,0,tranz])
cylinder(d=linerdia, h=height+.01, $fn=360,center=true);
}; //but the innards needs smooth finish
};

generates the 60 splines, then trims the inner face smooth, removeing the
bottoms of the splines infavor of a 1 degree of straight lines=fine
inner finish.

But cura renders just the outer facing portion of the tooth, doing 60 6mm
retractions at the end of each "tooth", then lays down the inner wall
ring, with the nozzle so close to the V it laid down that it catches the
top of the V and knocks it loose, ruining the print so I might as well
kill it. I even reverted to the last 4.9.1 version of cura from 4.10.0
But it had no effect on this.

But, 4.9.1 printed 3 of these and a 6 pack of bearing races thursday with
none of these problems, the only cleanup was the bump where cura did a
turnaround, and I've a dremel ball diamond thats just the right size to
remove those bumps, 5 minutes or less per race pair.

The only REAL change to this code since thursday, is the thickness of the
web connecting the bottoms of the teeth. Then it was about 2mm thicker,
which made the thing too stiff to survive the flexing. I'm about to
rewrite it, to make the smooth inner liner into a 1mm thick ring, and
make that a union with the base of the spline just to see it that will
fix cura. But before I do that, I want 2 good, matching, bearing race
pairs, which were failing in 10 minutes running at 2k+ rpms, because the
plastic web was so thin at the bottoms of the ball grooves that the
outer ring was breaking at the bottom of the groove. So the size of the
groove was better matched with the bb, and the code changed to allow a
thicker outer ring, but that affects the final size of everything
outside of that bearing, including this part which rides on the OD of
those bearings with zero clearance, and this part is adjusted to remove
as much stretching stress as possible while not needing a drop or 2 of
superglue to lock them togeher.  But printer/cura problems are very
discouraging.

Will my union idea fix cura from thinking the tooth and the liner ring
are 2 separate items? All those hundreds of retractions only plugs up
the printhead.

Thanks everybody.

[...]

Cheers, Gene Heskett

"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.

• Louis D. Brandeis
  Genes Web page http://geneslinuxbox.net:6309/gene

On Saturday 03 July 2021 16:42:11 dpa wrote:

nop.head@gmail.com:

That is an impressive amount of warping!

wrote:

It wouldn't do the bearing either, I rehomed it to reset the starting gap
and that is when I twigged on the fact that the side fan snoot was
dragging on the build plate, so I wedged the putty knife under it and
loosened all 5 of the screws which mount the fan and cover since the
replacement for the broken fan arrived yesterday, and retightened them,
and now it clears the plate by about a mm. But it went right back down,
so I removed it, and found it was warped by contact with the hot block.
It was doomed the instant I dialed up the higher nozzle heat for
something hotter than PLA.

The printer actually worked fine w/o the fan, so I left the %#@&^ snoot
off.  Rehomed it about .4mm closer to the bed since the primer run up
the left edge measured .55mm, shoulda been about .2mm and its working
normally now, building a bearing race pair. Thermoplastic casting, 2
parts snap together, cost me 2 damn days screwing with it. I think its
evident I am not a happy camper.

Thanks for reading my off-topic rant.

Cheers, Gene Heskett

"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.

• Louis D. Brandeis
  Genes Web page http://geneslinuxbox.net:6309/gene

On 07-03-2021 4:21 PM, nop head wrote:

I've had excellent results printing polypropylene using clear packing
tape (commonly used to seal cardboard boxes) stuck to the bed.  No heat
on the bed and no cooling of the hot end needed.

            - Michele

That will be because sellotape is made from polypropylene.

On Sun, 4 Jul 2021 at 17:03, Michele Denber mdenber@gmx.com wrote:

On Sunday 04 July 2021 12:03:45 Michele Denber wrote:

Thanks Michele, I'll give that a shot when this project is done.

I decided to throw money at it, again, so by late wednesday there s/b a
biqu hx sitting on that table, smaller than the CR10, no bowden tube but
all the other bells and whistles. And about $150 cheaper.

Cheers, Gene Heskett

"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.

• Louis D. Brandeis
  Genes Web page http://geneslinuxbox.net:6309/gene