Plexiglas painting anomaly

[scottp55]

Interesting Xxray.
Thanks for posting that test!
scott

[Xxray]

I think I found a repeatable solution here, finally - And I thank members here for steering my mind towards this solution.

Its called "Liquitex Professional Spray Paint" and is water based, available from dick blicks, Michaels ect. Drys in a couple of hours, clear has no ill effect on it, looks real nice. I did one original style and did one in yellow with a revised saw blade, not sure which one I like the best. But 0 crackling issues, and minimal cure time so really the best of both worlds. Only downside is it costs 3x more that rustoleum, but thats a small price to pay for avoiding the crackling issues - I estimate I can do 4 with 1 can.

Still have issues with my pockets, I don't understand it. You can see there are still lines and little streaks of black within the colored pockets. I think what is happening is the drag bit is mushing/melding in the paint to the plexi, leaving contamination that won't come off. Possible solutions:

* Longer cure time, if its completely dry this shouldn't be an issue
* Doing another pocket pass to scrape off the ingrained contamination
* Use a vbit instead, an actual cut instead of an etch should not leave residue

Think I'll try the Vbit first and see what happens. I just have to avoid going to deep, I still want to only scratch the surface. With lettering and lones this fine, going too deep will obliterate details.

[Mobius]

I'm loving the yellow one, it just 'pops' more to me.

[Xxray]

Am forced to agree, it is considerably more vibrant. The pocketed circle also makes it stand out more than the other.

I like the new blade but it is too thin, I tried copying it and shrinking the copy so I could pocket it, but apparently thats not the ways its done with things with lots of angles, unlike a square or circle. The smaller one doesn't come close to mirroring and fitting into the larger one, will take a bit more work than just that.

[Ms Wolffie]

How about offsetting it?

[scottp55]

Xxray,
I can't remember if at any stage you tried an actual engraving bit?
Wondering if it might help in this example to prevent"mushing paint"?
Just wondering.
Also wondering if a 2F would let you keep you speed up vs a D type.
http://www.ebay.com/itm/30-degree-bits- ... 1747562336
I can't use the .006" flat ones myself, as kept breaking tips in Bloodwood at .08" passes, but we use the standard .012" flat 30 degrees All the time
with wonderful results.
Maybe worth a shot for your application rather than a fully sharp tipped VBit?
scott

[Xxray]

Have hit upon a permanent solution, didn't happen the way I expected, but CNC is full of surprises.
I will as per my style explain in depth.

I tried a vbit on some scrap, did the hammers. Didn't look too sharp, lost some detail and was still opaque.
I do have engraving bits, 1/8 shank. Until recently all I had was a .25 collet but I got the collet set from precisebits, glad I did. Tried the little engraving bit using a plain pocket cut with great results. Not much loss of detail and the cut was perfectly clear.

So, using my new water based spray, I engraved the whole thing with that bit. That was a mistake - Pockets came out clear as expected, but didn't do so well on the profile, lost alot of detail, thats the 1st pic.
So obviously what I needed to do was do the pockets with the engraving tool, and the profile with the drag bit [I did some of the smaller pockets with the drag bit as well, like the little notches in the saw blades and the spikes in the collar]. It also struck me that since the pockets are going to be nice and clear, I didn't need to use a clear coat, so I went back to my rustoleum black.

Perfect combo, thats the 2nd pic. Pockets are nice and clear, profile is nice and detailed, no need for clear coat so no chance of crinkling. I decided to pocket the circle too, adds 20 minutes to the cut but the extra pop is worth it. Also decided yellow is the way to go, unless there is a brighter white I don't see any reason to use it again. One last thing I might try, I think the eyes might look better just profiled, looks kinda buggy with them filled in.

Thanks to everyone steering my mind this way. I often think outside the box and most if not all of what was said I have thought about, but I am also hard headed and I was thinking "I am going to find a solution with this bit and with this paint, and thats it". There might well be a solution with the bit, but I don't think there is with the paint/plexi/clear coat combo I was using. For whatever reason, that combo was entirely unpredictable and the odds better than not that it would fail.
Now I have a great design and a sure fire method to make more any time I need. For this one I am going to make a special base. 1" plexi and I'm going to paint it black. Going to etch "MRCC" on the front then install white LEDs. Should look pretty sharp with the letters beaming out the light and the design nicely lit.

I done ran through my stock of 3/8 plexi with this series of 12x12 cuts, going to have to order up some more, and for kicks and going to try one with .25 plexi.

[scottp55]

Glad it partially worked, good to know.
What was the size of the flat you used? Looks large.
What angle?
Wondering if maybe a .005-.01" flat might be good, but then again I wouldn't mess with a good thing after all your trials
scott

[Xxray]

Not sure of size or angle, had it for quite a while before use, here it is next to a drag bit

[scottp55]

Funny D.
Looks almost exactly like my broken tip 30 degree I linked to above.
Is it just pic? Or is it a snapped tip?
Blue is his "Sharp" .006"flat, but the ones I have no problems with and love are his "Standard" 30 with the .012" flat with the grey depth ring(unless he specifically mentions it in the 1/8"bits...it's a .012" flat Ivana said).
I'd think it was just me breaking the tips, but another Desktopper had the same luck with that one Blue bit, but we both cut hardwoods mainly, and thought maybe with your shallow cuts it might be better.
Try the grey's with his standard flat maybe?
http://www.ebay.com/itm/5-30-degree-ang ... 58c966364b
Hope pics are good enough to tell.
scott

[Xxray]

Thanks ill give those a try ... Tip is fine, has some black paint residue wrapped around it from machining.

[scottp55]

Ah...Paint:)
You might have the right one for your work now
Decaf triple espressos are for the birds!
scott

[Ms Wolffie]

Ah...Paint:)
Decaf triple espressos are for the birds!
scott

You mean the feathered variety, I hope.

[scottp55]

Yup Wollfie.
Us uppity Yanks don't use that term for the Divine Gender:)
Even took me a second to figure it out, and even then only because of English and Australian themed movies.
4'th day now of decaf trying to lower BP from dealing with VCarving onto domes/dishes for raised fonts:(
Go back to Sumatran's as soon as I go back to 2.5D
scott

[Xxray]

Here she is all lit up, 1.25" thick plexi base was a royal PITA but it came out pretty nice.