I have wanted to cut something like this for a while and this looked like a good project to test in Carveco.  I knew the cutting would be fairly straight forward but was unsure how long it would take because I haven't calibrated this type of cutting in Carveco.  The material is 1/2" MDF and it took 40 minutes cutting at 200 ipm, one pass with a 60° 5/8" diameter V bit, 18k rpm, 0.03125" stepover, and cut depth of 3/16".  Except for the perimeter cuts it rarely got close to 200 ipm.  I probably could have set it to 400 ipm and the results would have been about the same.

 

My goal was to make it look old, somewhat weathered, like it had been discovered in the sand on Tatooine and had been there for years.  In other words, 'pristine and perfect' was NOT my goal.

 

The finishing steps were as follows - 1) two fairly heavy coats of Nitrocellulose sanding sealer, 2) one really heavy coat of Rust Oleum brown Hammered paint, 3) brushed thinned black acrylic into the recessed areas and wiped it off, 4) placed in oven at 170° for a couple of minutes and turned off but allowed the piece to stay in until the oven cooled, and 5) one good coat of Nitrocellulose semi-gloss followed quickly by a lighter dusting coat. 

 

The lacquer caused the underlying coats to crackle a bit and gave me the desired look, at least I am pleased with the way it came out.

 

On the CNC -

 

Two coats of sealer -

 

Brown Hammered paint -

 

After black acrylic and wiped off -

 

Aged look -

 

Aged look close up -

 

Enjoy!
David

Looks great!   Now you just need to book a trip to Tatooine and when you get there find a place to bury it in the sand!  Maybe embed a solar cell in there so that when it is found a circuit starts and plays a message from Darth Vader. 

 

4D 

Edited April 19, 20206 yr by 4DThinker

Very cool David.  It looks to be maybe 10-12" round?  How much time was spent programing the CNC?

Now, shall we call "Ancient Aliens" for you and tell them that you have found proof of visitors from another planet?

It's 12" diameter.  I'm going to do another with the inverse on the cut, I think it looks better.  And it should cut faster by almost half.  Programming on the CNC wasn't long at all because the dxf file was basically ready to use.  Any length of time I spent can be cut in half by someone proficient in Carveco, of which I am not at this point.  So the couple of hours I spent toying with settings, trying this and then that, could be done in minutes by others.  Matter of fact, my learning curve is shortening and I did the second one in minutes.  Here is what I intend to cut when the weather clears, when we're past the tornado watch, and when I feel fairly certain power won't cut off in the middle of a cut.

David

6 hours ago, Cal said:

Very cool David.  It looks to be maybe 10-12" round?  How much time was spent programing the CNC?

Now, shall we call "Ancient Aliens" for you and tell them that you have found proof of visitors from another planet?

HAVE YOU LOST YOUR MIND?????   You think the toilet paper hoarding was bad, if this happens.  OMG, no tin foil will be in stock for years.   

53 minutes ago, Woodbutcherbynight said:

OMG, no tin foil will be in stock for years

Wait, you can still get real tin foil?  

Color me highly impressed! Very nice.

Busy morning cutting Longworth chucks and Star Wars Aztec calendars. I cut three 12" calendars and one 9" calendar.  These are all the inverse of what I cut the first time, like Mick's calendar.

Two of the 12" calendars were cut with a 60° bit, one at 250 ipm followed by the next at 125 ipm. In some of the details I can see pieces broken so I slowed it down to see if the feed rate had anything to do with it - it didn't. And it only made about 3 minutes difference in the total time because it never gets up to 250 ipm except when cutting the groove around the perimeter.

So I switched to a 90° bit and all the cuts came out much better and no pieces broken. In the end, given the way I will paint and distress these, it's not going to make any real difference anyway, but I just want them to be as close to perfect as I can get.

A couple of hours cutting calendars produced this -

 

Tomorrow I'll do my finish and see how these come out.

David

Just curious if you have a good market for these, or you are just experimenting to help pass the shelter-at-home days?

 

I'll confess I've booted up my CNC a few times this last month not because I needed to but was happy to have found a useful scrap and something to make of it. 

So you'll know just how bored I am I keep picturing a larger calendar as a basketball backstop, rigged so the swoosh of a light saber sound would play for any swish shot that didn't touch the rim.

 

The photo is a rough prototype of student's design I made to show her a simple way the parts could be assembled.   She insists on complicating things for no reason except a fear of asking about how a thing might be put together.  All parts were cut using my CNC from plywood scraps I had.   Her version will be a mix of hardwood for the exterior and plywood for the triangle sides. More detailed as well. She is making several of these that stack together in different arrangements to display her collection of model chairs.   5" x 5" x 5" each, and will use 3mm metal pins to align when stacked. 

4D