Trying to figure this out, and seeing some conflicting advice on this forum and various Youtube channels. Thought I would ask before starting experiments.
When I am cutting one of my catchall trays, the toolpaths are as follows:
Rough pocket
Finishing pocket - mostly using a 3/4" bowl but for this
Vcarve clearance - typically a 1/8" bit
Vcarve - Different vbits base on what look I am trying to achieve
Profile cut - 1/4" bit
So, adding in an epoxy inlay step, is the following correct?:
Rough pocket
Finishing pocket
Vcarve clearance
Vcarve
Fill carve with tinted expoy, let harden
Finishing pocket again
Profile
Does that sound right? When waiting for the epoxy to cure am I just pausing the operation, or should I shut down and then run a second operation? Do I need to re-zero in that case?
Also, does tinted epoxy “bleed”, or can I skip the sanding sealer?
I would leave the finish cut until after the epoxy. You’re going to want a good 24 hrs for the epoxy to harden up good. I would output a file for the rough & V-carve, and another file for finish and trim/profile.
Your order of operations seems sound. The rezero has been written about on the forum many times. In the newest versions of CM they changed after initialization. In older versions the X Y and Z zero were always remembered. In the newer versions of CM they are remembered but only after the bit has been measured. So what I mean is after initialization the bit comes to the front right corner and the previous X Y and Z are somewhere in memory but the machine does not recall that memory until a job is started and a tool is measured or you can do a bit change in software and the bit is measured (just leave the same tool in router/spindle). So you do not need to rezero if your project goes back to the same place as when machined the first time but you must have the bit measured by the BitSetter.
I think the change was to save time but not sure it is really saving any time or extra movement.
But the answer is yes the previous set X Y and Z are remembered. I have a large L bracket bolted to my spoilboard so it is easy to put my projects back to their original positions. According to @robgrz in previous posts many people never change their X and Y positions and rely on CM remembering those positions. For me even though I have the L bracket I at least go into jog and rapid positions to double check my X Y and Z positions before starting a new job.
I do at least one coat of shellac before the epoxy. Three coats is probably better.
I also have a planer that I run my parts through after the epoxy is cured. If I didn’t
have the planer or the the part was too big I’d run a flattening pass.
I used the Zinsser Universal Sanding Sealer (Dewaxed Shellac) before paint or epoxy. The sealer helps keep paint/epoxy from soaking into the wood fibers. When painting the paint can soak up inside the fibers of certain woods and cause a halo effect that cannot be sanded out. The same is true for epoxy. Depending on the epoxy many are like water and they will find any holes and leak out. There are hidden defects in wood and epoxy can find its way out causing a disaster.
There are other sealers but I like the shellac based. It gives a slightly darkening and warming effect to wood. If you dont like the changing of color of the wood you can use water based sanding sealer like Minwax Polycrylic Sanding Sealer. The only issue with water based products is it tends to raise the grain. So if applying water based products let the first coat dry, sand and then apply a second coat. On certain woods the grain may raise again. Generally after the first coat of waterbased finish you need to sand again before applying more coats or you will get a lumpy rough surface.
Every finishing product has its plus and minus. For me oil based finishes are my preference but that also depends on the project and the final outcome.