Hi
I’m planning on trying out Oramask 813 to engrave a door sign and infill paint the letters.
If there’s someone with experience of this I’d be grateful if you could advise.
The Oramask is 3mm thick. Should I zero my Z on the mask surface then set the vee cut toolpath to start at 3mm below the surface in order to get a proper vee cut width on the letters, or is there a better way of doing it?
You should do some testing on this. The V bit may not give you a clean enough result but that probably depends on the complexity of your design.
I have not used that specific OraMask. I typically use much cheaper shelf liner material.
The stingray is what I use when working with masks on the CNC.
Again, depending on complexity that has its own issues.
Oramask 813 is 80 micron (0.08mm) thick. ~0.003"
The best way to cut it is with a drag knife.
If a Vee bit is your only choice, I would set it about 0.001" above the stock, or as close as you can get it without touching. You’ll need to make sure the top of the stock is nearly perfectly flat & parallel to the XY plane of motion. Best to surface the top before applying the Oramask.
To prevent any cutting into the stock, score the Oramask with the V bit, then if necessary go back with an Xacto knife to free the sections to remove.
If it’s OK to have a small line in the stock, then set the Vbit to just cut into the stock a tiny bit.
If there is a lot of fine detail, you may experience the Oramask pulling up with a Vbit.
As Cullen mentions, the Stingray (or any drag knife) is the way to go.
I’ve even used the dragknife as a precursor to V carving when I want to paint the carved out section.
You should also use a sealer on the wood before cutting out your design. That way the paint shouldn’t bleed into the grain when you paint the letters
I use Oramask all the time. I rarely have problems with bleed-through. One thing that I think has helped is using Matte paint. Matte paint is more viscous and therefore less prone to bleedthrough.
I am going to spray the project with either a Matte, Satin, or Glossy finish anyway.
The matte paint trick has really improved my outcomes!
Another trick is you can do your carve, then spray the project with a clear coat before you apply your paint. That way, any bleed-through is clear. Since I’ve been using matte paint, I have not had to do that step.
I also do not adjust my Z for the Oramask. The wood is never perfectly flat. That .003 is not on my list of concerns.
Your right of course Todd. I read the thickness as 3 mil and, more used to working in metric, I assumed that was 3mm. I now see it is .003 inches…Doh!
Thanks Jeffish…I’m going to run a few test pieces first before tackling the final project and will do as you say
I have had excellent results with Oramask 813 on MDO and white oak. I first painted/stained/finished the MDO/oak in the major, background color and let it dry before any carving. One sign I just did a no offset contour cut with a 90 degree V bit at 0.020 inch depth. Then peel off sections for each color and spray bomb one color at a time with drying and covering painted areas before the next color. A++ and fast. Another sign I vcarved letters with a 90 degree V bit, removed any residual mask around the letters and spray bombed the letters. As mentioned, test. I recall not good results when the vcarved letters were small (<1 inch tall ) and I attempted use of a 60 degree v bit. If you do not need/want to use a v bit, a downcut end mill may give good results. Cheers.
Thanks Cullen, yes a few of the guys have mentioned the Stingray which I’ve never heard of before now. I live in Scotland so will search around to see if it, or something similar, is available in the UK.
Thanks for the tips Bozo…looking at all the good responses there’s a lot of options to consider!
Thanks Anthony…ibthink I’ve got some matt paint do I’ll givevthst a try alongside the acrylic i planned to use.
And thanks to all you guys for your quick and useful responses…really appreciated
I used the stingray to remove score the mask and paint and then carved. I can’t remember the specifics of that project as to why I did it that way. Do you get decent edges on the masking using the O flute on PVC?
Yes. The PVC needs to be wiped down with acetone first.
I guess I need to give it another try. We attempted to use it on HDU and epically failed (“under” spray was terrible.). As always the feed back here changes my view on what is possible.
Is the surface on HDU too porous or grainy do the mask to adhere properly?
That’s the assumption. She sanded it down to 150 grit and then cleaned it especially well.
I just did a 6’ long sign using oramask on the whole thing. V carve lettering. Worked great. Use a plastic straight edge (like the kind for installing vinyl graphics) to push down hard to get a good seal. Better the seal, better the results. I had very little bleed through, but it’s not perfect.
I would keep an eye on it while cutting. The first time I used it, somehow it got caught on the spindle shank of the bit and started pulling it all off and caused quite a mess. Learned to do some things different after that.
Not sure you need to precut the mask. Also you can zero it with it on there, it’s so minimal it doesn’t make a difference.
Others may have their way, but this has worked for me.
good luck.
-MK
Thanks MK…that gives me a bit more confidence in the Oramask solution
After cutting it out if you use something like Sanding Sealer it should prevent bleeding.
