Looking for some input from folks who do a lot sign making;
What’s your masking material of choice for cutting through to allow painting a secondary or third color? I’ve got some sheet vinyl on the suggestion of a yTube video and it works reasonably well, though I tend to get some frills along my cutting edges instead of a nice clean cut.
Are there are tricks when it comes to cutting with a mask to get a clean edge? Shallow, slow? Deep and Fast? Low/high bit speed?
I have used a mask called Oramask. it it not cheap, but it works well. Sharp down cut bits work best to it does not get pulled up. Vbits work well. I read all the time people using the shelf paper from Home Depot. I need to try that some time, as it is about 10x cheaper than Oramask.
This is my method. I’ve been using it for about 12 years.I start by staining/painting the stock with the background color I want. Then I put several coats of clear poly over that (I usually do five, but I’m sure two or three will be sufficient). Then I rout the letters/patterns/etc. This will yield natural lines cut into the background color. Now I apply paint into the routed grooves. It’s not necessary to be careful; it can slop out of the grooves and onto the background color. Once the paint is dry, sand the surface. It will take off the paint that slopped onto the background color (leaving it in the grooves) and the couple coats of poly will protect the background color from being sanded away. The paint doesn’t like to stick to the poly, so the overarge sands off very easily. Here’s an example: http://www.hilinski.net/woodgames//showme/Believe.jpg . Here’s a couple of colors http://www.hilinski.net/woodgames//showme/Signet.jpg . The board was stained georgian cherry and covered with five coats of poly. Then the image was routed on the CNC and the routed grooves were colored gold and the surface sanded to get the crisp gold lines. A couple of more coats of poly went on over that and then the black paint was applied. The whole thing then got about seven more coats of poly before polishing.
This method @Boothecus describes is exactly how I do this:
With exception of I used dyed 30 minute epoxy and micro balloon filler, and I applied another coat of poly after cutting. I’ve done the same with paint though, I only did the extra coat of poly after cutting because I was afraid with the dye I used it would creep into the cut edges.
I’ve got some Oracal 631, and have gotten so-so results. I’m meticulous about my surface prep and application, but depending on the bit I’m using, results vary. My 90 vbit cuts very well, my 60 furles the edges up. Downcut straight bits work well, but it’s vCarving I’m really after. Any wisdom on feed/speed/doc with vbits that you use @patonclover?
@Boothecus Now that’s an interesting idea I’d not thought of… and both your examples are just incredible! Have you had success with this process on a more open-grained wood like Oak? Do you find the secondary color is hard to get out of the grain structure?
@dtilton71 I’ve tried shelf paper and contact paper off the rack at the home centers and they do not do well at all I just grabbed some Oramask off Amz, getting here in a few days, will give that a crack - thanks for the suggestion!
I find oak is a little too chippy for my taste so I stick to Baltic Birch, which is dense, heavy and doesn’t ever have voids. I often fill the grooves with some sort of filler. The gold in the Signet pix is DAP wood filler dyed gold before application.My process is the same as people who use adhesive masking except I use coats of poly in place of the paper mask. If you think about it as doing stuff in layers (just like you would if you were drawing it out in Photoshop, Inkscape, The Gimp, etc.) it makes perfect sense.
Interesting Adam. I haven’t had any real problems. How does the wood cut under the furled up edges of the vinyl? If it is cutting nicely then I would suggest one of two things: 1) the surface is not fine or clean enough, but you say your prep is good. 2) You may have a bad batch of Vinyl or at least bad adhesive on the vinyl.
The work I have been doing I have taken the sanding down to 800 grit, probably a bit of overkill but it seems to work ok. Over the fine sanding I put a couple coats of Shellac to give the adhesive something positive to hang on to.
Feeds and speeds seem to be non-critical, at least I have found it that way. For what it is worth I run the following:
Feed: 40 ipm
Plunge: 10 ipm
Recently I have been working with Acacia wood a truly terrible timber to machine but the Vcarving looks good. And by the way, I run the toolpath twice (no change to the original toolpath) this seems to clean out the ‘gutters’ nicely.
As for cutters I use engraving bits of various angles - and cheap Chinese ones at that.
Almost forgot. The vinyl must be rolled down with some pressure. I use a round bottle and apply pressure. There must be no air bubbles and if they appear they should be rolled out to the edges.
Thanks a ton for all the process detail @patonclover! I’ll typically paint a base color coat, knock down the nubs with some 220, blow/brush/wipe the surface than apply the mask using a squeegee and a good deal of force.
I did some testing yesterday and found the (obiously) some downcut endmills yeilded a perfectly crisp edge on the vinyl. My 90 degree vBit left marginal edges and my 60 even worse edges.
Maybe the enamel paint I’m using isn’t a grippy enough substrate for the vinyl’s adhesive? Postman dropped of a sample of “OraMask” yesterday, will give that a crack today and see how it goes. Also need to try the poly-and-sand technique.
I tried out some “Oramask” over the weekend and had exceptional results with it. It seems a much more rigid material than the Oracal631 I’d tried in the past. Now, this wasn’t greatly scientific - different material/coatings/etc. I’ll do a side-by-side between bluetape, oracal and oramask at some point this week and post the results.
in the middle of a cut, using a 16th endmill to clear around the design.
I painted the board first.
then covered with oracale631vinyl mask.
every few seconds its accumulating on the bit and basically renders the bit useless. Does anyone have anything or any tips I can do to actually be able to continue the project: 1. without ending it and starting over. 2. so I’m not wiping the bit off, every second, for the next 4 hours? well, that 4 hours would increase if I have to continue like I have???
Are you using an up cut or down cut bit? And typically people use Oramask 810, 811, or 813 for masking and cutting. I have had some success with 813, but enough problems (paint related, not cutting) that I ordered a roll of 810S (solvent based adhesive) and 811 to try them out. That 631 may be the problem, as I imagine it is a “tougher” vinyl that doesn’t cut as easily.
I believe it’s an upcut, I don’t recall down cut being on the package of any endmills I ordered so…
I went back and looked, to confirm the bottom of the bit “does” remain clear and continues to cut, with a glob of masking right above where it’s cuttings, so I got a wire brush and have been cleaning it as it goes every so often. Will look into those others you listed though. Thanks