So I managed to finish the first sign, but I’m having problems with the paint bleeding into the fibers of the wood. I applied 2-3 coats of spray lacquer but it didn’t help. Anyone have any tips on how to avoid this? The material is soft pine.
I sanded the wood, cut it on the MPCNC and then applied the lacquer. After letting it dry for an hour or so I spray painted and then used the MPCNC again to cut the top 0.2mm off (I have no orbital sander so this was the easiest approach).
Perhaps I used the wrong products. I used nitrocellulose lacquer which isn’t maybe the best choice but that’s what I had quick access to.
I would have expected your approach to work, but maybe the paint has a solvent that dissolves the lacquer.
I have used Elmer’s school glue to prevent sharpie from bleeding, and it prevented bleeding but it runs when it gets wet. Next time I was going to use Titebond waterproof wood glue, but I haven’t yet had that next project that needed it. I expect it to work but I can’t say I’ve actually done it.
So, clear lacquer, and then spray paint on top? Depending on the paint, there’s a big possibility there are mineral spirits or similar, which can mess with the lacquer. That’s why you don’t apply lacquer on top of general spray paint. 2 coats may not even be enough because it’s basically endgrain.
I’ve used clear lacquer in only once scenario successfully, and that’s when painting on with brush acrylics or something similar.
I like shellac, dries super fast, solvent is alcohol, so it usually doesn’t react with anything. What they usually mean is the zinsser’s (sp) from the big box store, in the can at least in the US. If you can get the Seal coat, it’s unwaxed. I only mention this in case the reason you have nitro is because you make guitars, and by shellac, you might think of the actual ones used for french polishing acoustics or something.
I have had the same problem with a number of my projects. I have a process that is working for me on the signs I have been cutting. The paint I have been using is Rust-oleum spray cans from Home Depot.
Spray on two coats of clear gloss and let dry before cutting.
Cut sign
Spray on two more coats of clear gloss and let dry. This is a heavy coat making sure to get down in the areas that are cut. I usually let it set over night.
I also forgot to mention, and this may be a deal breaker, it’s a little difficult to sand if you don’t let it dry enough, it’s pretty gummy, even the unwaxed version. heat + Shellac = Gum. I generally used it with some kind of masking material that I carve through. It’s also my favorite finish since it dries so fas, so I use it on all decorative type items.
Oh no, I just took your post as a jumping off point. I did a lot of reading around the net after seeing dewaxed shellac in your comment since I’d seen it mentioned elsewhere. It just so happens that the specific brand/product you mentioned is the only stuff I can find locally that is dewaxed, haha.
Well, here’s my two cents. I did two carved plaques in maple. For the first one I grabbed a can of Krylon black and just shot it. Took forever to dry and never got hard. Bled like crazy and took forever to sand and you can still see bleeding. For the second one I broke out the airbrush and used Createx airbrush paint. (I didn’t use it first because I was too lazy to clean out the airbrush.) The Createx covered great, dried fast and sanded easily with no bleeding. No precoat on either plaque. You could certainly brush the Createx but Harbor Freight has really cheap airbrushes that would do fine for this application.
I tried putting down a few coats of shellac followed by contact paper. Let the machine cut out the design through the contact paper thinking it would leave a clean mask that I could paint through, unfortunately the contact paper tore out pretty bad and would have probably done more harm than good if I painted over it so I ripped it up and decided to just hand paint and quickly wipe off the excess.
After wiping off the excess paint it was a bit too dark for my taste and a few of the small details were a bit lost so I sanded it back a bit. I’m not very happy with the result and it doesn’t look like I pictured it in my mind but it’s good enough to give as a gift and looks pretty good from a few feet back.
Maybe somebody will get something out of my failed attempt!
I’ve been using 1shot enamel for lettering, bleed is substantially better/gone if I am careful. Coverage vs brushed acrylic or even spray paint is unbelievably good.
