Well, I can't seem to smooth out the dots but I figured out how to laser engrave progressive depths to make the deep rib cars: They look ok in person, but when I photograph them I can see the rough sides. I will look into a filler. Maybe a heavy shot of Glosscote pefore painting? Still thinking ?
Robert, I have a friend who has just started a business using a laser to engrave lettering and designs onto acrylics for house signs, as in street addresses and names. The finished etched sign is then placed upright on edge in a tray that has LED's in the bottom of the slot for lighting. Heres the link, http://www.1877gotlite.com/. Next time I'm over there I'll ask them if there is a way to smooth out the etched in parts. The black cars you showed looked good, it was hard to see the rough lines. Maybe dark colored cars only. Do the sides stay straight after etching like all your wooden sided cars do? Bob
The sides of the deep rib cars stay straight, but they are 1/32" thick, where the black cars are using 1/64" thick plastic, and are a bit more flimsy. I need the deep rib cars as NP had a bunch of them, so I must too.
Robert, if that is the best you can do with the laser, then maybe you can try something else to smooth it out. Maybe you can try to airbrush it with well thinned paint. They tend to go to valleys. It may take couple of coats, and you have to do one side at a time because they will run. Well, there is always a price to be paid for being a pioneer. Still, I think the car looks great.
What if you filled all the low areas with thick clear decal? You could trim the sheet to fit perfect with the laser. Just an idea. Then you could paint over that and do the lettering. With all these woodchip cars do you have a paper mill or maybe a rotary dumper planned?
Rob, Here are the things that can help reduce banding 1) In the printer driver setting there is a option for Quality or clipart or photo, select photo or change quality settings. 2) Make the object slightly out of focus. 3) Check belt tension Kim
Good looking car! Maybe try plastic instead of wood? :hmm4er: the wood looks good. a fine file is probobably out of the question. am I thinking on the wrong track here?
Good idea's everyone. This design is one of 2 Gunderson deep rib cars that NP owned. Also is one that has the exact panel orientation as the GN car in Hemi's post, which I am also doing. I like the variety. Today I'm going to try thinner plastic, less power, and defocusing the laser. Not all at once, but as some different tests till I get something workable. It's just a matter of developing a good recipe, and there are lots of variables to play with.
They have them on the NORTHERN PACIFIC RAILWAY HISTORICAL ASSOCIATION website under "Research" then "NP Equipment Diagrams". I joined the NPRHA a few years ago, and often order stuff from the company store. Back issues of the Mainstreeter have lots of great diagrams too.
Smooth sides Hi Robert, Cool car! I had the same problem on my last big design project at Disney, lots of draft angles and hard cuts. How bout this... Cut your ends and sides out of 1/32 acrylic..assemble. This gives you the smooth surface you need. The take some 1/16 or 3/32 acrylic and machine the draft angle on the back side...then cut out the frames and apply to the surface. I used a fly cutter on my mill, gave it 6-degrees of draft, put it on the laser upside down so draft angle is up...or you can prop the thin end up on the bed of the laser. This keeps the focal point flush for a clean cut. I know this requires some assembly, but I think the finished product will capture the look you want. I've done a lot of Raster/Vectoring as well and you need to do shallow cuts and give the material time to cool between passes so you don't get the kind of flow marks you seem to be getting. I was able to get some pretty smooth finishes that way. Just my two cents.. Cheers Joe MTL
I gave up trying to smooth out the bumps from laser etching and decided to try extra heavy weathering to make it less noticeable. I could go with Joe D.'s suggestion and make the ribs a separate piece, but after messing with it for a while, I was not getting any good results with plastic because it tends to melt and warp, and I could not get a piece to overlay flat. I can do it in wood, but in person, the bumps don't looks so bad, just photo's so I decided that since I am only making a dozen or so for personal use, I can live with the bumps. So I resort to very heavy weathering to hide it.
Rob, Dont give up yet, have you tried to flip the image and raster, it will take longer but two difference is the lines will be vertical , easier to camouflage and the power changes per raster line so you may see reduced banding. It will take longer to cut. Kim
Yes Kim, the GN car is with the image rotated 90 degrees, and the lines are gone, but there are still pixels. Here is a larger picture: GN Deep Rib Woodchip Car Yes, I plan on doing the NP cars next, but after seeing your post of the Big Sky Blue car above, I had to do that one before I did an NP in Boring Boxcar Red. If you notice Hemi, I modified the car a bit to match the GN car better than the first car posted at the top of the first page.
It looks fine to me! Besides, all gons are smashed full of bumps and dents anyway Probably a dumb question (the only Z I've seen in the last decade or so is a MT boxcar at the LHS :embarassed: ), but would it be possible to sand it a bit?
