dgfoster
Diamond
- Joined
- Jun 14, 2008
- Location
- Bellingham, WA
Maybe I missed, but what filament are you using to print patterns like this? I know some plastics don't play well with lacquer paints and fillers.
I appreciate your detailed posts on the process. I have a few projects needing one-off castings reproduced and that expensive pattern shaped gap between a paper print and the foundry gets a lot more manageable with tools like CAD and 3D printing. I have at least one that has so much draft and geometry causing errors in the model, that I think printing what I can and using paint and filler to manually smooth out the rest will make it a lot simpler.
I have only experience with PLA and PETG filaments both of which have worked fine for my pattern printing and for related parts.It is amazing how often it is the simple things that can drive you crazy.
Charles
I use Rustoleum Lacquer, a true lacquer and not an acrylic lacquer, because it goes on nicely, dries quickly and I can build it up by carefully making heavy (ish) coats and letting it flash off and repeating.
And I have found what you are saying about draft and geometry errors being possible if one tries too early in a drawing to apply draft or fillets. I have pretty much limited myself to getting the drawing generally complete except for draft and fillets and then applying them in that sequential order. One of the things I so appreciate about CAD drawing is that draft and geometry accuracy is so much better than even my careful woodworking. Yes, woodworking did work quite well. But I almost always had to fix up the wood pattern with Bondo and and sanding followed by more Bondo when molding revealed yet another subtle draft or geometry error. After making patterns with CAD and printing for almost a year now, my CAD error rate has diminished. Printed patterns typically pull from the sand more easily than "good" wood prints. I think that is because even well-made wood prints have some inherent "wow" or twist in them since the wood is non-homogeneous.
Even with a well-printed filament print I have to do some light sanding for good paint adhesion. I have just recently started using a matte filament, though, and it seems to really like paint even without sanding. And, on certain areas of prints where there are surfaces nearly tangential to the printer head travel there is inherent roughness that needs a few extra lacquer coats and/or judicious Bondo.
The other wonderful thing about CAD is the ability to "nest" parts accurately. I am making a core for this print even though I had hoped to be
to mold it in green sand only. That is out of reach of my abilities. So, the core involves several dimensionally inter-related parts that were much easier to fabricate with cad compared to the "woodshop method."
I may make another post about the core box and core print later. But, I need to get to work on what I hope are final steps.
Denis