What’s up everybody and welcome back to Gulfstream Outdoors! Today I’m going to give you my top five tips for 3D printed resin molds. Wait, no, eight tips. Holy crap you’re getting a lot of value out of this video. So if you’ve watched all my videos in their entirety, you’ve probably already heard some of these tips but I wanted to put them all into one spot so I can answer every ones questions.
Number one, pick the right resin. To me, there’s only one resin to use and that’s Siraya Tech Sculpt. It has a heat deflection temperature of 320 degrees Fahrenheit and all that really means is at what point it starts to bow and warp and get all messed up. I don’t really know too much about the parameters of the heat deflection test, I know it has a specific width of material. I’ve shot lures well above 400 degrees Fahrenheit and not had any deformation in my molds. All of my molds are a standard 15 millimeters width on each side so I think it’s even at a thinner material than 15 millimeters that are really starting to form at that temperature. It can handle a lot of heat, there are other high temperature resins out there just make sure your heat deflection temperature is above 300-320 degrees Fahrenheit. I believe Siraya Tech Sculpt is really want you want and I have it linked here.
My number two tip is to print it solid. Yes, you can hollow it out and yes you’ll save some resin but really what ends up happening is, especially with Siraya Tech Sculpt, is that it’s a brittle material. So if you have a hollow mold and you’re trying to put it together with a vise, screws or anything else, you’re probably going to crack it when you really want that mold to last. This mold here I’ve shot at least 100 times and absolutely nothing is wrong with it. It has a chip in it but that’s from me dropping it. If I had dropped it and it was hollow, the drop probably would have shattered the whole thing which is no good.
Tip number three is print it flat to the build plate and chamfer it. A solid block of resin, even a small mold, is a lot heavier than most of the things these 3D printers are used to printing so you want to give it the most support as possible. The best chance of success for me is printing it flat against the build plate and chamfering the edges in Fusion 360, or whatever you use to design your lure, that’ll help you get it off the build plate. Printing flat also compensates for the elephant’s foot that you’re going to get when you print something flat on the build plate. Elephant’s foot is when you over expose resin to the light and it leaks out to the side and your material hardens at the edges wider than the actual mold. If you do that flat without the chamfer, when you go to put them together you’re going to have a lip and you’re going to have to sand it and nobody likes sanding. So by chamfering it you give some room for that elephant’s foot to go into place and when you put them together it’s flat and no sanding is required.
Tip number four is related to tip number three and that’s that you want to print it at the skinniest edge to the build plate. A lot of people think when I say flat against the build plate that I mean literally right on top of the build plate and that’s really destined to fail. You have tons of surface area here on your FEP and it leads to peeling on the edges because a lot of pull force. Sometimes you can get away with the top edge on the build plate but I tend to notice that the edges will pull off. You can usually use those molds but the holes will deform slightly, but usually it’s okay. The absolute best way to print is vertically with a short side on the build plate. This is the longest print time possible since it’s largely determined by the number of layers you have on the z-axis. So printing horizontally is the shortest print time I could print at about 40 minutes on my Epax E 10. It would fail, but I could print it. It would probably be about 6 hours with the lures facing out and about 11 hours vertically. But printing vertically is going to get me a print that is pretty much flawless every time. I can probably print two or three molds vertically just by stacking them back and forth. So, the longest print time gives you the best results with the smallest edge going onto the build plate. One more thing about this mold, it is a little tricky because it has the injection port on the side, but if you have a mold in general you want to put the injection port at the bottom. That’s going to give you the cleanest print on that injection port.
All right, tip number five. Don’t use any kind of holes and keys for alignment- use nuts and bolts. I have my fiddle fin mold here and I have holes going all the way through it. I use a ¼ in- 20 which goes right through. For the ¼ in- 20, I use these wing nuts with the washers on then and then screw it down and it’s easily aligned. Now I need another one on the end but you really only need them at two or three point to be totally aligned. I can put my mold in my vice with my vice across the bottom and I’m ready to shoot. The reason why I don’t recommend keys is generally resin is not accurate enough for you to design it in Fusion 360 and move a key across and cut a hole. You’ll need to make that initial hole bigger on the other side and it’s going to depend on the resin and on exposure and I find that it’s not really consistent with a hole. With a nut and bolt, you get relatively consistent results and in Fusion 360 you can use the clearance setting in the hole which generally works without any issues.
Bonus tip- venting. Now I have some videos where I didn’t vent at all and that does seem to work fairly well. If you do decide you want a vent, only vent one side of the mold and not both. I learned from this guy on a Facebook group that does CNC molds and I use that technique on my latest big saltwater 8 inch grub and it seems to be working really well. What I do in Fusion 360 is literally turn off one side of the mold, draw lines where I want the VIN holes to be, use the pipe command and just carve only that one side of the mold and it seems to work really well.
All right, a few top secret numbers here really quickly as a bonus. The injection port size I use is 15.2 millimeters. Again, to make room in the mold. I use the whole command and I use the counterbore. What that does is the 15.2 size goes down a bit and then I can shrink my sprue hole to the size that I want in order to fit my bait right. That size can be totally dependent on what size bait you have. To not blow away the face of the bait and make it a lot easier. I also use the drill point tip and use the cone it has to poke into the front of my bait, just enough to get the plastic in there. For the vents, I use the pipe command and my pipe diameter is 0.2 millimeters. It really ends up being .1 millimeters because you’re going to use half of it which is two layer lines on my printer. That’s just enough to let the air out and not enough to let the plastisol all out unless you’re shooting like, molten hot lava.
Last tip I almost forgot for when you’re making your mold extrude each half at 15 millimeters. An easy way to do this is just to do a symmetrical extrude at 15 millimeters which is going to end up a little over an inch and a half. This should contain your lures since not too many lures are over an inch and a half in any one direction. Even if you have a thin lure, you want to print it 15 millimeters because that’s going to give you 30 millimeters total and that gives you enough area around the injection port to not cause any warping or weirdness.
If I missed anything guys, or if you have a tip I don’t know about please let me know. I don’t think there’s a ton of people on the planet doing what we’re doing so we all need to learn from each other!