3D Printing - Big Struggle Featured

I do see where injection molding is good for production parts, but injection molding makes a stronger part in seconds per cycle. 3D printing escapes me and yet I have fallen victim after a long time struggling with finding significant advantages. Bob La Londe

------------------------------------ I'm not convinced either but I keep looking. A promising use I saw at a fair was TPU resilient mounts for some old car or machine. That may not benefit you who can machine molds from a CAD drawing, though.

The more accessible air tank drain is a good suggestion. Mine is a rubber hose with a needle valve on the end that doesn't make it whip around if slightly opened. I drained it yesterday and was happy to see no sign of rust, as I had sloshed LPS-3 around the tank and dried it in hot sun before remounting the motor and pump. The white froth is air that dissolved under pressure.

Air can be compressed but water vapor can't, it just condenses. A steam table lists water vapor pressure at various temperatures. Water boils when its vapor pressure is 1 atmosphere.

I'm talking completely out of my hat, but maybe 3d printing would have advantages is making things like sacrificial patterns for investment casting. For example, a cylinder head needs some precision surfaces but also quite a few non-precision passages for gases or liquids. The precision surfaces for valves, cylinder seats, intake and exhaust manifolds are external. The internal ports and water passages are generally not, or at least not easily accessible. They need to be reasonably smooth and I think 3d printing might be good enough. It would allow much more intricate placement of cooling passages around valve seats and direct fuel injection ports.

The methods would be particularly applicable to smallish cylinders, such as those needed for drones. That is likely to be a growing market....

Countercurrent heat exchangers are another example that comes to mind, though brazed plate exchangers seem hard to compete with.

Thanks for reading,

bob prohaska

I'm talking completely out of my hat, but maybe 3d printing would have advantages is making things like sacrificial patterns for investment casting. For example, a cylinder head needs some precision surfaces but also quite a few non-precision passages for gases or liquids. The precision surfaces for valves, cylinder seats, intake and exhaust manifolds are external. The internal ports and water passages are generally not, or at least not easily accessible. They need to be reasonably smooth and I think 3d printing might be good enough. It would allow much more intricate placement of cooling passages around valve seats and direct fuel injection ports.

The methods would be particularly applicable to smallish cylinders, such as those needed for drones. That is likely to be a growing market....

Countercurrent heat exchangers are another example that comes to mind, though brazed plate exchangers seem hard to compete with.

Thanks for reading,

bob prohaska

------------------------------------------- When I was very young I watched sand casting molds being made in a small nearby foundry. The wood patterns didn't include reentrant details which they hand carved in the sand to templates. The critical features were oversized to be machined later. These were replacement parts for old looms and I think they needed to be custom fitted to other refurbished parts. For one piece or a small batch this method could be faster and easier than creating a CAD drawing.

Lost Wax is another casting method that enables considerable complexity.

So far everything strong I've wanted to make could be done by traditional methods of welding and machining, or braze buildup and filing for electrical contacts. Plaster, epoxy, Bondo or heat-hardening polymer clay (PVC resin) serve for shapes that don't need much strength. I practiced MIG and TIG puddle control by piling up metal freehand. Hot melt glue can be sculpted like wax or glass with a narrow nozzle heat gun. Some curves are easier to form by hand and eye than specify mathematically, wood lathe turnings for example.

This shows the potential of traditional sand casting:

The suppressor/silencer makers are going to 3D printing too. Allows them to make complex passages with materials like titanium that would be impossible to make by machining or so they claim🤷️

Lost wax is heavily used in jewelry making. A local jeweler I know has a small 5 axis mill on a bench in the back making wax blanks almost 24/7.

I've watch a few videos during my morning coffee that cast engine blacks. They used hard rammed sand around reusable patterns. I don't recall off hand, but they may have used a sodium silicate rammed and carbonated to bond the sand. Cores may have been sand formed in a mold. That's the way I would do it anyway.

There are some filaments specifically designed to be used in a lost foam method. They have to be well vented for all the gases to escape.

I think with machining CAD is based on background and opportunity.** They choose what feels natural or that has a learning curve for themselves that works. That being said I think a lot of 3D printing guys start out printing a gazillion patterns they can download off various free (or lost cost) files sites.

I think I bought it with the intent that it might turn out like my first CNC mill. Didn't have much idea what I would use it for, but once I had it jobs jumped out at me. They say, "If the only tool you have is a hammer everything looks like a nail," but I have to add, "and as soon as you have a screwdriver to your tool kit you discover an easier way to drive screws."

If I have an aha moment or an epiphany on 3D printing I'll try to remember to post about it here.

I was just thinking about silencers the other day. A friend of mine lives in a state that does not outlaw silencers, but does outlaw threaded barrels. He bought a target pistol that was integrally suppressed. I was thinking a ring groove, and concentric OD would allow two piece muzzle devices to be added, and simply clamped closed around the muzzle with screws... Actually my first thought was a constricting iris device to clamp in place and a ring to absorb shock and act as a gas check, but a two piece muzzle device seems so much easier. Maybe not "all" of those printed shapes could be made that way, but I bet they would be "good enough."

In other places I'm active... people are 3D printing repair parts for stuff that broke or doesn't quite work like they want. A lot of times a

I've read where obsolete sights for firearms and other missing parts can be done too. Like missing front blades and such that don't need a lot of strength.

I would love to play around with a Curta Mechanical calculator. The real item is kinda pricey and out of my play money comfort zone. But you can 3D print a pseudo version albeit a bit oinky to do🤷️

I bought an FLM 3D printer about 6 years ago and have found it more useful than I thought it would be as it made it much easier to make complex shapes for tools and fixtures where it being in plastic wasn't an issue I just had to up  my 3D modelling skills which are still basic but get the job done. Plenty of vice soft jaws for custom shapes and other guides for the linisher, 3D printed a core for the nozzles in a burner head in PLA and melted it out after the refractory castable had set. A mate prints various items including carburettor gaskets in TPU.

The sand has at minimum a little clay in it and when dampened can be formed like a snowball. The old and home way to make more rigid core sand is to add molasses or linseed oil. Half-round molds of any size can be formed with a core box plane. The desired final size is increased by the thermal contraction and machining allowances. The ends of cores fit into "core print" recesses from the main pattern, most easily on the parting line.

I acquired a bucket of sand and set of old tools from a foundry operator who was happy to see someone interested in his craft and stories. I made my cope and drag (mold boxes) from early childhood memory. The "riddle" needed a new wire screen which was easy. The floor-length leather apron came from a foundry supply company in northern MA.

My CAD experience is on electronic schematic and circuit board layout programs, whose line drawing capability is primitive, though adequate for machined RF-tight enclosures and my home machining projects. I may not have much to unlearn. I learned paper drafting practice in school.

Before cordless Makitas in theatre set construction a hammer was a "New York Screwdriver".

I was just thinking about silencers the other day. A friend of mine lives in a state that does not outlaw silencers, but does outlaw threaded barrels. He bought a target pistol that was integrally suppressed. I was thinking a ring groove, and concentric OD would allow two piece muzzle devices to be added, and simply clamped closed around the muzzle with screws... Actually my first thought was a constricting iris device to clamp in place and a ring to absorb shock and act as a gas check, but a two piece muzzle device seems so much easier. Maybe not "all" of those printed shapes could be made that way, but I bet they would be "good enough." Bob La Londe

--------------------------------- My gunsmithing is limited to custom screw heads and will stay that way. This formerly very conservative and free state has been made a "swing state" by MA intrusion. They don't know self-reliance and try to duplicate the restrictive socialist culture whose negatives they moved to avoid. We hear that first-hand in their arguments at Town Meeting. The laws here can flip either way.

The intolerance and attacks on Jewish students at Harvard was no surprise to those familiar with elitist MA culture. Self-superiority based on the beliefs you profess is everything and those beliefs must not be challenged. I get that from all sides.

I'd been in the Army where everyone's color was green, officially and often in practice. My father's family is from Georgia and Alabama so I've heard their side on race and religion too, and didn't argue.

Ah - the "peppermill" rallye calculator!!!

fascinating device. He was faster with it than I was n a digital calculator, he worked mostly by feel!

As I've mentioned many times before when I have my morning coffee I put YouTube or Rumble videos up on the big screen. Machining, some politics, forging, off road recovery, fishing, firearms, etc. As Jim has noted the level of knowledge is more of a dribble than a flow in such formats, but I find it a relaxing way to start my day. It also offers me the opportunity to start on chores or research tidbits on my laptop or cell phone while the video drones on.

This morning I went down a rabbit hole of things to print, various filaments available, testing (prints not machines), odd case uses.

1. Available designs.

There are a ton of available designs you can just download. Hundreds of thousands if not millions not counting CAD models that were not designed for 3D printing. One I would consider using is a cell phone mount or variations of it. No. Not for the car, although I have always felt a mount next to the display screen in my truck would be helpful. As a camera. For "light" macro to normal room distance a modern cell phone is the best digital camera most people will ever own. Its even okay for some action applications within its range. Sure it doesn't have optical zoom which is a must for distance video, but with the resolution, sound quality, and ease of use its pretty hard to justify buying a camera when you have one that good in your pocket.* More on that later.

Its an all printed holder with a "C" clamp style base, a swivel ball mount, and flexure to clamp the phone so it can hold a wide range of phones. Even in protective cases. This and variations would be crazy good for shop videos. I could certainly machine a similar mount, but some parts could be challenging to machine. I could also make a mold to make the parts, but again there could be some challenges. Its not strong, but other materials that are stronger would also be heavier. Strength can also be adjusted based on the next.

1. Filaments.

There is a confoundingly wide array of filaments available for a huge range of applications. Glass fiber, carbon fiber, metalized, water resistance, heat resistance (to a point), melt out, dissolvable, color, etc. If I get sucked down the rabbit hole of 3D printing I can see needing to start a notebook just for various filaments and their properties.

1. Odd case uses.

One fellow did a video using various 3D printers as injection machines. It was pretty bad except as an educational exercise. The video was well produced, but using a printer as an injection machine did not work very well for 99.9999999% of all case applications. He did sorta kinda get something that produced a part or two, but they weren't great, and he had to use all kinds of tricks, play with heat, get picky about filaments, and play with heat. I'm not saying it can't be done. Just that even a hobby desktop lever press injection machine (I have one) will absolutely produce better, stronger, and larger parts. If you have ever used a manual injection machine you know its not going to make large parts. **

1. Its a hugely popular hobby in the makersphere.

This means there are a million guys (maybe literally) sharing information, and thousands of influencers promoting product, or just trying to be pro YouTubers. The available knowledge base is huge, if somewhat watered down by the mixed quality of the information.

1. Price of entry.

Hold on. I know there are crazy cheap CNC machines. I bought one years ago for about 200 dollars on eBay. (Not my first CNC machine) I was able to do some crappy minimal work with it, and then I spent a several times its original price upgrading nearly everything about it. Spindle, motors, controller, etc. It still failed in the end, and I scavenged the good parts off of it for other projects. For something that works pretty good and worth repairing when it does have an issue you are going to pay a couple times what I put into that cheap machine. Something that can reliably cut modestly accurate (crappy) aluminum molds without a lot of tedium, upgrades, or repairs. The cheapest machine I use today to cut aluminum molds was about 10 grand and it would cost 25-30 to replace it today with an out of the crate usable machine.

A 3D printer is cheap with "pretty okay" ones starting around a thousand dollars or less. A lot less. Maybe some upgrades would be largely useful to start, but not necessary. I'm no expert (obviously) on 3D printers, but the popular brands being used by small commercial print farms (garage shops or maybe just a step up) just aren't that expensive, and there are usable 3D printers for hobbyists that are even less. The base price on the printer I ordered to "try out" was less than 500, and less than 1K even with a four filament feed box attachement, full enclosure, heated chamber and print bed, hardened steel nozzle for abrasive filaments, a couple spools of filament, and some other extras I tacked on.

• I have been making crappy videos, mostly to promote my business and business products, for a long time. I have cheap action cameras, an Insta360 X5 (arguably a top end action cameras), a digital SLR, and I have (and have had) a number of camcorder style digital cameras with actual optical zoom. I've been doing it a while. My first digital cameras used the large CF cards. One I still use sometimes is only 720P and has an actual hard drive for data storage. I still use my cell phone most of the time for shop videos. There are lots of "professional" YouTubers who use cell phones for their videography, and atleast one I saw recently with almost a million followers who said they use almost exclusively iPhones for the camera work. I have actually considered buying up used phones, nuking most of their capacity, and using them just as cameras myself. You don't need the latest and greatest either. Several generations back cell phone cameras were better than good enough for this sort of work.

** I know a little bit about injection molding. I'm not being modest. I mostly make low precision low pressure injection molds or low precision gravity casting molds. For high pressure injection I only know a little. My desktop machine technically counts as high pressure injection, but even with a cheater bar on the handle I doubt I even approach a ton of injection pressure when hanging off the handle. That being said, I do "know" that most common polymers make stronger parts when injected at the lower end of their temperature range for flow and at higher pressures. This makes item 3 a non starter for me. I'm not saying there are not odd cases that would be hugely useful. Just that the one I mentioned is probably not ever going to be tried in my shop. I may make a 3D mold and try medium pressure injection, but I can't see ever using the 3D printer as an injection machine.

Here is an example. Its only a minute long, and I am posting the YouTube link for those of you who want "smaller" bandwidth or live in restricted nations that can't view Rumble videos.

I have one of these, fits the Arca-Swiss quick mount. There's a LOT of different variations of this. I took the phone grabber knobs off and replaced them with slightly longer versions. It grabbed hold of my Moto Ace 5G in a rugged case but just barely.

When we were rallying back in the '70s all the pro guys had them. My navigator had a HP but seldom used it. It was faster for him even then to do the calcs in his head and on paper

Also got one of these Quick Release Plate for Arca-Swiss Tripods. It's what I adapted to the Vanguard Tripod mentioned in earlier post. These come in different size variations too. The Arca-Swiss is being used on tripod mounts for firearms nowadays. You might already have it. It's a really solid quick-mount...

On Wed, 3 Dec 2025 08:51:07 -0700, Bob La Londe wrote: ...

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Some printers in that price range (eg Bambu P2S) work great with PLA, PETG, TPU (although most TPU filaments aren't AMS compatible) but have trouble with GF / CF / metallized filaments, and can't handle high-temp structural filaments like PEEK / PEI / PEKK. The Bambu X1C, around $1000, is aimed at GF / CF filaments, with a far higher hot end range than P1/P2 series, but at 300 C doesn't get quite hot enough for PEEK. Some machine shops are making satisfactory short-run work-holding fixtures with PLA, which is ok in compression, easy to print, inexpensive. I've printed several thousand small parts in PLA and a few hundred in PETG (tougher and more flexible than PLA), and a few slightly bigger parts, like a 7" crown gear. Re design,