Recycling IPA for 3d Printing

Safety First

The following post describes how i do modest recycling of IPA to get more life from my wash bath. It's important to be realistic about how much life you can get from IPA. I'm not an expert, but I do know that IPA can form hazardous peroxides and peroxide crystals that can be explosive and more flammable than IPA itself.I limit the number of times I recycle IPA and always store it in sealed containers to reduce the amount of interaction with air and moisture. I never use heat. I stop recycling when the IPA no longer looks clear or if it develops an odor. If in doubt, bring it to the disposal center. Of course do this in a well ventilated space and wear gloves and a mask. Always avoid treating a high volume of very spent IPA--that is where people end up with a gelatinous monster that ends up being a toxic soup.

My Recycling Basics

When I started 3D printing I found very little information on managing IPA beyond advice to dispose of it properly. In most cases that means bringing to a recycling center for hazardous materials. I wanted to reduce the number of trips to hazardous recycling, and stretch the life of the IPA. The solution I found has three components that I will describe in turn. 

1. Get most of the resin off the prints with a small amount of IPA using a low volume pre-wash. 

I do this with a sealed storage container that allows me to slosh the alcohol around and a squirt bottle to get into detail and deep grooves. That keeps my main wash bath cleaner longer. I then drain the part and put it into my agitated wash bath to get off stubborn resin. 

Low volume prewash diagram.

2  I expose used pre-wash IPA to UV light in low volumes, and then filter the IPA. 

Not treating too much at one time solves a common issue with recycling; the curing of resin suspended in IPA is limited by light penetration. If you do a low volume, you can get good penetration and cure a lot of the resin out. If you try to treat a high volume of dirty IPA you don't get very efficient curing and end up with a big mess. Cured and partially cured material will settle after 24 hours and can be filtered out with a coffee filter. A second UV exposure will pull out more resin. The partially cured resin in the filter at the end will harden. You can do this in a well ventilated space, or, better, put it in the sun in a place not accessible to children or animals. It becomes very hard.

I typically pre-wash with a pint of alcohol at most. For reference, that is a beer at the pub. I split this in two deli containers for treatment, and let it pre-settle before I expose it to UV--some resin will fall out on its own. You can buy deli containers in bulk, or do as I do, and take them from the recycling bin at work where people toss their takeout containers. Wash them well, you don't want mayonnaise in your IPA!

This photo shows used pre-wash IPA set up under the UV light panel. The cured resin then clings to the side of the container where the UV is strongest. 

The exposed resin clings to the side of the container.

Give it a shake, then let it settle, and it will look like this. This is a little more than 1/2 pint. 

This is my pour through filter set up.

It has a 3d Printed lid (there is a hole in the storage container for the drips to go through) The lid fits well enough to contain fumes. 

This is what you're left with, or more, depending on how much resin came out.

Another example.

I let the used filters harden by the exhaust fan in my printer enclosure. It usually takes a day or so with some periodic UV for them to stiffen. 

You can then either reuse the IPA, or, if it's not sufficiently clean, use it one more time at most and dispose it at the appropriate recycling venue.

3. I replenish my pre-wash supply with the used alcohol from my wash bath. 

I don't ever let the wash bath get very heavily soiled. I check it with a hydrometer. What you want to avoid is treating a high volume of very dirty IPA at one time. I treat as I go and make it part of my printing routine.

So is it worth it?

This might seem like a lot of work for a little reward, but it has allowed me to get more use out of my IPA. Your experience may vary. Whatever you do, please be mindful of your safety and the health of our environment. Please take care. 

My Recent Appearance on the A Modeler's Life Podcast

I had the pleasure of reconnecting with Lionel Strang and his crew (Marcus Neubacher and Derrick Magnotta). It was a great and wide-ranging conversation that embraced all of the ways you can enjoy this hobby.

I was the fourth guest on the podcast nearly a decade ago, and it was fun to come back on and catch up. I've been able to join into some of the Wednesday night chats, and I'm a regular AML listener. The AML stays relevant by connecting with diverse model railroaders and telling the story of the people in the hobby. It has its ups and downs like any podcast, but manages to continue and grow because Lionel is a very good interviewer who can make people feel at ease and draw them out. He may be a lunk-head sometimes, but we all are. If you're on Patreon, check out the AML Patreon channel, where we got into even wider ranging conversations about work and life. 

Sign from Manitowoc WI

I made this Northern Elevator artwork (above) based on a clip of video I saw on the "Mark's Model Rail Services" YouTube channel. He was talking about using vinyl letters to label his modified Suydam grain elevator kit to look like a photo from the Soo Line historical archives. That showed what looked to me like a hand painted sign. The sign had some of the flair of hand painted signs, and I thought I would try to capture it. Mark, if you're reading this, go ahead and contact me--I'd be happy to mail you a laser cut stencil or, to email you an svg file that you could use to have a decal made. 

Here is the art tightly cropped:

Here's a link to Mark's video cued to the moment in the video showing the sign (1:23).

Mark's channel is not fast-paced, but he has a lovely approach to model building that is thoughtful and resourceful. 

Carving and Cobblestone for Lost Shore Harbor

Progress on Lost Shore is slow at the moment, mainly because I've been gluing down cobblestones in the extensive wharf area (there are a lot of these stones, which makes good mindless work). 

I also started carving the rock outcroppings for the point, what I'm going to call "seal rock", mainly because I already have the Miniprints seals to position there. No magic here, just using Dave Meeks rock carving methods.

I've also been working next to the revetment next to the wharf, cutting and glueing stones along what will look like a causeway to seal rock. All of this needs paint, and I'm motivated by the idea of getting to painting, which is my favorite part. 

 

Repair and weather for fun

 I kept on the painting kick after the Tals wagons with this little gem from the late 19th, early twentieth century by Brawa. It started with a broken step and broken hand rails. This required some fine soldering. When all was said and done I added a "Stoffdach" (fabric covered roof), did some acrylic weathering, and progressive fading to make this look like a cared for, but well used wagon at the end of the "länderbahn zeit" (state railway period) in Germany before the multiple railways were consolidated. Although this wagon does not have air brakes fitted, such wagons were allowed in mixed service provided they were affixed to the end of the train during the period when air brakes were being adopted--an interesting operational detail. 

Some shots of the repairs below. These Brawa wagons are lovely, but easily broken during handling, which is why I chose to repair with brass instead of 3D printing the grabs. 

Tals two ways

I bought these two Tals 968 wagons on my last trip to Germany at modelbahn Herman in Oberwesel with the idea of doing some weathering experiments.

The Tals wagons have pivoting roofs and are used to carry water sensitive, sometimes corrosive materials. It's not uncommon to see them entirely white from lime, or, streaked, or even with paint failure. I wanted to try two distinct things, paint failure and a bright streaked appearance I saw where the oxide red was vivid. This is the result, a combo of Valejo acrylic and oils. I'm happier with the paint failure, despite the epic amount of hand painting. I may return to the streaked version. There is a subtle difference between the doors and the top of the hopper that is hard to get right. It's different in the prototype, but difficult to do in the model, because it's just a bit too subtle I think. I'm going to live with them for a bit, then go back and add some dust and finishing touches when I digest them a bit more.

Some process shots showing the initial paint layers on each care and the variation in the initial shading/fading that was done:

Lost Shore Operating Switch Stands

 I've put a linkage below each turnout to turn a target 90 degrees when the turnout is thrown--this was fussy, but hopefully worth it. I've been making the switch stands by modifying Wiseman Model Services cast white metal stands. Mainly, I'm putting a brass sleeve in the base, and fabricating new targets from punched brass discs. A 3d printed handle completes it.

This photo shows the parts included in the kit compared to my fabricated part. The kit parts are just not stiff enough to operate well or last very long. The kit still makes an excellent starting point. 

I'll paint and install these once the groundwork on the layout is painted so I don't knock them around too much.

Oberwesel layout

I've long wanted to model Oberwessel. I lived in this region of Germany in the early 1980s. This stretch of track was hopping with traffic in those years and famous locomotives like the Br103 that looks more like a 747 than a train. The layout is designed as two modules that will plug into an immense staging system that I've been building for several months already. The staging will serve engine hauled trains through iconic scenery like a train jukebox. 

The layout is currently acting as a foam cutting station for the Lost Shore layout. The layout will be wider than this, I will attach a lowered sextion to the front of the layout for the Rhine and its bank.

I've been working on motive power and digital conversions. This is an engine room casting for a Br111. 

These are models from the 1980s, getting upgraded grab irons, pantographs and Lok Sound 5 before heading to the paint shop. 

Staging under construction.

Oberwessel Layout Staging

The staging yard for the Oberwessel Layout circles half the basement above my work benches and then has a return loop in the furnace room. It's all hand laid track with code 83 rail and a code 40 center conductor (the visible portion of the layout will use very small etched nickel silver contact points (pukos) that are hidden the ballast. This is also going to be hand laid. I've been building my own fixtures in the mold of Tim Warris, only in wood since they don't need to last forever.

Railfanning Oberwessel

Oberwessel has been a long time dream destination for me. THis is one of the most beautiful railfan spots in all of Germany because the old city wall parallels the tracks along the left bank of the Rhine (the "linke Rheinstrecke". After the bridges over the Rhine were repaired after the second world war this stretch of track became the route for many of Europe's fastest passenger trains because it was slightly faster than the right bank of the rhine. That continued until the new high speed line was completed this century. The line still hosts an abundance of regional, long ditance, and freight traffic.

If you visit nearby Bacharach you can sit in cafes that seem dangerously close to the tracks, relax, and enjoy the local wines with some tapas. WHile I had fun watching trains, I spent most of my time taking photos of the line itself, the walls, and the surroundings as this will be the theme for a layout.