Wednesday, March 13, 2019

Shredding HIPS, Reinforcing Table x2

First of all, I decided to start rocking on the giant box full of HIPS that's been sitting in the living room. High-Impact Polystyrene (aka PS-HI) is a firm plastic that's less brittle than standard PS. I've been finding it in printers, where it does a great job in many parts. However it also does a really good job of jamming my shredder! This was the worst jam yet, making me disassemble the shredder enough to pull several spacers out. You can see them sitting on the shredder.

I also looked at a recurring problem I've been having- that of ruining the elastomers in my Lovejoy coupler (red-orange thing at right). The coupler has been properly spaced but still has eaten that black elastomer spider, resulting in $30 of expense for a new spider as well as about a week of downtime before I could buy a new one.

I realized the thing HAS been going out of alignment, but not because of bad adjustment. The table has actually been flexing upward when the shredder encounters high resistance. To solve this problem and stop spending money, I threw some short 2x4 braces into the middle of the table.

  Here you can see the five screws I sent through the table. These line up with the coupler.

Below is a view from underneath the table. On left is the blue piece of aluminum that braces the motor. On right of course is the shredder, and at the bottom you can see that short bit of 2x4 recycled from a part of last year's 4P project. I could send a 2x4 all the way across underneath the table, but it would be more work. We'll see if this works, and if not I'll figure something else out.

I did a little more shredding after that and noticed that it did reduce flexing on the coupler. However the motor and gearbox tend to flex. I'm not sure how to fix that except for bracing near the bolt holes. If that became a problem I might look into steel tabletops. I don't anticipate having to do all that though. It seems like it'll work fine.

Tour of the Sheet Mold!

And now for a quick tour of my sheet mold designed and built by Artisan Metal Works of Flagstaff, AZ!

1. Filling the Mold. Install spacers of desired thickness. Pour in appropriate volume of flakes, about 3-4 scoops from an old chip-dip container in this case.

2. Topping it off. Put the upper portion on! This is a flat sheet topped with box section tubing. When the plastic is melted, I crank the jack under the oven, which smashes this mold together until the tubing hits the spacers. At that point I know the plastic sheet is of uniform thickness.

3. Melted & Cooled. The excess plastic squeezes around the edges, filling up the sheet entirely. At this point the plastic has usually contracted enough to let me pull the top right off, with sheet attached. If not I can unbolt the sides to really get everything free.

4. End Product. Here are five sheets I've made so far! These are all made from broken sleds collected from the forest. The top one is a thinner version with my short spacers. I'm hoping to experiment with a thicker one too. These are about the size of a clipboard, but maybe not long enough to actually use for that purpose.

Oven Comes Home for Good!

 Boy am I glad to have the oven finally! It came home on 19 February and I've been playing with it since. Thanks to Artisan Metal Works in Flagstaff for helping me out on this. They've done great work at a price that works for my project.

Above, of course, is the sheet mold inside the oven. This is a four-part system with removable spacers as well. All very modular and nice. Check out the next post for a tour of the mold.

Here is a photo of my oven and shredder tucked away in the garage. unfortunately I don't have much room so they have to be really crammed in there! You can also see bins full of broken HDPE sleds- all Paricon Model 648's.

Praxis Plastics Demo's Locally, Hits the Airwaves!

 I suppose it was one month ago now, but time has been flying. I hauled my shredder over to Snow Mountain River who I'm partnered with, and put on a little demonstration for them.

It went well despite being a cold and windy February day on the mountain. I didn't get much shredding done, but was able to chat with several interested individuals. One of those individuals turned out to be Melissa Sevigny of our local NPR station, KNAU. She posted the nice, three minute long interview at the following link:

You may notice I added some needed structural elements to the lower part of the table. This helps keep it from twisting too much with the torque of that 1-1/2hp motor.

I'm also happy to report that though it's heavy, the shredder pulls pretty well on the bike trailer! It was only a two mile ride but included a few hills.

Tuesday, March 5, 2019

Snow Mountain River Recycling Demo (Praxis hits the airwaves!)

I did a demonstration at SMR on February 13th! The weather wasn't great so the turnout wasn't as good as I had hoped, but one person who came was Michelle Sevigny of local radio statio KNAU! Here is the resulting interview.

Saturday, February 9, 2019

First HDPE Shredding- Sled Shred!

People love to drive to Flagstaff, buy cheap sleds from Target, let their kids break the sleds in the forest, then abandon their trash in the snow. I have partnered with a local gear shop called Snow Mountain River (SMR) to recycle them into something marketable.

Today I went to grab the first batch of sleds, 50 lbs of green Paricon Model 648's originally purchased at Walmart or Target for about $10 each. Only one of all those sleds in all the colors had a recycling logo. I contacted the company on Facebook and they were not especially helpful, saying the sleds were "either" HDPE or PP. Hah. Since the one is labeled HDPE and they are all the same model I'm going to ASSUME they're all the same.

The idea was to take them home, slice them down to shredder size, and see how well they shred.

I recently got this antique Shopmaster band saw in Phoenix for this express purpose. I figure if it's been running 50 years it'll run another 50 years. Even with the dull blade it cuts through plastic quickly, but for woodworking I'll need to buy a sharp blade. Next to the saw is the stack of broken sleds.

I ended up with one large Rubbermaid bin and three 5-gal buckets full of these scraps. They were all overflowing. I blew the shredder out with the air compressor and shoved some sleds in.

Success! They don't jam as bad as the polypropylene. Overall not bad.

Ended up with about 4 gallons, I think, after about four hours. Lovely! I'll have a few of these buckets before I'm done.

I will be demonstrating the shredder at SMR in Flagstaff on Wednesday! 2-5pm. If you're in Flag feel free to stop by. I might do another demonstration for them later too, if there is much interest in the project.

Shredder is operational

I finally got some retainer clips that fit the gearbox shaft (thank you McMaster Carr) so the shredder is working again!

Of course I promptly jammed the thing with some polypropylene. This jam was the worst yet. I pulled the mesh out of the bottom, chiseled at the jumbled up plastic, tried to pull it out by installing a screw and yanking it with a vice grip. Nothing.

So I decided to go with the nuclear option: partially disassembling the shredder. I pulled the bolts out of the spacers on the cutting side. The plastic was bunched up between the blade and the spacers.

With the spacers freed I was able to knock #4 down to let the plastic out. Then I straightened them out again and replaced the bolt. Good as new, but what a pain the butt.

Friday, January 25, 2019

Shredder Updates

The coupler and shaft have been a big sticking point. I still haven't been able to locate clips to keep that shaft in place, but will be seeking some out ASAP. Currently the shaft works its way away from the shredder, to the point that it put pressure on the elastomer "spider" middle piece.

Squidgy spidey. I'll be getting a replacement. I don't think the metal parts have touched yet, but they will if I don't fix it.

Real quickly I'll go over another broken product I've been given. This was an old humidifier. I pulled it apart and unfortunately could not use ANY plastic from it!

They're all marked #7 "OTHER". Is it ABS? PC? PA6? No idea, and I'm not going to do a melt test just to figure it out. Bad design. What annoys me the most is that any of those plastic type abbreviations would have taken less effort to enter onto the part than "OTHER". At worst it would have take two fewer letters!

I ended up throwing the wiring, metal, and motor into my e-waste pile for recycling, so it's not all being landfilled.

Short video of the shredder and my bucket of polypropylene!

Friday, January 18, 2019

Shredder and Motor Walkaround

And after that, I started shredding. Unfortunately I forgot to put keys in the coupler so that messed it up a bit. I took the shredder to the machine shop to get a key made, and brought the motor's key home to install. Ugh.

Tuesday, January 15, 2019

Motor works!

I've learned a lot from this project, and with the help of Ward got it all hooked up and running. The motor does pull a lot of current, but I'm hoping it will not have issues once load is put on it.

I also got a Lovejoy Coupler machined to fit the gearbox and the shredder. It has that black rubber part between the two halves, and allows the shafts to be slightly misaligned without causing bearing issues.

I took them all home and mocked them up on the table! Next is making a spacer to keep the shredder at the right height, then mounting everything up, cutting a hole in the table for plastic flakes, and mounting the controller.

More Deconstruction & Product Critiques

I have been collecting ever more broken products to recycle. Since we didn't get but one bike at the Fix-It Clinic this past weekend I ended up taking apart a Dyson vacuum there. Below I'll detail that and some of the other items I've been pulling apart. Some have been great, some have been horrible. Some have helped me learn how to efficiently disassemble products.

First up, the Dyson. I didn't get photos of this one during disassembly, but partial disassembly took approximately 2 to 3 hours. All the fasteners were hidden, and half of them were just plastic clips. This made it immensely difficult to just get the thing apart. And even when it was apart I found that the big yellow ball was a two-shot mold, which means one material was injected directly into the other, making them inextricable.

Additionally, one large portion of the main frame was created with two different types of plastic glued together. not usable. Actually, none of the yellow plastic was labeled for recycling either. Horrible.

The Eureka Maxima vacuum offered me a few parts including the red ABS head, but I didn't get to take that one apart. I believe the unknown black vacuum was the one that had a WOODEN brush roll. High five for natural materials!

The LG Model LUV300B vacuum was a treat to work on. Every bolt was easily accessible and changing a belt or even the broken motor would have been a 15 minute job. Unfortunately I got it partially disassembled, so I finished the job.

 You can see the brush motor here, held in by two or three bolts. The head cover was extremely easy to take off. There were very few plastic clips; almost everything was bolted in with Phillips head screws. The motors were large compared to the other vacuums I've taken apart. A well-made unit for sure, and probably easy to fix. Almost all the plastic pieces were marked for recycling, most being ABS or PP.

The HP Photosmart C5200 Printer lent a good amount of usable High-Impact Polystyrene (HIPS), some ABS, a little metal, and not much else. I will have to find a way to get rid of a few circuit boards from it too, of course.

This one started out looking promising. The entire outer shell was made of usable thermoplastics. I pulled the glass out of the scanner to hopefully use in a custom picture frame later- the third I've collected so far. But once I got into the printer things got grim.

The printer was very well-built with lots of metal, but part of the high build quality was also due to HP's liberal use of glass-reinforced ABS and polycarbonate (PC). Everything inside seemed to be made of the stuff, which is not recyclable as far as I'm concerned. Maybe someone could do it, but I'm not going to attempt it.

A few pieces were usable though. Here we have some POM rollers held by steel screws and unrecyclable roller carriers. The whole grey piece there is ABS as well. Below is a photo of all the larger usable pieces along with a small sample of the stuff I can't deal with, in red. I've gotten into a habit of marking things with a Sharpie to keep them straight.

Is it better to have a longer-lasting product which is less recyclable, or a more disposable product which has a higher percentage of its parts made of easily recycled stuff? I feel as if there may be a middle ground at the expense of size and weight.

Next is one product that someone from Facebook dropped off. I've gone through several vacuums from FB so far, but this the most annoying. It's a Shark brand vac. Everything is put together with either security torx screws, glue, or some form of two-shot molding. Several parts had paint or chrome plating which needs to be removed before recycling. Some parts were not labeled for recycling.

Below is the top of the canister, disassembled. You can see that out of six parts in this assembly, only three are directly recyclable as-is. I could try to strip the chrome off with oven cleaner as diecast car customizers do, but it's probably not worth the tiny piece of ABS.

Next, the canister itself. Only a small fraction of the material is actually usable.

Close-up of the screen. This had to be removed from the canister by use of a steel punch, a long piece of scrap metal, and a hammer. Anyway, the plastic was molded around the steel screen, making this piece unusable.

Here's the vacuum head with its GLUED-ON lighting windows.

No, you can't peel them off.

Wire cutter time.

Last was a Panasonic cordless land line phone from a Facebook person. I think I got more usable plastic parts off this little thing than I did the entire Dyson vacuum.

This glue might not come off without some work, though. Unfortunately construction like this greatly limits the item's disposal options.

Here is the e-waste. Quite a lot for such a small product.

 That's all the deconstruction I have for now. Stay tuned!