casting – Twisted and Delusional

Random stuff…

I have a little bit of time so I thought I would post some random things.

First off, most of you know that I have been growing my coffee plants for around 5 years. I have only had blossoms on them twice and earlier this year was the one of them. I was really happy to see blossoms, since its a good indicator that I’ve finally gotten close to making them happy. I was watering them a couple days ago and almost didn’t notice these…

Those are coffee beans! The very first time in years of growing I have had coffee beans! They are hard to notice because they really blend in with plant. As proof, see how many beans you can count in the next photo..

Hint: there are 5 beans in that photo, but I bet you counted 3. I’ll post more pics if they get to the ripe phase and turn red. Overall, I’m just happy to see any beans, ripe or not.

Switching gears…… Some of you know I enjoy making small engines and I have met many wonderful people going to miniature engine meets and forums. One of the great men I got to meet was Bruce Satra. He revived a model engine from the 1940’s called the Morton M5. The Morton model engine is actually based on the LeBlond engines in the previous post. Here is a pic of the Morton Bruce built in the ’80’s.

I started a Satra M5 from castings that Bruce sold several years back, but I didn’t buy a complete kit, just a few to get me started. When I ran into a couple machining questions I emailed Bruce and he was always super helpful. Unfortunately Bruce passed away several years ago and many of us were left without parts. A friend of Bruce, whom I will not name but is an easy Goggle search to find, was supposed to keep the Satra Morton M5 going in memory of Bruce. Alas, he has completely dropped the ball, even going so far as not keeping VernalEngineering.com (Bruce’s M5 webpage) running. Here is a pic of the fantastic castings Bruce used to sell…

So, left without a source of parts after several attempts over several years to contact Mike (oops, wasn’t going to name drop) I am left with my usual answer. I will make my own castings based on Bruce’s notes and conversations we had. (As if some of you out there couldn’t guess I was going to say that)

I’ve started the process and here is a little info on progress. I started by modeling the parts in CAD software and then printing out the parts to verify dimensional accuracy…

Those quick and rough prints checked out, so now I am making my wax molds. I’m a couple revisions in on the rod and piston molds, and have found a wax suitable to injecting into the small lines and cavities. Now I am just refining the molds to help with the last small imperfections in the wax parts. I’ll post more pics and info when I have some final wax parts before attempting the first metal castings.

Adding another machine to the shop…..

I do a lot of work on antiques and custom projects, so a lot of times I need to either produce or reproduce parts made of plastic. My go to technique has always been casting resins, but many times they don’t have the ‘feel’ of plastic parts even if they look the part. Sometimes there just is nothing like an injected plastic part.

I started work on a David Gingery style home made plastic injector a couple years ago, but I was never happy with the way the ram was designed. I purchased a nice electronic PID temp controller for the project, and temp control was never an issue, but there were enough other issues with it that I never put it into use.

Last week I saw this pop up on ebay…..

Hmmmm, a $2500-3000 injection unit that had been torn open and no one knew if it was working. The seller was asking a price that would put it on my doorstep for around $200. After looking at the pics, I figured that the ram and chamber were were professional made, the lever linkages would have proper geometry, there was a neat little filler for the plastic feed, and as a bonus there was a mold hold down clamp. Those were all things missing in my home made unit. If the only thing wrong with it is the temp control, then this would be a good purchase so I bought it.

It showed up on my doorstep a couple days ago and I didn’t waste any time tearing it down to see what I had received for my money.

I stripped the heat guards off of it to see what was left under the covers. Turns out that nothing in the heater and injection parts had been touched, things are looking positive!

Here is all the temp wiring as I received it. Everything looks good, I couldn’t see anything obvious wrong with it. I did notice that it is an older type mechanical temp control which are prone to temperature fluctuations, I decided to replace it with my digital PID controller. The data plate on the back said it’s a 220V unit, I will rebuild it as 110v since I will be rewiring everything anyway.

During the tear down to get to the heating cartridges I noticed a few things that the professional unit had that the home brew didn’t, like this bevel on the ram to make feeding pellets easier.

Another lucky bit were the heating cartridges used in the machine. They wired two 110v heaters in series to make a 220v unit. I could just rewire them parallel to make the 110v unit if they were still working. I decided to test them since I had them out of the machine. I put them on a large steel plate as a heat sink, wired them to my digital controller, and tested the system I wanted to install on the bench.

Everything worked. The heaters got hot, and the controller turned them on and off. The next thing to do was modify the heating chamber to install the temp sensor that feed information back to the temp controller.

In the upper center of the picture is the heating chamber and heat cartridges, in the middle is the temp sensor I need to install. I chose to drill out and tap the small hole towards the bottom of the heating chamber where the original heat probe was located.

Hole drilled and tapped. Temp sensor installed. Time to reassemble.

Reassembled with the new parts in it. I hadn’t put the heat shroud back on yet since I wanted to do a test of everything. The test went well, I brought it up to 131’C which is a good temp to begin melting polypropylene plastic for injection.

Since the digital sensor will let me regulate all the way down to room temperature I can melt several different materials for injection molding, so another use for this machine will be injection of casting wax into molds. This will let me make precise investment molds for metal casting.

Keeping Busy…

Posts have been few and far between since I have a few irons in the fire. I’m working on some emblems for a Datsun, the garden, finding rural property, a 3d printer build, and the usual clock and watch stuff. Yet, I still hear the question asked, “but you couldn’t find just a few moments to post…..?”

Lol.

The garden is growing well. I’ll post about that some other time. This year it’s garlic, tomatoes, corn, pole beans, squash, watermelon, and the usual herbs. The coffee is doing good, saw flowers for the first time this year but I’m not holding any hope for fruit.

I’m going to make this a quick post, so here’s a bunch of pics of the Datsun emblem progress. I’ve made a mold of the original and cast the first ‘waste’ piece from the mold. Now I need to cast a good piece to modify it the way the owner wants it.

On an interesting side note, I made some replica ‘Barracuda’ emblems for a friends car he was restoring. He only had a single good emblem and needed at least a pair for his car. The car has gone on to take many awards and is now in a recent Mopar magazine. The emblems are still on it, lol. Some pics of the reproduction emblems.

Complete, right down to the production numbers on the back and the company logo.

I also decided to challenge myself with an odd project. I purchased a large box of clockworks from ebay to have damaged clock parts to practice repairs on. 5 lbs of clock parts…… lol.

Also in that box was a severely unloved little clock movement that was almost complete, so I dug around and found a couple pieces that could make it complete with some ‘re-purposing’.

Someone has tried to ‘repair’ this movement previously. Here is a pic of one such ‘repair’.

Yup, a watch gear messily soldered to the back of the plate and drilled to make a pivot hole. didn’t even bother to file down the mess, unbelievable. Man is this thing full of gunk and dirt. I think they dipped it in clock oil and then left it in a dust-bunny colony.

A run through the parts baths make a big difference, check out the clean gears in the back compared to the still dirty gear in the front. Soon I’ll have the whole thing cleaned and ready to unsolder that hack job and do a real repair to the plate.

Ok, enough for now. I’ll post again when I can find the time.

Manly Arts?

Sometimes I just cant get things outta my head. I saw a blog the other day touting the ‘Manly Arts’ and just had to shake my head in wonder. Listed posts under manly arts were things like ‘how to build a campfire, ‘beard oils’, ‘mustache taming’, ‘car camping’, and my favorite (yes, that is sarcasm) – ‘what men complained about women 50 and 100 years ago’. W….. T….. F….. ?

I was thinking about this as I fired up the forge and collected the materials and tools to start melting old lead weights and scrap into usable ingots. In case no one out there has melted scrap down into ingots, there is actually a lot of time to contemplate life and its mysteries as you go about it. The only time you really need to pay attention is when there is hot liquid metal present and ready to splash everywhere it can and solidify. Thus plenty of time to let your mind wander….

So, what all is needed to melt lead down you ask? Does it require the insane amount of heat that aluminum and brass do? Nope, lead is easy, any campfire has enough heat to melt lead. Does it mean that we don’t respect it when you have hot liquid metal sloshing around? Nope, it will still F your sh*t up if it gets on you or something you dont want damaged, thats all the warning your going to get. Here’s a pic of my lead smelting set up.

Pretty simple really, something to hold the charcoal, a cast iron melting pot, and the charcoal to heat it up. I do use the blower on occasion when melting lead just to ramp the heat up for melting larger pieces quicker, but it isn’t a necessity. I throw a couple pieces of lead in the pot when I get the coals lit so I can see when I get to melt temp. As the lead melts and makes a nice puddle in the bottom it gets easier to melt lead that is added since you have a nice big thermal source immersing the new scrap. Almost all scrap lead, like old tire weights, have a bunch of dirt and junk on them not to mention the steel weight clips. Most of that stuff will float to the top so you can scrape it off, which you want to do. I lose a little lead with the crap, but in the scheme of things it’s better to have clean lead than try to save every last gram.

Enlarge the picture and you will see the weight clips and dirt floating on top the lead. I use a small casting ladle I have had for years to scrape the scrum off. I usually just tap all that junk out of the ladle onto the ground then sweep it up and discard it once I’m done with the melt and everything is cooled. Get enough lead melted and the top cleared of junk and you will have something that looks similar to this.

Here comes the fun part, and since I work solo I couldnt take any action shots. Lol. Pouring requires holding that little wire bail in the picture above and using the tab opposite the spout on the pot to tip and pour the lead. Having an aversion to serious pain (I know, not very manly, but I don’t have my beard oil on. In? What is the proper way of wearing beard oil?) I have made a small tool to hook the bail wire and lift the pot that keeps my hand away from it’s contents and I use a pair of pliers to grip the tab for tipping. Oh, and I wear a big ole pair of welders gloves for good measure.

Mmmmm, lead muffins. Seriously, this old cast iron muffin pan makes a heck of a mold for pouring all kinds of ingots. Just don’t use it to bake with or you may have elevated metal levels in your blood. Lol. There is no need for a release agent in the mold as the metal contracts once its cooled sufficiently and falls right out. You can see the gap around the cooled ingots in the pic above.

A couple hours of work turned half a 5 gallon bucket of scrap into the ingots above and it was done before the clock struck noon. I bet a few of you are thinking to yourself ‘Why does he have thick ingots and thin ingots?’ Well kiddos, put on your thinking caps and leave your ideas in the comment section. First one to come up with the reason I do it will get a little of the finished product in the picture sent to them.

One final thing. I did the above work with an untamed mustache, no beard oil, and without complaining about women 50 or 100 years ago. After all, I have enough complaints about women without having to go back in history……. LMAO!

Making molds, saving money

One of the things I love about being me is that I have attempted most everything that has caught my interest. That includes making RTV silicone molds. It’s really not the hardest thing, just a few basics to understand and you can make replicas of most objects. So, since I wanted to make some copies of a part I need in bulk I figured I’d take a few pics and throw it up here for those interested.

Lets start with the basics, this isnt inteded to be a step-by-step (I’ll do one if asked) but more of an overview of the general process. Here’s a pic of the basics needed to get started.

We have a paper plate, a wad of modelling clay, a chunk of abs (pvc will work, but I had this handy) plastic pipe, and a part to be copied. Double bonus points if anyone recognizes the part and what it is used for. The paper plate contains the mess, an important piece of the puzzle. lol. Now to start getting the part prepped to make the mold.

Here is the part mounted on a base of modelling clay. After looking at the part geometry I figured this made the most sense for casting the part. The end that is up needs the shape and recess in it, the other end mates up with another half and isn’t critical. The worst part about making molds is learning to view things as ‘negative space’ that needs to be filled. Remember everything you see on that plate will be a hole full of nothing when the mold is made.

So that is why I mount it to the clay with a tapered base that blends out into the end. It makes it easier when casting a new part in the mold. Just trust me, it will likely make sense later in the post. Now to put our outer container in place.

Just eyeball it centered around the part to be molded and press down into the clay. Unfortunately that wont make a good enough seal. The RTV mold material WILL escape from the smallest openings, trust me I’ve made my share of messes. Thats why I know to use a paper plate.

So to try and minimize the leakage I push the extra clay up around the base of the outer wall and hope its good enough. Usually it is, sometimes not. Now that we have the part to be molded in there, outer wall in place, everything looks sealed…

Time to mix and pour the RTV.

Damn. See the drips all over? The blue RTV sneaking out of the base between the clay and the plastic pipe? This stuff is engineered to make a mess… or maybe I am. Better just walk away and not think that one through…..

RTV has set up and its time to pull everything out. The clay ring and pedestal came out pretty easy, but they do if you use the right clay. We can see the part still in the mold waiting to be free so we can pour resin in the cavity. Best get to it.

HAH! Finished the mold and here it sits. The mold is fully cured and ready to use at this point. Next up is to clean up the mess, put the supplies away and start casting parts. The resin I use cures in around 5 minutes, so it doesn’t take much time to crank out bunch of replicas. I’ll have to count the number of molds on the shelf in the office, but I have made well over a hundred now and even the oldest still works as good as new if properly taken care of.

Melting metal…. with charcoal

Yup, anyone who knows me well knows I like to do stupid dangerous stuff. Things like really hot metal make me happy. Yes, I’ve burned myself (many times) and had some really really close calls but I never seem to learn my lesson. So if hot metal is good, molten metal is WAY better. I have a small kiln I use to melt down gold and silver for doing jewelry casting, but nothing big enough to do a decent pour in aluminum. Off to the internet I went and found plans to fabricate a small melt furnace powered by …. charcoal! I have to admit I was pretty excited, no propane or other gas fuels, nothing like a pesky cylinder to blow up if I get back-flask or the regulator goes wonky. So I built it, now to test it.

A handfull of charcoal and a blower fan out of a roadside dishwasher and we are in business!

After lighting the charcoal and turning on the blower I noticed that it didnt take long for heat waves to start pouring out of the vent hole, so being the smart person I am I opened the top to see what was going on. The charcoal was starting to catch good, lots of red ember. So I put some aluminum scraps in an old soup can and placed it deep in the furnace with some coals around it. Top goes back on and crank up the blower.

This is what it looked like at this point. Nice red hot color in their nice and bright….. wait, ….. whats that smell? Oh damn thats hot!!! I think I just melted off my eyebrows…..

Yeah, it was way hotter over that exhaust hole than I thought it would be. So I put a piece of aluminum over the top to deflect the heat coming out of that little hole to hell. In about 3 minutes I had this..

The exhaust had melted thought the aluminum 3″ above the hole and the force from the blower blew the center of the hole wide open. On the bright side, if its melting aluminum OUTSIDE the furnace, it must be hot enough inside to do the same, lets look at the pyrometer and see…

Yup, it should be nice and melty in there. Being me, I cant just leave it at that, I have to see for myself. So, turn off the blower, get welding gloves and some hay hooks to lift the lid off, pull out the soup can and turn it out over the concrete.

That my friends is melted aluminum. I made sure the concrete was plenty dry before casting the aluminum out on top of it, I dont need steam turning the concrete and aluminum into shrapnel for my face. Now to figure out something to cast for the next post……

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