lost wax investment casting of silver pendant

by:Max Apparel     2020-09-16
This is my follow-up to my silicone mold making.
I used the mold I made in there to inject the wax and use those wax to make the silver investment casting.
I have skipped the wax injection process now (
Because I forgot to take pictures)
, But I will come back next week when I run more wax.
I will learn the investment casting process with wax or any other organic material you would like to cast.
The whole process is tedious from preparing, designing and making masters to making molds, injecting wax to investing to pouring metal, but strangely, it\'s fun and rewarding.
There are a lot of places where things go wrong, which makes it more satisfying and exciting at the right time.
Here are my supplies for wax melting casting process: prepared cast wax or other organic form cast particles for cast925 sterling silver (
Clean silver crumbs)
Sandwinkel, who disclosed investment in the American Wax Museum
5 \"steel casting flash light 2.
5 \"rubber base with sprueRubber mixed bowlVolumetric flask hole for waterubber spatulavacum chamber vacuum assisted flask holder made of jim rubber gasket for vacuum assisted xacto knife for spruingTree sprue scale, the washer can be weighed with a stick on my phoneKilnSteel board to capture the waxborax powder)
As you can see, the little torch leather gloves, the protective glass bucket with the water big steel pliers can pick up the solution of the hot glitter paint, which unfortunately is not the one you can do in the morning of the day
It takes a bit of preparation to arrange everything and some workshop space in advance.
Step by step, you can do it!
The lost wax method did a great job copying all the details.
Out of expectation for this, I am trying to make my wax as perfect as possible.
I use Kerr\'s leaking wax and a fragile metal film as a spatula and my fingers apply it to any creases caused by an incomplete filled wax (
Wrinkles, dark lines, small flaws, etc. ).
The leaking wax is very good and can be used in small quantities and should disappear if applied properly.
I also used a very fine wet/dry sandpaper to smooth the edges, where the flash was small.
I took it off with my finger, but even the small wax burrs left will produce sharp silver burrs that need to be dealt with later.
Waxing is much easier.
For a couple of reasons, I made sure my exit was relatively clean and tidy.
First of all, I don\'t want to waste any silver on the gate block, and secondly, I want to keep the channels open as much as possible.
I have read that roughness can cause turbulence, which can cause problems with finished silver castings.
I cleaned them out of the roughness caused by the box with chisels and sandpaper.
Silver casting is more like chemistry class than art class.
Because this stage of making my pendant is more scientific than art, I followed my chemistry professor\'s advice over and over again in the lab;
Keep everything in your notebook.
Measurement/calculation :--
The weight of the no-wax Gate base--
Fill the flask with water and pour it into the volume flask to get the total volume capacity of the steel flask. --
According to the US directive, the volume of the steel flask has increased.
6 to obtain the amount of water needed for the portfolio. (
60% of water and 40% of investment)--
Calculate the weight of the required investment by multiplying the water ml by 2. 5.
The shorter the distance the melted Silver needs to travel, the better, so shorten the gate as much as possible while still allowing the necessary space between the wax.
There should be at least \"\" between the model and the side, and \"to 1\" between the tree and the top \".
If the top is too thin, the molten metal breaks during the pouring process.
We use the Xacto blade to connect the gate of the part to the trunk, heat it to two wax with the torch, and let them melt together.
I suggest to practice first before solving the real problem for the newbie and feel it on the junk wax.
It takes several times to get this feeling.
Make sure the connection points are firm and smooth, and there is no gap in the wax.
Any gap will be filled by investment, or broken into the mold during the pouring process, or interfering with the metal flowing into the part.
Fill with melted wax if necessary.
Note when pouring: Make sure your gate is large enough to feed your parts.
The gate needs to be connected to the thickest part of the wax and needs to be thicker than the thickest part of the wax.
This is due to the way in which the molten metal crystallizes inward from the wall.
If the gate crystallizes and sets faster than the part (
Because it\'s small)
It will cut off the flow of metal to the part (
It will be a painful ass).
When you build the tree, the smallest part should be towards the top of the tree, while the larger part should be towards the bottom, and you should start working from the top.
I only poured 3 wax this time, so we only separated them evenly in one row.
If there are multiple main parts in a single wax section, please pour each major part to make sure it is filled properly.
My pendant is small enough that I don\'t even need to take extra steps.
You should try to keep your exit to the 45 degree corner of the tree.
This allows the metal to flow down the tree more naturally and smoothly when you pour it down.
Our trees are small enough, so it doesn\'t matter. Science time!
In the notebook :--
Weigh the tree on the base-
Subtract the basic weight previously written from the total weight to obtain the wax weight--
Multiply the wax by 10.
4 get the required silver but then add an amount (
50% of the wax required)for button.
Carefully place the flask on the rubber base and place a masking tape on the top of the flask.
This will prevent overflow when de-gassing.
This is a very stressful step!
You have to do it in Window 7. 5-9 minutes.
If you finish too fast, the investment will be separated, and if you finish too late, the investment will start to build.
Pour the amount of water you wrote earlier into a rubber mixing bowl.
The manufacturer recommends deionized water.
It is recommended to deionize or distill because it is more stable and plaster paste is more likely to have predictable properties when mixed.
Additional ions or substances in the water can adjust the setting time.
Add the investment to the water and mix the blocks.
I use my hands so I can feel the lumps and crush them.
It is the consistency of pancake batter.
I started timing when I started increasing my investment.
I mixed for 3 minutes.
Put the rubber slurry bowl into the vacuum chamber and don\'t freak out when it starts to boil violently.
Let it cook the small heart for about 30 seconds.
Then turn off the vacuum and pull the Prede-
A mixture of gases discharged from the chamber.
Ready to pour wine.
Pour the investment on the side of the flask, be careful not to dump it crazily and add any air in the process.
Also, do not pour directly on the wax tree.
The weight of the investment may break the air of parts or traps.
Using the volume method I described earlier, you should get the right amount of slurry to fill your flask with very little to no remaining slurry.
Now put the flask full of investment back in the vacuum chamber and let it cook 60-90 seconds.
It spit out and it doesn\'t seem like it should. It’s ok.
Once the time is up, let it set for about half an hour and then remove the bottom of the gate.
At this point, let it dry anywhere from one hour to one night.
There is some room for maneuver in this step.
I burned the wax as per ABC\'s instructions/schedule.
I put the flask on the wax side on a few steel bars to give the wax a place to melt.
Since I don\'t have a controller for the kiln, I have to keep the temperature manually.
I put my little notebook next to me and write down the temperature and time so I can make sure I don\'t heat it too fast.
9 degrees per hour is a reasonable ramp time.
Do it according to your investment schedule!
You need to start slowly, otherwise the wax will expand in the early days.
Once the wax melts, the temperature rises to solidify the investment.
The last hour was a hot bubble because when we poured the silver we wanted the flask to be around 1000 degrees.
Get the numbers you previously calculated from your notebook.
Silver needs at least 50% virgins.
We used 60% virgins and 40% clean scraps.
Get the vacuum table while you are (
Party or center)
The prepared water and barrel have used the torch and keep it on the melt to prevent the oxygen from entering and thus reduce the oxidation.
Before removing the flask from the hot soak in the kiln, let it mostly melt.
Depending on how much silver you have, what power or torch you have, it may take a while for Silver to melt.
Add a little borax to the melt.
Turn it on if you are using a vacuum cleaner.
Place the rubber gasket on the vacuum table.
My next melt will get more photos, but my hands are full and I forgot to take enough pictures of melting and pouring.
I lit the silver light and put the torch on the silver light, but in order to keep the heat on the surface of the silver light, I turned around the silver light.
When the silver first melts, the surface tension keeps the silver in the ball.
I fell when the surface tension barely broke because the pour temperature was nearly 100 degrees Celsius higher than the melting temperature.
The VaUse clamp pulls the flask out and places its holes on the vacuum Workbench gasket.
Continue to ignite the melted silver until it loses the surface tension and then pour into the hole to keep the flame on the metal all the time.
You want the flame to turn back (low on oxygen)
Prevent oxidation.
Fast down, confident down.
The longer you spend, the greater the risk of metal crystals and blocking flow before you finish.
That\'s it.
After the pouring is completed, let the metal rest for a few minutes before quenching.
I don\'t have a picture of it.
Please forgive me.
I will update the picture soon.
After a few minutes, dip the whole flask into the water with pliers to break the investment.
After the foam stops, remove the silver from the bottom of the bucket. Forget the picture--
I will add it next time.
It comes with some oxidation and is easy to remove with Scotch whisky and warm kimchi.
Not that kimchi.
Kimchi is an acidic solution that removes fibers and other waste from the surface.
I use battery acid (sulfuric acid)
Dilute to 10% in a hot bath of about 150 degrees Fahrenheit and heat for about 20 minutes.
To avoid having to put my hands in battery acid, I put a thin silver thread on each pendant and put them in a glass jar.
Clean up very well
We dip it into the warm liver of sulfur, then polish it and add a little strategic oxidation.
I hope this helps, as I mentioned, I will add more pictures to my next pour.
Please feel free to contact me or comment if you have any questions or comments.
I love instructures, both learning from others and sharing what I have learned, I hope to help! !
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