bubble-free resin casts with modified paint tank

by:Keyuan     2020-06-09
This manual shows how to modify and use the pressure paint tank for pressure casting.
This is mainly useful for realizing foam.
Cast effect of free transparent or translucent resin/polyurethane.
The first step is to modify a low
The cost paint tank and the section below describe the pressure casting process.
I think you have a mold (
Here\'s a great guide on making the mold, and a video of making a simple block mold, as I used below)
Basic knowledge of casting.
Professionals 5-
Excluding compressors, the price of the gallon pressure chamber is over $700.
The price of the refitted paint can should be below $120 and of course you still need an air compressor.
You need: except for the mold (
Ideally no airbubbles)
, Casting materials and mold release agent.
Note: The Gallery image shows two projections of the same material (
Popular 325 polyurethane plastic at Smooth On)
One is pressurized and the other is not pressurized.
In addition to pressurizing the first casting, I used the exact same mold and process for each casting.
First of all, if you have never operated an air compressor, it can be dangerous to understand that it is a very noisy machine, especially with a pressure chamber.
Please read the safety manual before proceeding to make sure you understand how to operate the machine safely.
If you are buying an air compressor for pressure tanks only, a good compressor that is relatively cheap is \"pancake \"(
You also need a starter kit).
Do not forget to drain water after each use to ensure its maximum life.
Once you have an air compressor with an air hose and connect the 1/4 \"mother quick-
You will want a pressure paint can.
I have been using 2 & 1/2 gallon central pneumatic pressure paint tank from port freight.
The price was advertised online for $100, but I bought mine from a local store for $80 on holiday sales.
I don\'t think it\'s important which brand you choose.
Perhaps more importantly, make sure it holds the size of your mold (s).
To convert a pressure paint can into a casting pressure chamber, four things need to be done.
For the first three steps involving connecting a plug or connector, you will need to use a threaded sealing tape.
Make sure all three plugs/connectors are tightened.
Note: For steps 2 and 3, I recommend bringing your paint can to the local hardware store and testing the cap on the appropriate connector/socket to make sure you purchased the correct part(1)
Wrap the threaded sealed tap around the connector on the left side of the regulator with the wrench of your choice and attach a 1/4 female plug (
I think it\'s easier to use an adjustable wrench, but it\'s likely to scratch the cap.
I don\'t think it\'s important because I\'m not going to remove the hat, but use a shrink wrench if you\'re worried about that). (2)
Wrap the threaded sealed tap around the connector on the right side of the regulator and connect the 1/4 \"npt cover using your chosen wrench. (3)
Wrap the threaded seal faucet around the paint outlet and attach the 3/8 \"NSM thin line cap (
Different threads from previous cap)
Use the wrench of your choice. (4)
There is a metal tube on the underside of the lid.
Take a hacksaw and simply cut it off.
In the regular use of the tank, this is the drawing of the paint, but since we are closing the paint outlet and using the chamber entirely for something else, we want to create the maximum space in the room.
Now the paint tank is converted into a positive pressure chamber and now is the time to prepare the casting mold.
I will use Smooth-Cast 325 (
This process is also essential for crystal clear series)
Therefore, there may be some steps specific to this material.
During the purchase process, be sure to read the material data sheet and consult the technician for more details.
If you need to brush the mold-
This is a good resource.
Before we start pouring, I think it is important to discuss other potential issues, because in the process, a lot of problems go wrong, not only wasting time, but also causing serious money.
First of all, if you use silicone as a mold material, you should know that most RTV silicone kits require vacuum degassing to reduce surface bubbles inside the mold (
This is a video about the process, please note the bad pouring technique of 1:57
Smooth technicians to further reduce bubbles
It is recommended that you pour high, do not pour directly on your object, there is only one place, as shown in this video 1: 12).
The workpiece in the mold cannot be fixed by pressurizing.
The price of the professional vacuum degassing room is as high as $200, but thankfully, the guiding price for making DIY vacuum equipment is about $20.
There are other techniques for preventing bubbles, such as putting silicone in a large self-sealing bag, mixing, cutting off a corner and pouring.
I think it is worth a try, but if the mold you pour needs more volume, I think the DIY vacuum device is feasible.
Still, there are a few products that can
Although they are not perfect, breathe on their own.
One of the products is the Mold Star and of course you will want to practice the techniques shown in the product video.
I haven\'t seen any other products.
But I\'m sure they exist.
Unfortunately, there is no resin that can pressurize itself, so this manual is required. Ok moving on.
Once you have the mold ready and work in the well
Ventilation area, wear gloves, glasses and masks before spraying in the mold.
Let\'s sit for about 15 minutes or no matter how long your posting recommendation will take.
Man\'s easy release 200 is a smooth free product recommendedCast 325.
Next, mix Part B first (
Clearly marked on the product).
Keep the mixer stick at the bottom of the container and make sure to scrape the edges.
Smooth if you are adding dyes or any additives such as anti-UV treatment
Cast asks to mix it in this step.
After the B part is completely mixed, add the same amount of A part (Smooth-
The mixing ratio of Cast 325 is 1: 1).
You need to work quickly at this point because of the working hours (\"pot-life\")
About 3 minutes 325.
If this is too fast for your app, you can also try 326 or 327
7 minutes and 20 minutes respectively.
Be sure to set everything up before adding Part (i. e.
Compressor and voltage regulator ready).
When adding Part A, remember to mix gently as this material is low in viscosity and will splash around.
It is not necessary to mix as hard as you use silicone.
I mixed up for about 45 seconds and always timed it with a stopwatch.
Once the material is fully mixed, \"Low Down\" and in one place, this helps prevent the introduction of extra bubbles (i. e.
Close the mixing container as close to the mold as possible, then pour it in and keep it stable).
After pouring, you should notice that there are some bubbles on the surface, but since you are going to pressurize the castings, you don\'t have to worry about them! (
Note: When the pressure chamber is not used, it is much more important that the pouring is low. . .
Practice good technology will never hurt you anyway).
Next, put the mold into the tank.
I use a round piece of wood to make sure the mold doesn\'t fall down because the bottom of my paint can is concave.
Be careful not to move the tank once the mold is inside, as the mold may be dumped and spilled (
Learn from my mistakes and be conscious once the mold enters the tank).
Do not try to clean up the material if this happens
Wait until it is cured before taking it out.
If you\'re worried about this happening, spray some release in the tank ahead of time so it\'s easy to clean up.
The following steps are recommended practices in the paint cans manual.
The manufacturer recommends tightening the opposite lid screw while sealing the cover.
I tighten all these screws.
Before turning alternately to the opposite pair, turn once, which ensures that the lid is evenly sealed at all points.
If the seal is incorrect (i. e.
Too tight in one place or not tight enough in another)
, You will hear the sound of air leakage, will not reach the best pressure.
I think it would be wise to practice pressurizing the chamber once or twice before pouring the mold to check again if all the covers and covers are safe.
As shown in the figure, once the cover is tightly sealed, remove the end of the air hose, the peal back cover, and then connect to the plug.
Then open the compressor and monitor the pressure.
The compressor will reach 20-
Paint tank meter 30 PSI before moving.
Once the paint can is up to 45-
50 PSI, turn off the compressor.
You should not hear air leakage and the pressure should remain the same.
Leave the mold in the paint tank during demoulding time, which is the earliest recommended time to remove the casting from the mold.
After the removal time is over, release the compression coupler from the plug.
I suggest wearing earplugs because of the loud sound.
Then unscrew the lid and pop out of the mold.
While pressurizing helps to achieve excellent results, it is the sum of all good practices and techniques that ultimately produce the best work.
My pressurized crystals look great compared to unpressurized casting, however, if you look closely, there are some products that do not Degas (
I used the mold Star 15, or recommended the degassing, not done)
Too high pressure (above 50 PSI)
Causing \"measles \"-
Damage the small hole of the mold.
Initially, I followed the technical announcement of the Renault advanced material pressure chamber (
Pressure is recommended at 60 PSI)
After talking to the technicians, they advised me not to exceed 50 PSI.
However, my Mold was ruined at this point.
I hope you won\'t.
Due to the first experience, I did not damage other molds with a pressure of 50 PSI and wanted to show what would happen if you exceeded this threshold.
I wish you good luck in casting work and feel free to comment if you need more advice.
Although I am by no means an expert, I will do my best to answer your questions and get a lot of help on my journey as an object manufacturer.
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