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Remember those Happy Meal toys you couldn’t wait to get your hands on as a kid? Do you remember the texture in your hands and the lingering scent of a junior cheeseburger as you played with them for the first time? Well, some of those toys were made through the classic process of resin casting before mass production technology changed into what it is today. This article will take you through the ins and outs of using a pressure pot for resin casting as well as the best products for the job.
Table of Contents
- 1 What Is a Pressure Pot for Resin Casting?
- 2 What You Need for Using a Pressure Pot
- 3 Best Pressure Pot for Resin
- 4 How to Use a Pressure Pot for Casting
- 5 Can You Make Your Own Pressure Pot?
- 6 Frequently Asked Questions
What Is a Pressure Pot for Resin Casting?
Resin casting is used to produce a variety of models from casts. These casts can be characterized as molds into which the resin is poured and left to set. Once the resin has cured, the mold is then separated, revealing the newly “minted” figure inside. This process can be used to make figurines, toys, jewelry, ashtrays, decorations, book dividers, phone covers, and similar products.
So, if the resin is capable of setting on its own, what is the point of a pressure pot? A pressure pot is essentially a vacuum-sealed container that is pressurized by a small compressor unit. In short, you place your resin-filled molds in this container and seal it (always ensure it is airtight). The compressor then fills the resin pressure pot with air pressure, which causes any air bubbles in the resin to collapse in on themselves, leaving you with a flawless workpiece that is ready to be painted.
Why Do You Leave Resin in a Pressure Pot?
Ordinarily, when you create an object from resin and remove it from the mold, there is a high probability that there will be air bubbles trapped inside your new workpiece. These air bubbles create imperfections in the workpiece which then need to be removed, filled, and smoothed out before any finishes can be applied. A resin pressure pot makes the design process seamless, which is important when the material you are working with is time-sensitive.
The point behind using a pressure pot is to remove imperfections from the resin, although this is easier said than done, especially if you are new to this technique.
The problem with using this device is that it requires a lot of foresight and preparation, not with the pressure pot itself but in the mixing of the resin. Typically, when using a pressure pot for casting resin, your goal is to mold multiple pieces simultaneously, which means that the molds need to be placed in the pressure pot and filled from there as opposed to filling the molds from your workbench and then carrying them to the pot.
The tricky part is mixing a sufficient amount of resin for all the molds you will be placing in the pressure pot. As you can see, this requires a fair amount of measurement and forethought, especially considering that most resins set within minutes of being mixed. This means that you have just a few minutes from the time the resin is mixed to fill each individual mold, ensure they are sealed, seal the pressure pot for casting, and then start the compressor. All in the interest of ensuring there are no imperfections in your workpiece.
Pros and Cons Using a Pressure Pot for Resin
So, you know what a pressure pot is and what it does, but is it always the best tool for casting? Well, this depends on the volume of work you do and what you will be casting from your molds. Simple castings in low volume with fewer details and robust proportions tend not to have as many imperfections, but casting with thinner extremities and complex molds can certainly benefit from a pressure pot. Let us have a look at some of the pros and cons of using a pressure pot for resin casting.
What You Need for Using a Pressure Pot
So, now you know that using a pressure pot for casting resin not only has a huge advantage in terms of time-saving, but it also decreases the amount of vibration needed to remove your workpiece from the mold. This being said, you are probably itching to get your hands on one of these so you can start pumping out your marvelous creations in mass! So, what do you need to get started?
Pressure Chamber vs. Vacuum Chamber
Both the pressure chamber and the vacuum chamber are useful for their respective applications; therefore, it is imperative to know where each is applicable and under which circumstances you will be able to get the most out of each device. Let us have a look at both devices below.
Pressure Chamber (Pot)
The pressure pot is fairly simple. As implied by the name, it creates a pressurized environment inside itself through the use of an air compressor. This pressure directly impacts the resin inside the molds which collapses the little air bubbles in the resin that cause imperfections. Air bubbles in resin look like little holes in the workpiece, and you can prevent these by using a pressure chamber. It prevents air bubbles by causing the resin to fill the gap entirely instead of allowing small spaces for air bubbles to form.
The pressure in the pot can then be vented to the atmosphere via a release valve, although you should always ensure that this is done outdoors, as the fumes generated by the resin can be harmful if inhaled. Keep in mind that you will need a compressor to operate a pressure pot. Pressure pots are more often than not the tool of choice when working with resin that has a fast cure time. Cure time plays an important role in choosing between a pressure pot and a vacuum chamber because one device reaches its maximum effective state in a shorter period of time than the other.
Since a resin casting pressure pot can take several small- to medium-sized molds, which typically use a fast-curing resin, it is the machine of choice for using a fast-curing resin solution.
You should think of a vacuum chamber as the opposite of a pressure pot. Where the pressure pot uses compressed air to create a pressurized atmosphere inside itself, the vacuum chamber removes the pressurized air from the pot in the interest of removing imperfections.
Why would you do this if you could simply vent the pressurized air out to the atmosphere, you might ask? Well, as we covered above, resins do not retain the space where air bubbles once resided, but instead spread out and take it up. However, when working with rubber compounds, the opposite happens – the rubber often retains the void where the air bubbles reside when pressurized. In other words, the rubber prevents the air bubbles from collapsing in the pot.
Thus, instead of increased atmospheric pressure, it is best to remove the atmospheric pressure from the container when working with compounds that have good shape retention (like rubber compounds) in order to remove any imperfections.
The vacuum chamber removes all the air from the chamber, avoiding this problem entirely.
Do I Need Both Devices?
Like most things in crafting, it really depends on what you’re looking to do. Pressure pots are most conducive when working with resin compounds because the process of pressuring the pot is pretty much instantaneous. This is perfect because the average time resin compounds take to set in a mold is roughly three minutes depending on the brand and application. This means that once the compounds have been mixed to form the resin solution, you only have roughly three minutes to pour the substance into the molds and activate the pressure pot to ensure that all imperfections are removed from your workpiece.
Vacuum chambers are not always conducive to working with fast-setting resins, which, as we mentioned earlier, is due to the short amount of time resins take to set. Why? Well, it can take a few more minutes for a vacuum chamber to reach the right atmospheric pressure inside the chamber, and considering that fast-setting resins are often used, a vacuum chamber simply does not work fast enough for this application. However, if you are working with a resin that has strong shape retention and does not set as quickly, a vacuum chamber would be more up your alley.
Deciding on which resin is the right choice for you can be challenging. Fortunately, Incredible Solutions offer a wide variety of resin products for virtually any application, with everything from resin coloring, high-volume resin mixers, clear coating epoxy, polishing compounds, and even putty for your molds! For your convenience, we have detailed some of the incredible products they offer below.
Pourable Plastic Deep Pour Clear Casting Resin
This Deep Pour clear casting resin can be used for several applications. Typically, this type of resin is used to fill deep cracks to create a blended aesthetic effect, this technique is more commonly used to breathe life into old tables, countertops, and door even doorframes of the hardwood variety. The resin is easy to use – simply decide on which volume is best suited for your workpiece and mix the appropriate amount.
- A special deep pour 2" thick casting resin
- Low exotherm and low viscosity with long working times
- Colored epoxy compatible - mixes well with mica powder
Crystal Clear Tabletop Epoxy
Have you ever wondered how some people preserve things like stamps, butterflies, coins, and photographs in tabletops? Well, the older solution was to use pressed glass, which presses these objects into the recesses of the table base, but with the advent of epoxy, there is a much easier way to achieve a tabletop finish without breaking the bank! Simply mix the amount of solution you need and pour it into the tabletop recess. This epoxy can take between four to ten hours to cure (you can accelerate this process if you pass over the epoxy lightly with a blowtorch) and once completed, you will have a crystal-clear tabletop finish!
- This Table Top Epoxy cures ultra-clear and non-yellowing
- Perfect for tabletops, bar tops, and countertops
- Blemish-, water-, UV- and impact-resistant coating
UV PRO Formula Clear Tabletop Epoxy
The UV PRO formula is striking, just like the clear coating tabletop epoxy. The preparation is the same in that you mix the solution to your desired volume, but instead of using the solution to fill a recess, the intended use of the UV PRO formula seems to be to create a laminated finish. This can be used to create a sheen finish for projects like photo albums or scrapbooking pages. This product is ideal for surfaces that will be exposed to the sun’s UV light, as it is formulated to resist yellowing and will provide a durable, long-lasting finish.
Best Pressure Pot for Resin
Choices, choices…we’ve looked at what a pressure pot does and even where you can shop for all your resin and epoxy needs, but in the same way that there any many resins to choose from, there are quite a few pressure pots out there. So, are all pressure pots for casting resin created equal? Well, that’s for you to decide. Below, we have detailed a couple of units that we think hit all the right spots.
Best Professional Pressure Pot for Resin: CALIFORNIA AIR TOOLS 10-Gallon Pressure Pot
The California Air Tools pressure pot for resin makes its mark as a reliable product with a premium feel. This unit comes preassembled and allows you to get straight into the thick of things as soon as it’s been unboxed. If you need your pressure pot to be portable, this one comes with three wheels that attach directly to the flanges at the base, which is especially useful when moving the pot outside to vent the pressure.
It comes equipped with a pressure gauge, pressure release valve (to which an adapter can be attached), and a high-quality Teflon finish. This tank can be operated at a max pressure of 60 PSI but can be pushed to 80 PSI without fear due to its overload valve. Overall, the pot is reasonably priced, easy to use, and requires no assembly out of the box.
If you are looking for a pressure pot that you can order and use straight out of the box with no assembly or head-scratching required, the California Air Tool’s pressure pot for resin casting is exactly what you’re looking for. We find that the quality of this product justifies the price, so at the end of the day, you are definitely getting what you pay for.
Best Price-Performance Pressure Pot: Shop Fox Pressure Pot
Just so you know straight off the bat, this is not one of those “out of the box” pressure pots for casting resin. The Shop Fox is a paint pot designed to deliver pressurized paint to a paint sprayer, and although it may not be designed to function as a pressure pot from the factory, its fundamental application makes it a prime candidate for conversion. There are roughly 160 people who have successfully converted this paint pot into a fully functioning pressure pot for resin casting.
What makes Shop Fox a targeted unit for the pressure pot conversion is its design and features. It has a serviceable two-and-a-quarter-gallon capacity, is cast from galvanized steel for reinforced strength, comes with a pressure release and safety blow-off valve, and has a pressure gauge all as standard. Unlike the California Air Tools model we covered above, the Shop Fox’s gasket and seal are not attached to the lid but rather to the pot itself, which can hold a maximum pressure of 45 PSI and has a standard operating pressure of 30 PSI.
The Shop Fox might not be intended for use as a pressure resin casting pressure pot, but it does do the job quite well. With some modifications that can be done in a few minutes, and with the help of a YouTube tutorial, you will have a perfectly serviceable pressure pot for a fraction of the price compared to a factory unit!
How to Use a Pressure Pot for Casting
Using a pressure pot for casting resin is fairly easy when you know what you’re doing, and with some practice, you should be well on your way to making lots of little trinkets to your heart’s content! Below are some simple steps you can follow to ensure that your resin castings are flawless works of art.
Place Your Molds into the Pressure Pot
The first thing you should do is place your resin molds inside the pressure pot and leave the lid open. Make sure that you position them so that they are easily accessible later and remember not to close the lid or activate your compressor just yet.
Mix and Pour Your Resin into the Mold
Mix the resin you will be using into the appropriate volumes. Once this is done, fill the molds with your freshly mixed resin, being sure to act quickly as most pressure pot resins tend to set in just a few minutes.
Seal Your Pressure Pot and Turn on The Compressor
Your last step is to seal the pressure pot off and clamp the lid down. Once you are sure that the lid is secure, turn on your compressor and set it to the recommended PSI for your particular mold and resin. Take note of the curing time for the resin you are using and, when ready, release the pressure from the pot (be sure to do so outside or in a well-ventilated area) and remove your flawless new castings.
Working with pressurized containers can be extremely dangerous if they are mishandled, not used for their intended purposes, or pushed beyond their design tolerances. This means that there are a few things you should keep in mind when working with a resin casting pressure pot, spray paint pots, or any other pressurized containers.
- Never exceed the operating pressure and always follow the user manual when operating the device.
- Never release pressure pot resin fumes indoors or in an unventilated area, as they are toxic if inhaled.
- Never attempt to release the pressure from a pressure pot during compression or at any time when the pressure gauge dictates that there is pressure inside the container.
- Always wear a mask with particle filters when mixing and pouring resin.
- Do not allow the resin to come into contact with your skin – if it does, seek medical attention immediately.
- Always inspect the pressure release valve and safety valve on your container before using it. This could save your life.
Can You Make Your Own Pressure Pot?
There is an age-old saying of “what you cannot do yourself, you will pay for,” and this snippet rings true in many aspects of life. Is it impossible to design your own pressure pot? Not at all, but then again, rebuilding your car’s engine from scratch isn’t impossible either, but chances are you don’t have the expertise to pull it off confidently. Knowing what you’re doing is important because when forces like 80 PSI of pressure are involved, taking a chance really isn’t an option.
If you are new and would like to attempt it, some devices can easily be converted into a pressure pot. Previously, we discussed a paint pot for paint sprayers which over 100 people successfully converted into a pressure pot. There are YouTube tutorials that teach you how to do this with readily available devices, so if you are up to the challenge and would like to spend some elbow grease instead of a few bucks, then we say go for it! It honestly does not take too much work as with the correct hose attachments, the right know-how, some caution, and the right tools you can have your own pressure pot for your resin molds in a few minutes!
Regardless of whether you choose to make your own pressure pot, use a vacuum chamber, or go out and buy one that is ready to use, the important thing is choosing a device that suits your needs and ultimately provides you with flawless castings. We hope this that this article has helped in your decision making and as always, happy crafting!
Frequently Asked Questions
Can a Pressure Pot Be Used as a Vacuum Chamber?
Well yes, it can. Pressure cookers are designed to withstand quite a bit of pressure and with the right tools and attachments, you can successfully convert a pressure cooker into a vacuum chamber. We suggest that you start off with a smaller one as they are typically cheaper and a lot easier to replace if you’d like to practice first.
Can a Pressure Pot Explode?
It is possible for a pressure pot to explode, although this would require serious negligence with regards to the safety valve, pressure release valve, and gasket. On the odd chance that this does happen, it can prove fatal as the contents of the chamber along with the material that the pot itself is made of can become high-velocity projectiles.
Does a Pressure Pot Cure Resin Faster?
Not at all. Pressure pots are typically used with fast curing (setting) resins because they work at removing air bubbles fast. Essentially, a fast-curing resin needs its air bubbles removed quickly, and this is why these two are commonly used together. The resin cures via a chemical heating process and, since the pressure pot does not do much in the way of affecting air temperature, it does not cure the resin any faster.