Dr3w’s guide to HiTek coating
While there are many walkthrough tutorials on how to powdercoat bullets, there aren’t a great deal of in-depth walkthroughs of the Hi-Tek system that include pictures, troubleshooting, tips, and tricks, and those that are currently pinned are so old the images no longer exist. I will do my best to include everything I’ve gathered in my years of using Hi-Tek and centralize as much as I can in one place. This will by no means be definitive, and I’m open to comments and suggestions below so that I can add further guidance for others to learn from.
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Hi-Tek Supercoat is a polymer coating that encapsulates the lead bullet in a protective barrier similar to a plating. It functions similarly to a powdercoat in that it replaces the need for lubrication and virtually eliminates the concern of leading, however and unlike a powdercoat it provides minimal thickness. The Hi-Tek system is used by virtually all coated bullet commercial vendors as it is significantly easier to apply on a large scale.
What is Needed?
Bullets. Collect the batch you intend to coat – you may size them either before or after coating, but it seems that most people prefer doing it before. I do before and after, as post sizing is one last confirmation that the coating has been completed successfully.
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Hi-Tek powder or liquid. In this walkthrough we will be using the powder. The liquid can be thinned down using the provided instructions and used in the exact same manner as the powder.
Note: In my experience the solid non-metallic colors are the easiest to get good results with, and Brick Red has been incredibly forgiving. Metallic colors (golds, coppers, zombie green) appear to be more prone to significant darkening if baked too long or at temperatures outside the recommended range. Darkening isn’t necessarily bad, but if may spoil the look you’re going for.
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Acetone and Denatured Alcohol. MEK can also be used but I’ve always used acetone, and that is what will be used in this walkthrough.
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Containers. You’ll need containers for mixing your Hi-Tek in, cleaning your bullets, tumbling the bullets, etc. HDPE and Polypropylene are the most commonly used, but PP is likely the best option for the container used to tumble the bullets and the coating, as the impacts of the bullets will quickly crack HDPE. I use PP for essentially all of my containers as it’s simply more resilient to use and chemically resistant to just about everything. They can be purchased at most grocery and big box stores – look for Recycling Number 5 and the PP marking on the bottom.
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Syringes/needles. Syringes are necessary for accurately measuring your mix and distributing it among your bullets. Needles aren’t entirely necessary but they can make the job significantly easier and cleaner. You can buy blunt needles online or at some animal feed stores, but normal sharps can be used as well, just be careful. I typically use a 20mL syringe to measure out my solvents and make up the coating, and then a 6mL to actually apply the coating to the bullets.
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Oven/Toaster Oven and Mesh Trays. Either an oven or a toaster oven will work, but most people use a toaster oven as they’re available cheaply and your wife/girlfriend finding you cooking bullets in the oven may be hazardous to your health. Mesh drying/baking racks can be purchased or easily made out of ¼” hardware cloth, soffet vent mesh, or many other materials. In this case I have wired 1/4" hardware cloth directly to the baking trays that fit my toaster oven which gives them a great deal of rigidity.
Note: You will want to test the temperature of your oven/toaster oven using a separate thermometer to ensure accuracy. Many ovens, toaster ovens in particular, vary wildly in temperature compared to what it’s set to – in some cases being off by as much as 40 degrees. With most types of coatings, that could be a make-or-break issue.
Additionally, you should cover or otherwise ensure the heating elements are shielded, especially in a toaster oven. The direct infrared coming off the heating elements can and will scorch bullets that are very near to the element. If your toaster oven does not have a shield to prevent this, you can add tinfoil to block the direct IR heat.
Lastly, adding a heat reservoir/buffer to your toaster oven can significantly improve overall performance. Toaster ovens in particular lose a great deal of their energy when the door is opened and adding material to absorb and moderate that heat loss ensures the chamber comes back up to temp faster. You can use lead ingots, bricks, whatever you have to absorb and retain heat. In this case I am using two 12lb monotype ingots. While it takes a good bit longer to come up to temp, it’s much more stable once it’s there.
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Other items: You’ll need a scale to measure out powder by weight, if you have purchased the powdered variety. Aluminum foil works well to measure powder, and you’ll also see it heavily used in other places throughout this walkthrough. Hot pads/mitts are essential. Cooling racks or trays are helpful as well, as you will be rotating baking trays regularly. Nitrile gloves are helpful unless you like your hands being various festive colors. A mask or respirator is also recommended by the manufacturer when dealing with the powdered coating.
The Coating Process
Make your mix. I make up my batch of mix in 60mL polypropylene bottles. Based on the manufacturer’s recommendation, you should mix 20g powder with 100mL solvent. In my bottles, I typically halve that and go with 10g powder to 50mL solvent. When determining how much mix you need, plan for 2mL of mix per pound of bullets at the very least.
If you have read the manufacturer’s recommendations, you’ll know that they suggest using a blend of acetone and denatured alcohol, especially if you live in a warm, arid climate. The denatured alcohol slows down the evaporation and allows the mix to evenly distribute during the tumbling. This will vary based on your location and climate, and will change the drying time needed before baking the bullets. As my location is very dry and warm, I typically do a 75/25 mix of acetone to denatured alcohol. This works out to 37.5mL of acetone and 12.5mL of denatured alcohol in my normal 50mL batch. To this, I add 10g of powdered mix.
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I recommend adding a piece of buckshot or a 223 bullet to the mix, to help agitate the solids that will settle out of the mix over time.
Shake up the resulting mix and allow it properly dissolve, which will take several minutes. The manufacturer recommends waiting up to 30 minutes for a proper solution with full integration of the powder.
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Note: I personally prefer to only mix up as much as I expect to be able to use in the next few days – stored liquid mix starts to get clumpy and unusable with time – typically a month or two.
Additionally, I also “water down” my mix slightly. While I described making a 50mL coating solution above, I’ll typically add 2.5mL of additional acetone and 2.5mL additional alcohol to thin it out. This ensures that if I accidentally add slightly more mix than I was intending, it won’t go on too thick. It also allows for a bit more tumble time to evenly coat the bullets. This is not necessary but I’ve found that it helps, and doesn’t noticeably diminish the coating in any way. Overall it’s better to add slightly too little than too much – too little just means you may need to do another coating, too much may mean the coating fails entirely or is clumpy and problematic.
Wash the bullets. Yes, I rinse all of my bullets in acetone prior to coating them. It’s not necessary and if your casting area is clean and you use gloves when handling the bullets, it’s overkill. But for 90 cents worth of acetone I can wash all of the bullets I plan on coating and ensure that no oils or greases ruin my attempts. Small price to pay and you will probably agree if you’ve ever had to melt down 5lbs of bullets because they somehow got oil on them and you didn’t catch it until you tried to coat.
For this step I usually pull 80-100mL of acetone and rinse 3-5lbs of bullets at a time. You just need to swish them around for a moment and the acetone will ensure any oils dissolve off quite quickly. Pour off the used acetone to reuse on the next batch. I usually rinse all of the bullets I intend to coat that session right at the beginning. If the acetone looks reasonably clear and uncontaminated after washing all of the bullets, I set it aside and will use it in follow on steps for cleanup. If it appears contaminated or dirty, it can be discarded in a shallow dish and allowed to evaporate.
Once all the bullets have been rinsed, place them onto your mesh trays and allow the acetone to fully flash off.
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Coat the Bullets. Now that you have cleaned your bullets and produced your coating mix, it’s time to apply the first coat. I say the “first coat” because you will typically need two coats. If you’re looking for a perfectly even coat that’s “pretty” you may even need to do a third with some of the metallics, but overall two is typically plenty for functionality.
Measure out the amount of bullets you would like to coat by weight, and then ensure you mirror roughly that weight for each following batch. This ensures that once you get the bake duration right, it will be identical for all batches of that weight. I prefer to do 3-6lb batches in my small toaster oven, but you will need to determine what your particular oven can reliably handle.
In this example I was doing very small batches of only 3lb. Once the 3lb of bullets is weighed out, place it in your container that you will be tumbling in. Then vigorously shake your liquid mix bottle to ensure the powder/flake/dyes are all equally distributed, and use a small syringe to pull a 3mL amount of the mix. Drizzle the liquid over the bullets in the container as evenly as possible, and then vigorously agitate/tumble the bullets for at least 20 seconds to distribute the mix evenly.
Note: I use a tumble container that has a lid and immediately lid the container when I begin my tumble. After ten seconds of tumbling, I remove the lid and complete the tumble without the lid on for another 20 seconds or so. This initial tumble with the lid on ensures the evaporation of the solvents is slowed and allows the mix to spread more thoroughly.
Once the tumble is complete and the bullets have been coated, pour them onto a mesh tray to allow the acetone to evaporate. Depending on your location and climate this may take 5-30 minutes. Ensure the bullets are spread into a single layer and not laying on top of one another – this ensures they don’t stick together and speeds up the drying process.
After the tumbling container has been emptied, I typically clean it with a few mL of acetone and a wipe with a paper towel. It helps make sure no clumps from prior tumbling sessions adhere to bullets in later sessions. Overall I’ve not found it to be required but it’s helpful.
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Note: If you are not in a dry/warm climate, placing the bullets in front of a fan or on a dehydrator set on low may help speed up this part of the process.
Bake and Cure:
Once the bullets have been tumbled and fully dried, it’s time to cure the coating. The manufacturer recommendations are 8-12 minutes in an oven that’s been preheated to 385-400F (around 200C.) The appropriate time/temp will depend on your individual oven, bullet weight, and batch weight. For instance, I know that my oven will properly coat 5lbs of bullets in 12 minutes when at a temp of 390-400F.
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Once the bullets have completed the required bake time, they must be cooled back to room temperature so the coating can be tested and confirmed to be cured. You will typically notice that bullets will come out of the bake darker and somewhat more glossy than when they went in.
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Note: Under curing will result in some issues that we can troubleshoot later, but over baking can in some circumstances be less problematic. In practice, if the coating has been thinly applied and allowed to properly dry prior to baking, there are very few downsides with baking longer than recommended or slightly hotter than recommended. For instance, baking at 390F for 15 minutes provides bullets that are perfectly workable and the coating is not damaged whatsoever, and the only “negative” outcome are bullets that are slightly darker. This is especially noticeable on the metallic coatings.
Testing the cure: After the first batch has come back to room temperature, the coating must be tested to confirm it has properly cured. The two methods typically in use are the acetone wipe and the smash test, which are used together.
The acetone wipe test is simply taking a room temperature bullet after the first cure and wiping it with a paper towel soaked in acetone for 10-30 seconds. After you have wiped it back and forth for that period of time, inspect the paper towel for any color transfer – there should be NONE. If there is color transferred to the paper towel, the coating was not fully cured by the bake and either your temperature need to be increase, or more likely, your bake time needs to be extended. For instance, the below shows what an under-baked batch looks like. This bullet should have been baked for 1-2 minutes further.
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If your batch fails this test, don’t worry! Throw your thermometer back in your oven to verify your temps are in the correct range, and do your next batch extending the bake time by 1-2 minutes. Alternatively, you can lower the total batch weight to see if that improves the issue. You want the acetone wipe to come back totally clean to ensure full adhesion and curing of the coat. Once you have a bake time/temp that works, you can simply re-bake the previously failed batch, and you should be good to use that for bullets of the same general weight, and for batches of that total weight. For instance, .358 projos of 180gn and 30 caliber projos of 200 grain should be able to use the exact same settings if you’re doing 5lb batches of both and it works appropriately on the first.
Below is a picture of bullets that were baked for the appropriate amount of time and passed the wipe test after one bake (on the left) and bullets that failed the first test and had to be baked again but slightly longer (on the right.) Both bullets now pass both the wipe and smash tests and are serviceable. Similarly, if you accidentally bake a batch too long by several minutes, it will darken in the same way but the coating will not have been harmed.
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The smash test is the next step to ensure appropriate mechanical and chemical bonding of the coating to the bullet. This is a destructive test in which you hit one or more bullets with a heavy hammer to see if the coating stays applied. Place the bullet on a solid, hard surface and hit it a couple times with a hammer so that it is clearly deformed. Ensure the coating on the area hit is still adhering, and the coating on the bulged out areas on the side is also continuing to adhere. Run your fingernail up and down the bulged side of the bullet and see if the coating flakes off – it should not. Coating may be scraped away by the impact of the hammer and that is not an issue, and I personally mostly focus on any flaking of the coating on the bulged areas.
If you are experiencing flaking or other issues where large amounts of the coating was removed, your coating did not cure and bond to the bullet properly. This may be the result of oil contamination on the bullet, a lack of a full cure, or a lack of the bullets being fully dried prior to baking.
Unfortunately, if you cannot get the coating to fully stick, the batch will need to be melted back down and recast.
Below are pictures of a bullet that passes the smash test. You can see that the coating is still sticking without flaking or loss all across the bullet – there are some lighter areas where there is no coating but that’s not uncommon on a first coat pass. So long as the coating does not flake or chip away, it has properly adhered.
Note: I size my bullets after coating and that is another helpful process to determine if the coating has properly cured and adhered. If the coating is poorly adhered or cured, you can typically scrape it off with a fingernail after sizing as well.
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If your bullets pass the acetone wipe test as well as the smash test, you can confirm that they have been properly prepped and the coating has been fully cured and adhered to the bullet. Coat, dry, and bake the bullets again to complete the coating process. Once two or more coats have been applied, the coating process is complete.
Note: Typically bullets only need two coats, but if you’re going for pretty AND functional bullets, you may want to coat a third time.
The below bullets have two coats and have been sized and are ready to load.
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Other considerations:
Gas checks may be applied before OR after coating with hitek. I typically add them before coating, as I size my bullets before coating and it’s easy enough to do it then, but overall it can be done whenever is convenient for you.
Water dropping the bullets after the last coating is applied may increase the final hardness slightly depending on alloy composition. TATV did a fantastic video exploring this, totally worth watching. https://www.youtube.com/watch?v=2fbjs-lErL0
You can mix powders to get different colors and effects, just keep the ratios the same.
Multiple thin coats are better than fewer thick coats. The resulting finish looks better and has less problems with proper cure overall.
Hopefully this has been helpful to some of you that might be starting out with Hi-Tek coatings! Feel free to comment anything else that's helped you with your Hi-Tek coatings, from processes to equipment, I'm always happy to learn how to improve my own methods.
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Originally Posted by kevin c
