How to Coat Bullets Using a Vibratory Tumbler
While “naked” bullets are just fine for most applications, some shooters like to put a friction-reducing coating on their projectiles. Coating bullets can benefit guys who run very high round counts between barrel cleanings. Reader Mike Etzel has come up with a simple, cost-effective way to apply HBN, Moly, or Danzac (WS2) coatings to your bullets. And you won’t need any expensive gear other than your regular vibratory tumbler and some small plastic containers.
Mike explains: “For a number of years I have been using a very convenient way of coating my projectiles with DANZAC in a tumbler. Instead of using a separate tumbler filled with DANZAC and stainless steel balls for coating applications, use small resealable plastic cake or pudding cups filled with stainless balls and DANZAC. Each cup will accommodate between 20 to 70 projectiles depending on caliber once the polishing balls and DANZAC are added. When I need to polish some cases, I insert the sealable plastic container(s) into the polishing material in the tumbler, add cases to the media, and in the process clean cases and coat the projectiles simultaneously in one tumbler. This does two operations in one session, saving on time and resources.”
While Mike uses DANZAC (Tungsten DiSulfide or WS2), you can use the same impact-tumbling method to moly-coat your bullets, or to apply HBN (Hexagonal Boron Nitride).
TIPS for COATING your BULLETS, by GS Arizona
1. Start with Clean Bullets. This is simple enough, but some people overlook it and others overdo it. Get the bullets out of the box, wash them with warm water and dish soap and dry them. No need for harsh chemicals, after all, we’re only removing some surface dirt from shipping and maybe some left over lanolin from the forming process. Don’t handle them with bare hands once they’re clean, your skin oils will contaminate them.
2. Get Everything Hot — Real Hot. This is probably the single most important element in producing good-looking moly-coated bullets. I put the tumbler, the drum and the bullets out in the sun for at least 30 minutes before starting and then do all the tumbling in direct sunlight. On a summer day in Arizona, everything gets to the point that its uncomfortably hot to handle. If you are tumbling in the winter, you should heat the bullets in some form, a hair dryer can be useful, but they will cool off in the drum if you’re tumbling in cold temperatures. Your best bet is to plan ahead and do your coating in the summer. I coated about 3000 bullets in a couple of days recently to see me through our winter season (we’re a bit reversed from the rest of the country in terms of shooting season).
Similar Posts:
- Tumbler Method for Coating Bullets with Moly, WS2, or HBN
- Efficient Method for Bullet Coating with Moly, WS2, HBN
- Boron Nitride Application Procedures for Bullet-Coating
- Applying Boron Nitride (HBN) to Bullets
- Sinclair Product Report: Thumler’s Tumbler with Stainless Media
Tags: Anti-Friction, Boron Nitride, Coated Bullets, Danzac, HBM, Moly, Molybdenum
I clean my bullets 100 or so at a time with denatured alcohol in a tray, then pour the liquid into a jar for re-use. Drop the bullets on a doubled paper towel, and rub them dry. Then into a plastic Rx bottle filled with a dash of moly and several #8 lead shot.
Tape the bottle lid tight,rotate them in the tumbler for 2 or 3 hrs.,take them out, roll in a clean towel, and they are done.
Watch out for water absorption by the denatured alcohol (ethanol + additives) solvent! Contrary to popular belief, moisture does adversely affect the lubricity of sub-micron dry lubricant particles of Moly (MoS2) and tungsten disulfide (WS2), by causing particle clumping etc.
A more effective solvent would be isopropanol (isopropyl alcohol, ~99% pure), as it is significantly less hygroscopic than denatured alcohol (i.e. ethanol + minor additives) and will thus absorb less atmospheric moisture and at a slower rate. This should allow you to re-use your alcoholic Moly (MoS2) or tungsten disulfide (WS2) slurry longer without sacrificing efficacy due to moisture absorption.
Your moly/WS2 slurry will also absorb significant moisture from the bullets themselves, as metal surfaces hold surprisingly large amounts of water due to surface adsorption from air. Therefore you should heat-dry your bullets before Moly/WS2 coating by first oven-drying at ~120-150 C (250-300 F).
For best results, first clean your bullets with pure (99%+) acetone, then air-dry thoroughly to remove residual solvent liquid and vapors (VERY IMPORTANT, acetone is FLAMMABLE!!). Lastly, heat pre-cleaned bullets in an oven at 120-150 C (250-300 F) for at least 60-90 minutes, making sure to keep the oven door ajar to release liberated moisture. Also, turn on the convection fan if your oven has one, or periodically open oven door and manually fan the air every 20-30 min (to displace humid air with “dry” room air). Let bullets cool in a dry environment if possible (ie. a container filled with desiccant). Alternatively, let bullets cool on the counter to around ~40 C (104 F) or until they’re just cool enough to handle, and begin the dry-coating process in a vibrating bullet tumbler. However, for alcoholic-slurry coating (like “tenring”), allow bullets to cool to room temperature.
-synthon
No such thing as DANZAC.
Should stop perpetuating misnomers.
Editor: DanZac was a popular tradename for Tungsten Disulfide ( Ws2 / DanZac ). See: https://www.bulletcoatings.com/
I dump out the media and wipe out the bowl.Put a lb. of bbs and a tablespoon of HBN . Let it vibrate a couple hours Separate the bullets and bbs then slosh back and forth in a towel.
I never knew you can do coating for this. Thanks for sharing.