Powder coat varieties

Ian

Notorious member
I take it that most people who are powder coating their bullets are using the polyester powders with the TGIC cross-linkers. The only drawback that I can see to that is that TGIC is the mother of all carcinogens and without a really, REALLY good mask and extreme care in handling it's really tough to keep from inhaling it. For men who are still trying to father children, (like me), TGIC could be a particularly serious problem.

As a solution to that problem, some kinds of PC have been formulated to be TGIC-free and thus a lot less harmful. Problem is, like most things, that kind might not be as good. I also have found that there are acrylics and polyurethanes, as well as epoxies and hybrids. The epoxies are supposed to be hard and brittle, I would think that's not a good thing (HiTek anyone????), though the urethanes might have some promise and the TGIC-free polyesters might be fine, too.

Has anyone tried out powders that they know to be TGIC-free? I ordered some polyurethane a few days ago and will give it a go, will report how it does when I get around to using it.
 

gman

Well-Known Member
Ian,
Do you happen to know what type smoke4320 sells? That is the powder I'm using. You have me curious.
 

Brad

Benevolent Overlord and site owner
Staff member
I don't know that Hi-tek is really that brittle. I find that even extremely expanded bullets keep a good coating over all surfaces. Might be the extreme adhesive nature of it?
Hi-tek is also a much thinner coating. More on the order of .001 at most, not the .002-003 I see on many PC bullets.

I do wonder how the differences in coating make up change the properties for shooting. I had a guy PC some bullets for me and just the difference in slickness of the gloss and matte finishes was amazing. The gloss sized down easily, the matte fought me tooth and nail. I can only imagine the difference in barrel behaviour.
 

yodogsandman

Well-Known Member
I think many of us are buying small packages of PC powder that's been dispensed from a larger container. Say a 25 lb box into a zip lock baggie suitable for about a pound of powder. No further information about the powder is supplied with the baggie. At least that's been my experience.
 

fiver

Well-Known Member
I'd just ask Smoke he has been pretty up front about everything anyone has asked.
 

Ian

Notorious member
Something else that has me interested in checking out other kinds of powder coatings is chemical resistance. Urethanes and epoxies are indicated to be more chemical resistant than polyester or acrylic, which has me wondering about the Titegroup Phenomenon. I'd really, REALLY like to be using Titegroup in a couple of my PC loads like subsonic .308 with x-tra heavy bullets, and .38 Special.
 

fiver

Well-Known Member
I really think you'd be fine using titegroup.
but I wouldn't do a long term storage thing with it.
 

Brad

Benevolent Overlord and site owner
Staff member
I wonder how much nitroglycerin is lost from the Titegroup due to contact with PC.

Looking into the literature I found a study where up to 60% of a nitroglycerine IV was lost to a absorption into IV tubing. That isn't a long trip and is a big loss.

I sure wouldn't want to leave high nitroglycerine content powders loaded for long periods of time in contact with PC. It could be made better by storing the ammo bullet up so the powder rests in the bottom of the case and contact is reduced.

Would be interesting to see a properly conducted investigation determine the extent of the powder degradation. Hard to say if ballistics would be changed and if so how much.
 

Brad

Benevolent Overlord and site owner
Staff member
Oh, PVC is about the worst plastic for nitroglycerine handling. Harder plastics like polyethylene are far less likely to absorb nitroglycerine.
Not sure what plastics are used in powder coat but vinyl isn't good with Titegroup.
 

fiver

Well-Known Member
power pistol sticks to it too.
you could always turn them bullets up in the storage box.

soooo um,,,,,,,,, are there any impractical uses for a nitroglycerin soaked IV line?
 

Brad

Benevolent Overlord and site owner
Staff member
Not that I know of? I don't work hospital and I tend to avoid hazardous medical waste.

Bullet up would work well except for rimmed cases, most ammo boxes won't accept them rim down.
 

Ian

Notorious member
I think most of the powders being used for bullets are polyester based, at least the ones I've been using up to now. The modern powder containers are made from HDPE, #2. Titegroup softens the plastic that RCBS used for their Uniflow reservoirs in the 1980s. This is pretty much all I know for sure at this point.

If it's the nitroglycerin in the powder that is interacting with certain polymers, then I guess I need to be worries about Reloder 7 powder. Last check it had been bumped to around 15% which is pretty dang high.
 

300BLK

Well-Known Member
My polyester powder came from Powder By The Pound. I've only used it a little so can't comment (yet) as to how powders do or don't react with it. I did coat a batch of 9mms that I could combine with some known high NG content powder(AA5744) and see what happens.

I have a number of measures, but only use the Reddings these days (other than the Dillon). Never have I had powder stick in any of them.
 

Ian

Notorious member
Ok, got in my new order of powders today and played around with some tonight. The Polyester TGIC powders still shake'n'bake the best, hands down....except for the low-gloss varieties, which simply won't coat with the bb/shake method.

I'm very encouraged by the urethane powder I got (Black Magic is the color), but still working on the best way to apply it. Shake'n'bake is so so, it coats well but it takes nothing to scratch and ding it to bare metal, so it's virtually impossible to pick them out or pour them out of a tub without lots of ugly marks. There's another issue, too, it flows. I say issue because it will leave significant flashing on the bullet bases if they are stood up to bake. So far the best method seems to be just pour them out on screen wire after shaking/coating, then roll them onto foil and bake on their sides. This leaves a little flat spot on the side, but not a bare spot. If the bullets stick to each other, very little coating is pulled off either one when they are separated while warm. This coating sticks well and has a completely different feel than the poly powder. The bullets have a satin, soft feel and don't clink and tink when you run your hand through a pile of them, it's almost a true "plastic coating" feel. I like it. The urethane powder is quite abrasive and actually roughens the surface of the bullets when they're aggressively shaken (like fine blasting sand), which may be putting lots of tiny, conductive metal flakes into the mix that kill the static cling somewhat. I think this powder would work best when sprayed with an ES gun, but the bullets would have to be placed on their bases with smaller-than-base-sized washers under the foil to prevent base flashing.

I'm going to try the urethane powder in a vibratory tumbler with no bbs to see if that doesn't get the powder to stick better, and continue to either pick them out with needle nose pliers and lay them on their sides on foil to bake, or just pour them out on hardware cloth, shake a time or two to remove excess powder, and cook them in a pile like most of the utoobers do. I'd like my 300 Blackout subsonic bullets to look nice and have an even coating for best accuracy, so figuring a way to coat and bake them without flashing, flat spots, or lots of little contact defects is going to be a challenge. I'll probably coat some more laying down on foil and shoot them to see how they do before trying to invent a new way to make this powder work.

The Poly TGIC powder is easy as pie to shake/bake (IF you get the standard glosses and buy quality powder), and shoots great, so it will take a lot to pull me away from that stuff, even if it's toxic. I'll continue to wear a good dust mask while handling it, and the shake/pick method makes for very little mess if the work surface is covered in a thin bath towel, so really there's not much health concern if one is careful and isn't spraying or vibrating the bullets to get them coated.
 
F

freebullet

Guest
All my test used hf powders.

I got red to work in 9mm and a few other successful tests with it but nothing special. Had some loaded over titegroup for just over a year they all fired as normal.

I can tell you under cooked powder coat will gum your barrel and take an hour per inch of barrel to clean out. Not fun!!!

The process of coating takes to long to cover our volume loads.
 

Ian

Notorious member
I think the HF powders are the epoxy type. Still trying to determine whether polyester or urethane will tolerate nitro.
 
F

freebullet

Guest
I would guess the hf powder is polyester due to price and it being single part. Epoxies ime usually are not cheap or single part.