Hi tek flaking off

[Petander]

Virtually impossible to get 3N37 here now.
Bloody brilliant powder.

3N37 is not very common around here either.

I bought a can today, visited a quite a big gun store that's been around for decades. But it was my first visit there. The guy told me "I've worked here for two years and sold quite a lot of gunpowder. But you're the first to buy 3N37."

People use faster powders... often for economy reasons. I always aim for the best ammo I can make and once again 3N37 makes it, this time 9mm 160 grain cast FN Hi-Tek. Pressure/vs velocity is under control,very very good accuracy around 950 fps.

[glockfan]

3N37 is not very common around here either.

I bought a can today, visited a quite a big gun store that's been around for decades. But it was my first visit there. The guy told me "I've worked here for two years and sold quite a lot of gunpowder. But you're the first to buy 3N37."

People use faster powders... often for economy reasons. I always aim for the best ammo I can make and once again 3N37 makes it, this time 9mm 160 grain cast FN Hi-Tek. Pressure/vs velocity is under control,very very good accuracy around 950 fps.

i have several pounds of 3n37. it work, but what i don't like is it's too slow for the typical load density of 9mm. you can see it burns much slowly than 320. i get more flash out the ejection port
and muzzle , some unburned powder.....

it's slow, and the recoil is quite different than 320.more like a
delayed, longer recoil. however, this specific powder is used by the guys in the open class.

btw i only use vitahuori powders because it is consistent batch to batch, and it burn very,very clean.

[Petander]

Glockfan,you're right,3N37 is very slow for the usual 9mm. Heavy bullets like it. It feels like a "push" with my 160 grainer, N320 is a quiet,fast,"snap" with this same bullet. But I can get much more velocity with 3N37. And a very low velocity variation,silhuette-like accuracy up to 100 meters.

But now,I really need to check N320 again because I discovered tha .357 size is shootable too. This has been .358 only,for accuracy.. Now that I got my alloy based coating problems sorted out.

Part of my "slow-and-heavy" -liking must come from my 1911 past. It took me years to switch to 9mm from 45 ACP and actually start hitting things again with doubles etc.

I've used 3N37 for heavy bullets in 10mm,357 and 45ACP,too. Also works for 308 subsonics.

[Petander]

Petander,
I am glad that all has worked out.
I was getting quite concerned with your previous failures.
You have exposed the difficulties when using "unknown" alloys.
Please finish last coat, and take picture, then load and shoot and report back.
Joe

Excellent results with those white,cleaned bullets. Cleaning rules again.

Here is a loaded,crimped round pulled apart. Coating is absolutely fine. Shoots super clean.


Attachment 223179

[Petander]

Attachment 223334

To the left is a bullet as cast,to the right is the same bullet after an overnight HCL soak and a wash. I tried some mystery monotype in the mix,the letters look rusty.

Anyway,the left bullet fails and flakes after the second coat, the right bullet is very very good and easy to coat.

[Petander]

No flaking. Just a perfect coat.

Attachment 223357.

Attachment 223358.

Overbaked,I know but these work great. My oven does not drop below 200 C when I load the bullets in, it won't go over 204 either. Ten minutes.

It seems that I get better gloss and quality now,when I am completely avoiding the initial temperature drop in the beginning of the bake. It is 230C before I open it, I then load it and when I close the door it says 202.

[Petander]

Out of curiosity,I also tried fluxing with sulfur.

JAttachment 223361

I used small amounts, about a tablespoon altogether in a 20 lbs pot. It burned and fluxing got some black powdery stuff floating out of the alloy. Zinc?

But well, I get black stuff on the bullets in HCL. I rather wash it away from bullets than burn sulphur with molten lead anywhere near my nose. (That sulphur is oooold,I used to make Black Powder when I was 13 or so.)

[popper]

Probably a lead sulfate. Sulfur turns red when melted and black just before it burns. Your boolits will stink. Trick is to melt the sulfur, then immerse it. Zn sulfate should be a brownish dusty powder. S is a good alloy hardener but yes it is stinky. I prefer the cuso4 trick. It will add Cu and remove Zn & Sn. HCL removes oxides, calcium residue AND removes tin. Vinegar actually etches the lead, converts to a rough oxide (I can't spell it) so IMHO the Hitek holds better. http://nautarch.tamu.edu/CRL/conserv...ual/File14.htm
Also why red lead artist paint turns white.

[Petander]

Popper,thank you for the excellent article.

Bonding good here,too:

Attachment 223376

[Stephen Cohen]

Stephen,
I am looking forward to your results.
If things are considered, a lot of crazy alloys are acid treated, (Anodized) using Phosphoric Acid type systems, so that coatings can be applied that will bond.
Unfortunately, Phosphoric Acid is not suitable for removing such things as Zinc and Magnesium, as these metals form an insoluble compound with Phosphoric acid, that would leave a loosely adhering powdery surface which will compound the coating adhesion problems.
As suggested, Vinegar will work but very slowly as it is very dilute. With Hydrochloric, you control strength, and metal contaminants that you are removing are soluble in water using the Hydrochloric acid and the Vinegar.

I can now state with certainty that water quenching cast as they drop from the mould, does not cause flaking, if a good alloy is used, in my case Lino. I would suggest that water quality may play a good part perhaps. I suspect that quenching with a suspect alloy may well add to a flaking problem. Regards Stephen

[glockfan]

I can now state with certainty that water quenching cast as they drop from the mould, does not cause flaking, if a good alloy is used, in my case Lino. I would suggest that water quality may play a good part perhaps. I suspect that quenching with a suspect alloy may well add to a flaking problem. Regards Stephen

water quenching is often the culprit i guess. it all depends of the water quality in your specific area. i'm in the mountains,and the water comes directly from underground sources-streams . a high quality water, but it is unfiltered.of course unfiltered waters are no good for high tek since foreign microscopic elements may be found in it,preventing the correct bonding. i don't water quench for this specific reason,and anyways, the heat cycle associated to the baking process act quite the same as water quenching.

[Stephen Cohen]

water quenching is often the culprit i guess. it all depends of the water quality in your specific area. i'm in the mountains,and the water comes directly from underground sources-streams . a high quality water, but it is unfiltered.of course unfiltered waters are no good for high tek since foreign microscopic elements may be found in it,preventing the correct bonding. i don't water quench for this specific reason,and anyways, the heat cycle associated to the baking process act quite the same as water quenching.

I tend to agree that water quality may well cause flaking, I actually started water quenching to speed up my process and have had no adverse effects, I use a clean plastic bucket and replace water often. I will admit that I will not be doing so anymore as I no longer need to add another step to the process. I would drink that water in your area as if it were fine wine as nature intended. You have taken me back to a time when I would drink water from my Grandads spring and live off the land. Regards Stephen