film blocking flash hole

[bow shot]

'Never seen this before... after tumbling some brass, I found many of them have a strange film covering (likely plugging?)the flash hole... on the outboard side. Here are the details:

Laupua brass processed after this manner:
1) F/L sized , using RCBS lube
2) Tumbled in a Thumbler's for 24 hr
3) Media is crushed walnut, with 1 Tblsp of Brasso polish (mixed well befroe tumbling)
4) Tumbled on the back porch, 20 - 30 degrees temp.
5) Media has been used for perhaps 500-1000 cases of 204, 6.5x55, 6.5 grendel...

I'm guessing it was the temperature? Anyone else ever experience this?

 

[Immike]

It looks like moisture got in the tumbler or the cases. Probably condensation from temperature change.

 

[bow shot]

I think you nailed it.

Tumbled 'em again all night (inside this time). Nice and shiny but still plugged. Not that I expected them to clean up...

Time to get out some tools, LOL!!

 

[jonbearman]

What kind of primers were you using?

 

[ar10ar15man]

i might susggest getting away from walnut and go with fine ground corn cob.
i sell brass for a living and not one of the other retailer/wholesalers that i deal with use walnut to polish brass.
i know one large company that uses a propritery wash, ALL others use corn cob.
look it up on drill spot ot grainger as blasting media.
add NUFINISH car polish...half the cost of brass polish...a cap full or so..

looks like walnut powde/dustr that got damp and packed in the hole.....

 

[Old Navy]

I had several problems with junk in the flash hole. Decided a long time ago to de-prime after cleaning. Later! Frank

 

[RCurtis]

Decided a long time ago to de-prime after cleaning.

+1.

 

[ronemus]

NEVER use a polish containing ammonia (such as Brasso) to clean cartridge brass - the brass becomes brittle and is likely to crack with catastrophic results.

 

[LCazador]

NEVER use a polish containing ammonia (such as Brasso) to clean cartridge brass - the brass becomes brittle and is likely to crack with catastrophic results.

Yeah ten four on that ! The Brasso is breaking down the brass and the walnut media . I have heard of this before . Use treated corn cob media and if you have to add anything Flitz or Rooster Brite work very well .

 

[ar10ar15man]

i missed the brasso ..yep big no no...toss all the media in the tumble.

skip high priced metal polishes.....nufinish is half the cost.....

 

[bigedp51]

There is a very simple way to prevent the film from forming over the flash holes, just wet tumble your cases with stainless steel media.

Stainless steel pins were made in China. They must be Asiatic metric sized. :

 

[bow shot]

Thanks for the excellent intel folks! I shall heed.

Now does this mean my brass is junk-o? I probably need to at least wash it?

Funny you should mention tumbling with primers intact Frank, that's my normal method. However, this was a lot of brass that i purchsed from a "brother", and it came to me de-primed.

'Probably the only reason I've never encountered this before is I've always tumbled before de-priming!!

 

[ljhsniper1]

Try Kitty Litter,works great and MUCH cheaper. Walnut/Corn Cob way more expensive.

 

[bow shot]

I ended up washing it all by hand (dawn) and tumbling agan with a little Nufinish added. All nice now.