Fat 30 and Gas Checks

[StanDahl]

I finally put the Lee Fat 30 mould to work a while back after sorting the boolits by diameter due to the rather large variation in size. (Maybe it's me and my casting technique, but maybe I should use it like a 2 cavity mould.) I sized and gas checked the ones that were .314 and larger to .314 using a Lee push-through sizer die. The shank isn't very large and most of the gc's wiggle. Wasn't that supposed to have been fixed before they were sent out? Any recommendations for a fix that even I could do without ruining anything?

Another question - what's a good top punch for lubing these with an RCBS luber?

Thanks, Stan

[NVcurmudgeon]

Stan, a fix that has worked for me in undersize shank situations is annealing the GC. Softening the check eliminates springback and makes them hold tighter. I heat the GC on the electric stove until the coating turns black and flakes off, at which point they are done. For reasons of continued good health, heat the GC in a wide, shallow tin can or pie tin rather than one of SWMBO's good pans.

[PatMarlin]

curmudgeon-

Does that weaken copper? Reason I ask is not for gaschecks, but I've got a water heating coil of copper tubing wrapped around the woodstove pipe, and heat water by thermosiphon. If water stays in the tubing, the copper stays bright and shiny.

I had to do some plumbing work this winter, so I had to drain the system. Meanwhile. the tubing gets heated then cooled over and over on the woodstove, and now is black and flaky.

Does this weaken the tubing? Prolly a good question for a metallurgist.

[StarMetal]

Copper and brass will get dark with exposed to the atmosphere, but I know it gets black when exposed to hydrogen sulfide. I worked at a chemical plant and one of the pollutants we put out into the atmosphere was indeed hydrogen sulfide and it turned anything copper or brass in the plant black. In fact people would ask me my my keys were black. I'd say "Oh, that's from a pollutant where I worked". Usually it was pretty fast too, pennys in my pocket would turn black in less then a week. I remember the cooling coil on a big airconditioning unit in the control room would constantly develop leaks because the hydrogen sulfide would attack it. They ended up coating it with epoxy. That slowed it down. I believe hydrogen sulfide is a by product of combustion too, might explain why it's black around your stove...might be from minute exhaust leaks. Just taking a guess here so don't get excited you have a leak. Would be good to check frequently with a carbon monoxide tester.

Joe

[PatMarlin]

Joe this is turning black simply by heat. The parts that do not directly touch, and set out a bit from the hot stove pipe stay copper colored.

I just wondered if by constant heating and cooling with no water in it, will it weaken it to the point that I should replace it before I send hot water through it again?

[PatMarlin]

Usually it was pretty fast too, pennys in my pocket would turn black in less then a week.
Joe

That's remarkable..

[Ricochet]

Usually it was pretty fast too, pennys in my pocket would turn black in less then a week.

Maybe you should've cut back on the eggs, Joe.

[StarMetal]

I knew John would know what that gas smelled like.

Joe

[NVcurmudgeon]

Pat, sorry but I'm not much on metallurgy. I am of the "if it works for me, that's good and I don't care why" school. I think that's called empirical methods.

[MT Gianni]

Patmarlin, yes it weakens it some but I don't know how much. I have seen fire damaged water heaters and boilwers that have had the tubing turned black from smoke and it wipes off. If it is black and flaky it is wearing. The difficulty is figguring out how much wear you have and how thick it was originally. Bendable tubing isn't near as tough as water pipe and it will expand and contract at a much faster rate dry than empty. Gianni.

[Oldfeller]

Excuse me, but I really don't follow all this discourse on annealing gas checks and stuff. Don't you really just need a very slightly larger gas check shank?

Why don't you just fix the gas check shanks so they will grip the gas checks like the first wavers did, the ones who didn't have their FAT 30 molds sent back to LEE to have them "fixed" ?

[StanDahl]

I did anneal a few gas checks and tried them on. The only bullets I had left were rejects, but those that were fat enough to be sized all around the shank to .314 were left with a snug-fitting gc. Those that were smaller and only partially sized, had a looser fitting gc. So, annealing works, thanks, NVCurmudgeon. However, it is annoying to have to do that to hundreds of gc's at a time, and that leads me back to wondering how that 'first wave' of Fat 30 buyers modified their moulds. I figured that I would need a slightly larger gas check shank, but I had forgotten that that was probably discussed back when, so I'll look it up in the archives. Thanks, Stan...we now send you back to the plumbing discussion still in progress.

[45 2.1]

I did anneal a few gas checks and tried them on. The only bullets I had left were rejects, but those that were fat enough to be sized all around the shank to .314 were left with a snug-fitting gc. Those that were smaller and only partially sized, had a looser fitting gc. So, annealing works, thanks, NVCurmudgeon. However, it is annoying to have to do that to hundreds of gc's at a time, and that leads me back to wondering how that 'first wave' of Fat 30 buyers modified their moulds. I figured that I would need a slightly larger gas check shank, but I had forgotten that that was probably discussed back when, so I'll look it up in the archives. Thanks, Stan...we now send you back to the plumbing discussion still in progress.

As one of the few that have both (first wave and modified by LEE)molds, I didn't modify it and have absolutely no problems with retaining Gator or Hornady checks. Since it worked so well, I have never cast with the modified by LEE version.

[Oldfeller]

Two methods were used to modify the gas check shanks, one proposed by Buckshot was to buy a reamer and milling machine ream the check shank area. I don't know if he did this or not.

I used a lapping approach using a well cast bullet and using the gas check shank itself as a lap form. Use mild lap abrasive like Comet powder, put the bullet in a drill chuck with the gas check end sticking out, charge the gas check end with comet paste (water and comet) then lap out just the six gas check shank holes.

Caution: control the straightness of your drill and don't let the taper "bite" and drag itself in -- gentle and straight is the key word here.

The gas check shank is a taper. You are sticking the same taper into the mouth of the mold in reverse, so it will start (just barely). Do each hole a just a little bit at a time and then go on to the next hole.

You need to stop using a particular lap bullet when the gas check taper will go in the hole all the way up to the driver band -- the lap zone is shot when the lap bullet will do this.

Using only mild abrasive comet powder makes the lapping action relatively slow, so it is nice and controllable. Just a little in each hole then go on to the next hole, the next hole, the next hole -- rotating through the holes multiple times so the amount lapped is equal in each hole.

In effect, you are removing part of the gas check shank taper by doing this reverse taper lap job. Stop and cast after every worn out lap bullet so you know when to stop (when the shank will just barely pick up and retain a Hornady gas check).