Reviving an Abused Mould . . . Lyman 358311 RN

The Lyman 358311 RN description:

358311 Standard bullet for revolvers using .38 S. & W. Special and .38 Colt Special Cartridge. These two wide bands are strong and hold the rifling well. Case should be slightly crimped in bevel groove. (PlainBase, RoundNose, 158gr. – Top Punch is 311)

Reviving an Abused Mould . . . Lyman 358311 RN 3

The Abused Mould

This is the shape she arrived in a week ago…

Reviving an Abused Mould . . . Lyman 358311 RN 5

At first glance this mould almost appeared to be serviceable right off the bat so instead of my usual routine of putting her in a boiling soapy bath, I skipped and went to a two day soak in an Acetone jar followed by a good scrubbing with a soft bristle brass brush to clean all the little cooked-on flakes of lube and rust particles from the surfaces.

Reviving an Abused Mould . . . Lyman 358311 RN 7

In the cavity I used a .410 shotgun mop for scrubbing the old patina and getting back to the raw steel. The patina is good, that’s what you want in there, but with a used mold one can’t be sure that the previous caster had used mould release which will build in thickness over time and you get shortchanged on the cast actual size.

Reviving an Abused Mould . . . Lyman 358311 RN 9

You can see that the mop will conform to the cavity when it starts spinning at a slow to medium rate…first one direction and then reverse the drill motor and run in the other. This will ensure you get the cavity cleaned all around and up to the mould face edge. I used to run a plastic bore cleaning brush to do this and sometimes it might be necessary if you have stubborn release agent in there. I like to avoid hitting the wire of the brush against the cavity at the nose end where I could scar this soft steel of the mould.

Reviving an Abused Mould . . . Lyman 358311 RN 11

From here, assuming I had her clean as I could get her, I went into the pre-lubing of all the screws, their threads and the threaded holes they screw into, the bottom and top of the sprue plate and the shoulder of the screw that it pivots on and the alignment pins both the male and female counterparts. I like the small artist brush for getting a minimum amount of the Anti Seize into all the hard to reach areas. Notice below that I put it on the tongs of the handles, bottom and top where the mould blocks ride and swivel to open and close.

Reviving an Abused Mould . . . Lyman 358311 RN 13

Notice the shiny bottom of the sprue plate in the picture above. It started out looking like below, it is sitting on a piece of wet sanding paper of 150 grit. I put my finger in the sprue fill hole and apply pressure and sand that plate on the paper until I get it looking like the next picture. I want the hole in the sprue to be sharp for easy cutting and I want the sprue to lay flat on the top of the mould.

Reviving an Abused Mould . . . Lyman 358311 RN 15

The rough looking interior edge of the sprue hole is little fragments of lead still stuck within the hole, they are no problem as I just use a tiny scraper and get rid of them before first casting.

Reviving an Abused Mould . . . Lyman 358311 RN 17


Reviving an Abused Mould . . . Lyman 358311 RN 19

At this point I’m ready for a test casting of the type of bullet metal I have blended up for this cast. It’ll be a typical Clip On Wheel Weight lead with enough Tin added to bring the mix up to about 2%. I fire the pot up to about 725ºƒ and throw in some wax to top the bullet metal off to prevent oxidation of the surface and get ready to test cast.

Next I put the mould into the mould oven and wait for it to warm enough to give a pretty good cast right off.

Reviving an Abused Mould . . . Lyman 358311 RN 21

I pull the mould a little too early and before it’s at least 350ºƒ and I get wrinkles on the casts…that’s to be expected and will cure itself when those blocks come up to temperature but the first thing I see is the mould trying to fin and the parting lines on the mould seem to be open a little bit. This is a problem I hadn’t anticipated.

Reviving an Abused Mould . . . Lyman 358311 RN 23

Well, I open the blocks and look closely but I don’t see any little particles of lead holding the faces apart. Next I open the sprue plate and hold the mould in a closed position up against the light and try to see a light coming through as I peer in to the cavity but I see nothing but a dark hole. Now at this point I think the blocks may be warped but that’s a long-shot…there must be a ding on one of the mould halves that is doing this. I’ll have to cool and disassemble the mould to work on it farther…these fins will not do.

As it turns out, I have to use a fine file to flatten the mould faces as I had discovered that the blocks had raised bumps all around the edges. This will happen if you don’t store the moulds with rubber bands or tie wire around them to keep the halves together. If they get knocked together this soft steel in the blocks will ding and raise an edge ever so slightly as if they were made of modeling clay. You can see the shiny steel showing all around the edges where I carefully filed with the file flat against the face.

Reviving an Abused Mould . . . Lyman 358311 RN 25

I reassemble the mould once more and decide that I might just peek under the sprue plate to see if there is any gap there…I raise it to the light, peek and see a line of light coming through. It seems that those dings and bumps are affecting the mating of this plate also. I had already made sure that the sprue plate was even and flat when I sanded the bottom side. So…back to disassembly and filing on the top of the mould to remedy this situation.

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I was more than amazed when I saw how badly the top surface actually was. No biggie, the file does the work. See the shiny places where I removed metal? Peeking between the sprue plate and the top of the mould after this did not allow light to come in between. Doing this ensures that your base of the cast does not rise above the top of the blocks adding weight to the cast and giving an irregular shaped base. The sprue will cut very clean also.

Reviving an Abused Mould . . . Lyman 358311 RN 29

I’m now ready for another test casting. I put the mould in the oven to preheat once more and wait with baited breath for a good result this time. If you look closely, you will see that the mould parting lines are still there in some instances but they are not raised and finning out between the mould faces again.

Reviving an Abused Mould . . . Lyman 358311 RN 31

I think I can remedy this situation with another careful filing of the faces and careful inspection of their mating. Also, I can put the blocks together, clamp them tightly and use a 1/8″ punch to insure that the male mating pins are fully engaged in the female counter part of the mould faces.

I’ve run out of time this day to go farther as I determine that these casts will be fine ‘if’ these small parting lines do not show when I Poly Coat these casts. Off to the PC tumble tub and then to the oven to find out…

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I am very pleased at this outcome and decide to make a dummy set-up .38 Special. I go off to the sizer and then to the Lyman T Mag II for a dummy cartridge. I have placed that dummy round amongst other old .38 Special rounds I have collected over the years. My objective with this color PC is to replicate the looks of that old cartridge that I grew up with back in the late 50’s when I first started shooting the .38S. Which one is it?

Reviving an Abused Mould . . . Lyman 358311 RN 35
(It’s 4th from left)

That’s the story boys and I’m sticking to it. There are many different ways to refurbish these old moulds, it all depends on the tools you have available in your shop. What you have read is just the way I have done it with this mould. Below you see four different .38 Special / .357 Magnum casts that I have found in old used single cavity moulds…each one had to be refurbished to some extent but they survive from as far back as the 40’s and are still casting today.
L to R you see (1) a Lyman 358430 a 200 grain RN (the old Police Special), (2) the 358311 you just saw refurbished, (3) the 358429 a 170gr. SWC, and finally (4) the 358477 a 150gr, SWC.

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When your extra moulds that are not on handles are stored away I would suggest that you keep them in their original boxes, but in most cases those old boxes are long gone to us collectors today. I would suggest you look at your local big box store to find some type of tool/parts case that will do that job and protect them for decades to come. My brother Manny gave me this box and it is perfect for my storage. As my collection grows I will add another box like this one for my precious old girls of times past.

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In years past I have used WD40 sprayed liberally on these girls to protect them from rust. Here in California in the Sierras I have a warm and mild climate but you boys over in the South and East along the Atlantic seaboard, where humidity is a real problem, will not find WD40 satisfactory. I liked it because a quick spray of brake cleaner would ready the mould for the preheat oven and the mould would not make gas marks on the casts. I am changing now, thanks to a couple of members here at TRN and their advice, and now I will be using a coating of Mineral Oil USP. I am using an old mason jar and a cut off artist brush I can keep in the jar to keep this new mould protection oil handy. They say this will not gas in the mould, rather it burns off clean and the brake cleaner is not needed anymore…”Good riddance to that stuff!”

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If you are interested in reading about a mould that really tested my abilities to refurbish it, I have written about a year ago in TRN about a Hollow Point mould that almost drove me crazy…here’s the link to that article:

Reviving an Abused Mould . . . Lyman ‘Devastator’ 356637 – 9mm 125g. HP

Thank you for reading this article, I hope that something here might help you save your old problem mould or just tune up a mould that you have not been satisfied with. I have other articles I’ve written over the years, the following link will take you to my TRN Author Page, please take a look as you might find something interesting…


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