Deburring a mold cavity??

[SgtDog0311]

I cast with a nice mould the other day but when opening the mould I found the right half to be much more tenacious in retaining the bullet. I suspect burs but don't see anything obvious. Still, it made me wonder what is a good technique that is not aggressive or even reckless to deburr a cavity? I read the lee-menting sticky so if that's the answer then I have it but wondering if there are other techniques, particularly for a steel mould?

[OS OK]

A pencil eraser, rub it against the edges of each cavity and any little burrs will break off.

First mold I did I used a narrow pointed blade razor knife, sketchy method and took a long time doing a 6 banger. I didn't try to cut the burrs, I drug it backwards across the edges to break them off...don't bother trying this because the first time that razor edge is moved in the wrong direction it'll try to dig into the soft aluminum...big mistake.

[427smith]

had a lee mold last year that was cut off center, about wore my arms off trying to tap bullets out.

[longbow]

First, to check for burrs take a cotton swab and drag it around the edges of the cavity, if there are burrs the fibers will stick. If there aren't then possibly the cavity is slightly off center.

If it is an iron mould and has burrs I would take a piece of copper or brass rod and drag that around the edges of the cavity to try to break off any small burrs or wire edge. Alternately a "Lee menting" or light lapping with very fine abrasive like Comet or a super fine polishing compound should do it.

What make is the mould? is it new or used? Are there any dings around the edges of the cavity?

Whatever you do best to be gentle even with an iron mould. Burrs on iron moulds are very much stronger than burrs on aluminum moulds but if you get too aggressive you can round off edges. Something softer than the iron should be used for sure.

That's my take anyway.

Longbow

[SgtDog0311]

Pencil erasor... had not thought about that. Was just fiddling with a piece of leather having a stropping strap in mind and thinking that would be safe but lots of grooves in this and hard to get a good swipe at it.

This particular mould is a BACo and casts a nice bullet but one side drops easy and the other side hangs on like it has teeth. Saw mention of an exacto knife elsewhere besides OS OK's post but that is not something I would attempt. I'm sure if I did I'd slip. My eyes are bad as it is so that's out.

I was thinking of a cloth rotary type buffer on a slow speed but getting in the grooves would be an issue I think.

[country gent]

I check with a cotton q-tip and the pencil eraser to work the edges. A wood pop cycle stick can be cut to fit easier and a light rubbing will smooth the edges also. I have also used bamboo skewer sticks from the grocery store. Look at the bullets and see if there are bright spots on the grease grooves flats. Mold may have grease grooves that arnt relieved to allow release. This is a problem with square grease grooves. I would look over the mould under magnification for rough edges burrs and unsquared surfaces. Work slow and carefully. A piece of brass rod on steel moulds works well also.

[SgtDog0311]

A good friend sent this to me unasked and I gave in and cast a couple hundred - time to send it back. Don't like to borrow moulds but he's kinda like that. Give you his shirt if you don't watch him. So last thing I need is to abuse it. Popcycle stick is about as aggressive as I'll get. Thanks!

I did use a magnifier and it does look rough along the edges of each driving band but no burrs you'd fasten on and say "there is the culprit". Not sure how much of that is normal or something that a lee-ment kind of process would improve. It's not my mould so I won't find that out, but I will buy one from BACo pretty soon and I'll see how that one drops. I'd still be a little uneasy about tapping then turning a cast bullet inside a cavity and following the whole lee-ment process with a custom mould. I can go to change a thermostat, watch the steel bolt shred the threads in the base and wind up having to tap and drill the thing for a new bolt. Good carpenter maybe, otherwise not so much. I've never used any release agent in the cavities other than smoke on some aluminum molds. I'm still at that stage where I learn something about every time I cast. Also at that stage where I need to write it down - since I got started a lot later than most of you fellahs.

[OS OK]

Is that you and your hog in the Avatar? I love to ride too...I have a V-Rod...faaaast!

[country gent]

We kept q-tips in the tool crib at work for this. Die cast and injection moulds can be fussy and it no fun having a tree stick. A little fine work should fix it. I will perfom the rub test on a new moiuld before even trying it casting just to save possible issues. Its more patience than hard

[SgtDog0311]

Is that you and your hog in the Avatar? I love to ride too...I have a V-Rod...faaaast!

Never rode a V-Rod OS. But love my Roadking. One of the last EVOs. Bought it new in 98. I'm like that guy in the FB placards: I don't ride often... but when I do it's in awesome country. I trailer it to Northern Idaho ever so often and ride the Northwest Hwys and some into Canada. My wife complains about not being able to carry a gun. There are grizzly signs about every park you stop to take a walk in. Every once in a while I ride out to Colorado Springs and went on a Run for the Wall a few years back. Those platoon formations and 2-second intervals are a little nerve wracking but the experience was a great one. Almost got taken out when a semi blew a tire next to the rider in front of us. Ten foot of tread stood straight up in the air for split second before sliding across the highway right in front of me. Deer are the treacherous thing up north. Never ride before sun is well up and put her away before dusk. Have known a couple up there who lost their lives to deer.

[SgtDog0311]

Wayne, I tried a cue tip and the rough edges didn't catch very bad. But a piece of leather pushed hard against the edge and drug out left some behind. If there are burs at all they are very small but I imagine they are what prevents it falling out on that side. Just enough to kill your cadence is the problem. I'm gonna try the popsicle stick on mine once I order it and get it in.

[longbow]

Popsicle stick might work but I'd try a copper or brass rod. Won't hurt the mould at all.

[SgtDog0311]

Popsicle stick might work but I'd try a copper or brass rod. Won't hurt the mould at all.

Ok longbow, help me out here. I'm not sure how I'm using a brass rod. I imagine using a popsicle stick to sort of saw back and forth 'on edge' in each relief of lubegroove and band and along the ogive relief. But I have no image of how a round rod is being used to get in the corners at junction of bands and grooves.

[OS OK]

You could use a file to shape the end of a 1/4 or 3/16's to a profile like a flat tip screwdriver, make it as small as you need.
But...I thought you were talking about an aluminum mold...I don't think I'd use brass on that!

Deer are 'the' problem here in the hills and higher Sierras. I ride at night but I have a couple of small added lights up front that are incredible, they light everything in a blinding white penetrating light...when I run without them on I sometimes think my regular headlight is faulty.
The V rod has 5 speeds and red lines at 9K, I can ride all day using the gearing on the mountain roads and never tap the brake until I come to a stop. I enjoy the speed and power but more than anything else I like the torque it has in the mountains, smooth and best of all it is not loud that engine just purrs. I had an irrigation project going this past summer and didn't put even 200 miles on it...I'll try to change that this summer.

[country gent]

A trick is to trim the popcycle stick or bamboo skewer so the end is at an angle and flat to work the edge of the surface easily rubbing along the edge ( think sanding with the grain) will smooth rough edges and remove burrs. If really bad a little fine polishing compound worked into the end of the stick will speed things up. Red Rouge, flitz, simichrome, toothpaste, or auto rubbing compound will all work.