Ruined a Mold

[leadman]

I have a Lee new style 2 cavity mold for their 200gr 30 caliber boolit that I ruined. I have been using the mold & sprue coating that comes from J&M Specialities (Hi-Tek) but don't think this was the cause.
The mold had gotten very dirty with alot of specs of lead stuck to the surface. I used Bar Keeper's Friend cleanser (like Comet) and a toothbrush to clean the crud off the mold halves to make it easier to see the lead specs. Thought all was good and lubed it up and starting casting then noticed the boolits looked strange. They were about .005" out of round.
When looking things over to find the problem I noticed that all of the venting lines were gone from the mold faces. Apparently the scrubbing had removed these and now the cavities are out of round. I know that the new style venting is a very fine pattern unlike the older style. Guess it is more prone to damage than the older style.
I do have another mold on the way and am glad this was a Lee 2 cavity rather than a more expensive mold.
All is not lost though since I have been thinking about modifying a mold by removing the lube grooves for use with the Hi-Tek coating. I can't make it any worse so it is a good test subject.
Just thought I would pass on my experience as I did not do a scrubbing any different than I did to the older style mold. Just use caution and a light hand with this new style venting and you should be ok.

[dbosman]

Thanks for the caution notice.
Bar Keepers Friend has or is oxalic acid. There is a slight possibility that you anodized the surfaces unevenly.

[btroj]

Wow

I would think it would take quite a bit of abrasion to make a mould .005 out of round. Was the mould out of round before hand?

[nanuk]

this may be a stupid question, or two...

are they smaller along the parting line, or 90* to the part?

are the vent lines perhaps just filled in with gunk from BKF?

I have to wonder if you CAN even wear off aluminum with BKF and a toothbrush.

did you scrub the mould by using a flat surface also?


is just can't imagine taking aluminum down that much with a toothbrush and some BKF

[MTtimberline]

Can you get some photos to show the results?

[detox]

Alignment pins receeding is causing out of round...this is common with the new two pin Lee moulds. I doubt your vent lines have vanished. Try using a ladle to prevent black spots on bullets.

[leadman]

The boolits at first were out of round by less than .001" when I cast the first couple of batches. The alignment pins are not backed out at all.
I'll take pictures tomorrow in the daylight. It is very easy to see that the cavities are out of round with the smaller dimension 90 degrees to the part line. The faces of the blocks are smooth with an occassional vent line visible. I would say 99% of them are gone.
The new style molds have a very fine venting pattern and Andy Lee agreed that it would be possible to wear them away. I don't know if the Hi-Tek mold and sprue plate lube would have an effect on this metal or not. I will contact Joe tomorrow to check on the possibility.
The aluminum Lee uses seems to be softer than what it was before. I know that at least a couple of the custom mold makers use a heat treated aluminum for their molds.
Not a great loss, just want other members to use caution when cleaning their molds.

[dkf]

I use the "lead" on a mechanical pencil to remove any little lead sickles that may stick to the mold. Some rubbing alcohol on the q-tip removes the pencil marks. Have to be careful with a lot of cleaners and degreasers (like purple power) as they can eat away/pit the aluminum.

[HNSB]

With 220 grit sandpaper it takes several minutes of flat sanding to take a similar size block of 6061 down by .005.
Either the Barkeeper's friend is a super abrasive, or something else happened.

[leadman]

Here are some pictures of the mold. Only .0025" would have to be taken off each side and this could be about how deep the new venting lines are from looking at one of my other new molds.
If I drove the pins in as suggested then the mold would not be closed all the way.

[nanuk]

Here are some pictures of the mold. Only .0025" would have to be taken off each side and this could be about how deep the new venting lines are from looking at one of my other new molds.
If I drove the pins in as suggested then the mold would not be closed all the way.


The pic of the closed mould shows the mould is not closing square, the top (sprue plate side) is over to the left a bit.

could this 'out of alignment' issue be causing the diameter difference?

nah... prolly not, as then it would be undersized by a large margin, if the 0.306 is the correct diameter

[leadman]

The mold is closing like it should but the one side of the rear cavity looks offset because it is worn away. I forget now how much shallower the cavity is than the front one but that is why it looks strange. The pins are set to touch to align it also. No daylight can be seen thru the blocks when held up to the light. There is no movement in the blocks and the front cavity lines up well. I was also holding it with 2 fingers of one hand to get the glare from the sun off it and the camera in the other hand.
The mold used to drop .311" boolits but not anymore, at least not all the way around. LOL

[rsrocket1]

...well there's $20 down the drain. Look on the bright side. That lesson cost only $20. What kind of training course could you get for such little money :)

The frustrating thing is the time lost waiting for an order to arrive and the added shipping.

[leadman]

All is not lost since I have been thinking of trying to remove the lube grooves from a mold for coating with Hi-Tek and now this is a perfect candidate to practice on.

[Springfield]

Cleanliness isn't always your friend. I just use my pocket knife to pick off the lead bits. For sure scrubbing it like the dickens with an abrasive cleanser is not the way to go, as you found out.