Home Made Constant Pressure Mold Handles

[rbertalotto]

I was made aware of boolits dropping heavier towards the end of a casting session as your hand and therefore grip gets tired. Makes sense to me!

So I decided to do something about it and modified a set of locking pliers to accept boolit molds and hold the molds closed exactly the same from the beginning of the session to the end.





I wrote a whole "How To" article on my web site so you can build one also.......

www.rvbprecision.com

Now I need to try it out to see if it improves my boolit weight consistency.

Thanks!

[Pitchy]

Love your inventiveness my only concern would be the handle getting hot but let us know how it works.

[rbertalotto]

If the handle gets too hot, can you imagine how hot the die would be? I wear welders gloves anyways, but I used it tonight and after about 150 bullets, the handles were warm, but not hot. But if this is an issue, I see there are locking pliers available with plastic covered handles.

BTW, due to the need to open the handle with two hands, it has slowed my cadence down to just about exactly the right speed. I always seem to move too fast and the mold heats up too much and bullets start getting frosty.

I don't know if it's a combination of slowing down a bit or the handles acting as a sort of radiator and removing a bit of heat, but the bullets came out great!

Now I need them to cool a bit so they can be weighed and see if my weight consistency has improved.

Thanks!

[Ysabel Kid]

Very cool!

[Hobie]

[Gobblerforge]

If the handles get too warm, simply turn them around and cool with water and dry with compressed air for safety. Very quick and won't cool the casting die. Then another hundred casts to warm them back up. In the blacksmith's world this is known as spot cooling and is used to cool tongs quickly without cooling the working jaw end thus keeping from shortening working time per heat.
Gobbler

[rbertalotto]

Handles don't heat up enough to be an issue. I'm not sure I want water anywhere near my casting furnace. A simple drop of water could be hiding in the joints of the pliers and my luck when I tap the sprue plate it would jump right into the pot.......TINSLE FAIRY!

[Gobblerforge]

That's why I recommended compressed air to dry with. As far as water near the casting area, I quench cast all the time without incident.
Gobbler

[gundownunder]

Looks like a useful tool to me and as I always wear gloves anyway the hot handles shouldn't be an issue

[Ben_Rumson]

Great post.. I might just do it... Thanks

[Griff]

Since, when I'm working a casting session, and using upwards of four molds at a time, they would probably be useful... however, I never set a mold down until I'm sure the sprue has solidified. I'm sure they'd slow my production down. Maybe not.

[Catshooter]

rb,

Very nice set up.

A couple of points for you that I have learned over on the CastBoolits forum.

Frosty bullets shoot and perform the same as not frosty.

Water on top of your melted lead will not be bad. It's when water gets under the surface of the lead that the tinsel fairy can visit. The water turns to steam so fast that if it's under the lead's surface then it can expand so fast that lead is flung from the pot.


Cat

[rbertalotto]

UPDATE:

Results with "Constant Pressure Pliers Handles"

I finally had a few moments to analyze the results of using the constant pressure handles I built;




As you can see. Huge improvement. 3.7g variation. I'm still not sure how you folks are getting 1/2 grain variations. I have a long way to go to get there. But this is huge for my stage in the game.

Here's a quick video of how the pliers are connected to the temperature probe.

BTW, I found my best bullets were cast with the "1-20" Allot at 750 degrees and the Lyman mold at 425 degrees..........

http://public.fotki.com/Rbertalotto/gun ... 20782.html

A few notes on the pliers......

At 425 degree mold temperature, handles got to 91 degrees. No issue even with thin welding gloves.

The tension set screw on the pliers will need a set screw installed or a jam nut to stop it from loosening during use. When the handles are opened to drop a boolit and the pliers are tapped with a wood mallet, the screw is no longer under tension and will loosen after a few taps.

I had to modify the jaws on my pliers. I ground them so only the area around the bolt that holds the pliers to the mold was touching. Before I made this modification the tips of the jaws were holding the top of the mold tightly, but the bottom of the mold showed daylight. I'll do a quick sketch and post.

The handles act as a very good heat-sink on the mold. It was hard to keep the Lyman single cavity mold at 425 degrees. If I slowed down my cadence the mold would go to 400 degrees within 20 seconds. (I did have a fan running to keep me cool and I'm sure it was drawing heat away from the pliers)

It's extremely convenient to be able to "lock" the pliers and then go about pouring and sprew removal without worrying about applying constant pressure.

BTW, "Frosty Bullets are MUCH lighter than shiny bullets. To the order of 10g-15g with this lead and this mold............Thought you'd like to know

All in all, very pleased with the results.

[rbertalotto]

[Jacko]

Interesting Thread. I've only just started casting my own projectiles and some of the issue's I've had have been discussed in this thread. I have also never heard of constant pressure mold handles ?? Over the coarse of my life I've had numerous finger and hand injury's and have lost a lot of dexterity as a result. I can see a clear advantage to not having too work so hard at applying even pressure to the mould handles.

First time I used my 2nd hand mold the timber handles broke, I made new longer timber handles and found with more leaverage they were easier to operate. I did wonder why manufacturers don't use longer metal cores and timber for the handles to keep hands away from 700 degree lead and too apply more leaverage to the mold halves - perhaps a weight issue ??

I've not had a wider variation than 2 grains when casting .358 and .429 projectiles but I put than down to mold and lead temperature more so than mold handle pressure. I have dropped the odd oversize proj that definately was conected to tired hands and inconsistent pressure

regards Jacko

[rbertalotto]

Sometimes I think way TOO MUCH!!

But in the shower this morning, where I do my best thinking, I thouight the best type of pliers to build a "constant pressure mold handle" would be a set of high quality electrical wire crimpers. The pressure they exert in an electrical crimp is ABSOLUTE. The "AMP" folks have a truck that will come by your shop and calibrate your AMP crimpers within ounces and then certify them for government work.

But then again, a set of these crimpers are $200+....................

I think I've gone over the ledge here............going to go ride my motorcycle................

[Don McDowell]

For those that are less mechanically inclined, these locking mould handles do work very well. I've ran several batches of saeco 645 bullets and had about a 1% discard rate keeping the weight variation to 1 gr +-, and that's using the bottom pour lee pot.
http://www.buffaloarms.com/Detail.aspx? ... 8&CAT=3847