MP mould question

Brad

Benevolent Overlord and site owner
Staff member
Does anyone know if the alignment pins on MP moulds are hardened?

I have one and the pins are walking. I want to drill for a cross pin to keep in in place but prefer not to destroy a drill bit or deface the mould.
 

Brad

Benevolent Overlord and site owner
Staff member
Ok, found the answer.
His website says they are hardened steel.

Any suggestions? Web between pin and outside of mould is awful thin, not sure a set screw would hold without risk of stripping.
 

smokeywolf

Well-Known Member
Sounds a little like what you need to do is replace the existing pins with pins that are .0002 bigger in dia.
 

Brad

Benevolent Overlord and site owner
Staff member
I could make a new one but hitting that kind of tolerance wouldn’t be easy.

I may push out the existing pins, heat them red hot, and let cool slowly. See if that anneals them so a file bites.
 
F

freebullet

Guest
With the tolerance your talking just peen it. The female side is easy with a tapered punch & a quick bump with an air hammer. The male side can do same from back of block.
 

Ian

Notorious member
Then you'd have to-reharden them if you annealed.

The universal extreme-temperature thread and sleeve retainer is Na Silicate. Soak the pins in the refrigerator for a while, warm the mould up to a couple hundred degrees, coat the pins, and press together. Once the water cooks off, the pins will be stuck fo-evah.
 

Brad

Benevolent Overlord and site owner
Staff member
Water glass? Didn’t know that.
Easy enough to do Ian. Thanks.
 

fiver

Well-Known Member
part of the problem is the different expansion ratios between the steel and the brass.

if you do a set screw, taper the point and put a taper in the pin that matches it.
then you don't have to crank down on it.
 

Ian

Notorious member
Water glass? Didn’t know that.
Easy enough to do Ian. Thanks.

A mixture of sodium and postassium silicates is what Silencerco sells as heat-proof muzzle brake threadlocker....for 20 bucks per half ounce. I use stove gasket cement at 2 bucks per four ounces, plain water glass but works just as well. Mechanics have been using it to retain pesky exhaust manifold studs and nuts that tend to back off since forever. The only way to defeat it is water immersion, time, and can be expedited with a pressure vessel if you have one the part will fit in, such as a pressure cooker.
 

Pistolero

Well-Known Member
I assume that sodium silicate is something that a pharmacist can easily order up a pint of.

We used it in our chem set back in the 50s and got it from the local pharmacist.

Bill
 
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Ian

Notorious member
Or buy a bottle of Imperial stove gasket cement at the home store for a couple bucks.
 

Pistolero

Well-Known Member
Hmm. All the stove gasket cements I have had had fillers in them, were not a liquid but more a thinnish
paste. Must be something different than I have seen.
 

Ian

Notorious member
Yes, it's different. It's gasket glue, not seam filler. 100% sodium silicate.
 

Pistolero

Well-Known Member
I've never seen that product, but then again, I was in a hardware store, not a stove store. And
not too many folks around here heat with wood, so the selection isn't going to be the best, I'm
sure.
 

fiver

Well-Known Member
your ace store probably has it too.
they use it for dumping on leaky roofs and letting it find it's way into the leak before setting up.
 

CZ93X62

Official forum enigma
Sodium silicate (AKA "Egg-Keep") from the drug store kept both of the flathead V-8s in my old '53 F-100's block cracks from getting water in the crankcase oil for 3-4 months at a time. One full bottle into the radiator water every three months sealed the cracks securely. The 4# pressure cap was enough to enable the magic. Another trade secret passed along by John Peete, the orange grove shop machinist.
 

Tomme boy

Well-Known Member
Make your own water glass. not hard. Look it up on youtube. I made some a while back when I built a rocket stove.
 

Pistolero

Well-Known Member
We used it in our chemistry set when I was a kid, I remember it as a clear syrupy liquid. And I had heard that dipping
eggs made them last a long time unrefrigerated.

Gee, Ian, what a bargain. 2 oz for $61. 46. :headscratch: Seems about 10 times what it should be.
 
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