Tobho's HT1-Inspired Cement Mixer Muller Build

alcohol is a substitute for for catalyst , you can buy 70 or 90% here is exactlry what i use
https://www.walmart.com/ip/Equate-91-Isopropyl-Alcohol-Antiseptic-32-fl-oz/276040459

i have heard about using watered down Alcohol, I have no idea where the Idea that came from
but from this patent
https://patents.google.com/patent/US6669770B1/en

"Suitable catalysts include that known as “P1 Catalyst” provided by Bentonite Performance Materials which is a propylene carbonate. Similarly methyl hydrate is known to serve as a catalyst."

Rubbing Algohol is chemically very similiar to both these compounds

Here is p-1's MSDS https://msds.halliburton.com/msdsdo...oader/Document?prd=HM005247~~PDF~~MTR~~US~~EN

Reconditioning your sand:
1)Get an oil squirt can for the oil
2) a spray bottle for the alcohol I use the upside down bottle from tractor supply

oil burns out in use , if you see smoke you burn't out oil, you need more catalyst to get the oil to react with the clay
how much oil to add ( It depend on how much you burnt out ) big heavy castings , will leave lots of burnt sand , you can see this, it will be grey, if you do cast Fe it will be a solid layer possibly stuck to your casting, if you do cast Fe in petrobond seriously consider throwing out the grey/white sand . with Brass/bronze or aluminum dont worry about it,

for aluminum, I add NO oil, and just mist the sand with Alcohol , the Alcohol seems ( this is just my observation no science here) to make the sand "fluffy" and it will mull better, in the Professional foundry about every third time we mulleed we would power riddle the sand after mulling which makes it very fluffy and gets all but the smallest bits of burnt sand .

Lets talk for just a second about fluffy while not a technical term if you ever get to aeriate or power riddle sand this term is really understandable, the sand all but doubles in volume and flows really well, but takes more effort to ram , if you store the sand , it will settle out alot


For Brass, I add about two squirts of oil per muller load , and 3 mists of alcohol remember the longer you mull the better your green strength, though there are diminishibng returns 11 minutes is the longest practicable time to mull, I shoot for half that


keepiing in mind my 12X12 flasks I add about one half a mold to the Muller and call it a load so most pours make me run 20 loads through the muller , so i mull about 1.5 hours after casting

V/r HT1

 

Methyl hydrate is cheaper than rubbing alcohol and easy enough to find so why mess around with rubbing alcohol at all?

 

I could be mistaken but I vaguely remember something about methyl hydrate being capable of being absorbed through the skin, maybe look up the MSDS to make sure you use it safely.

 

Otherwise known as wood alcohol or methanol. Never heard of trouble topically. Not good for drinking though.

Denis

 

Just looked it up, the MSDS for methyl hydrate says to avoid drinking it, inhaling it or getting it on your skin. FWIW, the MSDS for isopropyl (rubbing) alcohol is similar it says to avoid, drinking it, inhaling it, or prolonged contact with skin. Either way, it's no big deal, just be aware and take appropriate measures to protect yourself. "Better safe than stupid"

 

here is my muller running Petrobond , Hot petrobond from Brass molds about 2 hours old




here is a closeup of my blades the blade at the top of the muller catches sand after the wheel and puses it towards the center, the lower blade catches any sand in the center of the muller and directs it outward, while its other side directs sand directly under the wheel


you can see in the video, that ALOT of the mulling action actually happens betweeen the trailing edge og the wheel , and the wall of the muller, this was not intentional, but it certainly works , BTW that wheel is from Harbor freight, I have replaced it once or twice like $16 (bearings) i used to have a 10Lb Lead weight on the Wheel, it broke off, I have never welded it back on (shrug)

V/r HT1

 

I have tried a few things with mine and have been using HEET fuel additive now. you dont need much, keeping it in the muller for 10-15 min really does an amazing job at getting it back to near new even if its completely black from getting burned out. I have never had to add more petrobond clay to mine and have used it for 100+ bronze casts. I try to pull the parts after about 5 min cooling time and stamp out the sand so less burns up.

New petrobond 2 does not need any catalyst.

 

FWIW, according to its msds, HEET fuel additive is 99% methanol and 1% other proprietary ingredients. They also make iso-HEET fuel additive which is 98.5% isopropyl alcohol.

 

The only reason to add Clay is having added too much oil, I had this issue, before I switched to the oil squirt can and was just pouring oil in to my tiny muller ,

the problem that will eventually develop is the fines (crushed sand) will lower permiability, and you will begin to get gas related issues , in the Hobby setting this could be YEARS down the road or never,
be prepared though as the cure is to replace all your sand

V/r HT1

 

Whereupon it is metabolized into formaldehyde...

I knew someone whose father died from contact with this stuff, though I think he said it was due to long-term exposure... (45 years ago or so.)

Seems he was right: https://www.google.com/url?sa=t&sou...FjABegQICBAE&usg=AOvVaw3uQwoKqsWLxqns8cC9mGBQ

 

And ethanol that so many DRINK is also metabolized into formaldehyde. Sounds scary to note the formaldehyde connection. I well remember someone rather self-righteously raising a question about my use of a photochemical listed as possibly carcinogenic. This was at a dinner where most people including this guy were drinking wine and beer. He looked a little shocked when I pointed out to him that ethanol is listed as a known carcinogen. I told him that at least I did not drink the stuff!

“


The chemical formula for ethanol is C2H6O whereas the formula for methanol is CH4O. Alcohol dehydrogenase converts methanol into formaldehyde (CH2O) and aldehyde dehydrogenase turns this formaldehyde into a formic acid radical (CH2O-).

Denis

 

The radical is the carcinogen - or is it?

Acetaldehyde doesn't sound healthy, either - over and above the nightmare/flashback-inducing way it makes people smell. (To me, anyway.)

I'll stick with rubbing alcohol when I (finally!) get my (itching) hands on some Petrobond - unless I can get propylene carbonate easily/cheaply.

Amazon has this stuff, but it's pushing 37$ a quart shipped!

 

That question is above my paygrade. The human body metabolism is so complex that it usually impossible to pin down a chemical/drug action to a single metabolic alteration or step. Observation and large scale controlled and careful studies allow determination of net actions. But individual steps and their effects----harder. Quoting the existence of a scary sounding metabolic step and attributing it special significance is treacherous ground.

Denis

 

I bought propylene carbonate a while back in bulk from a refractrory supplier in your backyard---Portland. It was not OCL. But OCL might have it now sincew they bought out a supplier in Portland---details are fuzzy now. But may be worth a couple calls. Gabriella at OCL is a good contact person.

Denis

 

Thanks. OCL is about 5 miles from me.