How do I fix Petrobond

[stevehuckss396]

I bought 100 pounds of petrobond about 2 years ago and have just gotten around to using it. It seems a little wetter than I thought it would be and seems to crumble easier than it should. I need to do something to it to get it to firm up and stay together better. I have a small cement mixer, I was thinking of tossing it in there and giving it a twirl thinking the oil may have migrated to the bottom of the box. That might get everything mixed up and evened out. If that fails should I add a binder. bentonite? cat litter?

How can i fix the sand?

 

[aonemarine]

You need to re mull it, the cement mixer will work if you thow something in there like a shot put to help it mull. Id also add a bit of methyl alchol to reactivate the bentone.....Oil should not be necessary....

Bentonite is in green sand
Bentone is in petrobond
not interchangeable!!

 

[stevehuckss396]

You need to re mull it, the cement mixer will work if you thow something in there like a shot put to help it mull. Id also add a bit of methyl alchol to reactivate the bentone.....Oil should not be necessary....

Bentonite is in green sand
Bentone is in petrobond
not interchangeable!!

I also have an adapter made so I can put a 5 gallon bucket on the mixer motor. Would that be a better option? I hate to think what a shot put would sound like in the steel drum. I could fill the bucket up about 3/4 of the way and twirl that for a while. How long would it take?

 

[rrnutsplitter]

Hi Guys!,
First time post for me.
I used to own and run a small mom and pop size foundry in New Hampshire. The recent (2008) financial problems put me out of business. Went from one or two orders a day, to one a month, hard to make money at that rate. Enough said about that.

I used to use a discount store $99.00 mortar/concrete mixer for my core sand. It was sodium silicate and 100 grain sand. I used cannon balls (4 about four inches in diameter) for the mixing, mulling action. You dont even get much noise, just some thumpthumpthump sound. Mixed and used about 100 pounds of core sand a week. It made silky smoth core sand with no lumps or bumps.

I never used petrobond much mostly just for facing on fussy bronze jobs and backed up with my regular olivine #120 and bentonite.

I am now a hobby machinist, and ex-railroader, printer, machinist, foundry man with
Multiple Sclerosis. At 52 thats why I;m an ex.

Will be on here and Practicle Machinist, so if you have any questions I'd be happy to try and help. Not to mention needs help myself occasionally.

rrnutsplitter
Jeff Albright
Charlestown, NH

 

[stevehuckss396]

Welcome aboard Jeff!

 

[aonemarine]

The bucket sounds like a good idea. Still need something in there to help it mull.
15 minutes is usually more than enough in a normal muller.

 

[stevehuckss396]

The bucket sounds like a good idea. Still need something in there to help it mull.
15 minutes is usually more than enough in a normal muller.

I was on ebay looking at 8lb shot put balls. I have the word out to my club members that i am looking for shot put or cannon balls 3 to 4 inches round.

How about moonshine to reactivate the bentone? It's done wonders for me.

 

[aonemarine]

It doesn't have to be a round object, good heavy chunk of round stock works too. Shine might also work lol.

 

[Wizard69]

Welcome aboard, immrather new here myself.

Hi Guys!,
First time post for me.
I used to own and run a small mom and pop size foundry in New Hampshire. The recent (2008) financial problems put me out of business. Went from one or two orders a day, to one a month, hard to make money at that rate. Enough said about that.

Sorry to hear about the business issue. It has been pretty tough around here with major businesses collapsing.

I used to use a discount store $99.00 mortar/concrete mixer for my core sand. It was sodium silicate and 100 grain sand. I used cannon balls (4 about four inches in diameter) for the mixing, mulling action. You dont even get much noise, just some thumpthumpthump sound. Mixed and used about 100 pounds of core sand a week. It made silky smoth core sand with no lumps or bumps.

That is a lot of core sand compared to what most hobbiest do. It would help many of us if you could list out your suppliers for stuff like sodium Silicate. I do believe the one thing that keeps me from DIY casting is just finding the right materials to work with. Sadly about 25 years ago I spent some time working diecasting, but I never paid attention to where stuff came from.

I never used petrobond much mostly just for facing on fussy bronze jobs and backed up with my regular olivine #120 and bentonite.

I am now a hobby machinist, and ex-railroader, printer, machinist, foundry man with
Multiple Sclerosis. At 52 thats why I;m an ex.

Will be on here and Practicle Machinist, so if you have any questions I'd be happy to try and help. Not to mention needs help myself occasionally.

rrnutsplitter
Jeff Albright
Charlestown, NH

Thanks for the intro post.

 

[CallMeAL]

Wizard69: I had the issue of finding material when started my foundry. I discovered the local pottery supplies shop had the following: sodium silicate, bentonite clay, very fine silica sand, fire brick and castable refractory used in kiln repair. If there are any near you should check them out.

 

[CallMeAL]

rrnutsplitter: Welcome. I just returned to posting on this site myself. Multiple Sclerosis - ain't it a drag! I was diagnosed with MS myself last August. It was causing me to stay out of shop, but now I've determined that you just have keep plugging along as much as you can for as long as you can. I'm 62, and just retired last July so having this sure puts a crimp in my expected retirement years in my shop.

I hope you can still around ok and that you will post some of your hobby projects.

Al

 

[Lakc]

I just shove it around by hand in one of those plastic home depot cement mixing tubs. Just adding some rubbing alcohol got its "sticky" back, and my sand is going on 16 years old.

 

[stevehuckss396]

I just shove it around by hand in one of those plastic home depot cement mixing tubs. Just adding some rubbing alcohol got its "sticky" back, and my sand is going on 16 years old.

Copy that! Machining 4 new patterns to be fixed to a match plate. Should be pouring the sunday after Easter.

 

[mnay]

Steve,
Just looked at your thread. I haven't tried this but I passed it along to a friend and he said it made his 20 yr old sand work like new. I can't remember where I got the info, but I had it stashed in my foundry files.

My friend just added the alcohol and said the next day there was much improvement in the characteristics of the sand. See below Hope it helps

used Petrobond 1 can be reconstituted by adding 2-4 oz. of either proplylene carbonate or a mixture of 90% methanol and 10% water per 100 lb. of old sand (the water is absorbed by the alcohol). This will bring back the gellation properties of the clay. If you simply add more oil and you don't get the strength you wanted, that's a good sign that you need to add some of the "catalyst". Propylene Carbonate is the best, but hard to find in small amounts. Methanol is fairly easy to get as 'Heet' at WalMart or any auto store. It can also be bought by the gallon at a real paint store (not Home Depot or Lowe's).
(original form Tom Corbet, altered by Richard Kern)
Petrobond

Here is what it says word for word for remixing old petrobond sand:
Note: Oil base sand cannot be kept at its peak strength indefinitely without reconditioning. A muller (a mechanical mixer) is essential to effectively recondition petrobond (oil base) foundry sand. This is accomplished though the following technique:
1.) Shovel the old oil base sand into the muller.
2.) Add 1% by weight of binder (petrobond) to sand. Mull 1 minute
3.) Pour in slowly 1% by weight of oil (40 wt.) Mull 10 minutes
4.) Add 1/16% of catalyst (P-1 or 1/8% of methyl alcohol) and continue mulling for an additional 5 minutes.

 

[stevehuckss396]

Thanks for all the info. I was hoping to pour this weekend so couldn't have come at a better time.

 

[Bastelmike]

Hy all in this thread,

I have similar problems like Steve.

25 years ago I was apprentice in a small foundry nearby. They made aluminium and iron castings. Several years later I built an oil-fired furnace for aluminium and got some sand and silizium from that foundry. I got some sand several times from them, but sadly that foundry went bankrupt years ago.

I took a look on my sand weeks ago, and it's so dry it will not bind together in this condition.
Don't know much about that black sand, except its petrobond. Also it seems to be specifically for aluminium, because they used different sand for cast iron and kept these sands strictly separated.

How can I rivitalize this sand? Or does anyone know where to buy new sand in Germany?

Mike

 

[Lakc]

Take a small dish of sand and add some alcohol, see if that helps.

 

[stevehuckss396]

Hey Jeff!

I mulled the sand today and added alcohol. If Rick shows up today i'll give the stuff a try. Did'nt seem any different when I finished. If I drop off this coil I would like to see your petrobond to compare it to mine

 

[Lakc]

Hey Jeff!

I mulled the sand today and added alcohol. If Rick shows up today i'll give the stuff a try. Did'nt seem any different when I finished. If I drop off this coil I would like to see your petrobond to compare it to mine

My sand probably needs it too. Your welcome to come by if you feel like excavating to the back of the garage with me, its been a long winter...

 

[stevehuckss396]

Rick never showed. I did finish all my bases for spark plugs. Drilled all my insulators. I need to get some plugs done. NAMES is in 2 weeks!!