Author Topic: Petro Bond Sand  (Read 875 times)

Offline fidlstyks

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Petro Bond Sand
« on: August 24, 2019, 02:07:04 AM »
I am wondering if many on here have used this sand. I was at Lancaster Foundry Supply in Pa and bought a barrel full. It was suppose to be brand new unused sand.
    How ever it would not work right. My first thought of course was to ad the  catalyst which I substitute with Rubbing alcohol 91%. Still did not work. So I painstakingly mixed 10# batch experiments.  I ended up with 2oz of oil, 1 cup of clay and 2 plus tea spoons of Alcohol.  Mixing and screening each 10# batch. This took me 2 days.
    I remeber from past use that it likes being packed down a few times to make it work well.
  Does one add alcohol at every use?  I noticed on a big 350# mold about 10# gets pretty hot so assume it evaporates out . I added a couple of tea spoons to this burned area.
    I down loaded a formula to mix new sand. I bought a broke bag of the clay at a discount and plan to mix more new up. Am wondering if anyone has a good formula. My download calls for 2 quarts of synthetic 2 cycle oil. Seems like alot.   

Offline fidlstyks

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Re: Petro Bond Sand
« Reply #1 on: August 24, 2019, 02:10:55 AM »
I am always wondering what makes things tick. I use to think Petro Bond made alot of smoke. But today after pouring a flywheel I started thinking that oil does not burn without oxygen?  So once metal goes in, it does  burn out the sprue, but then it suddenly quits burning. It must be because it burns till the oxygen is gone from the mold.
    Opinion ?

Offline littlelocos

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Re: Petro Bond Sand
« Reply #2 on: August 24, 2019, 02:21:30 AM »
I've been using Petrobond sand I purchased on eBay (petrobondforsale) and have been very happy with it.  I use steel and aluminum flasks and have gotten in the habit of separating the two halves after the pour and carefully separating the black, burnt crust from the fresh, red sand.  It almost sounds like the barrelfull you got at LFS may have been old stock. Sounds frustrating.
Todd.


Offline ART

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Re: Petro Bond Sand
« Reply #3 on: August 24, 2019, 01:17:11 PM »
      I have been using Petro Bond casting sand from LFS for over 20 years, and have not had any problems. I use the same sand over and over slightly retempering it when needed with a little alcohol and 2 cycle smokeless oil. Yours might have needed further mulling. When the weather gets cooler I let the Petro Bond container set in the sun for a while to get the mix warm. This seems to help distribute the liquids. Mine does smoke after casting, but not a lot. Good luck.
       Art

Offline ART

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Re: Petro Bond Sand
« Reply #4 on: August 24, 2019, 01:35:26 PM »
     Was the barrel you bought "pre mixed" somewhat red in color, and ready for use? If so then you might be mixing a lot more "catalyst" than you need with the sand. If the mix was dry than 2 quarts / 350 lbs. sounds about correct.  With your test mixes 2 ozs. of oil to a cup of sand seems too high. The ratio will be about the same as the alcohol. Do you mull your Petro Bond or just riddle it to retemper ?
    Art

Offline fidlstyks

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Re: Petro Bond Sand
« Reply #5 on: August 24, 2019, 01:41:56 PM »
 I am fairly certain it was not made properly with correct clay and oil. All the way through I kept trying adding alcohol first. It just never would get hard.
   Not knowing how much oil was in it flumixes me . I think it would have been better to have packed it down and mauled it over and over before I added so much oil. I did maul pack and maul and sift, but still see dark spots the size of peas all through it.
    I take it no one has experience with making all new sand. I still have enough new clay to make more sand mix. Was wanting to save it for cutting the sand as it gets burned.
  I may just keep it for aluminum. I am now using for pattern work.
   The green sand I have comes from a large foundry that pours ductile and heavy cast. So their sand size is too coarse for patterns. But not nearly as coarse as some foundry' s that pour hundreds of pound castings that have very coarse sand for breathing of steam. Which makes smaller castings look pitted when cast.
   It makes nice castings now, but it sticks bad in areas and am sure that is because of pockets of oil.

Offline fidlstyks

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Re: Petro Bond Sand
« Reply #6 on: August 24, 2019, 01:48:58 PM »
     Was the barrel you bought "pre mixed" somewhat red in color, and ready for use? If so then you might be mixing a lot more "catalyst" than you need with the sand. If the mix was dry than 2 quarts / 350 lbs. sounds about correct.  With your test mixes 2 ozs. of oil to a cup of sand seems too high. The ratio will be about the same as the alcohol. Do you mull your Petro Bond or just riddle it to retemper ?
    Art

 I just shovel and screen it.
  I mixed 2 tsp al., 2 oz oil and 1 cup of clay for 10# of sand.
  It now has a red tinge to it. Before more dark.
  What I use to buy for $0.50 per pound  and used was well mixed. I think heat drives the oil to disperse better with mauling.
It was always black. 

Offline ART

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Re: Petro Bond Sand
« Reply #7 on: August 24, 2019, 06:40:22 PM »
         It looks like you have way too much oil in your mix as evidenced by your saying that it " would never get hard". You should be able to grab a handful of your mix and squeeze it into a ball. You should not see any oil squeezing out from the ball, and the ball should release cleanly from your hand. Your hand might have a little residue left but not much. When you break the ball in half it should make a clean break, and both halves keep their shape if they do not then the mix probably has too much oil. 
       When I combine new Petro Bond ( red color ) with some which I have previously used ( black color from the burnt oil ), and riddle / sift them both together I also get small Pea sized dark dry balls in the mix. These are from the burnt portion of the used Petro Bond and are related to the size of the mesh in my riddle. I never mix my Petro Bond with regular sand. The granular size in the Petro Bond is much smaller than the sand and leaves a better finish on my castings. If the Petro Bond seems to stick to your patterns when preparing to cast it might be because there is too much alcohol in the mix and it is dissolving the finish ( paint or shellac ) on your patterns. I have had this happen, and had to let my mix sit open for a few days so some of the alcohol would flash off.
        Art

Offline fidlstyks

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Re: Petro Bond Sand
« Reply #8 on: August 24, 2019, 08:39:41 PM »
 Thankyou for the advice.  When I said not get hard I ment when I squeze a ball ot just fall apart. Not strength. Now I can pound it into a square and it stays.
   It has been some time since I ran PetroBond. We had jewlers sand , PB and Albany sand. A fine red color from Albany Ny. All natural sand. Dad hooked up with some old sand crabs from Desmoines Ia back 35 years when they still had foundries around.  Always kicked myself for not paying attention. They're all long time gone Now   

Offline ART

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Re: Petro Bond Sand
« Reply #9 on: August 24, 2019, 09:31:33 PM »
   Sorry for the misunderstanding. Water based greensand is  a lot simpler to diagnose, but Petro Bond is basically the same just oil based. Maybe when you bought the barrel the components had not been thoroughly mixed although new. I have spoken with sales reps from Lancaster Foundry Supply  a few times, and they have always been very knowledgeable and helpful. I would call them and let them know what happened, and hopefully they would know what to do. Good luck.
      Art

Offline the artfull-codger

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Re: Petro Bond Sand
« Reply #10 on: September 02, 2019, 09:34:22 PM »
When I make plaques with fine detail & lettering I sieve a layer of petrobond sand on to the pattern then fill up with greensand,after casting & shakeout I scrape off all the petrobond & discard it, making sure none of it mixes & contaminates the greensand, some of my petrobond is over 40 yrs old & is still ok, I occasionaly sprinkle some hybond 100 [bentonite] in the greensand to keep up the bond, looking at the net it would appear to me that adding acohol etc to petrobond seems to be in america, not the uk.
Graham.