Things they dont tell ya when you start casting. :)

Home enthusiasts discuss their Foundry & Casting work.

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Lazz
Posts: 134
Joined: Sun Jul 29, 2012 11:06 pm
Location: The Warm Arizona Deserts... Phoenix to be precise...

Re: Things they dont tell ya when you start casting. :)

Post by Lazz » Thu Jun 06, 2019 12:27 am

Even more stuff no one mentioned about casting....

7) Buying casting parts and materials from Amazon can be iffy. Some great and lots of complete disappointments. Not to knock imported items.... But my Amazon Cheap thing record is poor to say the least... The mounting end of the thermocouple I bought to check temps melted on the first use. it said it was rated for 1300C. Its replacement shows it was effected by the heat.
The crucibles from Amazon were surprisingly good. Both the cheapest #4 and the #4 priced twice as much.... $18 something and $35 ish...
The recent propane regulator didnt work.
FYI Milton air connectors from Amazon can be complete trash.

8) A fluffer does not work well with petrobond. Olfoundryman of youtube fame makes it look like a necessity... If you use petrobond put your effort into a muller...

9) On the subject of a muller.... Casters might not be a good thing on the feet of a muller. Even locked they can allow the muller to move... The very things that allowed me to store the muller in a good spot did not have enough surface area to stop movement... They just slid without rolling. Funny and alarming all at once... I should have made a video...

10) Match plates are hard to make... and SO nice to use when they work... That is why people use them. Using match plates can lead to small internal leaks that can burn wooden flasks....

11) Lost foam casting in the raw makes for some nasty surface finishes.... Maybe with a coating it works better... my experiences were with items that the surface finish didnt matter. Also the sand can fall into the casting as the foam melts.

12) A casting that requires more material than your crucible holds can be done in multiple melts. Let me explain this... I needed a leather piston cup for a hydraulic pump.... This required a way to hold a 7" exterior diameter, 3" tall hunk of wet leather until it dried. Casting a 10 inch donut 4 inches tall took 4 melts for me with my #4 crucible. The best part is it worked really well.... Turning the donut in the lathe was worrisome at first. And I did have to bondo the interior to fix the many surface flaws. But it did the job....If surface finish is important this is not an option. This method did work while under compression.... BUT as I cut it up to reuse it did separate. I did a test run and laminated leather I have on hand. It worked. Since the cup is in a cylinder compressed around a piston delimination is not likely. This saved a Dake 70H from a trip to the scrap yard....

13) Petrobond changes with use... My petrobond has cast a couple hundred items.... It has gone from a orange sticky sorta paste.... to a black burnt grainy something.... If I had separated the burnt material I would not have any remaining sand.... Adding oil and alcohol does help... but the stuff Im using now is very different from new petrobond.

14) Where can you find useful information about petrobond care and maintenance. As of recently I have found a need for another 100 pounds of sand....Buying petrobond powder/clay and oil seems to be questionable at best... Commercial foundry suppliers offer petrobond 2 clay and oil to make 1000 pounds batches... Ebay has an offering of material to make 100 pounds. I have petrobond 2 and on ebay is material to make petrobond 1 can I mix them? who knows. The ebay seller doesnt answer. The seller I bought my original couple hundred bucks of sand from doesnt answer. And the internet forums I have asked are silent on this subject.... Are these some of the reasons the people Im learning from on youtube these days do not use petrobond... they use greensand.

Thanks to all that read this... and please comment...

Harold_V
Posts: 17696
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: Things they dont tell ya when you start casting. :)

Post by Harold_V » Thu Jun 06, 2019 1:52 am

Interesting comments on petrobond. I am aware that it is expensive, and appears to have a "cult like" following, especially considering most folks don't use their sand daily, so greensand isn't a great option. Wish I had some experience so I could share what I might know with you.

That said, because I intend to pour iron, I'm thinking I'll head in the greensand direction, likely with something like olivine, so should I desire to pour steel or stainless, I'll have the recommended sand. I'll still have the same problems others have, however, in that I won't use my sand daily, so it will most likely need to be conditioned just prior to any attempts to do some casting.

Thanks for posting your thoughts. I enjoy hearing the experiences others have, and hope to be able to share mine in the future.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

RONALD
Posts: 566
Joined: Sun Oct 26, 2003 7:27 am

Re: Things they dont tell ya when you start casting. :)

Post by RONALD » Fri Jun 07, 2019 6:26 pm

As I wrote in previous posts, I started with greensand in the night school class I was attending, and then when we switched to the other shop with Petrobond, I was convinced it was for me. I used that shop exclusively for many years, because I had a special permit even tho the night school had long been closed.

In the 90's, when I got hold of what was left of the closed shops, I did not bother to move the Petrobond, but bought bags of PetroBond II from a distributor. I had bought 20,000 pounds AFS Wedron 105 sand in the 80's and still had many bags stored in the school when I took early retirement in 1994. I got students, for extra credit of course, to move those bags, several each day, into my Suburban; I took it all home!

So, I have lots of stored sand, and I mixed up, in one of my Simpson Mullers, ~ 1500 pounds of PetroBond II ~ in 2000.

Great stuff, use it all the time, thro away the real burnt stuff and mull every couple of months. I use a a great deal of that AFS 105 sand for the Sodium-Silicate/CO2 Process, and with that process, the sand is not recoverable after one use. It's too difficult to recover, cheaper to thro away.

As far as Information is concerned, there is not much knowledge on mixing the two, as you found out when you got zero replies on Alloy Avenue.

I was surprised to find out, on the Internet, I could not acertain who now produces PetroBond 1 & 2. Used to be the Bentonite Corp.

I have no need for any now, what I have will outlast me.

As I wrote before, you may be the first to mix the two - try it!

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