Pugmill question

[Disciple5]

I took pottery in college as a hobby while completing my degree.  I loved it so much that I have slowly been trying to put together a home studio.  I would like to get a pug mill/mixer so that I can mix my clay from scratch (dry components), reclaim used clay, and use the de-airing features to save time and work.  I am looking into the Peter Puggers, specifically the VPM-9SS and the VPM-20.  Is the stainless steal worth the extra money (in the case of these two it would be $100 extra) and a smaller hopper?  Or should I go for the bigger hopper and $100 cheaper with the VPM-20.  

Though I have thrown on a wheel and sculpted for years I am somewhat new to this piece of equipment and any information would be appreciated!! 

[oldlady]

welcome to the forum!   you will find all kinds of good info on this site.   the question is not about the money, though it is a consideration, it is about the kind of clay you use.   if you want to use totally absolutely white clay, go for the stainless.   if you never intend to use anything but dark clay, you do not need it.   if you think that maybe, someday you would like to use white porcelain or stoneware or earthenware, go for the stainless.    you do not want rust in your claybody.

btw,  could you please edit your question to be something like "pug mill question" so it can be found later by someone looking for an answer to a question about pugmills?   mentioning the specific pugmill is good, too.    

[CactusPots]

I love my VPM 30 pug mill.  Because I trim a lot.  (20% on the last session)  I can't bear to throw it away, so I saved it for years until I found a used pug mill.  The previous owner wanted a stainless steel unit.  I'm almost caught up to my back log 5 years latter.  I can't easily center 15 lbs of commercial clay.  It's easier to finesse soft clay than center firm clay.  I haven't tried mixing from scratch.  I don't think that would be any more fun by hand than wedging recycle was.  It can't justify itself financially.  It does make me a true recycler though.

[Mark C.]

As a owner/user of a Petter Pugger VPM 30 aluminum model I van say a few things

1st is that small unit 9ss holds pugs very little clay _Its made for the hobby market as the output is so small-If you are looking to make clay geta bigger unit.

I would get a bigger unit-I'm saying this twice  for a reason

If you give up on clay say in 5 years the lager models are easier to sell I feel.

The 20 is a really nice size.I know of many in use of these units.

I'm a professional potter and the 30 is more my size 

Now as to is stainless worth it -well that depends on weather you are going to use any porcealain or talc clay bodies which attack the aluminum barrel (all Petter Puggers have stainless augars )These clay bodies pit the barrel and will wear thru over time (long time). The  ss 20 is the largest they offer in stainless size 

If you plan on using stoneware clay only in your whole life of pugger use no need to get stainless but if tou plan on white clays and Porcealin or low fire talc bodies get the stainless models which will be easier to resel down the road as more buyer/users are out there.

I recommend the stainless and the larger model both-hopper size for making clay is a key point. 

I know of a potter whoi bought the small one and regreted it wishing he. had thoiught more about the amout of clay that outputs(If it holds 25# of clay ) you get far less out of it. My unit holds 85# and outputs about 55#-60#sKeep thgis in mind.

Hope this helps-I know of no one that thinks they bought one to large only to small.

[I.K.]

Hi everyone. My question is about pug mills. My current and only pug mill a Shimpo NVA 04S and it was my biggest investment to date at the time of the purchase. Thankfully, I got 3-4 good years out of it but then I realized that it had corroded on the inside, only in only one area, near a "seam" but like Swiss cheese, it was not just superficial rust. But it was so bad that I started getting bits of metal (the machine was disintegrating!) in my porcelain. Needless to say I had to throw away a lot of pieces (because some parts became visibly speckled after the firing). The person I’ve talked to at Shimpo kindly suggested that I use a wire brush to clean this and then keep using the machine and then open it up, clean and empty it every 2-4 weeks and not leave any clay inside between uses. 

I’m a professional potter, artist and teacher. Not only do I use porcelain, but I also I use it in a way where the exterior of my work is left “raw”, without any glaze and I polish by hand to show the beauty of porcelain. I cannot have speckling or contamination… Also on average I work 6 days a week. So to be asked to open up my pug mill and clean it every 2-4 weeks seems, well, unrealistic to say the least. 

Could you please tell me what you think I should do with this one and what other brand you think would be a good long term investment? I prefer not to have to open up a machine often, since especially because I never use even scrap porcelain, I only put fresh porcelain out of new bags to prevent contamination. I would, if possible like to buy a machine that will last me at least 10 years. Is that too long a life time to expect from a pug mill? 

Looking forward to hearing your opinions, especially from professional potters who've had pug mills a long time. Thank you!

 

[neilestrick]

@Ipek Kotan I'm not sure which part of the machine we're looking at here, but is the part that's rusting supposed to be exposed to the clay inside? I'm guessing that because it's only rusting in that one spot, that there's a bad seal there? A broader picture and more explanation of the construction might help us diagnose the problem.

[I.K.]

Hi Neil, thank you very much for your prompt reply. It's the upper part (upside down) of the machine and the corrosion is on the seam, near the tip of one of the augers located righ below the clear oil filter chamber. I think yes, there was a bad seal there because it looks like there was no gum sealant. Please see below.Hi Neil, thank you very much for your prompt reply. It's the upper part (upside down) of the machine and the corrosion is on the seam, near the tip of one of the augers located righ below the clear oil filter chamber. I think yes, there was a bad seal there because it looks like there was no gum sealant. Please see below.

[CactusPots]

Have you talked to Shimpo about this?  Is the upper part that is corroding so badly steel inside the clay chamber?  That seems like a bad design flaw to me if so.  I would think everything in the picture should be one part cast and machined aluminum.  

I would be important for people considering purchases from Shimpo to hear how they respond to this.

[I.K.]

Yes, I agree. And especially because it's only in one very local area near a seam where there does not seem to be any gum sealant... They said stainless steel doesn't mean rust free and that I should clean my machine completely every 2-4 weeks and empty it between uses. For a professional potter and teacher who works 6-7 days a week this is really not realistic. I am very disappointed with Shimpo, I have to say... 

[CactusPots]

Ok, sure, but it's only degrading in one specific place.  Why is that spot different?

If the lower cast part and the machined surface are 2 different pieces, is that seam where the sealant is needed?

Has Shimpo seen this picture?

If they are going lame on this, my suggestion would be to take it to a machine shop that does stainless and ask their opinion.

[I.K.]

I think it's because there was not enough gum sealant there. Yes, the machine's barrel is made of a two part mold so the upper part and lower part are put together with multiple screws, gasket and sealant. Right around the corrosion, I could not find sealant, it seemed to be missing or at least not enough. If you look closely at the picture you'll see that the sealant sort of stops there. They have seen this and about 20 other pictures. They say "brush it with a wire brush, clean it." then I'm advised to open it up and clean it every 2-4 weeks and leave it free of clay between uses. It's a ridiculous suggestion if you ask me. Who has time to clean a pug mill every 2 weeks? It's a 2-3 day job! 

[CactusPots]

The arrows pointing to 1 and 2 are separate pieces of metal or machined from one piece?  They should be one piece, but if you're questioning the seal across the machined surface of 2, I don't see how you're saying this problem was caused.  A failure of gasket or seal across the machined surface should cause a failure on the machined surface of 2, I would think.  I'm thinking an expert machinist or metallurgist opinion would point to a manufacturing flaw.  That's really a localized corrosion. 

I'm thinking the fix is going to be either a replacement part or grinding out the corrosion and refilling and machine work.  Expensive either way, but Shimpo's "clean every time you use it" is not the industry standard for pugmills.  I don't use porcelain, so maybe someone else has a contrary opinion.    If you can bring expert opinion to Shimpo's attention, they may reconsider their position.  Them replacing the part would be the best case.

[I.K.]

Thank you, there is a technical university in Delft, not far from where I live so I'm hoping to talk to a metallurgist from there and hope to get a letter from them to send to Shimpo. "Clean evewry 2-4 weeks and keep clean between uses" is simply impossible and certainly not what I expected when I paid top Dollar for a brand new, top-of-the-line machine... Thank you. Good to hear others agree that this is most likely a manufacturing error.

[Mark C.]

I do not see any gum sealant -the two mating surfaces look like they are not tight. The Stainles steel case that looks like it dropped into that . Maybe a repair can fix this with a mig or tig welder and stainless welding rod and a grinder.You need a great repair metal shop to do this work-seems doable

In terms a of a better machine its a Peter pugger for me as I work in Porcelain . Since you are on the otrher side of pond your options are less.

[neilestrick]

Is there any way to add sealant there when you put the machine back together?

If it's an issue with the original machining done by Shimp,, then Shimpo should replace it. Just because it's out of warranty shouldn't matter when it's an issue that won't show up during the warranty period when it's a manufacturing defect that renders the machine unusable by normal standards.

[Min]

I think the seal is a red herring. Stainless can rust if it doesn't contain a high enough amount of chromium. I don't think a new seal is going to help. We have seen rusting on stainless kiln jackets, same deal, poor quality stainless.

https://www.polymersolutions.com/blog/why-does-stainless-steel-rust/

[Bill Kielb]

Almost looks like someone tried repairing this with a torch. Is it stainless, cast aluminum? Is it slightly magnetic? More magnetic at the damaged spot?

[I.K.]

I'm the only owner of this machine, bought it brand-new and no one torched it. It's black due to corrosion. Stainless steel. Yes, slightly magnetic but not more magnetic in the damaged area. Actually feels slightly less, maybe a tad bit but certainly not more magnetic than undamaged areas.

[Sorcery]

It's possible the Auger is out of whack, and it removed that polished surface when passing.

That red stain seems indicative of heat.

What does the matching other side look like?

Sorce

[I.K.]

No, that's not the issue. Auger is in place. Red stain is rust.

[I.K.]

7 hours ago, Min said:

I think the seal is a red herring. Stainless can rust if it doesn't contain a high enough amount of chromium. I don't think a new seal is going to help. We have seen rusting on stainless kiln jackets, same deal, poor quality stainless.

https://www.polymersolutions.com/blog/why-does-stainless-steel-rust/

Thanks, I agree. It's definitely poor quality stainless steel. Wrote to Alex, the guy who wrote the article you posted above. Thanks!

[Sorcery]

2 minutes ago, Ipek Kotan said:

Auger is in place.

But is it in the right place?

Can you operate it with a visual on that area, manually or otherwise?

I edited that late question, what does the other side look like?

 

Sorce

[I.K.]

Yes, it is in the right place. It's at least 2 fingers width away from the red spot and sitting straight. 

[Sorcery]

2 minutes ago, Ipek Kotan said:

Yes, it is in the right place. It's at least 2 fingers width away from the red spot and sitting straight. 

Does it stay there throughout operation? 

Forgive me I don't know how they work. 

Says 5 year warranty on Sheffield's.

Sorce

[I.K.]

8 hours ago, neilestrick said:

Is there any way to add sealant there when you put the machine back together?

If it's an issue with the original machining done by Shimp,, then Shimpo should replace it. Just because it's out of warranty shouldn't matter when it's an issue that won't show up during the warranty period when it's a manufacturing defect that renders the machine unusable by normal standards.

I was thinking the same thing as the gum sealant seems to be missing from the area where there is corrosion. Maybe there was an air bubble in the casting and they didn't properly seal the machine around the seam so the water present in the porcelain got to sneak onto the unprotected area. Who knows. But I find that it's truly amazing that they expect me to clean a machine like this (2-3 day job) every 2-4 weeks and leave it empty/free of clay between each use. It's ridiculous.