Paint or Plastic lining of galvanized sap tank?

[PoorFarmFarmer]

I have a 1500 gallon tank that I traded for helping a guy out last season. It's a little rusty and he suggested either painting the inside or lining it with plastic? Is there a safe paint?

[DrTimPerkins]

I have a 1500 gallon tank that I traded for helping a guy out last season. It's a little rusty and he suggested either painting the inside or lining it with plastic? Is there a safe paint?

Although paint has been used for buckets and tanks for this purpose, there is no food-grade paint suitable for prolonged contact that can be readily applied with a brush or spray. I know some will argue that point, however the paints out there that are suitable for food grade are typically only suitable for "incidental" contact, or are not something the average person could apply because they need to be baked on after application. We've looked at hundreds of paints, and others have given us the name of paints they think are suitable, however to date nothing has been completely suitable.

If it's just a "little" rusty you may be able to just sand off the surface rust and rinse clean.

Tim P.
UVM PMRC

[Haynes Forest Products]

I think visually rust is a turn off but when it comes to a good heavey coat of rust what is the danger. Other than flaking off and entering the food in solid form What is the danger. Houses with Galvanized water lines still have rust exposed to the water. Most visual rust in new water lines goes away after the rust gets a good coating over it. I have seen plenty of water cisterns that are old galvanized tanks sitting in dank, dark, crusty old buildings that pass water tests and the people using them seem healthy.

[ennismaple]

The issue with any contaminants is they are concentrated 40x by the time you turn sap into syrup.

[TapME]

the water that we drink as a whole has more rust in it that would be lifted off the bottom of a tank with sap in it. Also remember that all fruit juices and caned fruit are all packed in galv cans. If it's good enough for all of us to have fruit out of, then sap standing in it till it's taken away to be boiled is not a problem. Those of you that want to say that sap is acidic should see how much acid is in the fruits packed in these cans have. I'm sure it's more than sap.

[sugarmountain]

I wonder if you could coat the rusty area with two part epoxy, like west system. These epoxys are wicked rugged and wouldnt think they would be any more toxic than galvanizing. Most releasers etc. use this type of material in production? I have a similar situation and thought this would be a good alternitive. I often wonder if rust changes the grade of syrup, and flavor(most old timers say it does). feed back would be great!

[DrTimPerkins]

I wonder if you could coat the rusty area with two part epoxy, like west system. These epoxys are wicked rugged and wouldnt think they would be any more toxic than galvanizing.

We have heard many people say that there are suitable paints or epoxies to coat rusty/leaking/galvanized tanks or buckets, but at least in my experience over the past 13 years, nobody has ever been able to come up with a paint/epoxy material that is completely suitable. We spent a lot of time and effort looking back when we were researching the lead issue.

Most epoxy and paint systems are for "incidental" food contact, not prolonged food (sap) contact. Big difference as far as the regulations go.

The epoxies that are food-grade are not workable for non-professional application in that they typically require a clean surface, are highly toxic before they cure, and need to be baked on at several hundred degrees F for a couple of hours in order to "set" properly and be food-grade. This isn't something a sugarmaker could do. A longer dry time at lower temperature will not suffice. They also tend to be so expensive that you could almost buy a new stainless tank by the time you got the entire surface coated.

As far as toxicity....galvanizing is mainly zinc. The epoxies typically have some very nasty chemicals in them such that you aren't supposed to even breathe the vapors. Not something you want in your sap or syrup.

Tim P.
UVM PMRC

[johnallin]

Tim,
Just finishing up a new sugar house here and have been looking at tanks. Is is ok to use galvanized stock tanks? They seem to be a better choice than the plastic tanks, as they have open tops which should make it straight forward to clean out and they are cost effective until the budget allows stainless. Thanks for all of your input to this forum.

[DrTimPerkins]

Is is ok to use galvanized stock tanks?

Hmmm.....sticky subject (sorry bout that)!

Although from a contamination perspective these are certainly better than trash barrels made of regrind material, the reality is that:
- galvanizing was never approved for food-contact
- these tanks are for "stock", not for human food or water use
- do you know what they are soldered (or brazed) with?
- if not welded or soldered, is the bottom rolled to form a seal (this is unacceptable for food storage as it leaves an area you can't get into to clean)?

So I guess overall I wouldn't say that if you already have one you should not use it, but if I were going to buy new I'd try to get stainless. Chances are you're not going to "replace" that stock tank in the future....just shift it to another spot.

I suspect what you're going to see over the next 10-20 years is a phase out of galvanized materials in the industry (and other industries). It is already starting with barrels to some degree, and is being driven by the large industrial buyers. They purchase ingredients from all over the place....and aren't used to buying food in galvanized containers. If they won't purchase even what is probably a minor ingredient in their product if it's in a galvanized barrel....what are we doing to our consumers when a good share of our total crop is in galvanized. There is no question that a good stainless barrel will keep syrup quality better than an old beat-up galvanized barrel.

[red maples]

the black rubermaid "stock" tanks are ok right.

I see folks use those all over the place!!!

[Bucket Head]

I don't think the Rubbermaid tanks are any better or worse than the galv. tanks. That plastic could leach out unwanted chemicals too. What are they made of? I do not think they are food grade plastic. Are they?

I've been telling folks for a while that if they can they should replace everything they have with stainless or food grade plastic. There will come a time when everyone's state regulatory dept. for maple is going to tell you "stainless, or food grade plastic, or else". I would hate to be told I could'nt produce syrup or sell what I made because the equipment I used was deemed unsafe.

If your absolutely going to go with a galv. tank, make sure its brand new and made in America. No Chinese stuff with a great threat of lead. Make sure the plastic tanks are new too.

Steve

[TapME]

with plastic totes look for the number 1 in a triangle and that will signify food grade. With stock tanks if they are rated for water storage I would think that they would be fine. As for galvy, I just had some pears from a brand name packer(producer) and the can is galvy on the inside. You make the call. Just my 5 cents

[KenWP]

For food grade they can have a 1 like juice containers are or a 2 like milk containers. They could even be a 6 like a lot of little yogurt cointainers but it's unlikely you will see a 6 on anything big. I just had to take a test on what all those numbers ment especially when this goofy french teacher origianlly tried to tell us it ment how many times the plastic had been recycled. I sort of got bent out of shape an that lesson.

[WESTVIRGINIAMAPLER]

Isn't a lot canned food still being canned in galvanized cans, especially the larger 3 quart bulk size cans??

[twobears1224]

i,am waiting for stainless to be banned seeing how osha has a notice on welding it now..

delbert

[KenWP]

And what is the notice specify is wrong with SS.

[red maples]

pretty soon we won't be able to use anything!!!! just eat your food raw.

[twobears1224]

HERE YA GO :http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=FEDERAL_REGISTER&p_id=18599

A compound used to make stainless steel can give you lung cancer,ect and it,s water soluble .

delbert

[red maples]

Well I am not really good at reading that legal jargon... ADD kicks in and I get board with it and I start skimming.

what I did get from this article was that it seems to be directed at iron workers, welders or anyone who has alot of contact with SS, and any extreme exposure to just about anything will cause bodily harm in one way or another. (drink too much maple syrup will give you a belly ache:) )

We had our water tested reciently so I know these figures.

As for a safe amount of chromium injested some is good for your body and healthy at that. the safe range is between 50 to 200 mg (micrograms) per day, but that is total chromium ( chromium 3 which is naturally found in foods and chromuin 6 the bad one). So if you were to cook a meal with stainless cookware you injest about 45 mg.

the better grade of SS you use the better. And as long as your equipment is in good shape there are only traces that leach into food and are non-threatening. although... what my water guy told me was that there are more and more studies coming out about this topic so stay tuned.

As for boiling sap I have no idea how much chromium would leach into syrup the only way is test sap before to get a control then test the finished syrup to see what in there and what types of chromium and the concentration each.

And for that you would have to ask Dr perkins to see if anything of this nature has been done.

[DrTimPerkins]

A compound used to make stainless steel can give you lung cancer,ect and it,s water soluble .


This is an altogether different thing. The chromium VAPOR is harmful if you inhale it. You aren't going to get your evaporator hot enough to vaporize the chromium (I hope) unless you're welding it.

The notice is for people welding stainless steel to be sure to use the correct protective gear, not a prohibition against using an evaporator.

[twobears1224]

DR WROTE:The notice is for people welding stainless steel to be sure to use the correct protective gear, not a prohibition against using an evaporator.

your right.but,i didn,t say that warning had anything to do with using stainless steel for pans,ect..what i said is there a warning about welding it and i wonder when that will turn into a warn on or ban on using it for food/sugaring use.
at one time it was ok to use lead for water pipes and dishs..look at lead now.i have a feeling stainless will be no diffrent at some point.

delbert

[TapME]

Isn't a lot canned food still being canned in galvanized cans, especially the larger 3 quart bulk size cans??

the little packs that the kids bring to school(8oz) with the pull top are galvy. Just had one and it's from a large brand name co.
As for the stainless and use in cooking, time will tell. I myself use cast iron cook ware and you see the warnings on that stuff. most anything in moderation will no harm you if you use common sense.

[Grade "A"]

I have some "microseal" I was going to use to coat my cast spouts. The info about it say's "Hardened Microseal is non-toxic and odorless and can be used in contact with food (FDA approved)." I didn't see anything about the amount of contact time, but this stuff looks like water, easy to put on. It looks like it would work great to coat a tank but I wont say it is 100% safe because I don't know. Heres the link http://www.microleak.com/brochnew.htm

[KenWP]

It says for uses it's used for water tanks. It's like the old water glass we used to use on cisterns to seal the cement. Trick would be to put it on the inside of a tank and not gas yourself with it. You can contact the company and find out if it would work on sap tanks also.

[DrTimPerkins]

It says for uses it's used for water tanks. It's like the old water glass we used to use on cisterns to seal the cement. Trick would be to put it on the inside of a tank and not gas yourself with it. You can contact the company and find out if it would work on sap tanks also.

Ask if it is good for food grade prolonged contact or incidental contact. Tell them you what you want to use it on and ask if it'll work. Then if they say it'll work, ask them to put in writing that it's OK.

If you do use the MEK (methyl ethyl ketone) variety, do it with a respirator or with LOTS of ventilation. Very nasty stuff indeed.

[farmall h]

Hmmm.....sticky subject (sorry bout that)!


I suspect what you're going to see over the next 10-20 years is a phase out of galvanized materials in the industry (and other industries). It is already starting with barrels to some degree, and is being driven by the large industrial buyers. They purchase ingredients from all over the place....and aren't used to buying food in galvanized containers. If they won't purchase even what is probably a minor ingredient in their product if it's in a galvanized barrel....what are we doing to our consumers when a good share of our total crop is in galvanized. There is no question that a good stainless barrel will keep syrup quality better than an old beat-up galvanized barrel.

I went searching for "food-grade" paint today and Rustoleum makes a food grade paint. It is called "dairy white" and can be purchased from Grainger for $52 gallon. I am going to prime and paint the bottom of my galvanized tanks before I invest thousands in stainless steel. I will first check out the MSDS sheet and see about prolonged contact with milk, sap, water etc. Your input Dr. Tim?
Maple Grove mentioned to my father when he took the bulk syrup that they have plans of replacing all their galvanized drums for poly and hot packed by 2012. Just wanted to pass on the info.:)

[Haynes Forest Products]

The welding prosess is alot differant than the finished product when it comes to ill effects.

[3rdgen.maple]

Farmhall it all sounds good at first glance but I did a little search for you and here is the product info on the dairy white. The lableing on the can make you think it is safe but the data sheet explains it all. ALso notice the states that it has been restricted to sell it in.

Food and Beverage Alkyd Enamels (8400 System)
For use where resistance to constant humidity and repeated scrubbing with detergents is desired.
Help prevent mold and mildew growth in the dried paint film. Suitable for food processing plants, shower and locker rooms, fresh and waste water treatment plants, tanneries, and laundries. USDA acceptable for incidental food contact.Hazardous Material
This item has been restricted from sale in the following states: [CA, CT, DC, DE, MD, ME, NH, NJ, NY, PA]
California Proposition 65 Warning: This product contains a product known to the State of California to cause cancer. Warning: This product contains a chemical known to the State of California to cause birth defects or other reproductive harm.
Paint, Can Capacity 1 Gallon, Finish Dairy White, Coverage 270-550 Square Feet, Dry Time 4-7 Hours, Dry Time Recoat 24 Hours, Dry Time Tack Free 2-4 Hours, Practical Area 270-550 Square Feet, VOC Less Than 420 Grams per Liter, Industrial Food/Beverage Grade Enamel

Product Tags
paintrust-oleum paint

[ADKMAPLE]

I have always heard galvanized, why is this?

[farmall h]

3rdgen, hey thanks for the quick research. I guess that explains why I was not allowed to purchase it via. Fastenal Inc. They explained to me that it could not be shipped into VT from Mass. PROHIBITED! Guess that idea is gone. Gonna buy new poly tanks...the heck with it.:)

I am glad I revisited this thread. Might as well send the galvanized to the scrap yard...or put them in the pasture for the cows.

[3rdgen.maple]

No problem at all. I especially like the part how it says the product contains a chemical known to the state of Ca to cause cancer and birth defects but yet the stupid can says food and beverage on it. I guess you can say anything you want these days just as long as the fine print tells the truth. WTF

[farmall h]

WTF for sure. Thanks again 3rdgen. Hope everybody read this thread....kinda takes the "what if I use......" question out of it. End of discussion, lets all move along now!:)

[argohauler]

If you want a good scare, read "Death By Rubber Duck: How the toxic chemistry of everyday life affects our health." Authors Rick Smith + Bruce Lourie.

My wife looked around at everything in the house and felt like running away and living in a cave and living off the land and realized that wasn't safe either after she read that book.