IPA and Galvanized Steel

[rstor]

I would like to store/dispense Isopropyl Alcohol (99.9% Anhydrous or 99%). The dispensing container that I will be using is made of galvanized steel (Justrite 10018 [Galvanized] Steel Plunger Can). The IPA is for electronics use (removing flux, cleaning PCBs).

According to Justrite (who manufacturers the storage can), they mentioned in the link below that 70% IPA is not recommended to be stored in a galvanized steel can (they recommend stainless steel or polyethylene).

Link

I am assuming this is because 70% IPA contains 30% water which has the potential to rust galvanized steel over time, is this correct?

According to The Dow Chemical Company they mentioned in a document that:
"..Transfer lines may be of carbon steel. For Isopropanol, 91 or 95 percent, stainless steel, galvanized or lined piping should be considered if rusting is to be eliminated."

Would storing 99.9% or 99% IPA in a container made of galvanized steel cause rust or any other issue which would compromise the safety of the container?
Logged

 

[tbuelna]

Why wouldn't you use a stainless steel storage vessel and polypropylene squeeze bottles for applying the IPA solution? What quantity of IPA do you intend to store at your facility?

 

[rstor]

Thank you tbuelna. I've returned the steel galvanized dispensing container. I am now trying to decide between either this:

(HDPE bottle with Stainless Steel pump)

http://menda.descoindustries.com/Me...le/StainlessSteel/Natural/35396/#.VKm6xCvF_ps

or this:

(HDPE container with plunger assembly made of Brass and Ryton)

http://justritemfg.com/products/saf...nger-cans/plunger-dispensing-can-1quart-hdpe/

The one made by Justrite indicates that the "perforated upper pan serves as a flame arrester". I am not sure if the brass used will be an issue with IPA.

I only need to use small amounts of IPA as this is for hobby electronics at home. My main concern is fire safety. I like the feature of the dispensing pump by Menda has it prevents the main reservoir from getting contaminated.

 

[EdStainless]

The other serious concern is preventing the IPA from absorbing moisture from the air.
I would prefer the Menda.

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P.E. Metallurgy, Plymouth Tube

 

[moltenmetal]

While there's a theoretical risk of fire on transferring your 70% IPA, the vapour is much more of a concern than the liquid. It's got a lot of water in it and it's very conductive, so static discharge is much less of a concern than when transferring solvents which are less conductive. An ordinary wash bottle with pressure relief would be fine. I wouldn't be worried about dispensing 70% IPA from a plastic container. Denatured ethanol, dry, is dispensed from polyethylene wash bottles in labs every day without incident, and it's much more of a fire risk than 70% IPA.

 

[rstor]

I'll be using 99.9% Anhydrous IPA or 99% IPA. Menda has a conductive pump and a dissipative pump. In this case I guess it would be better to go with an ESD safe HDPE pump.

Would it make much of a difference if I go with conductive vs dissipative?

 

[rstor]

It appears the dissipative model is rated as "excellent" for IPA, (conductive has a rating of "good"):

http://www.charleswater.co.uk/PDF/MendaCompatibility.pdf

For acetone it is the other way around (dissipative has a rating of "good" and conductive a rating of "excellent").

I wonder why that is...

 

[moltenmetal]

Sorry- misread. Anhydrous IPA is still reasonably conductive as solvents go, but much less so than 70%. It's also of not much concern to me with respect to galvanized steel unless you let it sit around and hydrate a lot. But if cleanliness is the primary concern, plastics are going to serve you better than zinc on steel. The material may last forever, but it can contaminate your solvent a little. Fire risk is still very modest in practice with anhydrous IPA.

 

[rstor]

Thank you for your help. Regarding the conductivity of IPA: I always thought IPA was non conductive as it is used in the cleaning process of electronics. Google results indicate many saying the same (non-conductive) however looking at reputable websites from chemical manufacturers, they indicate it is conductive as you mentioned.

Is it because IPA evaporates quickly without leaving any conductive residue the reason why it is used as a solvent for cleaning electronics?

 

[tbuelna]

You note the IPA dispenser will be used for cleaning electronic components. So the dispenser will mostly be used to apply small amounts of IPA to something like a swab or cloth patch, right? And since it is for home use, the amount of IPA used will be fairly modest. What I have found with using these types of cleaning solvents at home is that the containers need to provide a tight seal. I recall using a poly squeeze bottle

to store a few ounces of acetone for degreasing metals surfaces before welding. After leaving the squeeze bottle on the shelf for a couple weeks, I always found it empty. And I could not see how the acetone was able to escape from the squeeze bottle through simple evaporation given its design. Eventually I figured out that the liquid acetone was being forced out of the nozzle due to the heating/cooling cycles it was subject to each day while siting on the shelf in my garage.

 

[moltenmetal]

A pressure relieving squeeze bottle will eliminate that problem tbuelna. The one you've pictured isn't designed for volatile solvents use. And I too think that the tool of choice is a squeeze bottle, which you decant into from the original storage container whenever you need.