Finger prints on stainless steel sheets 3

[quark]

Hi guys!

I being in a pharma company, we fancy covering everything in stainless steel sheets. To reduce time scales, nowadays, prebuffed SS304 sheets are used. When you peel off the sticker on the sheets, the become prone to finger prints even if you have clean hands (washed by IPA, and don't suspect IPA). First I tried soap solution but it leaves dark patches and they are very much visible at the illumination level of above 500 lux (and this is the minimum level). I tried HNO₃ and K2Paste (I don't know what you call it at your place) but not to my help.

I will be a happy soul if I get some sort of solution.

Thanks in advance,


Believe it or not : If a person becomes invisible, he/she becomes blind as well.

 

[atad]

Try some Johnson and Johnson Baby Oil - works every time!

 

[mcguire]

atad is correct. Any oil, human or otherwise, will leave a mark on stainless of any surface finish. The solution of having a thin, innocuous film already there is the best solution.
AK Steel makes a coating, Agion, I think, that is anti-microbial. It kills al bacteria on contact and also doesn't fingerprint because it's a thin film of polymer and acts in the same way baby oil would.

 

[quark]

Thanks guys. Atleast there is a start. Having costlier material(for better properties) and nursing it like a baby is really annoying me. As we work with cleanrooms and micorbially controlled spaces, I have to check the swab analysis.

I presume applying the oil as soon as the plastic is peeled off.

Thanks once again.

Believe it or not : There is a three dimensional figure but only with one face, called Mobius Strip.

 

[mcguire]

Quark...question for you. Isn't the presence of oil from skin contact indicitive of the presence of some bacteria, or at least a medium in which they could live? If so, wouldn't the fingetprints be a useful sign of loss of total cleanliness needed for sterility?

 

[quark]

mcguire!

It is a good question. Generally sterility checking is statistical and random. For example, for class 10000 sterile clean rooms the limits are,

20cfu(colony forming units)of bacterial contamination/25-30sq.cm of swab area and nothing mentioned about how many swabs you should take with respect to surface area.

Airborne contamination is limited to 10cfu/cu.m, 5cfu/plate if 90mm settle plates are exposed for 4 hours and personal contamination is 5cfu/glove (5 fingers). Fungal count should be nill.

Generally any material taken inside the sterile area is either sterile filtered or sterilized by either dry heat or steam. Oils and grease are also being sterilized. So likely chances of contaminants born inside a sterile area are quite reduced.

My main concern is during the installation of these panels. Mostly we prefer dull(matte) finish to reduce glare and this is causing more trouble with the markings.

Regards,



Believe it or not : It is believed that Archimedis single handedly sailed the 4000 ton ship Syracusia from the dock when dock workers failed and quoted his famous saying.

 

[mcguire]

When I worked for J&L Steel we developed a finish for Reagan Airport roofing which was very dull (15% relectivity) and very cleanable. It is called Architex. It has a very controlled roughness on a previously smooth annealed, pickled surface. It might be ideal for your purposes.

 

[PeterCharles]

This reminds me of one of the downsides of the deLorean sports car with its stainless steel body.

 

[bsg]

Dear Quark,

In my bulk Drug Plant I used this technique to shine the S.S. exterior parts of the vessels,containers.

With a rubber gloves we used Muratic Acid ( Dilute Hcl for use in toilet cleaning)and a little quantity of sand and rubbed the surface. After a little rubbing we used to clean the area with clean water.

Regards,

bsg

Sengupta, Jayneil Technologies Pvt.Ltd.

 

[mcguire]

Use lots of water, if you do this. HCl causes pits and abrasion of the surface does likewise.

 

[mechdesigneng]

Quark,

I dont know if you tried this but did you consider IPA itself to clean off the surfaces? Commently used to clean panels in semiconductor. Use a tech grade (not from Home Depot) and it will evaporte w/o leaving a residue.

Goodluck

 

[cb68]

Not being in pharma industry I'm not sure what the Ra values of your prebuffed sheets are. I have had a similar problem with fingerprints and marking on grained stainless. I switched over to 2J finish OPTISHEEN stainless steel from Aalco with good success.

 

[quark]

Recently I came across with a 3M's product called Stainless Steel Cleaner and Polisher which seems to be doing good work. The fingerprints are not as conspicuous as they were before and after 2 to 3 rubs the steel is becoming resistant to these. One drawback is the cost, at around Rs. 1000 (about USD 20).

Regards,

 

[unclesyd]

Here is a material that we use on SS fume hoods in the laboratories at the plant.
I also use it on SS on the boat.
I would never use HCl on SS surfaces , period. We used any proprietary H3PO4 Cleaner at full strength with an appropriate 3M pad for the existing finish. After a water rinse we applied the “SheliaShine”.
I have got some beautiful finishes on SS using the following method. Clean with H3PO4; polish with “Semichrome” ; Protect with “SheliaShine”. Using the 3M pads as needed.
I'm experimenting with "Micro-Cloth" with the above systems at the present time.

http://www.sheilashineinc.com/index.htm

 

[mx2mx2]

I have been testing a clear non-stick coating that works well for not showing fingerprints. I actually coated my glass table top at home and it works really well. Also, it does not allow bacteria growth on the surface. It is also used to coat artificial hearts, very inert. It can be found at

http://www.kiss-cote.com.

Malcolm