Sandblasted & Passivated Stainless Steel Property Line Marker NYC

[rossmosh]

I've been going back and forth with a customer for a while now. They're doing iron work for a big project in NYC and they've decided to be a middleman for getting the property line marker signs done.

The architect has spec'd "standblasted and passivated 3/16" thick stainless steel with etched letters 1/16" deep and then color filled with black paint".

I've contacted all my usual companies about this project and they all say basically the same thing "I have no idea what they're talking about. We'll etch you 3/16" stainless, color fill it, clear coat it, and you'll be good to go for a VERY long time."

I tell my customer this. They say "okay". Then they come back a month later and say "the customer wants it to spec." I didn't mind researching it originally as we were slow and figured I'd learn something new, but this is the 3rd time they've said this to me. I've sunk too much time at this point and I'd like to come up with the right product (if possible).

Anyone ever hear of sandblasted and passivated etched stainless signs?

 

[CanuckSigns]

Call gemini, they do it.

 

[signbrad]

Sandblasting removes passivation and introduces contaminants that can cause stains and rust. So if you sandblast to etch the graphics, it sounds like they want you to passivate the sandblasted area before you paint fill. Passivation will keep the metal from rusting, and it may help the paint to stick. It may be as simple as brushing on a passivating solution and rinsing it off before you paint fill, but I really don't know. Someone at Gemini might give you better information. I know I would use Matthews or some other cross-linking polyurethane for the fill rather than something like lettering enamel that won't be nearly as hard or moisture-resistant.

Here is a Gemini page about maintenance stainless:
https://geminimade.com/signage/maintenance/

By the way, I didn't know people clear coat stainless. But I'm not an expert on stainless steel, either. I noticed that in my Matthews Paint manual there is no prep protocol for painting or clearing stainless.

Brad in Kansas City

 

[rossmosh]

Gemini won't meet specs

1. They won't sandblast stainless

2. They don't passivate.

3. They won't do a deep etch. They'll print only etch to approximately 1/32".

I've spoken to them a bunch of times trying to get someone willing to accept this job as a special circumstance, but they won't do anything outside their standard process.

 

[Jburns]

I guess it comes down to how deep is an "etch" - wonder if they will check to see if the etch is 1/16th inch deep.

edit: Actually - once its painted how does one measure the depth of the etch?

 

[Johnny Best]

Have a CNC guy “etch” down 1/16” to cut your copy, then sandblast it, fill letters with two part paint.

 

[signbrad]

When my boss receives specs from architects, he sometimes simply ignores them.
For example, we receive requests all the time for "photopolymer" signs for ADA compliance. We never do photopolymer. We had a photopolymer machine at one time, but rarely used it. I don't even know where it is, now. In the last ten years, our ADA signs have always been acrylic with stick-on ADA material that is routered, together with bead Braille, or else we use sandblasted Corian. I don't recall a single rejection in ten years, and we do hundreds of ADA-compliant signs every year. If there has been a rejection, I didn't know about it.

I'm not suggesting that you ignore specs, but my boss does—all the time.
...................

So, did you hear about the architect who had an unhealthy obsession with designing intricate shopping malls?
He had a complex complex complex.

 

[rjssigns]

Agree with Johnny Best. Have it CNC'ed. Can passivate after everything is done. Passivating is nothing more than wiping down with an acid solution. It removes surface contaminants and builds a thicker oxide layer. I used to do this way back when I worked in a fab shop building dryers for converting.

 

[Notarealsignguy]

By the way, I didn't know people clear coat stainless. But I'm not an expert on stainless steel, either. I noticed that in my Matthews Paint manual there is no prep protocol for painting or clearing stainless.

Brad in Kansas City

We prep and paint stainless the same way that we do aluminum.