Specifying Paint on US commercial drawings

[KENAT]

What is standard practice for specifying paint on commercial drawings in the US?

On military drawings in the UK we used to call up the type of paint or paint system to a DEF STAN (like a Mil std) and the color to a British Standard (can’t recall the number but it was virtually a book of color samples like you get from Home Depot or somewhere, each color had an ID).

I didn’t really work on commercial drawings but from what I recall on the few I saw we’d specify the paint system, typically supplier and their part number, and the color either from the British Standard or the vendors designation system.

Here they just say things like ‘POWDER COAT BLUE’ or ‘PAINT BLACK’ which I can’t help think may not be adequate. Sometimes they refer to paint chips for color but it seems inconsistent at best.

So what is commercial best practice in the US?

Thanks,


KENAT, probably the least qualified checker you'll ever meet...

 

[ewh]

We call out the manufacturers part number or our own stock number, and the process and thickness if required. No problems (yet).

Believe it if you need it or leave it if you dare. - [small]Robert Hunter[/small]

 

[drawoh]

KENAT,

What standards does your paint shop understand?

I am under the impression that paint shops in Canada and the US understand the FED STD-595B paint chips. Graphic artists and the people who silkscreen panels, understand Pantone colours. I designed a fibreglass shell, and the fabricator used the Pantone charts to figure out his gel coat colour.

After that, you specify the type of paint.

JHG

 

[MadMango]

Let's not forget RAL codes and BS-381C paint colors either.

KENAT, do you have internal powder coating at your place, or are you sending to an outside vendor? We did similar, but wee had our own powder coating, so specifying YELLOW PWDR COAT or GREY WRINKLE made sense. When parts were sent outside, we provided our powder manufacturers information in a General Note.

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of Eng-Tips Forums?

 

[Heckler]

We callout the paint manufactures part number, color pantone number, texture, thickness, surface masking and FED-STD-595.

Heckler
Sr. Mechanical Engineer
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_`\(,_
(_)/ (_)

This post contains no political overtones or undertones for that matter and in no way represents the poster's political agenda.

 

[KENAT]

Thanks,

We send all our stuff out, we don't have our own shop.

I've seen it called up various ways on our drawings, most of which I would not consider explicitly clear (as my examples above).

We have a bad habit of sending stuff out to vendors without complete definition, verbally agreeing things (or maybe in an email or PO) and getting a first article that's good and we just go on from there, sometimes for years, never incorporating these comments etc in the drawing pack.

Then when staff leave us, or the vendor, or we change vendor we no longer have complete definition of the part and get stuff in that doesn't work but isn't explicitly 'not to drawing'.

I have a question out to our manufacturing guys to find the answer for a specific part but wanted to know the general best practice. What the 2 of you suggest is pretty much what I'd expect.

KENAT, probably the least qualified checker you'll ever meet...

 

[MintJulep]

I don't know if it's "best practice", but a "good practice" is:

"Prepare surface, prime (primer color), and top-coat (top coat color) per procedure XYZ123."

You would then need to develop procedure XYZ123. It will need to include:

What surface preparation and cleaning is required.

Required environmental limits for application.

Required safety equipment.

Required application equipment.

Required settings for the application equipment for both primer and top-coat.

What paint and primer and thinners, etc. to use.

How to mix the primer.

How thick to apply primer, how many coats of primer, time required between coats, any additional processes required between coats (sanding, cleaning).

How to mix the top-coat.

How to apply the top-coat, how many coats, time between coats, and additional processes between coats.

Post-application processing.

 

[ctopher]

I do the same as Heckler. Same as machining, coating, etc... leave the process details off.

Chris
SolidWorks/PDMWorks 08 2.0
AutoCAD 06/08
ctopher's home (updated 10-07-07)

 

[KENAT]

Thanks all.

If these were internal I might consider the procedure but as I mentioned in my second post (which I was probably typing at the same time as you mint) these are parts made externally.

Also as Chris says, I don't really want to give processes, just the required end result.

As a few of you have hinted part of my concern is that I correctly specify the complete paint system and factors there in. That was the beauty of the government standards I used to call up in the UK, done correctly it covered all of this.

Also as the painting is usually done by the external machine shop (or their vendor), we don’t have direct control over the paint shop being used so I want to make it general.

Do you think just saying some thing like “in accordance with manufacturer instructions” covers most of these points e.g.

SURFACES INDICATED TO BE PAINTED WITH (insert paint manufacturer part number/description, name & address/Cage code) COLOR (insert relevant FED STD-595B, Pantone or Vendor color identification) IN ACCORDANCE WITH MANUFACTURERS INSTRUCTIONS.

For certain applications I can see the thickness, texture etc requirements might also be needed.

Also, I’ve just discovered that one of parts that prompted this chain of questioning was actually anodized not painted. Is it reasonable to invoke the fed std or similar colors for anodized parts?


KENAT, probably the least qualified checker you'll ever meet...

 

[Gymmeh]

All of our drawings call out BLACK, BLUE or YELLOW. Then we work out the details about brand and paint code with the supplier/end user by email.

As noted, it’s a real mess, if you have to change suppliers. I don’t know if there is a really good way to track paint and not waist space on the drawing. Currently our PO’s have the info written by hand after the fact buy our purchasing person.

I definitely would recommend coming up with a better method of tracking paint.

 

[MadMango]

Anodize is going to be:

AMS-A-8625 (older MIL-A-8625)
Type I (chromic)
type II (sulfuric)
Type III (hard)
Class 1 (non-dyed)
Class 2 (dyed)

or

AA-A42-Class I (architectural exterior)
AA-A32-Class II (architectural interior)
ASTM B 580

You'll have to read up on those standards to determine what Process, Type and Class you need.

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of Eng-Tips Forums?

 

[MintJulep]

Good paint, done properly is expensive.

Buyers and estimators don't understand this.

So when you end up with and "outside painting vendor", that is very likely exactly what you will get.

Bubba, in the back yard, somke'n a stogie, with burgers on the grill spraying your parts with a cheap spray gun from Home Depot and left-over house paint.

 

[KENAT]

Thanks MAD, I have that information. The problem is we have a couple of different parts that we apparantly want to match the shade of gray on across batches/vendors as well as between the 2 different parts.

The note on the drawings talks about this matching (which is pretty pointless in my opinion unless you always use same vendor at same time etc). It also mentions comparing to a sample but, big surprise we don't have one, or at least don't know where/what it is.

So the 2 options I see are we either refer to a national/recognized standard, if there's one that's applicable, or we get a sample and somehow keep track of it this time.

Hence my question on invoking the Fed Std when the color is from anodize not paint.

Mint, you're probably right, but there's only so far I can take it. Even if I created a detailed process I doubt we'd enforce it and I'd be concerned at opening myself/us to liability with OSHA/environmental issues, plus I don't know enough about 'paint' to do it. I figure if I at least spec the paint/coating properly, and specify IAW manufacturers instructions that gives us a fighting chance. I may well be wrong though.

KENAT, probably the least qualified checker you'll ever meet...

 

[KENAT]

This was the drawing note I mention above.

2. ANODIZE PART. MIL-A-8625 TYPE 2 CLASS 2 LIGHT GRAY. USE LIMON'S
METAL FINISHING OR EQUIVALENT. MAINTAIN CONSISTENT COLOR FROM
BATCH TO BATCH. MATCH COLOR TO DIPN 130-004-678, AND SAMPLE
PROVIDED.

Just to make it more fun, the grade of aluminium isn't specified which in turn may affect the color as I understand it.

KENAT, probably the least qualified checker you'll ever meet...

 

[ctopher]

I'm not familiar with "USE LIMON'S METAL FINISHING OR EQUIVALENT". The rest is OK. Usually a note like "MAINTAIN CONSISTENT COLOR FROM BATCH TO BATCH" would be on a quality document. But, I think it may be OK.

Chris
SolidWorks/PDMWorks 08 2.0
AutoCAD 06/08
ctopher's home (updated 10-07-07)

 

[WHITMIREGT]

In military work we called out MIL-STD-595 color using the word "approximate" and to my knowledge, never had a problem. I don't recall if we gave the vendor other imformation as to the application.