Alodine Question 2

[macduff]

Hello,
Is alodine tied to a specification like TT-P-1757? Or is it something different? Both protect againist Galvanic Corrosion, right?

Thanks for your help.

Macduff
Colin Fitzpatrick
Mechanical Design Engineer
Solidworks 2006 SP 4.1
Dell 380 XP Pro SP 2
nVida Quadro FX 3450/4000

 

[WKTaylor]

Macduff..

"Alodine" is a trade-marked name [like xerox] for an aluminum surface chemical conversion coating [see MIL-C-5541]. This coating provides a significant increase in primer-paint adhesion [on aluminum] and [usually] enhances corrosion rsistance if the paint finish is damaged.

TT-P-1757 is and alkyd base primer [paint] loaded with "zinc+chromate pigments" for enhanced corrosion protection.

Typically aluminum is "alodined"... then primed... then topcoated for greatly increased corrosion resistance and [ultimately] "exterior appearance".

Regards, Wil Taylor

 

[macduff]

wktaylor,
Thanks so much and a star for you!

Best,

Macduff
Colin Fitzpatrick
Mechanical Design Engineer
Solidworks 2006 SP 4.1
Dell 380 XP Pro SP 2
nVida Quadro FX 3450/4000

 

[kenvlach]

Hi, since a July revision, the spec. is MIL-DTL-5541F CHEMICAL CONVERSION COATINGS ON ALUMINUM AND ALUMINUM ALLOYS:

http://assist.daps.dla.mil/quicksearch/basic_profile.cfm?ident_number=5499

Alodine is also tied to MIL-DTL-81706 Chemical Conversion Materials for Coating Aluminum and Aluminum Alloys and its associated Qualified Products List, QPL-81706. Both available at

http://assist.daps.dla.mil/quicksearch/quicksearch_query.cfm

You will notice several verions of Alodine, depending upon whether a Class 1A (thicker, more corrosion protective) or Class 3 (thinner, lower electrical contact resistance). Also, there are various application methods; see MIL-DTL-81706 for the codes in the QPL. Alodine 1200S is perhaps most common in the USA, and overseas it's sold as Alocrom 1200. See also competing products such as Iridite 14-2 on the QPL.

A new QPL revision including Type II coating materials (containing no hexavalent chromium) is rumored to be about 7 months overdue. Either some test failures or more manufacturers trying to get their products listed???

Another relevant specification is ASTM B449, 'Standard Specification for Chromates on Aluminum.'

http://www.astm.org/cgi-bin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/B449.htm?L+mystore+jgam6538

 

[macduff]

Wow, I knew I came to the right forum! Thanks guys for all the info you provided me. Let's close this thread now.

Have a great weekend!

A star for you too, kenvlach

Macduff
Colin Fitzpatrick
Mechanical Design Engineer
Solidworks 2006 SP 4.1
Dell 380 XP Pro SP 2
nVida Quadro FX 3450/4000

 

[kenvlach]

My 2nd link above was a temporary page.
Just go to ASSIST:

http://assist.daps.dla.mil/quicksearch/

and enter 81706 as the Document Number.