Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

RE: Hot-Dip Galvanizing of A 307 Bolts and Related Nuts

[Subject Prev][Subject Next][Thread Prev][Thread Next]



The project I am currently working on is marine and if bolts are not galvanized, they are stainless or Ti. My galvanizer assures me that there is no such process as mechanically galvanizing or cold galvanizing and that many people mistake cadmium plating for mechanical galvanizing.


As for comment, we have had no fit-up problems and no bolt fit problems. We also are using A325 galvanized bolts with the same success. I am told that the hot dip galvanized coating will last a min. of 20 years whereas the cad product will not last the first year.





-----Original Message-----
From: Bill Polhemus [mailto:bill(--nospam--at)]
Sent: Monday, December 08, 2003 1:40 PM
To: seaint(--nospam--at)
Subject: Q: Hot-Dip Galvanizing of A 307 Bolts and Related Nuts


I have a job going for purchasing. I got shop drawings on miscellaneous steel which will be connected to some timber members using A 307 bolts.


The bolts were shown on the shop drawings as “hot-dip galvanized.” I changed it to read “mechanically galvanized.” Now the supplier claims it will take them over a week to get those.


The contractor wants me to “handle it” (implying “use hot-dip galvanized bolts”). I am uncomfortable with this because of past reading where hot-dip galvanizing of bolts caused fit-up problems and heat-related problems with the bolt material.


However, A 307 is not considered “high strength” I believe, so it may be all right to hot-dip galvanize.

Comments, please.


William L. Polhemus, Jr. P.E.

Polhemus Engineering Company

Katy, Texas USA