Letter 114

Zinc "gunning" supplies for ship repair

-----

Dear Sir, I'm most surprised that all over the net, there is a lot to find about zinc and anti-corrosion techniques, though there's nothing on a technique used in shipbuilding and ship repair: - blastcleaning (AlO2) a surface. - "gunning" with a zinc wire which is melted down and sprayed onto the surface thickness till 900 gr/m2 I'm looking for info about the technique and suppliers. Can someone help me ? regards,

Van de Walle Ghislain
- Belgium

You might talk to Tafa Corp. [Concord, NH].

Although it's expensive, ASM International has a CD-ROM covering thermal spray technology. See http://www.asm-intl.org/mi.

 
Ted Mooney, P.E.
Finishing.com Inc. - Brick, NJ

Many thanks for the Tafa info. Considering buying the Tafa equipment we have talked with some major clients about the process. Most of them know the process of spraying zinc but don't see it as a replacement for hot dipping of zinc. Altogether one can say that the process over here is little known, and thus opinions are reserved about the quality. We should prefer such a process above hot dipping because we lose jit-delivery control and receive the materials often deformed.[Lorry- transport of about 70 km].

Does such a process withstand weather conditions like hot dipped zinc? Is there an adhesion problem? Can the layer thickness be controlled in an semi-automated process? Are we right to convince our costumers? Is there really a fe-contamination in hot dipping and how severe is the risk? Does sprayed zinc withstand better the outside air? Is the whole process of shot blasting and gunning zinc really less expensive?

Sorry for the amount of questions, but I'm a doubting soul whether we should go one way or another. Many thanks,

Van de Walle Ghislain
Belgium

1). Iron contamination is not supposed to be a real problem in a well-operated hot dip line.
2). My understanding is that it doesn't matter whether you apply the zinc by hot dipping, electroplating, mechanical plating, or whatever: zinc is zinc and the corrosion resistance and longevity are proportional to the thickness.

The advertisers in our directory listings may have some answers for your questions.

Ted Mooney, P.E.
Finishing.com Inc. - Brick, NJ

I want to post a question or inquiry of my own.

 

I want to answer or follow-up on this question publicly

 

This letter is within a monitored forum, very much "alive" here in 2008. If you spot any broken links or obsolete info, please advise!