# Forum Home Renovation Pools, Spa & Water Features  Dynah bolts for Pool Fencing

## yhenig

Hi. I'm about to install a new Aluminum fence around my pool. The Aluminum poles are powder coated but I was wondering what readers think of the type of bolts I should use: Stainless or Galvanised? (yes, it's going on top of concrete slab). Thanks in advance.

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## cherub65

Stainless steel studs chem set in concrete, (buy length  booker rod and cut to lenght)

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## yhenig

Thanks Sherub. My main concern is the posible reaction between the aluminum and the bolt. Will the Chem Set provide the protectio between the two?

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## cherub65

Are you close to coastal position, as two different metals are more likely to react in that position 
From memory 400 series stainless should be alright. I see if i can chase the answer for you, But for a domestic application dont think it would be a major problem.

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## yhenig

Yes. We are about 200-250 metres from the beach. I ended up buying the SS bolts but it was interesting to note that there was no agreement among the several fencing contractores I rang to ask same question. They did agreed however that normal bolts is definetly a no go but some suggested that Gal would be sufficient. Thanks for your help.

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## ScroozAdmin

just to clarify this, galvanic (or bimetallic) corrosion between aluminium and stainless steel is high risk *on paper* as ally is a lot less noble than stainless, the metals have to be in 'electrical contact' to start corroding so just add a nice conductive liquid between the 2 surfaces such as salt water and bingo you've got a corrosion cell. 
The fact in reality with these 2 metals is that ally and stainless often need a pretty big contact area to generate enough energy to begin this corroding and so generally the head of a bolt doesn't prove a problem, also bear in mind the metals need to be  
1. in bare contact (so the powder coat will break this) to start this process 
2. wet. 
The industry standard method for avoidance of any galvanic issues is to seperate the metals with an insulator such as a nylon or rubber washer or if possible just don't mix metals, in your situation I'm sure they'll be fine, if you notice anything just undo slightly and squirt some silicone sealant between the 2 metals to break the contact and tighten em up again.  :2thumbsup:

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