Alloy, Stainless and brass

[Hightower]

I'm fixing down some battery support fabrications down in the console. These are made from Aluminium Alloy and I want to bed these onto a Silkaflex or Polyester resin base and fixed in position with screws.

What material screws can I use? I was going to use stainless, however don't these react badly with the aluminium though electrolisis? Would brass screws be better? I'm screwing into a wooden/glass floor.

[codprawn]

Most things will react with aluminium - you best bet would be good quality zinc plated or galvanised screws - failing that stainless is much closer than anything else you have mentioned - just make sure you get the right grade as they vary so much - the problem is most fasteners are NOT the right grade - either A2 or A4 which are much higher up the scale......

The best thing is to try to isolate the screws from the aluminium as much as you can - use washers and sikafles so they never touch!!!

[Hightower]

Well I'm hoping the bonding of the frame to the deck will do most of the job with the screws being a backup.

I have Stainless A4 screws to hand, so will use them if know one says any different.

[codprawn]

Originally Posted by Hightower

Well I'm hoping the bonding of the frame to the deck will do most of the job with the screws being a backup.

I have Stainless A4 screws to hand, so will use them if know one says any different.

Make sure they don't touch or otherwise eventually the aluminium holes will enlarge until they are bigger than the head if there's salt water around - as I said washers and sikaflex!!!

[jwalker]

They'll be fine until you get some saltwater on them. In fact, if you accidentally flood that compartment your batteries will see to it that the alloy disappears in a couple of hours.

[Hightower]

Originally Posted by jwalker

They'll be fine until you get some saltwater on them. In fact, if you accidentally flood that compartment your batteries will see to it that the alloy disappears in a couple of hours.

Oh your nice and cheery on a Sunday night

Got work in the morning or something

What I might do is to drill and csk some largish holes thought the frame. Fix the whole lot with the polyester, then after it's cured take out the screws bung in some silkaflex and retighten.

To OTT?

[jwalker]

Get those batteries way up above flood level and use all stainless fastenings.

[Hightower]

There's no way I can get them above flood level, just doesn't factor I'm afraid.

[Downhilldai]

Weigh in the ally and get some stainless brackets

[jwalker]

Originally Posted by Hightower

There's no way I can get them above flood level, just doesn't factor I'm afraid.

Where there's a will there's a way.

[codprawn]

For an easy way out spray the screws with silicone grease - fill the holes with epoxy and pop the screws in making sure you have a washer in place - then they won't even touch the aluminium!!!