I'm no metalurgist by any means, but this boat owner, that I'm wanting to buy from, is telling me all the support structure for his hardtop is stainless steel. It looks exactly like aluminum to me, except no corrosion at all. Even the welds look like aluminum. He said he had it installed in 2004. What is the sure fire method for determining the composition of the tubing?
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How to tell a stainless hardtop from an alum one ?
- Thread starter hogheaven
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SmokyMtnGrady
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Ask him what he paid for it? The Grady equipped hardtops are aluminum. Aluminum does oxidise some leaving a whiteish powder discoloration. Aluminum also gets pitted. Poor quality stainless steel will have magnetic properties. The more nickle and chromium added to the alloy, the less magnetic it becomes. I am williing to be a boat drink it is aluminum.
seabob4
Well-Known Member
Virtually all boat top frames, T/Top or Hardtop, are aluminum...
The weight of a SS frame would be prohibitive...
The weight of a SS frame would be prohibitive...
richie rich
Well-Known Member
The stainless will have a more grainy appearance, like you see on public bathroom handrails, unless this guy took the time to completely buff it out......Aluminum will be more of consistant uniform finish, whether its matt/satin or highly polished.
The aluminum will be about an 1/8" thick....the stainless will be 1/16...otherwise it would be way too heavy as Seabob mentioned....you can check for thickness anywhere there is a bolted fastener in the tube, except for the mounting plates which are normally thicker anyway.
Stainless may have some magnetic effect depending on grade.....very little, but you may be able to feel a very slight pull with a strong magnet...aluminum will have no magnetic pull at all
The aluminum will be about an 1/8" thick....the stainless will be 1/16...otherwise it would be way too heavy as Seabob mentioned....you can check for thickness anywhere there is a bolted fastener in the tube, except for the mounting plates which are normally thicker anyway.
Stainless may have some magnetic effect depending on grade.....very little, but you may be able to feel a very slight pull with a strong magnet...aluminum will have no magnetic pull at all
NO REGRETS
Well-Known Member
Stainless welds will be as shiny as the tubing, aluminum will be more dull than the tubing and usually been painted at the build.The welders of aluminum usually paint the welds to keep them looking good. :goodjob
seabob4
Well-Known Member
NO REGRETS said:Stainless welds will be as shiny as the tubing, aluminum will be more dull than the tubing and usually been painted at the build.The welders of aluminum usually paint the welds to keep them looking good. :goodjob
This is true...
Early Albemarles are the only factory Stainless Steel hardtops I've ever seen . A magnet is the way you'll know on this one ,plain and simple aluminum is a non-ferrous metal and non-magnetic. The only way this top is SS is, it's aftermarket and someone had alot of coin for a top.
Thanks for all the replies on this subject. Since the first post, I finally got a call back from the installer of the hardtop, S & S Marine of Va. Beach, Virginia. He told me the hardtop was polished or brushed aluminum and that the owner apparently has taken good care of it since there is minimal oxidation after 6 years in saltwater. He also said he has never built, and never will build, a hardtop out of SS due to the many cracking concerns that are comon with that metal fatiguing. So, apparently the boat owner does not know what he has, but I will certainly let him know.
jekyl
GreatGrady Captain
Just for interest sake guys.....in Australia most hardtops and tuna towers are still being made from Stainless. Always have. Here the theory is Alloy has more potential for cracking .
I love my alloy hardtop mostly because of the weight it doesn't add to my towable 265 express. I don't know which material is better but they are quite different in weight, finish, and exterior durability. It seems athe alloy needs more care.
I love my alloy hardtop mostly because of the weight it doesn't add to my towable 265 express. I don't know which material is better but they are quite different in weight, finish, and exterior durability. It seems athe alloy needs more care.
seabob4
Well-Known Member
jekyl,
Wouldn't that have to be relatively thin wall SS, to keep the weight down? That would explain the cracking...
Wouldn't that have to be relatively thin wall SS, to keep the weight down? That would explain the cracking...
jekyl
GreatGrady Captain
Well I'm not sure what "thin wall" would be, but most of the older marlin towers on our Heavy Tackle fleet still have stainless and they are a lot heavier, than the newer alloy ones. Certainly the newer big boats are rapidly moving to alloy but most of the trailerable baots still use stainless.