5052 Question
5052 Question
Ok I'm a bit confused about 5052. Some say builders use it because it's less expensive. However, I've come across builders who use 5086 yet their boats are less expensive than the 5052 builders. I've talked to a few non production boat builders (kit builders) who say I really shouldn't use anything less than 5086 as well as a couple of marine architects. I read that it's not as strong nor does it have as good as the noncorrosive properties of 5086. So what's the deal with 5052? Is it better than 5086? Why do builders use it if their boats are actually more expensive than 5086 builders? Should one not consider a builder who uses 5052 just because they use it? I'm also refering to boats that are just built for ocean use.
Re: 5052 Question
I'm not an naval engineer but understand a bit about what goes into an engineers mind when considering a material. You need to consider not only the physical properties of the material, but also the working properties of the material and the processes you'll use to form the material into a hull. Also when running the calculations on a hull design you'll come up with scantlings which in the case of a plate alloy boat yields the thickness of plate you will use.
While 5052 of the same thickness isn't as strong as 5086, 5052 can be more easily formed into complex shapes which is an advantage. Also lets say the scantlings show 1/4" 5086 is marginal, go up to 5/16" plate and you'd be good to go with 5052 and you'l have the advantage of more easily formed plate, which makes a big difference as the thickness of the plate increases. And while 5052 of the same thickness will be slightly less expensive than 5086, increasing the thickness 25% will definitely drive up the cost
While 5052 of the same thickness isn't as strong as 5086, 5052 can be more easily formed into complex shapes which is an advantage. Also lets say the scantlings show 1/4" 5086 is marginal, go up to 5/16" plate and you'd be good to go with 5052 and you'l have the advantage of more easily formed plate, which makes a big difference as the thickness of the plate increases. And while 5052 of the same thickness will be slightly less expensive than 5086, increasing the thickness 25% will definitely drive up the cost
Re: 5052 Question
There are many considerations to look at when comparing 5086 versus 5052. The 5086 is much stronger in the as welded condition. So increasing the plate thickness doesn't do anything to the seams you weld. Also the H116 temper heat treating process is designed to help prevent intergarnular corrosion.
I feel that you should always use 5086 for your hull plating at least any boat that is 20' and going more that 20 knts. We use 5052 above the waterline for the decks and cabin.
Weldrbob
I feel that you should always use 5086 for your hull plating at least any boat that is 20' and going more that 20 knts. We use 5052 above the waterline for the decks and cabin.
Weldrbob
-
kmorin
- Donator 08, 09, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24
- Posts: 1743
- Joined: Mon Aug 18, 2008 1:37 am
- 15
- Location: Kenai, Alaska
Re: 5052 Question
jj225, the question is not quite an apples-to-apples question because you'd need to do some isolation (like your last sentence ) to be able to compare the two (or other) alloys.
First, you can look up the properties (search the 'www/i'net' including reading what the definitions of each mechanical property means) of the two alloys 5052 and 5086 and find that 5086 'outperforms' 5052 in all but a few categories. '86 is 'stronger' for the same wt and thickness but '52 will bend for a bit longer before it tears/fails/ruptures/gives up.
'86 is "more metal for the mass" so it costs more per pound; but.... we now have to turn to the boats and builders.
Unless you were able to find two boats from the exact same builder, one of one alloy the second of the other alloy then you can't make a head's up comparison. If one builder uses '86 alloy and takes advantage of the properties of that alloy they may be able to use thinner parts, fewer parts and overall save the materials' cost differences (form any savings in '52) but you won't find that out because no builder is sharing that type of information.
Next part of that problem, trying to make a decent head's up comparison in the actual design differences of the two builders' products. We're not easily going to find one builder who will build a pair of identical boats of the two alloys so the designs become another added variable that we can't very easily 'account for'. If not then the shape and design difference may make the materials cost more in one boat even if they were both built of a common alloy.
Still on this heading, one designer or builder may decide to use a 10% over-strength factor in their designs. But another has decided to use a 50% or even larger 'safety' factor. I've been accused of over building in many boats and that came from a hull problem from when I was a new designer/builder and used the minimum needed strength in a boat that ended up with some cracks. That left me with the impression that if some is good, more is better, and there are other builders who have the same building experiences and they too may build with more metal than is absolutely necessary.
So to try to answer your question(s). The are lots of factors that go into the cost of a welded metal boat, and the materials cost(s) based on alloys is only one line item that may not make it all the way to the bottom line. Different designs, different business overhead, different labor costs, different .... well there are lots of differences that may outweigh the original 'market' cost difference between the two alloys of aluminum.
Next, 'better' is a relative term. So if someone reading your question is interested in the increased mechanical properties of 5086 they may be willing to pay the cost difference and would agree: "5086 is better than 5052".
However, if another reader was concerned with more ductility, like some river jet boats where a bending bottom is better than tearing bottom while scooting over rocks at 40 mph, then they may say "5052 is better than 5086".
Point of view seems to govern 'better' unless you're willing to put up some sort of criteria for the comparison?
I'd say there are a few ways to compare builders. First is the boat they build, but then many new welded alloy boat owners don't have the knowledge to make a reliable 'survey' of the boats. Next is the resale value of the boats, if the boats don't go on the market much, they're retained by the original owners- that is the best credibility check available. But if any do resell, what are the market values compared to original pricing? The farther down the value they have to go to sell, the less the market as a whole wants that builder's work.
Last but not least is the state of the boats built after years of use. If that builder's boats hold up well, then they're a higher quality builder than the boats that don't hold up. What is 'holding up'? Are there repairs, on the used boats? Were there corrosion issues anywhere? I've seen some boats (from a 'name brand builder') that are repaired each season but still in use, they resell lower than much more expensive cousins from other builders and this same builder's boats corrode so regularly; they actually tell clients 'that is normal' for aluminum boats.
I hope the reply, lengthy as it is, helps you to consider more of the variables in your questions?
Cheers,
Kevin Morin
First, you can look up the properties (search the 'www/i'net' including reading what the definitions of each mechanical property means) of the two alloys 5052 and 5086 and find that 5086 'outperforms' 5052 in all but a few categories. '86 is 'stronger' for the same wt and thickness but '52 will bend for a bit longer before it tears/fails/ruptures/gives up.
'86 is "more metal for the mass" so it costs more per pound; but.... we now have to turn to the boats and builders.
Unless you were able to find two boats from the exact same builder, one of one alloy the second of the other alloy then you can't make a head's up comparison. If one builder uses '86 alloy and takes advantage of the properties of that alloy they may be able to use thinner parts, fewer parts and overall save the materials' cost differences (form any savings in '52) but you won't find that out because no builder is sharing that type of information.
Next part of that problem, trying to make a decent head's up comparison in the actual design differences of the two builders' products. We're not easily going to find one builder who will build a pair of identical boats of the two alloys so the designs become another added variable that we can't very easily 'account for'. If not then the shape and design difference may make the materials cost more in one boat even if they were both built of a common alloy.
Still on this heading, one designer or builder may decide to use a 10% over-strength factor in their designs. But another has decided to use a 50% or even larger 'safety' factor. I've been accused of over building in many boats and that came from a hull problem from when I was a new designer/builder and used the minimum needed strength in a boat that ended up with some cracks. That left me with the impression that if some is good, more is better, and there are other builders who have the same building experiences and they too may build with more metal than is absolutely necessary.
So to try to answer your question(s). The are lots of factors that go into the cost of a welded metal boat, and the materials cost(s) based on alloys is only one line item that may not make it all the way to the bottom line. Different designs, different business overhead, different labor costs, different .... well there are lots of differences that may outweigh the original 'market' cost difference between the two alloys of aluminum.
Next, 'better' is a relative term. So if someone reading your question is interested in the increased mechanical properties of 5086 they may be willing to pay the cost difference and would agree: "5086 is better than 5052".
However, if another reader was concerned with more ductility, like some river jet boats where a bending bottom is better than tearing bottom while scooting over rocks at 40 mph, then they may say "5052 is better than 5086".
Point of view seems to govern 'better' unless you're willing to put up some sort of criteria for the comparison?
I'd say there are a few ways to compare builders. First is the boat they build, but then many new welded alloy boat owners don't have the knowledge to make a reliable 'survey' of the boats. Next is the resale value of the boats, if the boats don't go on the market much, they're retained by the original owners- that is the best credibility check available. But if any do resell, what are the market values compared to original pricing? The farther down the value they have to go to sell, the less the market as a whole wants that builder's work.
Last but not least is the state of the boats built after years of use. If that builder's boats hold up well, then they're a higher quality builder than the boats that don't hold up. What is 'holding up'? Are there repairs, on the used boats? Were there corrosion issues anywhere? I've seen some boats (from a 'name brand builder') that are repaired each season but still in use, they resell lower than much more expensive cousins from other builders and this same builder's boats corrode so regularly; they actually tell clients 'that is normal' for aluminum boats.
I hope the reply, lengthy as it is, helps you to consider more of the variables in your questions?
Cheers,
Kevin Morin
kmorin
Re: 5052 Question
Thanks for the replies. Something to think about. Given the lenghty but informative reply by KM, it makes me think I'm on the right track for the boats I'm looking at to have built. Well at least I'd like to think I am. One is Canadian the other U.S. (but may add one more in the mix). One uses 5052 the other 5086. Leaning more towards the 86 but not because of the type of aluminum. What KM wrote really rang true to what I've been able to find out about the builder so far. Actually very uncanny although the same could be said for the other builder too. Next thing will be to fly up for a visit when it warms up a bit. I'm not into cold weather lol!