Make a mold and manufacture fins from carbon with a abrasion resistant coating.
Be cheaper to make and you wont need a forklift for the fin
I looked into coatings and experimented with a few concoctions, but in the end I did not proceed with any of them. The reason being that the coatings were all effective to varying degrees, until they were worn through. At that point the wear on the leading edge became irregular wherever the original surface was exposed.
This is problematic for the owner who does not have access to the coating and/or ability to repair the coating. So in the end I researched different aluminium alloys and settled on a compromise between hardness, corrosion resistance and susceptibility to pitting when cast. My thinking is that everyone has access to some sandpaper to repair a worn leading edge and it is very user friendly when sanding and polishing.
As far as the cost is concerned, Aluminium is really really cheap if you do it China. But because I am pig headed and wanted to ensure support for Aus manufacturing, I have accept a high unit cost. Plus ,when you are done with sailing, you can throw them in the recycling bin 
Select to expand quoteelmo said..
Make a mold and manufacture fins from carbon with a abrasion resistant coating.
Be cheaper to make and you wont need a forklift for the fin
i recon hooray for fangy for coming up with a new concept in fin design then have it printed and off to the foundry ,as for me i would go the mold and carbon as you have the option of changing and making mods, keep the ideas coming fangy
Select to expand quotekeef said..elmo said..
Make a mold and manufacture fins from carbon with a abrasion resistant coating.
Be cheaper to make and you wont need a forklift for the fin
i recon hooray for fangy for coming up with a new concept in fin design then have it printed and off to the foundry ,as for me i would go the mold and carbon as you have the option of changing and making mods, keep the ideas coming fangy
See Hardie? That's how you do it. No fin for you, You come back one year. But Keef, fin for you and piece of bread for free. 
(oh and Keef, be patient - you might want to go get some bread while you are waiting)
Select to expand quotefangman said..keef said..elmo said..
Make a mold and manufacture fins from carbon with a abrasion resistant coating.
Be cheaper to make and you wont need a forklift for the fin
i recon hooray for fangy for coming up with a new concept in fin design then have it printed and off to the foundry ,as for me i would go the mold and carbon as you have the option of changing and making mods, keep the ideas coming fangy
See Hardie? That's how you do it. No fin for you, You come back one year. But Keef, fin for you and piece of bread for free.
(oh and Keef, be patient - you might want to go get some bread while you are waiting)
Bloody Keef and his compliments
Select to expand quoteFroude said..
Have you tried these guys Fangman? www.veem247.com/foundry/
No, but I noticed they have already got foils that might even lift up my PartyBarge board.
(Thanks for the heads up Froude - I will get in touch with them. I suspect I might be too much of a small player for it to be worthwhile, but no harm in asking ;-)
Fangman, what casting process are they using?
The Investment casting process gives a sandblasted like finish which may mean less finishing. Mould might not be as critical as well.
I have used a mob in Sydney called Hycast Metals. Have a look at their website and see if it looks interesting? My Google search showed Investment casters in other capital cities as well.
Good luck with the fins.
Select to expand quoteGeoffS said..
Fangman, what casting process are they using?
The Investment casting process gives a sandblasted like finish which may mean less finishing. Mould might not be as critical as well.
I have used a mob in Sydney called Hycast Metals. Have a look at their website and see if it looks interesting? My Google search showed Investment casters in other capital cities as well.
Good luck with the fins.
Cheers Geoff the foundry I am currently using is investment sand, but not a particularly fine grade. The main problem I have had in the past when finding a foundry, is that because my quantities are so small, it's not commercially viable for them, or the tooling set up costs are enough to give The Minister for Excessive Windsurfing Spending a trip to the hospital. Not unreasonably, most of them are used to dealing with the oil, gas and mining guys, not tadpoles like me.
Have you looked into doing your own casting.
Im not sure of the process so just sayin.
When you have your final final design visit the Perth Mint.
Gold one for the Man Cave.
Select to expand quoteBSN101 said..
Have you looked into doing your own casting.
Im not sure of the process so just sayin.
When you have your final final design visit the Perth Mint.
Gold one for the Man Cave.
I started this process with the deluded idea that it I could design and facilitate manufacturing. I want to spend my time boffinising or sailing, so I chucked out the idea of DIY.( and mainly I am just too lazy 
)
I like the idea of on for the Man Cave. I might organise that for my 30th birthday.
Select to expand quotefangman said..BSN101 said..
Have you looked into doing your own casting.
Im not sure of the process so just sayin.
When you have your final final design visit the Perth Mint.
Gold one for the Man Cave.
I started this process with the deluded idea that it I could design and facilitate manufacturing. I want to spend my time boffinising or sailing, so I chucked out the idea of DIY.( and mainly I am just too lazy )
I like the idea of on for the Man Cave. I might organise that for my 30th birthday.
Gold spray paint would be fine.
Or a water bead effect, so it looks like you just used it. Simple to do too.
Look into using a casting jeweller to do a lost wax casting for you, it will be more accurate with a better surface finish than the best sand castings. Also, best material to use is nickel aluminium bronze (AB2), very strong and corrosion resistant. A bugger to drill however. Make sure you allow for shrinkage, it is significant and enough to make the head of the fin loose in a tuttle box
Select to expand quotePacey said..
Look into using a casting jeweller to do a lost wax casting for you, it will be more accurate with a better surface finish than the best sand castings. Also, best material to use is nickel aluminium bronze (AB2), very strong and corrosion resistant. A bugger to drill however. Make sure you allow for shrinkage, it is significant and enough to make the head of the fin loose in a tuttle box
Cheers Pacey, my initial plan was to use lost wax, but it required a much longer production run to be cost effective and more importantly it is difficult to reproduce the hollow section in the foil. I did briefly consider AB2, but I was advised that cost per unit will be frightening 
That might be worth revisiting though, as shrinkage is not an issue - one of advantages of the fillet is that all the load is taken on the flange portion, so the fit in the box is not so critical.
Select to expand quotefangman said..Pacey said..
Look into using a casting jeweller to do a lost wax casting for you, it will be more accurate with a better surface finish than the best sand castings. Also, best material to use is nickel aluminium bronze (AB2), very strong and corrosion resistant. A bugger to drill however. Make sure you allow for shrinkage, it is significant and enough to make the head of the fin loose in a tuttle box
Cheers Pacey, my initial plan was to use lost wax, but it required a much longer production run to be cost effective and more importantly it is difficult to reproduce the hollow section in the foil. I did briefly consider AB2, but I was advised that cost per unit will be frightening That might be worth revisiting though, as shrinkage is not an issue - one of advantages of the fillet is that all the load is taken on the flange portion, so the fit in the box is not so critical.
Hi Fangy,
The photo below shows some fittings I had cast about 10 years ago for a an old boat I was restoring. They were done using lost wax by a casting jeweller somewhere in Welshpool I think. As you can see complex shapes are not an issue, so I can't see the concavities in your fin causing a problem. The original fitting was over 100 years old and the roughness of the surface in the new castings is from the sand casting of the original fitting. The lost wax casting was so good it faithfully reproduced the surface pitting in the original fitting as well as scratches from when the original was filed after casting.
AB2 should be only a small amount more to cast than regular bronze, but it is way stronger and more corrosion resistant. There is a good reason that virtually every high performance marine propeller made these days is done with AB2. Whatever you do don't get your fin cast in aluminium, it will be weak and will snap like a carrot. Cast aluminium is nowhere near the strength of forged or milled aluminium.
Don't go to companies like Veem to do your casting, they are ludicrously expensive because they have their procedures set up to comply with quality assurance requirements for doing things like seawater valves on the Collins submarines or the ride control fins on Austal ferries. They are good, but you pay through the nose for it.
Noice Pacey - got any pics of the boat?
The current foundry is an 'Art Foundry' so it sounds like a similar sort of set up. They are going to pass my work on to another 'similar' set up - I just don't know who yet, and so I am preparing contingencies. Just to clarify, I was advised the hollow inside the leading edge was the issue. (it's long and relatively fine)
I like the idea of using the AB2 - Apart from it looking uber cool, I will have to look at the density as well. Part of the appeal of aluminium was the weight issue and to take advantage of its lower elastic modulus. It has about the same density as G10 but better hardness and lower elastic modulus. Because the fin is designed for sailing in shallow water, it will invariably touch down. I wanted some 'give' so that it can ride out any impacts without fracturing like G10.
It's also a delicate balance of where do I put the point of failure? Powerbox designs make this easier having been designed from the outset to fail at the bolt insert, but Tuttle is hard. If the alloy I use is too strong, the bolt holes in the fin will be too strong as well - so rather than the fin peeling away as per Powerbox, with Tuttle the back end of the board is likely to be the point of failure. I am still not sure how to tackle this one and still be user friendly.
If I can have a bigger hollow inside the fin because the AB2 is stronger, I can then pack more foam inside and create more buoyancy to offset the weight. But any redesign requires a new 3D design and print - the costs to get this far makes that idea pretty unsavoury at the moment.
The fins I have had cast already were designed by the engineer to be cast in 6k series Aluminium and to withstand fatigue failure. Thus far they show no signs of snapping. I clamped the base to edge of my trailer and stood on the foil (110kgs) with no harm done. I stood toward the end of the foil and managed to get some bend in the tip.
So whilst I am satisfied that structurally it outperforms G10, I need to be very careful about the costs creeping up. At the moment I am aiming to get the cast done for about $110 per unit. (Just as a comparison - ex-factory in China, $8.00 each for minimum order of 100fins!). Add in the postage/courier from the foundry and I think then I will have DIY finishing fins available for about $135 each. 'Finished' fins will be about the same as a Delta G10 in price but will easily outperform them in every aspect of my design criteria.
I am waiting to hear back from Veem. I suspect you will be right and I will need to do a very large production run to make it worthwhile. I dont think the market for these fins is ever going to be big enough to justify that and although I dont ever expect to be profitable, I would like to keep my losses to a minimum.
Here endeth yet another grand effort from me in procrastinating, instead of doing what I was meant to be doing.
Select to expand quotefangman said..It's also a delicate balance of where do I put the point of failure? ...... with Tuttle the back end of the board is likely to be the point of failure. I am still not sure how to tackle this one and still be user friendly.
What about using Brass bolts instead of S'steel? Will the Brass bolts strip out or break before the tail of the board breaks off? 
Select to expand quotesailquik said..fangman said..It's also a delicate balance of where do I put the point of failure? ...... with Tuttle the back end of the board is likely to be the point of failure. I am still not sure how to tackle this one and still be user friendly.
What about using Brass bolts instead of S'steel? Will the Brass bolts strip out or break before the tail of the board breaks off?
I thought of other materials or thinner bolts but always came back to trying to keep it user friendly - most of us carry M6 S/S bolts around, but I don't think too many of us have alternatives in the kit box. I also thought of just tapping the last 5-10 mms in the bolt hole so the aluminium thread will strip out - but how much is enough to give durability vs stripping out with wear,and galvanic corrosion etc? Is it a moot point? Will a Tuttlebox allow the fin to rotate out - my guess is the back of the box is going to get munted whatever happens, but I am happy to be guided by those that have done the experiment already...
( I only have old Powerbox boards that I have crash tested, so I can only confirm that they work)
Select to expand quotefangman said..
Noice Pacey - got any pics of the boat?
The current foundry is an 'Art Foundry' so it sounds like a similar sort of set up. They are going to pass my work on to another 'similar' set up - I just don't know who yet, and so I am preparing contingencies. Just to clarify, I was advised the hollow inside the leading edge was the issue. (it's long and relatively fine)
I like the idea of using the AB2 - Apart from it looking uber cool, I will have to look at the density as well. Part of the appeal of aluminium was the weight issue and to take advantage of its lower elastic modulus. It has about the same density as G10 but better hardness and lower elastic modulus. Because the fin is designed for sailing in shallow water, it will invariably touch down. I wanted some 'give' so that it can ride out any impacts without fracturing like G10.
It's also a delicate balance of where do I put the point of failure? Powerbox designs make this easier having been designed from the outset to fail at the bolt insert, but Tuttle is hard. If the alloy I use is too strong, the bolt holes in the fin will be too strong as well - so rather than the fin peeling away as per Powerbox, with Tuttle the back end of the board is likely to be the point of failure. I am still not sure how to tackle this one and still be user friendly.
If I can have a bigger hollow inside the fin because the AB2 is stronger, I can then pack more foam inside and create more buoyancy to offset the weight. But any redesign requires a new 3D design and print - the costs to get this far makes that idea pretty unsavoury at the moment.
The fins I have had cast already were designed by the engineer to be cast in 6k series Aluminium and to withstand fatigue failure. Thus far they show no signs of snapping. I clamped the base to edge of my trailer and stood on the foil (110kgs) with no harm done. I stood toward the end of the foil and managed to get some bend in the tip.
So whilst I am satisfied that structurally it outperforms G10, I need to be very careful about the costs creeping up. At the moment I am aiming to get the cast done for about $110 per unit. (Just as a comparison - ex-factory in China, $8.00 each for minimum order of 100fins!). Add in the postage/courier from the foundry and I think then I will have DIY finishing fins available for about $135 each. 'Finished' fins will be about the same as a Delta G10 in price but will easily outperform them in every aspect of my design criteria.
I am waiting to hear back from Veem. I suspect you will be right and I will need to do a very large production run to make it worthwhile. I dont think the market for these fins is ever going to be big enough to justify that and although I dont ever expect to be profitable, I would like to keep my losses to a minimum.
Here endeth yet another grand effort from me in procrastinating, instead of doing what I was meant to be doing.
Boat was Aorere, originally launched in 1898:
I can thoroughly recommend AB2 as a material, hard to mill and drill but strong and tough as nails. But yes, may be too expensive to consider.
You could always try laser sintered titanium :)
Select to expand quotePacey said..fangman said..
Noice Pacey - got any pics of the boat?
Boat was Aorere, originally launched in 1898:
I can thoroughly recommend AB2 as a material, hard to mill and drill but strong and tough as nails. But yes, may be too expensive to consider.
You could always try laser sintered titanium :)
Oh that it's beautiful! I have always loved the big sweeping overhangs of Hereschoff and designers at the turn of the last century. Wooden boat porn is my only vice, (apart from lying :-). I have a feeling I have seen her somewhere. Is she berthed at Freo?
Oh and I did get a quote for the fins in titanium. $2-3000 per fin depending on size and amounts from China. I didn't bother with getting a second opinion from the Minister of Excessive Windsurfing Expenditure on that one. 
Select to expand quotefangman said..Pacey said..fangman said..
Noice Pacey - got any pics of the boat?
Boat was Aorere, originally launched in 1898:
I can thoroughly recommend AB2 as a material, hard to mill and drill but strong and tough as nails. But yes, may be too expensive to consider.
You could always try laser sintered titanium :)
Oh that it's beautiful! I have always loved the big sweeping overhangs of Hereschoff and designers at the turn of the last century. Wooden boat porn is my only vice, (apart from lying :-). I have a feeling I have seen her somewhere. Is she berthed at Freo?
Oh and I did get a quote for the fins in titanium. $2-3000 per fin depending on size and amounts from China. I didn't bother with getting a second opinion from the Minister of Excessive Windsurfing Expenditure on that one.
It's a good price comparison to have up your sleave when you are pleading to the minister.
Is is there any good sailing in china when you go over to discuss the fine details of possible production.
Select to expand quotesailquik said..fangman said..It's also a delicate balance of where do I put the point of failure? ...... with Tuttle the back end of the board is likely to be the point of failure. I am still not sure how to tackle this one and still be user friendly.
What about using Brass bolts instead of S'steel? Will the Brass bolts strip out or break before the tail of the board breaks off?
Or Acetal rod?
I use it in all of my fins, similar material to nylok nut inserts.
Screw never comes loose but I imagine a big impact would strip it ok.
I use 12.7mm diameter inserts to get a bit longer purchase.
I also use UNC thread bolts (coarser) rather than metric, since it's a plastic material.
Select to expand quoteTe Hau said..sailquik said..fangman said..It's also a delicate balance of where do I put the point of failure? ...... with Tuttle the back end of the board is likely to be the point of failure. I am still not sure how to tackle this one and still be user friendly.
What about using Brass bolts instead of S'steel? Will the Brass bolts strip out or break before the tail of the board breaks off?
Or Acetal rod?
I use it in all of my fins, similar material to nylok nut inserts.
Screw never comes loose but I imagine a big impact would strip it ok.
I use 12.7mm diameter inserts to get a bit longer purchase.
I also use UNC thread bolts (coarser) rather than metric, since it's a plastic material.
PS.......referring to the insert material as Acetal rod
Select to expand quoteTe Hau said..Te Hau said..sailquik said..fangman said..It's also a delicate balance of where do I put the point of failure? ...... with Tuttle the back end of the board is likely to be the point of failure. I am still not sure how to tackle this one and still be user friendly.
What about using Brass bolts instead of S'steel? Will the Brass bolts strip out or break before the tail of the board breaks off?
Or Acetal rod?
I use it in all of my fins, similar material to nylok nut inserts.
Screw never comes loose but I imagine a big impact would strip it ok.
I use 12.7mm diameter inserts to get a bit longer purchase.
I also use UNC thread bolts (coarser) rather than metric, since it's a plastic material.
PS.......referring to the insert material as Acetal rod
Great minds think alike! I was just finishing off a pm with exactly the same plan. I like the idea of a nylon/acetal rod tapped to size to act as a barrel nut. Easy to do,glue and replace with no corrosion.Thanks fellas :-)
- got any pics of the boat?
- got any pics of the boat?
- got any pics of the boat?
Three days of printing and the FangyFin 28 print number two has arrived. The wall thickness is doubled on this print to give the fin tip more strength and rigidity. The tags all need to be cleaned off and the typical surface toughness cleaned up with judicious sanding and spray putty.
(I am just waiting for news from the foundry as to how they are going with the batch of 20 and 24's, which hopefully they will get around to before they shut up shop...)
