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Forums > Windsurfing   Gps and Speed talk

FangyFin DIY help, hints and show us ya fin page

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Created by fangman > 9 months ago, 29 Oct 2017
fangman
WA, 1758 posts
2 Apr 2022 9:20AM
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On a little more mundane level - how about the dishwasher on a pots cycle a few times. Alkaline detergent and pressure washed. A few years ago I did it few times on fins to see if I could remove oxides after long periods of non use. It worked pretty well, but I remember there was a discussion along the lines of using the dishwasher to clean fins was not meeting the requirements for Happy Wife, Happy Life. Haven't done it since.

decrepit
WA, 12405 posts
2 Apr 2022 9:32AM
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you've now got me thinking of how to disguise a fin so it can be sneaked in with a normal load.

waricle
WA, 732 posts
2 Apr 2022 9:51AM
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Time to load the dishwasher...... I'll do a before and after pic...

remery
WA, 3279 posts
2 Apr 2022 9:52AM
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Just say it's a charcuterie plate.

kato
VIC, 3448 posts
2 Apr 2022 4:58PM
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Select to expand quote
remery said..
Just say it's a charcuterie plate.


No , it's a BIG Knife

fangman
WA, 1758 posts
2 Apr 2022 2:28PM
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Select to expand quote



My experience so far would agree with that article. The silicon seems to be the main mischief. Anodising a casting (Al_Silicon_Mg alloy) straight from the foundry still produces lots of black smut. However I have found its possible to anodise the fin and achieve as coating. The colour is a gun metal dark grey, typical of silicon contamination. The uniformity is poor and this is exacerbated when dyeing is attempted. The variation in pore size in the anodised layer leading to some interesting patterns, but hardly aesthetically pleasing. Post processing (sanding) can produce a really smooth surface ( but not uniformly so because of pitting) that is also very hard. I suspect that if the casting has regions of high silicon, it pits in that spot. At this stage I think the two anodising steps suggested by Flex might give the best result. The fins I have done appear to have good enough coverage and thickness to fulfil the main aim of suppressing oxidation build up - time will tell.
There is lots more experimenting to do with acid concentrations and current density, and perhaps some investigation into methods of removing the silicon in the surface layer. It's good fun playing Mad Scientist even if the results are more Frankenstein than Weird Science.

Imax1
QLD, 4831 posts
2 Apr 2022 5:53PM
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Can it be chromed ? Alloy castings get chromed . Then anodised . ? Black chrome ? Cutter plating ? Ceramic ? What other plating options are there ?
And ,
What about casting in glass infused resin ? Should be strong enough .
Cos , you need more to think about

fangman
WA, 1758 posts
2 Apr 2022 5:19PM
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A long time back I went through the options and most failed on the basis of cost per unit, durability and 'repairability'. Things may have changed (and TBH I don't remember looking at chrome), so it maybe worth a revisit. Personally, I treat my fins poorly and subject them to a lot of grief, so on top of the list is for me is; once I prang it and the material is chipped/broken, how do I repair it?
This is the decision making chart I made up to look at all the stuff I could think of at the time:
www.seabreeze.com.au/Photos/View/13040834/Windsurfing/Process-Map/?m=3&p=fangman

waricle
WA, 732 posts
2 Apr 2022 7:43PM
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I'd like to see some more results from double anodised fins before I go to the trouble of setting up my own anodising. I don't care at all about appearance just smoothness and the toughness of the oxide layer.

fangman
WA, 1758 posts
3 Apr 2022 12:56AM
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Select to expand quote
waricle said..
I'd like to see some more results from double anodised fins before I go to the trouble of setting up my own anodising. I don't care at all about appearance just smoothness and the toughness of the oxide layer.


Toughness is in the bag I reckon. The issue is the pitting - mucking about with less aggressive cleaning/de-smut and perhaps even a decrease in anodising acid/current density might help bring this down too. As I said, much more Mad Scientist to come yet.

Flex2
WA, 353 posts
3 Apr 2022 6:54PM
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Not much time spent this weekend but tried sanding the new 'pox' and seems I've introduced new pitting. 20mins at 1200 grit didn't budge it. Old pitting is now much more pronounced/deeper thanks I think to the caustic bath. Based on that, will try and avoid caustic from now on. So went and got a high-powered ultrasonic cleaning kit from Altronics (Jaycar sell same kit)...for those outside Australia this was the original project www.siliconchip.com.au/Issue/2020/September/Advertising+Index Seemed to be the best way to go as can fiddle with power, make own tank, self calibrates, cheaper etc.

Got the ultrasonic cleaning electronics all completed and started working on cleaning bath....knew I had an unused stainless roasting tray lying around which didn't fit in oven for some reason which meant it might fit a FF28. Spent way too long finding this only to find it was about 10mm short on one corner. Damm Fangy fin, the gift that keeps on giv'n!

Was about to chuck it (the tin, not fin) in the vice and get to it with a hammer to get that extra 10mm when thought better (seems nice tray after all) and started making another custom cleaning tank from some freebie dumpster dive acrylic I'd scored whilst scrounging for some abrasion resistant polycarb for that other project. I hate acrylic as it cracks, polycarb rules as can't break it, but midway through that process there seemed to be a breath of wind so went to do what all this is about and go sailing.

Plan will be to ultrasonic clean in bath of Methylated spirits for starters (or other solvent since getting a water reaction)...since the 'crud' is heavy should be able to let it settle after each clean to reuse majority of solvent. The ultrasonic transducer that came with the kit is optimised for about 4litres of fluid which is the other justification for custom tank. (aside: can further optimise electronics by changing the transformer windings so acoustic impedance matches electric impedance so spent some time 3D printing winding machine to make this easier as is painful process hand winding transformer. ..hopefully will not have to rewind this thing...which is why in photo its mounted weird)

Hopefully this helps remove the sanding goo quicker. Whether it helps with the end objective remains to be seen..

For the other suggestions like chroming, the problem is cost...have tried HVOF..at least I tried to get my old subcontractor to try but they won't even look at it for a price Fangman would give you a lifetime supply of disposable fins for. Cold spray might be good future option but will be outside most user abilities.

Anodising 'seems' to give a good outcome of cheap (roughly $100) to set up a basic and simple anodising system which you can then use forever) and very good wear resistance. If you have a few Fangy fins then its not much investment compared to all the other gear. The trick seems to be in the details of how to best go about the process.

Also going to revisit CNC'ing these from solid billet to avoid 99.999% of all these issues. Will try dumpster diving scrap and new. Billet for a big FF28 will/should be roughly $250, machine cost...not much if you do yourself but will try and get some quotes from my old contacts.


Ne

w

Flex2
WA, 353 posts
5 Apr 2022 6:58PM
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More mad scientist stuff. Since the FF28 didn't fit my stainless tray I built custom tank for ultrasonic cleaner using dumpster dive acrylic. Probably could have made tank 1cm thinner to save 1 litre volume but was lazy to cut perfect cut scrap (used Methylated spirits in this test). In the end didn't seem to make much difference. Put another drain at bottom to decant cleaning fluid which was almost a disaster as could not fit my arm in to fit the tank fitting in. Managed eventually to fit it using yet more custom tools. Then I 5 minute Araldited the transducer on, centered perfectly, waited a few minutes then walked away....came back 20 mins later and it had somehow managed to walk around 3cm off center whilst being dead flat. Arg! Probably not important but annoying. Spent a pile of time rewinding the coupling transformer via trial and error to optimise the power transfer at resonant frequency which for this setup was 38.65KHz for those interested..the kit is pretty cool as lets you fiddle with frequency and power. The transducer runs at around 100V at 38KHz which will wake you up if you touch it, so a bit of PVC pipe can be seen hanging to cover the HV once sorted. (can now put it all back in box to make it look a bit less mad scientist) To cut a long story short had lots of satisfying bubble action going on...was hoping lots of black goo would ooze out but alas not. Played with various volumes of fluid from 3 litre to 6 litre but did not really effect outcome much. Not sure if need to rotate fin to get better exposure to each side of fin or not. Ran it for an hour then wind came in (and since there has been none for nearly a month here had to go sail) so drained tank and there was some sediment from the effort. Not convinced it has been worth the effort at this stage but need to try water, other cleaning stuff or leave it far longer after sanding to see if makes any difference. I'm certain hitting a casted Fangy fin with caustic soda does more harm than good so all alternatives should be explored. Meanwhile made some good progress on the alternative option CNC'n from billet which should eliminate all these porosity/anodising issues.




fangman
WA, 1758 posts
6 Apr 2022 11:44AM
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To add to Flex's post ( fine work with ultrasonic bath there BTW Flex) I have been mucking around with current density and acidity. My feeling is that regardless of whether its silicon, silica, magnesium or whatever in the aluminium it's a pain to anodise. The electropolish is good for blasting off big mobs of oxide and that's about it. The investment in phosphoric acid is not justified for something that a bit of Gumption and elbow grease does just as well.
High current and high % acid baths do more damage than good. The surface will anodise in places where the aluminium is of high purity, but wherever there is a spot rich in other alloying material in/near the aluminium surface, the current and acid just blast a hole. With time the pits gets deeper and do not seem to start anodising to any degree. The high current flow also heats the bath, so the sulphuric acid gets more aggressive with time. As proof I now have a fin that looks like the surface of the moon.
I am currently trying 'low and slow' approach. I guess I am down to about 15% Sulphuric acid. The current density is very low, for example 2-4 amps on a FF18, but I run it for about 8 hours. This seems to inhibit the pitting and so far I am getting consistently anodised surfaces. There are still issues with high silicon spots not anodising, but the results are good enough for me to keep playing around with this low and slow approach.
The really exciting bit is that Flex has done a shedload of work on the CNC option using a high quality billet that we should be able to anodise easily. The costs appear to be a fraction of what I was quoted a few years ago, but it seems, while still $, a high precision super tough FF made locally might be within reach.

Stretchy
WA, 974 posts
6 Apr 2022 8:00PM
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CNC cut and anodised billet alloy fins sound pretty damn sexy Ross. The mad scientist power of Fangy+Flex is a truly awesome thing to behold. respect! I don't feel worthy to even read this thread
love your fins Ross, but one thing I hate about all deltas is getting gaskets to fit properly and then stay put. For the Fangy fin I don't bother trying to get anything to stick on any more. I cut a gasket out of an old bucket which, because of the fillet, can fully encompass and be held in place by the Tuttle head - no glue, just screw it down.
If you CNC cut your fins I'm wondering if you could design a recess in the base of your fin to take a custom fitting gasket that would be 3D printed. Maybe even have the whole fillet 3D printed so it fits on like a shoe?

Flex2
WA, 353 posts
6 Apr 2022 9:09PM
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Was about to do data dump of todays efforts when saw your post. Thankfully Fangman and I have worked out how to digitally communicate using a coke can and string method so a perfect fitting 3D printed "Flex" gasket is trivial exercise. Whether it works it of course subject to testing. Will try and model what you are saying..

Flex2
WA, 353 posts
6 Apr 2022 9:26PM
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here is 3D Printed flex gasket that suits Fangy tuttle or Fangy universal. I think you want the fin to have recess and print gasket to mate with that so its less inclined to wander.





fangman
WA, 1758 posts
6 Apr 2022 9:45PM
Thumbs Up

Haha Stretch I read your post and thought that is so far up Flex's alley he has probably already done it! And voila, scroll down one post and Flex gaskets are born.

Flex2
WA, 353 posts
6 Apr 2022 9:59PM
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recessed 3D printed gasket..its hard to actually get a shot to show it but the fin has a 2mm wide x 1mm deep recess, whilst gasket has a 1mm high lip 2mm wide. The idea being once you mash it by tightening your fin screws, it won't wander away





Flex2
WA, 353 posts
6 Apr 2022 10:29PM
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Another day, and another day without wind so had to resort to playing with the Fangy Fin again. It really should be in the running for gift of the year as this thing just keeps on giving. I'd be hard pressed to decide between a ball, some cardboard and hot glue or a Fangy fin for long term entertainment. My kids are getting bigger so its a Fangy fin for me now....I have a Netflix account too but I don't think I've used it in months thanks to this thing. Was really not gonna post anything until made some decent progress....however..some of you are obviously very bored from lack of wind...

Today: Started resanding the FF24, (anodised once) with the idea to do a light sand and anodise again to replicate the success of my first FF22 attempt. Failed, the porosity was really bad, way way worse than the native fin and I really lost motivation....why spend all this time sanding only to get a result that is way worse than when you started. Whilst sanding was thinking of how to go about actually making a supersonic cold spray device when it occurred to me haven't tried something basic. Hopefully others have tried and will stop me before doing this if its not a good idea. (I already know its a good idea and nobody has tried but putting it out there)

I'd had enough of all this sanding and porosity after just 5 fins (no clue how fangman has done 300+ of these things) so ordered some nice fresh billet to cut a nice fin from scratch. Fangman and I had made some progress speaking digitally enough that we could communicate between ourselves and to the outside world. I managed to convince someone to agree to bring Fangman's love child into the real world using a CNC and eliminate 99% of all this sanding/trying to get a surface finish BS/time wasting. No doubt there will be some other issues arising but they will be trivial compared to this current saga.

Simultaneously to all that, I thought bead blasting the cast fins to seal/close/hide the porosity prior to anodising might be a good plan. I'd spent 10 years in previous life perfecting this process so probably should give it a try before abandoning the cast. Motivated again, I aimed to have three fins ready for bead blasting tomorrow as the CNC machine is just a few yards from my bead blaster of choice. First fin,the new Skunk works Fangman special cast FF18V4, exactly the same as the CNC one so can compare the orange to apple but at least exactly the same same size. Have finished it to a rushed maybe 400 Grit, 2nd fin, a FF24 anodised with low desmut, resanded (looks like ****) at 1200 then 800 and then lost interest, FF28 (just looks like ****..but you would too if you went through what it went through). Me thinks bead blast will bash surface of all three so you won't be able to tell them apart.

To close the day off, I'd read that brake cleaning fluid gets rid of silicates and silicon so I got myself some and applied it to the freshly sanded skunkworks cast FF18V4. Not one sign of black goo coming out. Like zero...of anything. So chucked fin in a warm (50degC) bath of soapy water and hit it with ultrasonics. I'd calibrated this thing to a tank of methylated spirits so maybe the power xfer was a bit out with water. I fiddled around with position of fin in bath and it made a massive difference to acoustic power applied. From almost zero to overload. I measured the current from battery and got a max of 2.5amps at around 13.X volts when fin was in optimal position. Assuming electronics are around 90% efficient that's about 30W good vibrations into the bath. (the electronics limit the power to 36W best case for a 40W transducer so 30W is probably a reasonable max)....regardless still did bugger all as far as getting that black goo out.

Not many bubbles compared to methylated spirits and didn't want to leave in tank so pulled it out but was surprised to see 'blast marks' coming out of the porosity adjacent to where the ultrasonic transducer was. These are in the metal and can't be rubbed off. Damm, more sanding.

In the same photo you can see the porosity...its never ending with one almost bullet hole size, I hit this thing with 80 grit flapper disc till it now bears no resemblance to Fangmans original intended shape and the effort was completely pointless. (oddly the opposite side has almost no porosity which seems to be the case in all fins I've played with, note to self: is porosity only on one side? and same side for all fins)

Tomorrows mission, get the CNC loaded and bead blast the hell out of 3 various buggered up Fangy fins to see if it makes the slightest difference. Luckily I can find the almen intensity if needed but thinking this process will either do nothing or large improvement.

From memory we always did an almen intensity of 7 but can't remember if it was A or C. (It might sound impressive but the Almen is how much a piece of metal of thickness A= 0.051" or C=0.094" deflects when you blast one side with whatever you've got. The more intensity (faster or heavier) the more the material deflects due to cold working just one side. Its vaguely similar to anodising in that it hardens surface but in this application I am hoping it will clean out/mash the porosity into surrounding material to give a uniform surface to anodise. If this fails can still try shot peening or sandblasting...showing how much joy just a single Fangy fin can bring.

Stretchy
WA, 974 posts
6 Apr 2022 10:50PM
Thumbs Up

Select to expand quote
Flex2 said..
recessed 3D printed gasket..its hard to actually get a shot to show it but the fin has a 2mm wide x 1mm deep recess, whilst gasket has a 1mm high lip 2mm wide. The idea being once you mash it by tightening your fin screws, it won't wander away






Love your work Flex!

Imax1
QLD, 4831 posts
7 Apr 2022 6:54AM
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Some more thinking ......
If CNC ing the fin , I like stretchys idea of the flange being a seperate part . Being accurately machined , the fin could nicely slide down into the flange . This would save a lot of money in the thickness of the billet . The flange could be made out of a tough plastic , ( polyethylene) , that can be easily shaped to the bottom of the board .
Whilst being CNC'd make all fins box universal .
Discuss , and get onto it chaps .

Flex2
WA, 353 posts
7 Apr 2022 9:03AM
Thumbs Up

Select to expand quote
Imax1 said..
Some more thinking ......
If CNC ing the fin , I like stretchys idea of the flange being a seperate part . Being accurately machined , the fin could nicely slide down into the flange . This would save a lot of money in the thickness of the billet . The flange could be made out of a tough plastic , ( polyethylene) , that can be easily shaped to the bottom of the board .
Whilst being CNC'd make all fins box universal .
Discuss , and get onto it chaps .



I had a quick look at doing a gasket for the FF18V4 and whilst it sounds a good idea it might be impractical..at least for a full length gasket. Once you make the gasket thicker than 2mm you are into the foil profile and it quickly reduces at the tail section. This makes the gasket extremely thin in this area. In reality it would be thinner than the model as the model has square sides for the first 2 mm but most users would sharpen this to knife edge. This in turn would make it harder to machine but also prone to breaking easily. Attached are some shots showing a 2mm gasket (first image) and a 5mm gasket (next 2 images) that hopefully illustrates the point.

You could make the gasket just the front 2/3 section and have a recess in the fin to hold it in place with the tail section solid as it is. This would still save on material costs and help in the area that collects weed. Will do another fiddle later.

Since I've already purchased the material think I will stick to solid option for this attempt. Universal fin design as going into CNC attached (last 2 images and section). I think I followed Fangy's instructions correctly. 12mm hole for PowerBox brass nut and 3mm pilot holes for tuttle. Tuttle holes 80deg to gasket plane and Powerbox 90 deg. If anyone sees error, please advise as this thing about to be born.














decrepit
WA, 12405 posts
7 Apr 2022 9:51AM
Thumbs Up

Select to expand quote
Imax1 said..
I like stretchys idea of the flange being a seperate part . Being accurately machined , the fin could nicely slide down into the flange . This would save a lot of money in the thickness of the billet . The flange could be made out of a tough plastic , ( polyethylene) , that can be easily shaped to the bottom of the board .
Whilst being CNC'd make all fins box universal .
Discuss , and get onto it chaps .

This sounds like a great idea, but the reason fangy fins can be "box universal", is that the fin is "seated", by the flange not the box. A separate flange would have to be securely fixed to fin and be strong enough to take the loads. Not insurmountable, but needs to be taken into account.

remery
WA, 3279 posts
7 Apr 2022 5:24PM
Thumbs Up

I have a couple of fins that, unlike the Fangyfin, spin out easily and are really difficult to clear. It would be interesting to stick a flange on with double sided tape and see what happens to both top speed and spin out.

An aftermarket "FangyFlange" if you like.

Windxtasy
WA, 4015 posts
7 Apr 2022 6:01PM
Thumbs Up

Flex, you are having way too much fun. Your lateral thinking, problem solving and tech skills are impressive and entertaining even for someone who is an absolute tech newbie. Now what on earth is a bead blaster? Sounds like something from Star Wars.

Flex2
WA, 353 posts
7 Apr 2022 7:40PM
Thumbs Up

Another glorious Perth day but not a breath of wind so another good day to fiddle about with something entertaining. First got the printer pumping out a 'flex' gasket...me thinks it won't compress enough but worth a try. I think neoprene rubber with a self adhesive might be better option.

Supplier called to advise material for the CNC'd FF18V4 ready to collect. This material was quick to get but paid almost double market so will be cheaper on subsequent efforts. Since the bead blaster of choice was equal distance from both a pie shop and my CNC chap I furiously sanded all fins with their respective histories to 400 grit. There seemed little point going further with sanding as bead blasting is a far rougher finish and all three fins had serious porosity issues.

(Beadblasting is just firing ceramic/glass beads at the surface of material using air. This improves surface properties and all sorts of stuff, shot peening is doing the same with steel shot and sand blasting is doing same with sand...most aircraft Aluminium is bead blasted to an exact Almen intensity as it slows fatigue cracks so the wings don't fall off as they flex etc)

Went to my bead blaster, caught up with the gossip and got the fins blasted in a few mins. They looked great but the porosity was probably worse...this suggests the porosity is caused by gas during the casting cool period as the porosity is bigger under the surface and why it is pointless trying to 'sand' it out. Only way around it is cold spray which is a complete new world.

Dumped the material off at CNC chap (after stopping at pie shop midway), for those worried about wastage, fret not as the excess material will be used to make jigs to hold the fin whilst machining, any excess to that I will grab to do some anodise tests before dropping the new fin in the bath and all the swarf is either recycled or potential melted down to another fin.

That was 1/2 the day done...now currently cooking the bead blasted FF28 and just about to pull it out after 4hrs...will update later

First photo, new billet with 400grit finished FF18V4
2nd Photo, bead blasted same, different light, probably pointless photo
3rd photo, obligatory lawn shot showing FF24, FF18V4, FF28 (left to right) after bead blasting
4th photo, close up of porosity after bead blasting on FF18V4...probably worse
5th photo, op side of FF24, FF18V4, FF28












decrepit
WA, 12405 posts
7 Apr 2022 7:40PM
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Select to expand quote
Windxtasy said.. Now what on earth is a bead blaster? Sounds like something from Star Wars.


Nah, more like Red Dwarf, or Hitchikers Guide to the Galaxy

decrepit
WA, 12405 posts
7 Apr 2022 7:42PM
Thumbs Up

Select to expand quote
remery said..
I have a couple of fins that, unlike the Fangyfin, spin out easily and are really difficult to clear. It would be interesting to stick a flange on with double sided tape and see what happens to both top speed and spin out.

An aftermarket "FangyFlange" if you like.


There's a few of us that "fangyised
problem fins, in all cases they were improved in spin out terms, but I haven't noticed any speed difference.

Imax1
QLD, 4831 posts
7 Apr 2022 9:50PM
Thumbs Up

What flavour was the pie ?



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Forums > Windsurfing   Gps and Speed talk


"FangyFin DIY help, hints and show us ya fin page" started by fangman