Ok so I made an aluminum motor mount for a crazy foil extruded mast. It was theoretically a 100 micron slip fit though it becomes a partial interference fit as it gets slid up the mast (the extrusion bulges a bit). I had planned to weld the mast to the mount to reinforce the mast where I bored a hole into it for the power cables as they are both aluminum but my neighbor who has 30 years of aerospace welding experience has advised me that the weld will almost certainly crack and that a better approach is to sand blast the mast and then overwrap it with carbon fiber or leave it as is and use 5200 or epoxy to stick it in place effectively he is saying that the weld will make it worst than if there is no weld.
The hole is 14mm and so it effectively removes the back 1/4 of the mast obviously including the leading edge.
galvanic corrosion is not a problem in practice for something that doesn’t continuously sit in the water (i.e. your surfboard is going to come out and get washed by freshwater) but in any case it could be solved by adding an anode
This is my second efoil build With an aluminum mast. I also have a small boat with an aluminum outboard and transom jack that have been in the ocean for extended periods and about 5 years of ocean engineering experience with carbon fiber hulled UUVs that have plenty of aluminum, titanium and stainless. I will say it again, aluminum
Corrosion is easy to mitigate with a sacrificial anode and not a major problem for something like a surfboard our outboard motor that can get washed down with fresh water and saltaway on a regular basis
As it turns out I am probably going to use fiberglass as I already have the materials in hand.
You are clearly trying to draw me into an argument over an incredibly esoteric subject where the specific techniques used make more difference than the materials. The discussion may be interesting but the argument is a waste of time.
At work we have done carbon fiber over aluminum tubes for pressure vessels on a number of occasions, the aluminum is prepared with a couple coats of resin and the the carbon is vacuum bagged over the cylinder. The end result is painted with a 2 part bottom paint and then top coated with a bottom paint containing copper to prevent bio growth. Unless the system has failed (which it sometimes does) there will be no low impedance path between the aluminum and the seawater.
A difference of opinion doesn’t equal an argument.
I dont think it’s a good idea to laminate carbon to aluminium. I am not expressing this opinion to you, but to others in the forum that might not know any better.
You might not have noticed, but this hasn’t been an interesting discussion. More of a monologue from you.
So first you say that because I have different opinion than you “Obviously never owned and used an aluminum foil before.” Which is actually not the case. Then you call my approach silly without even understanding the specific nature of the approach or understanding what difference the gory details make.
Your attempt at an insult calling this discussion a monologue which you are clearly egging on projects an attitude of overconfidence and conceit this attitude is an impediment learning and improvement. I probably wouldn’t have bothered to reply after your first except that I had surgery today and I am drugged up with nothing to do.
I have already altered my plan in a way to mitigate these issues by changing my plan to use a fiberglass layup with an adhesive promotor designed for applying composite layups to aluminum. So I have still benefited from the monologue despite your non answers.
The galvanic corrosion can off course be mitigated, i normally make a first glass fibre layer before the carbon. I think special care must be taken with alu/carbon combinations and it was worth mentioning.
