Fitting NASA wind assembly to curved mast

[paulwornell]

The NASA wind unit fits to the top of the mast with 2 x pairs plastic clamps/mountings. The mountings have a flat profile, and naturally my alloy mast has a curved profile. Is it in order to just screw the mountings to the mast such that they have mast contact in the middle and a small space at each end (revealing a short length of the screw thread)? Or is there a better way that provides full mast contact??

 

[nigelmercier]

It it were me, I'd re-profile the plastic mount. It's only going to last a season anyway

 

[Billjratt]

Are you sure it wasn't supplied with dished spacers? - or make one out of plastic chopping board

 

[pvb]

I don't think you can easily reprofile the mount without removing too much plastic. I'd make a profiled padding piece to fit the mast instead. Actually, although it's too late for you, my advice would be never to buy any Nasa kit with moving parts. Quite how any manufacturer of mast-mounted equipment would consider it acceptable to supply flat mountings is beyond me.

 

[prv]

I just hope you're not planning to mount it with a pair of turbogolds as in the picture

Pete

 

[macd]

Agree it needs a saddle cut to the mast's profile, with a flat face bearing against the NASA bit. Without this, it's bound to splay when the fasteners are tightened, deforming the hole that's supposed to clamp the upright tube. Daft bit of design.

 

[paulwornell]

Many thanks to all for confirming my fears. Any suggestions for what I might use to craft a seating. A chopping board sounds good but might be too thin to cut to profile??

 

[Caer Urfa]

Many thanks to all for confirming my fears. Any suggestions for what I might use to craft a seating. A chopping board sounds good but might be too thin to cut to profile??

What about a standard VHF aerial bracket riveted to the mast then mount the wind support post to it??

Mike

 

[nigelmercier]

I'd make a profiled padding piece to fit the mast instead.

Surely the part in the picture is the padding piece, so why make another?

 

[pvb]

Surely the part in the picture is the padding piece, so why make another?

Because it doesn't fit a curved surface and, as macd pointed out, it will splay when tightened and not clamp properly.

 

[prv]

Surely the part in the picture is the padding piece, so why make another?

Because NASA have done a half-arsed job of it

Pete

 

[Amulet]

Squidge a dollop of Sikaflex large enough to pad it out on under it. Screw it on loosely so as not to squeeze it out. Wait 'til the Sika goes off, and then tighten it up. If you want to do it tidily put masking tape around the area where you want the sika, form it all nicely with a wet finger and take the masking off while the sika is still wet. A slight bodge, but it'll work. Mine lasted 12 years.

 

[nigelmercier]

Because NASA have done a half-arsed job of it

This is true

OK, if there is not enough to trim to shape, I would do this:

Cut two strips of fibreglass CSM or cloth slightly larger than the base of the fitting. Cut several smaller pieces to be used as packing for the ends. Dry assemble the packing between the mast and the fitting to check you have enough. Stretch some thin polythene over the fitting area and tape down. Now make a moat around the fitting using plasticine or masking tape folded up. Pour in a little mixed-up epoxy or polyester resin, lay one of the large CSM strips inside, then build up the ends with the smaller pieces. Keep the CSM moist by adding more resin and working it in. When the ends are packed out enough, lay on the second strip and work in more resin. Clamp the fitting with a ratchet strap, and allow to go off. When it is all solid, remove the fitting and trim away the excess.

 

[paulwornell]

Thanks for all replies, and be assured they are not the intended screws. Meanwhile I have spoken to the NASA people who advise that I am the first person to ask this question to which they have no answer?? I am in process of testing the use of epoxy putty to bed the fixing against the mast on a mock up.