Mounting stainless steel bracket on aluminium masthead

[MattS]

I need to get a custom bracket made to mount my new wind instrument to the of my mast (images of my plans included for reference).

Being a relative novice, and still struggling to get my head around all the rules about mixing metals, what do I need to know to make sure I don't create a corrosion monster on top of my mast?

Should I use stainless steel to create the new bracket? Should I use stainless bolts to bolt it to the mast?

I have Duralac which I understand I should coat the stainless bolts with. Anything else I should do? Is it ok to have the stainless sitting on top of the aluminium, or do I need something between them there too?

Nothing is too obvious to point out!

 

[Ceirwan]

Stainless is fine for the bracket & common. Duralac should be used on the bolts & you should also smear it thinly on the back of the stainless plate where it will sit onto the mast.
Bolts will be fine for this application.

 

[Norman_E]

If possible make a stainless bracket you can bolt permanently in place, from which you can easily remove the instrument to take it down for the winter. My old VDO wind instrument had a spring clip system for easy removal that could scarcely be bettered

 

[MattS]

If possible make a stainless bracket you can bolt permanently in place, from which you can easily remove the instrument to take it down for the winter. My old VDO wind instrument had a spring clip system for easy removal that could scarcely be bettered

Thanks - that's my thinking. An L-shaped bracket which would be permanently bolted onto the masthead top plate, and then the wind instrument would be bolted onto the vertical side of the bracket, and could be unbolted and removed if necessary. The Nasa bracket could just be loosened to slip out the mounting tube.

 

[MattS]

For completeness of the thread - here was the final solution.

I specified a stainless L bracket (probably a bit overkill on the strengthening to be honest) - cost about £40 quid to get fabricated.

I then put re-used two existing bolt holes, and added a third, to bolt it to the mast top plate. Frustratingly, one of the previous holes was too close to a cross support, so I had to file down one of the bolt heads to have a flat edge so that it wouldn't sit through the hole straight.

Then bolted Nasa wind instrument bracket to vertical piece and the rest is obvious!

Excuse the Duralac mess - let's say it was my first lesson in how messy the stuff is...

Thanks for the tips @Norman_E @Ceirwan

 

[Ceirwan]

For completeness of the thread - here was the final solution.

I specified a stainless L bracket (probably a bit overkill on the strengthening to be honest) - cost about £40 quid to get fabricated.

I then put re-used two existing bolt holes, and added a third, to bolt it to the mast top plate. Frustratingly, one of the previous holes was too close to a cross support, so I had to file down one of the bolt heads to have a flat edge so that it wouldn't sit through the hole straight.

Then bolted Nasa wind instrument bracket to vertical piece and the rest is obvious!

Excuse the Duralac mess - let's say it was my first lesson in how messy the stuff is...

Thanks for the tips @Norman_E @Ceirwan

View attachment 114997

View attachment 114998

Nice neat job.
If you are ever able to use Duralac without making a mess then let me know how!

 

[captainboo]

Nice neat job.
If you are ever able to use Duralac without making a mess then let me know how!

I just use trade wipes - will clean off excess Duralac/Silicone/Buty mastic/Sikaflex etc. Haven't met much that they won't shift!

 

[Ceirwan]

I just use trade wipes - will clean off excess Duralac/Silicone/Buty mastic/Sikaflex etc. Haven't met much that they won't shift!

Actually what I use as well, seem to do the job. I was thinking about not making the mess in the first place, I'm usually end up with the stuff everywhere.,

 

[captainboo]

Actually what I use as well, seem to do the job. I was thinking about not making the mess in the first place, I'm usually end up with the stuff everywhere.,

My last tube of the original yellow Duralac went hard/tube split so replaced recently with a smaller tube of the new Green Duralac. This comes with a narrow nozzle and screw on cover, similar to tubes of super glue. Works well as it is easier to apply only where you want it - downside is it is the same price as the yellow version for a tiny tube!

 

[Amulet]

Good to see success, but I'm baffled as to why you didn't just make it out of aluminium like the mast. It would have been dead easy - mine was.

 

[MattS]

@Amulet don't really have a good answer for that to be honest - my brother-in-law works opposite a stainless steel shop so that seemed like an easy option!