Mast Fixings (SS into Aluminium)

[RichardTaylor]

I am about to fix a hailer/horn to my aluminium mast but seem to recall issues with stainless screws into aluminium. Can I just drill a hole and use SS self tapers or should I follow a different process?

 

[yotter]

I use Duralac (comes in a tube) to prevent/reduce corrosion due to dissimilar metals. Other products are probably available.

 

[rotrax]

We have a Hoyt Boom on our boat. When the UK agent or their sub contractors rigged it in 2008 they just screwed all the fastnings into threaded holes in the aluminium boom tubing. I found appalling corrosion under the S/S screws and eyes which had lifted the powder coated finish.

I had it blasted and re powder coated. When I assembled it I painted the areas where fittings and threaded fastners were used with Duralac. The faces and threads were also painted with Duralac. When almost touch dry I assembled the boom fittings.

No way to know the long term effect of doing it properly but I suspect it might last better and without lifting the finish as before.

The galvanic corrosion is easy to see under the new powder coat and is quite deep.

 

[V1701]

Duralac works well, use with care there's bad stuff in it - Boron? A tube of it will last you the rest of your life...

 

[Malish]

Duralac works well, use with care there's bad stuff in it - Boron? A tube of it will last you the rest of your life...

Cromium, the hexavalent form, + some oils, safety sheets available, wash your hands before eating lunch.

 

[VicS]

You could use Duralac Green which is chromate free.

 

[MikeCC]

You can also use Tefgel PTFE based products. Much nicer to use albeit quite pricey. Various brands available.

 

[vyv_cox]

You can also use Tefgel PTFE based products. Much nicer to use albeit quite pricey. Various brands available.

I think that using Tefgel only excludes water whereas I believe that Duralac also provides some chemical protection. I am not very clear about just what this is but it is a long established product.

 

[Neeves]

http://www.llewellyn-ryland.co.uk/downloads/duralac.pdf

Strangely there does not seem to be an alterrnative. It has been the 'go to' answer for many decades.

Chromates are carcinogenic.

Duralac is very effective but treat with considerable caution, note post 5.

Jonathan

 

[VicS]

You can also use Tefgel PTFE based products. Much nicer to use albeit quite pricey. Various brands available.

I think that using Tefgel only excludes water whereas I believe that Duralac also provides some chemical protection. I am not very clear about just what this is but it is a long established product.

http://www.llewellyn-ryland.co.uk/downloads/duralac.pdf
Strangely there does not seem to be an alterrnative. It has been the 'go to' answer for many decades.
Chromates are carcinogenic.
Duralac is very effective but treat with considerable caution, note post 5.
Jonathan

Yes Tef-Gel works by excluding water. For that reason it is better suited to close fitting joints. I'm not sure if self tapping screws would fall into that category.

"Duralac Green" is the alternative if seeking to avoid chromate

http://www.llewellyn-ryland.co.uk/downloads/DuralacGreen.pdf.​

.

 

[UK-WOOZY]

never realised duralec was carcinogenic , it gets on your hands and arms so easily

 

[vyv_cox]

never realised duralec was carcinogenic , it gets on your hands and arms so easily

Chromates are generally quite nasty but I suspect it would take massive exposure to Duralac for cancer to develop. Truly carcinogenic products, e.g. coal tar, are usually banned.

 

[dankilb]

I’m busy completely ‘re dressing’ our 16m double spreader mast (all new wiring, rigging, hardware, electronics etc.). I’ve used monel rivets in favour of ss screws everywhere I can. It’s quicker, more secure (in my opinion) and less mess (and apparently, now, carcinogens!) than duralac.

I do use duralac where rivets are impossible. Luckily I wear gloves anyway as the sticky mess is bad enough everywhere else apart from my hands!

 

[VicS]

never realised duralec was carcinogenic , it gets on your hands and arms so easily

ITYWF there is no mention of carcinogenicity in the safety data sheet except perhaps for butanone oxime

Although chromates generally are carcinogenic barium chromate is classed as a category 4 carcinogen which means there is evidence suggesting lack of carcinogenicity in humans and in experimental animals

 

[Neeves]

I did not say Duralac was carcinogenic - I carefully said Chromates are carcinogenic.

Talc was considered safe, it was used liberally (by respectable manufacturing companies who employed experts to keep them on the straight and narrow) - until is was not (considered safe - not because it has been proven unsafe but talc may contain asbestos or asbestos like products). The legal cases destroyed the talc industry. I know, I was involved, my background is geology, I worked for a company that sold talc to major UK consumers, one of my colleagues was responsible for talc sales..

Chromates are generally considered carcinogens - personally I would be careful. I'd be the first to admit 'our' exposure is pretty minimalist and it can be a bit messy - so the mess demands pretty rigorous cleaning - thus minimising potential risks.

Now just try some lateral thinking of the effects of other carcinogens that people have exposure to - accidentally - and what is said now.

I just suggest caution. As long as you are aware you will be more rigorous with your cleaning. I am quite happy to use Duralac, but then I was involved when talc became a dirty word.

Jonathan