Jump to content

Stainless onto aluminium


John B

Recommended Posts

Stainless fittings to go back onto the old ali boom after refurbishment and painting, I'm getting a bit of varying advice as to how far to go with insulating the SS against the ali. Cheek blocks etc.

There's some monel rivets and some bolts to go back on , I intend to use tefgel for any threads etc... do I need to make plastic or glass gaskets to go between the dissimilar metals, or as one party is telling me ' the paint is the insulation, just use the tefgel on the threads and as the gasket'.

Link to post
Share on other sites

Have seen various different ideas about this - Some people have used Insulation tape on the Stainless parts - easy as to do and easier than making gaskets...

Others have made elaborate gaskets out of ice-cream container lids etc. Others have just banged it on and hoped for the best.

 

I would put my vote in the "Cover it in either Tef-Gel or Duralac" basket. Or if really worried do the Insulation tape and Tef-Gel...

 

Paint as the insulator doesnt really work as it ends up blistering the paint around the fasteners and you get a mess

Link to post
Share on other sites

The old fittings actually did have what looks like insulation tape on them.... fairly successful given the age of the boom but I think I could do better.

Link to post
Share on other sites

Yes the insulation tape is the way to go. As CN states, Paint bubbles after a few years. You probably noticed that when you took the stuff off in the first place. You can also use a smear of Adhesive Sealant as a bedding compound if you want to really make sure the component is on there well and truly.

Link to post
Share on other sites

I personally like the look of some thin-ish sheets of UHMWPE cut to the shape of the fitting looks nice and guarantees good insulation, don't know if it's any more effective than anything else but looks classy when done properly.

Link to post
Share on other sites

I like ice cream containers or cutting up thin chopping boards. Paint doesn't really work for very long in my experience. Durlac is great but really flippin dear and the tin tube it comes in is crap as it always splits and let's the expensive yellow stuff get all over everything!

Link to post
Share on other sites

Mother loads of a good silicone like product so it oozes out the sides. Let it cure a bit then carefully trim. Take more care the lower in the rig the fitting is.

 

Then do something many people have no idea exists, maintenance i.e give the rig a once over now and again. In that check look hard at the fittings for signs of corrosion. fix if required. Done well that won't be for many years.

Link to post
Share on other sites

Thanks fellas, I'm hearing what I wanted to hear I guess, a gasket is worth fiddling with.

I've also been thinking about glass tape on the fittings as a gasket and will experiment with that.

Link to post
Share on other sites

You can put stainless direct on to alloy and not a thing will happen to either in 30 years, maybe even 100 years, not a dickey bird. But add salt water and hello it can suddenly be all on. The same thing applies to SS gear in a mostly steel anchor system, both play perfectly fine with each other until the shite stirring salt water comes for a visit. Lift the anchor and it all drys out sending the problem child away, issues stop. The key is salt water, nothing bad can happen without it, assuming you don't just have crap quality gear or electrical issues aboard.

 

How is a gasket or similar going to stop water getting between the fitting and the mast section? If water gets in there can you see it and what it's doing? Why not seal the fittings down so water just can't get in and hide under them?

Link to post
Share on other sites

The problem is how to get two different 'sealants' to play together? How do you get tefgel on the threads to isolate the bolts/ rivets as well as something like sika on the body of the fitting? Don't you want one or the other?

And to take the thought a bit further , thinking reef cheek blocks for example , the loading on those is not symmetrical. there will be mostly shear but also tension on two rivets and compression on two. So that means there's an 'edge' of the fitting being levered into the paint against whatever is there ,sealant or other. Its that sort of dynamic which makes me think that the fitting should have a gasket as 'belt and braces' against an edge cutting the paint.

Link to post
Share on other sites

I can't see any problem but are wondering why you expect salt water will get in the threads of your bolts and why your reef blocks will be wet all the time.

Link to post
Share on other sites

I'd say probably the same way that my car decided to start developing a rust spot in the boot scupper when all I ever did was park it on the island at westhaven for some weekends and occasionally a couple or three weeks at a time :lol:

This boom might be getting its first or possibly second refit in 40 odd years, its had what looks like tefgel and insulation tape gaskets but I think that could be improved. I take your point about sealant keeping the water away from the fastenings in the first place .

Link to post
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...