Rivets or Machine Screws When Splicing a Mast?

[Chotu]

Originally Posted by neilpride

Call this guys...

386-462-3760
800-928-0786

US Spars Inc.
6320 NW 123rd Place
Gainesville, FL 32653

Welding a sleeve question goes to Us Spar.

Do you think sparcraft is a better one? Because that’s the one that quite Francespar?

I already reached out to spar craft this morning.

[neilpride]

Yes you can try Sparcraft..but frankly , they are going to tell you the same thing that I am telling you.. 6000 T6 series alloy its not welding friendly..

[Chotu]

Originally Posted by neilpride

Yes you can try Sparcraft..but frankly , they are going to tell you the same thing that I am telling you.. 6000 T6 series alloy its not welding friendly..

OK. I was just asking because I figure maybe they have the historic records of what my mast might be made out of. Since the entire Mast is already welded. There are no bolts anywhere. The gooseneck, every piece of hardware attached to it. It’s all welded.

Probably will still end up sticking with machine screws, but it sure would be a lot faster and easier to weld this thing.

[Chotu]

Originally Posted by neilpride

No, moving the lower shoruds from the diamond to the bottom of the mast dont solve the compresion issue, in fact the area compresed from the diamonds is out of reach from the joint, you say the joint its at deck level, to gain extra feet on the mast, so, the compresion forces are coming from your cap shrouds, forestay.

If you by pass the sleeve area with a new tang in the bottom of the mast then you are adding more compression load to the joint.

Yes, that’s exactly what I’m trying to say. It would be in compression.

What do the double diamonds do? They hold the mast in column. They take bending forces and translate them into compression forces.

That’s good stuff for a butt join. The enemy of the butt joint is the out of column bending force.

Very similar to the Crossbeam on the bow. The forestay is trying its best to bend that thing up. The seagull striker translates this bending force into a compression force.

That’s ideal for a butt join

Making sure that the splice is within the diamonds gives it a better support when it comes to lateral bending forces. Of course it does nothing fore and aft, but it does help with lateral. That can’t hurt.

[neilpride]

Originally Posted by Chotu

OK. I was just asking because I figure maybe they have the historic records of what my mast might be made out of. Since the entire Mast is already welded. There are no bolts anywhere. The gooseneck, every piece of hardware attached to it. It’s all welded.

Probably will still end up sticking with machine screws, but it sure would be a lot faster and easier to weld this thing.

Yes , shrouds tangs, its a piece of aluminium inserted from one side crossing the interior and comes out at the other side, the welding lines are around the tangs , mostly to secure those in place, nothing else, mast head its a piece inserted on top and welded around to secure in place, not big deal, and spreaders brackets can be welded in place , but the load its in compression from the shrouds, not big deal to, try to conclude if your France Spar its a 6000 series alloy, could be a lower series more friendly welding, if you choose the other way.

[Chotu]

Originally Posted by neilpride

Yes , shrouds tangs, its a piece of aluminium inserted from one side crossing the interior and comes out at the other side, the welding lines are around the tangs , mostly to secure those in place, nothing else, mast head its a piece inserted on top and welded around to secure in place, not big deal, and spreaders brackets can be welded in place , but the load its in compression from the shrouds, not big deal to, try to conclude if your France Spar its a 6000 series alloy, could be a lower series more friendly welding, if you choose the other way.

Ok. Thank you for setting me straight in the last minute of panic here.

Your contributions to this thread have been so helpful it’s hard to even thank you enough.

I will go with the more expensive and more difficult way. At least there is no question about it working. Even if it is more difficult and more expensive to do it.

That’s probably a better way to think about it than risking it by welding.

With the welding, even though it has been done on the mast already, there are unknowns. There are no unknowns using machine screws.

[team karst]

Originally Posted by Chotu

….What I don’t understand is why everyone has a different opinion. This sucks ……
What the hell? This is crazy. There’s no answer to this.
…,.
There should be a right way and a wrong way to do this.
……
My frustration level is getting pretty high because there’s no answer. But there should be an answer. ….ha

Logic flaw. Is there only one successful rocket design; even for the exact same mission? You should expect various engineering submissions here with critical review.

[Chotu]

Originally Posted by team karst

Logic flaw. Is there only one successful rocket design; even for the exact same mission? You should expect various engineering submissions here with critical review.

Good point.

I just got back from the metal shop. Wow!

They are absolute artisans with the brake

Absolutely perfect match to my mast section. Could not be happier with that.

We are going with screws. Three-quarter inch long. Picking up the Loctite right now. Getting the screw order in for today. 316 stainless. 100 degree countersink.


My guy is talking about welding the seam between the joints. Close it up. Good idea or no?

And the loctite should be good for isolating the aluminum and stainless hopefully.

[s/v Jedi]

A gooseneck fitting is welded, then it gets the heat treatment to T6 temper.

To attach it to a mast it is epoxied and bolted, right?

What they mean with welding with an internal sleeve, is that the sleeve is to make up for loss of strength due to welding.

I can even see manufacturers do the T6 temper for a whole welded mast assembly.

[Chotu]

Originally Posted by s/v Jedi

A gooseneck fitting is welded, then it gets the heat treatment to T6 temper.

To attach it to a mast it is epoxied and bolted, right?

What they mean with welding with an internal sleeve, is that the sleeve is to make up for loss of strength due to welding.

I can even see manufacturers do the T6 temper for a whole welded mast assembly.

I don’t really have any way to know. But there is no epoxy and there is nothing going on like what you are describing. Nothing. It looks just like the tangs. It’s just a piece of three-quarter inch aluminum hanging out of the mast welded there. Actually, two pieces. One for the top and one for the bottom. A pin goes through and that is your gooseneck.

I’ll take a picture next time I see the mast

[thinwater]

Originally Posted by stormalong

The true answer is that if done properly any of these options will work. Don't loose sleep over it.

This is the truth of it. I've tested them side-by-side and the differences are very minor, and depend on the materials and methods.

[Chotu]

Originally Posted by thinwater

This is the truth of it. I've tested them side-by-side and the differences are very minor, and depend on the materials and methods.

Thank God for this post. Thank you. And thank you to everyone saying this kind of stuff.

Honestly, the stress levels have been way too high for my heart.

For weeks now.

If I can get through this though, hopefully I will be back to normal stress levels.

Just to double check on some more opinions, I’m looking at a 60 inch internal splice piece. I’m also looking at a 58 inch extension. So the splice will cover more than half the extension.

Does that sound good?

I’m also looking at 16 machine screws for each row over the 60 inches…. Or one machine screw every 3.75”.

There will be 3 rows on each face (3 on port face, 3 on starboard face) and one row down the front as well to help resist the rake put into the mast.

Ordering these right now and getting them today because they are starting to go in today.

[boatpoker]

Originally Posted by Chotu

And the loctite should be good for isolating the aluminum and stainless hopefully.

Sorry, it won't. You'll start to see the white powder of aluminum oxide within a couple of months.

There are other brands but the only one I've used (with longterm great success) is Tef-gel

[Chotu]

Originally Posted by boatpoker

Sorry, it won't. You'll start to see the white powder of aluminum oxide within a couple of months.

There are other brands but the only one I've used (with longterm great success) is Tef-gel

Damn. Just bought $40 of locktite. Good save. Thank you.

Gotta find TefGel locally.

I had no idea the guy was going to be doing the machine screws already. He’s really moving right along.

[Chotu]

Note: upthread ItDepends says he did this with blue loctite and it was good 10 years later when he removed screws. Thoughts?

I got red locktite of course