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Mast base rivets loose
http://www.hobie.com/forums/viewtopic.php?f=14&t=63840
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Author:  mjggjm [ Sun Oct 07, 2018 5:23 pm ]
Post subject:  Mast base rivets loose

I noticed 2 of the rivets on my mast base are loose. Is it as simple as just drilling them out and replacing them? Should I replace the mast base while I am at it? Do I use the original size rivets or go up one size in case the hole is worn out?
Thanks for any advice.

Author:  speed633 [ Mon Oct 08, 2018 5:25 am ]
Post subject:  Re: Mast base rivets loose

Drill out and replace, likely with larger rivets.

The mast base uses stainless rivets. Over time galvanic corrosion eats away at the aluminium crossbar where the rivets touch, and the rivets get loose.

On my H18 I replaced the rivets with 1/4" Al rivets, and they have held strong over the years*. I went with aluminium because my rivet gun can't pull 1/4" stainless.

*Matt Miller will likely tell you to stick with stainless, and this is not bad advice. The original 3/16 stainless rivets are stronger than 1/4" aluminium rivets.

Also see this:
https://www.hobie.com/forums/viewtopic.php?f=14&t=63835

Author:  mjggjm [ Mon Oct 08, 2018 6:44 am ]
Post subject:  Re: Mast base rivets loose

Speed633, just to be clear, you are talking about the mast base and not the mast step, right? My problem is with the base on the bottom of the mast and not the mast step attached to the crossbar. I just want to be sure we are talking about the same thing. Thanks.

Author:  Hobiewonkenobi [ Mon Oct 08, 2018 9:02 am ]
Post subject:  Re: Mast base rivets loose

Yeah just drill those out. If you are drilling them out you may as well pop off the mast base. Repair any other parts of the mast assembly that require riveting. Then allow all the old rivet parts to roll out before you pull new rivets on the base.

Author:  srm [ Mon Oct 08, 2018 9:07 am ]
Post subject:  Re: Mast base rivets loose

The other option would be to drill another pair of holes around the circumference of the mast base and add two more rivets.

sm

Author:  speed633 [ Mon Oct 08, 2018 9:28 am ]
Post subject:  Re: Mast base rivets loose

Well, I suppose I was talking about the step....

In that case, I don't know if the rivets in the mast base were Al or SS. On the H16 the compression of the mast onto the base holds things together, so failure of the rivets would be less bad. Either way the repair is about the same. Drill out the old rivets. If need be go to the next size up. Taking the base off to clear out loose parts and reseal is usually recommended.

Author:  srm [ Mon Oct 08, 2018 12:23 pm ]
Post subject:  Re: Mast base rivets loose

speed633 wrote:
On the H16 the compression of the mast onto the base holds things together, so failure of the rivets would be less bad.


The compression of the mast only holds the base together when the mast is raised - up in the air. During the stepping and de-stepping process, the mast base is trying to pull away from the mast extrusion. There have been more than a handful of posts on this forum from people who have had the mast base rivets pull out while raising or lowering their mast, and the end result is that the mast comes crashing down.

Definitely make sure that this part of the mast is structurally sound and always follow the rule to never stand directly beneath a mast that is being lowered. Always stand off to the side and only come under the mast after the person lowering it has safely brought it down.

sm

Author:  mjggjm [ Mon Oct 08, 2018 3:28 pm ]
Post subject:  Re: Mast base rivets loose

Thanks for the great responses every one. Any suggestions on a rivet gun that can handle the 3/16 stainless rivets.

Author:  srm [ Mon Oct 08, 2018 5:07 pm ]
Post subject:  Re: Mast base rivets loose

I’m not a big fan of Harbor Freight, but their $20 heavy duty rivet gun has been worth every penny. I’ve used it to pull up to 1/4” stainless rivets.

The only issue (and this is probably not unique to the HF riveter) is you have to keep a good amount of down pressure on the tool, or else it can jump when the rivet pops and scratch the aluminum anodize on whatever you’re riveting. Otherwise, it works great.

https://m.harborfreight.com/hand-tools/ ... 66422.html

sm

Author:  mjggjm [ Mon Oct 08, 2018 6:40 pm ]
Post subject:  Re: Mast base rivets loose

Thanks ,srm. I want to try and get the rivets by this weekend so I will probably have to get them locally. Does anyone know where I can get the rivets around the Tampa/CLearwater area?

Author:  srm [ Tue Oct 09, 2018 2:47 am ]
Post subject:  Re: Mast base rivets loose

mjggjm wrote:
Thanks ,srm. I want to try and get the rivets by this weekend so I will probably have to get them locally. Does anyone know where I can get the rivets around the Tampa/CLearwater area?


I always just order them from McMaster Carr. Good selection, good price, and they are typically delivered in a day or two.

sm

Author:  mjggjm [ Tue Oct 09, 2018 5:52 am ]
Post subject:  Re: Mast base rivets loose

I am not sure which ones to order. The self sealing rivets mcmaster has are for hole size .192-.196. If I used the rivets with the sealing sleeve on Murray’s that says required hole is 13/64. Not sure what the original hole size is. I will have to drill the rivets out today and measure the hole size and thickness.

Author:  srm [ Tue Oct 09, 2018 6:54 am ]
Post subject:  Re: Mast base rivets loose

3/16 Diameter stainless rivets. Generally, 1/2" long grip range will work for most applications on a Hobie. Going a little longer usually doesn't hurt.

3/16" = 0.187"
13/64" = 0.203

You're only talking a few thousandths one way or the other. It's really not that critical.

They do not need to be self sealing. The bottom of the mast has a foam plug that will prevent any water that gets in from migrating into the main part of the mast. Just put a dab of silicone on the rivet before installing it and then after it's been pulled, put another dab in the hole of the rivet.

sm

Author:  mjggjm [ Sun Oct 14, 2018 3:09 pm ]
Post subject:  Re: Mast base rivets loose

Thanks Srm, did what you said. It all worked out great.

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