Which Butyl Mastic for rack?

[brsasquatch]

Do you mean the expandable foam, right stuff? If so, I would not use that. Even though the butyl is messy, it's still removable.

I would be afraid that, especially with the front most casters, if you used foam and get a leak, mold will start growing in the hard top. I would also be concerned that once dry, the foam doesn't really shift. If you were to put a load on the rack it would compress the caster against the hard top. When you remove that load, the great stuff foam wouldn't bounce back, whereas the butyl should.

Personally, even though it's messy, I would stick with butyl. I would probably try the tape first, then the caulk tube as a second choice.

not the foam, but the rubber eletrical tape.
https://www.amazon.com/3M-Scotch-Se...&keywords=butyl+rubber&qid=1594903946&sr=8-14

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[nU7OuxIx]

not the foam, but the rubber eletrical tape.
https://www.amazon.com/3M-Scotch-Se...&keywords=butyl+rubber&qid=1594903946&sr=8-14

Oh yeah, wrong stuff. I was thinking great stuff...

The link you provided looks a bit more like electrical tape than actual waterproof sealant. I've used electrical tape similar to what is in the link and it was more like wrapping a rubber bike innertube around the connection than stickeyness.

I'm not a butyl expert, but I would leak more towards something like this:

https://www.amazon.com/Second-Skin-...tyl+mastic+tape+RV+auto&qid=1632946993&sr=8-4

I think the key is you want something that's going to work for RV's and Auto's to seal out water.

 

[donmontalvo]

Not sure why RhinoRacks keeps advising using Butyl Mastic, when it's impossible to find.

I wrote RhinoRack an email, and I asked for an escalation, to ensure the response is from someone in a qualified position, and not an intern or new call desk person Googling for an answer.

 

[jim00]

This is what they recommend. (amazon link). I have used it for the last few months and had some nasty storms, no leaks.
https://www.amazon.com/gp/product/B000HBM4FQ/

 

[donmontalvo]

not the foam, but the rubber eletrical tape.
https://www.amazon.com/3M-Scotch-Se...&keywords=butyl+rubber&qid=1594903946&sr=8-14

Hmm...

"* Use over a temperature range of 32F to 100F (0C to 38C) without loss of physical properties"

 

[psucanary]

I used butyl tape (second time around after both fronts had dribbles) and it was way easier to work with and been almost a year without a single drop. Also been through extreme temps (hot and cold), still pliable. Wish I woulda just used that to begin with. It'll also be way easier if you have to remove one or two in the future to retrieve a nut (they can fall in; you need to remedy with some sort of spacer under the nut to keep it in place IF a nut falls in). Tape won't permanently adhere to the roof surface like various caulk options seem to do..

 

[donmontalvo]

This is what they recommend. (amazon link). I have used it for the last few months and had some nasty storms, no leaks.
https://www.amazon.com/gp/product/B000HBM4FQ/

Thanks, the link in the original post seemed to be for this, but was a dead link.

Now that it's getting cooler I'll give this a shot. I ordered one of them, should be in in a few days.

 

[Bogdan_P]

This is what I wound up using for my backbone system in the absence of Butyl Mastic. It was easy to work with, and no leaks after several days of soaking rain.

https://www.homedepot.com/p/Permate...ce-RTV-Silicone-Gasket-Maker-82180/308852434?

 

[4a4c55]

if you have to remove one or two in the future to retrieve a nut (they can fall in; you need to remedy with some sort of spacer under the nut to keep it in place IF a nut falls in).

Er, yikes? What do you mean? Which nuts fall into what?

 

[DarkAardvark]

I used RTV on a hole in my flappy soft top for my TJ and it lasted for 7 years (would probably have gone longer, but I replaced the whole top)

I have it on my JL's hard top with the maximus 3 rhino rack system and it hasn't leaked in the whole month it's been on there

Just updating here. Still no leaks using the original permatex RTV I used during install.

I had rubber washers under the feet to distribute the load and keep it from scratching the hard top. They seem to have dried out and cracked, but the RTV is still fine

 

[nU7OuxIx]

Er, yikes? What do you mean? Which nuts fall into what?

On the casting that attack to the hard top, there is a luck nut glued inside of the casting. When you attack the crossbars, the feet bolt into the casting and use that nut. When the glue in the casting fails, the nut drops down and prevents you from bolting the feet on the roof. The fix? You have to remove the caster, remove all that RTV or mastic, glue the nut back in and then reapply the mastic and bolt it back down, praying it doesn't least again.

I ended up using my 3d printer to print a spacer washer. I put the nut in first, then the spacer, glue the spacer in, and then glue the casting back down. When the glue fails that keeps the nut from dropping, that spacer is there so that it doesn't drop far enough down there the foot is unable to be bolted on. So far, it hasn't failed.

 

[stephanadams]

I have it on my JL's hard top with the maximus 3 rhino rack system and it hasn't leaked in the whole month it's been on there

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[4a4c55]

I ended up using my 3d printer to print a spacer washer. I put the nut in first, then the spacer, glue the spacer in, and then glue the casting back down. When the glue fails that keeps the nut from dropping, that spacer is there so that it doesn't drop far enough down there the foot is unable to be bolted on. So far, it hasn't failed.

Sorry, I thought I responded to you months ago. I'm finally coming around to ordering my rack, and I see lots of people complain about the nut falling out of the casting. Have you ever made your parts available, or would you consider sharing your STL files? It would be great to have a solution from the beginning and not worry about the nuts falling out.

 

[nU7OuxIx]

Sorry, I thought I responded to you months ago. I'm finally coming around to ordering my rack, and I see lots of people complain about the nut falling out of the casting. Have you ever made your parts available, or would you consider sharing your STL files? It would be great to have a solution from the beginning and not worry about the nuts falling out.

Well, I guess I didn't think there would be a lot of interest. I'm no designer and I just threw it together. But if it helps others out here it is.

https://www.thingiverse.com/thing:6338198

You may have to sand it down a bit to get it to fit. I also probably just did 100% fill but it's up to you. Just make sure that it fits the caster well, the caster sits good on the Jeep, and that you can get the screw in and out of it before you glue the caster down.

 

[4a4c55]

But if it helps others out here it is.

OMG, thank you so much for sharing!

So you've just got this spacer/washer under the captive nut in the casting base, so that it rests on the roof and keeps the nut in the pocket in the casting base. Do I have it right?

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