Antisieze / Sealing External Fastener

[mobiledynamics]

I'm mounting unistrut onto a brick parapet - into lead anchors that are in the brick. In removing the bolts that were in there already, head and most of the thread were clean and rust free...however, at the very end, I suppose water might pool and get in and settle there - there was some mineral corrision/buildup and very slight rust.


What's a good grease/antisieze to use for these 3.8 machine bolts. It sees PLENTY of sun during the hot summer months and all 4 seasons. Dielectric dries out over time ??

Instead of caulking the bolt heads, caulk IMO is really for indoor stuff and I hardly even use that except for certain applications, I'm thinking of usking my NP1, etc on the bolt heads ?

 

[bmwpowere36m3]

Is the uni-strut mounted horizontally or vertically? Can water pool at the bolt head and seep in?

I would just apply a little anti-sieze to the bolt threads and caulk the bolt head if there's a
chance of water pooling and wicking in. Something like a roofing lap sealant would work on the bolt heads... at least that's what we use our RV roof with tons of penetrations.

 

[rsanter]

I would just apply a little anti-sieze to the bolt threads and caulk the bolt head if there's a chance of water pooling and wicking in.

This

Bob

 

[mobiledynamics]

Isn't lap sealant for ~flat surfaces~.

The anchors are in brick. The bolts I removed were put in about 5 years ago. About 2 1/2 long. Granted the original install did not use anything on the bolt head. I'm thinking water wicks in and the only sign of mild corrision/mineal buildup is on the last 1/2 of the bolt. I'm thinking water just absorbs though the brick as well and anything that doesn't pools in the bottom of the hole.

Strut will be installed Vertical.

 

[pelletman]

Maybe Fluid Film

 

[rlitman]

Is the uni-strut mounted horizontally or vertically? Can water pool at the bolt head and seep in?

I would just apply a little anti-sieze to the bolt threads and caulk the bolt head if there's a
chance of water pooling and wicking in. Something like a roofing lap sealant would work on the bolt heads... at least that's what we use our RV roof with tons of penetrations.

WHAT?!?

First off, anti-seize on a bolt in a lead shield? You don't need anti-seize if you're screwing a bolt into LEAD!

Second, caulk on the bolt head? No. The interior of the brick is still a moist environment. You either want galvanized or stainless fasteners to resist the corrosion.

 

[gsmith22]

a brick is driest when it leaves the kiln. it absorbs water increasing in size for the rest of its life. The interior of the brick will probably be wetter than the exterior surface. I would use stainless. Of course that probably means your unistrut is going to corrode but that is a separate issue. maybe can isolate the dissimilar metals somehow

 

[mobiledynamics]

The roof sees sun everyday, even during winter. Hot as hell during late spring--mid fall...
FF maybe for the top of the bolts, with occassionally topping off. I thinking something like urethane just might last longer and just *bond* seal the perimeter of the nut head to the achor a touche better.

The anchors in the wall are either single or double expansion anchors. I'm like 90% sure they are double as there is a ~cone~ in the front and one in the back (I've only been on the roof 3X during this initial discovery process). The outer shell is some lead variant or soft steel, but the machine bolts 3/8, really only touch the cones, which is some variant of steel. I didn't install these but this is what it looks like when I peek inside the anchor hole.

And to recap, these were installed about 5-6 years ago The heads are clean, and so is 3/4 length of the bolt. It's only the last 3/4 inch that show some slight rust on some, and others just have heavy mineral buildup on the threads. I suspect the inner cones as well, as some bolts can hand tighen and some others I tested with the same bolt, it's not easy doing a hand tighten..


They were formally installed direct on the anchors with regular minisplit brackets.

I'm switching things up, utilizing all previous anchors and creating vertical unistrut legs.
Once the legs are established, I'm running two 20' creating one large frame.

 

[Leaflessshadetree]

How long were the bolts installed? I wouldn't be too worried about slight rust, especially after several years.

 

[Bondo]

What's a good grease/antisieze to use for these

Ayuh,.... I've thrown away my never-seize, years ago, when I was taught that form-a-gasket #3 works Sooooo much better,....
An ole salt that was a saltwater boat mechanic for decades, always called never-seize, Always-seize,...
He's the 1 that convinced me to try form-a-gasket #3,...
Even on tractor-trailer spring u-bolts, it works much, Much Better than never-seize,...

 

[Wakefield]

Would the white teflon antiseize in a tube that is sold for pipe threads work?