Fuel Tank Mount

[FourPoints]

MS, I am installing a new custom 9.5 gal fuel tank from RDS Aluminum. I have 4 mounting tabs installed on the corners, and I am considering using either the Weld Mount 1/4-20 Stainless Steel Female Threaded Standoffs, or the 1/4-20 Stainless Steel Studs inside the hull to attach the tank on, similar to a motor mount. They seem like 4 of them would be plenty strong enough for a tank this size using the AT-4020 adhesive, which I understand is rated for (breaking strength) around 600lbs per mount.

I want to make sure I hold the tank a half inch or so above the hull as to not trap any water against the bottom of that tank that may find it's way down there.

My original/alternate thought was counter sink some 1/4-20 Stainless Tee Nuts flush into the back side of square pieces of plywood, and epoxy the assembly to the inside of the hull with west systems epoxy. That would give me the stand off from the hull to prevent trapping of water, and gives me the ability to bolt down from the top into the Tee Nut receiver without being too tall to create mounting concerns. The only concern is that this would not provide a way for water to escape from the bolt hole if it makes its way down, possibly resulting in corrosion of the stainless Tee Nut and rotting of the wood.

Aside from the question of being able to fit the tank over the height of the weld mount piece, do you have any suggestions / feedback on either option?

 

[Steve Dion]

Have you considered glassing in some epoxy soaked plywood or G10 fiberglass board. Then you can just use screws and the sealant to hold the tank in place.

Many tanks also use banding and mounts to secure them.

 

[FourPoints]

Maine Sail - any thoughts on my or Steve's idea? I need to order my equipment in the next week, would love some feedback before doing so.

Thanks

 

[Maine Sail]

I would feel much better with the larger OD HS200 mounts...... Be sure to properly prep the area where you bond them to.... Dewaxing, then sanding especially.

 

[FourPoints]

I would feel much better with the larger OD HS200 mounts...... Be sure to properly prep the area where you bond them to.... Dewaxing, then sanding especially.

Can you give me a link to where you get the "OD HS200" mounts? I'm not sure what you're referring to.

 

[Maine Sail]

Can you give me a link to where you get the "OD HS200" mounts? I'm not sure what you're referring to.

Sorry "OD" is overall diameter and the model is the HS200. They come with a 5/16 X 18 stud or a 3/8 X 16 stud. I use them for heavier loads.

Weld Mount Studs

 

[FourPoints]

That makes more sense. I suspected that you meant OD, but the HS4200 confused me.

Given this is a 9.2gal tank which when full will weigh less than 75lbs, and with 4 of the 1/4-20 studs have a rated tensile strength of 500lbs each, it will have a 2000lbs tensile strength combined rating, do you really think I need to go bigger?

My understanding is/was that the underlying glass in the hull isn't much stronger, so upping the size won't result in any significant strength increase. (something around 600-650 PSI of breaking strength before it delaminates).

I don't mind going larger, I just don't really want to spend $168 on studs ($42 per stud) if the 1/4-20 studs will provide roughly the same effective strength, and at the greatly reduced cost of only $24 for a 10 pack.

FYI, priced from Jamestown Distributors, if you have a better suggestion let me know.

 

[Maine Sail]

That makes more sense. I suspected that you meant OD, but the HS4200 confused me.

Given this is a 9.2gal tank which when full will weigh less than 75lbs, and with 4 of the 1/4-20 studs have a rated tensile strength of 500lbs each, it will have a 2000lbs tensile strength combined rating, do you really think I need to go bigger?

My understanding is/was that the underlying glass in the hull isn't much stronger, so upping the size won't result in any significant strength increase. (something around 600-650 PSI of breaking strength before it delaminates).

I don't mind going larger, I just don't really want to spend $168 on studs ($42 per stud) if the 1/4-20 studs will provide roughly the same effective strength, and at the greatly reduced cost of only $24 for a 10 pack.

FYI, priced from Jamestown Distributors, if you have a better suggestion let me know.

Wow for that price try the 1/4 X 20 studs.. Last time I purchased the larger studs I do not recall them being anywhere near that expensive. IIRC they were $7-8 each.. Hamilton Marine also has Weld Mount....... For me Weld Mount is a huge time saver and despite it being expensive to use the savings in labor to the customer are a lot...

 

[CarMechanic27]

Hey, just registered on the forum, and this is my first post so I hope this isn't breaking any rules.

I believe the prices you saw for the hs200 were a 5 pack at this website they come in a 5 pack for the same price of 42$

http://www.iboats.com/Hs200-Stainless-Steel-Studs/dm/view_id.885979

Hope that helps.

 

[FourPoints]

Thanks, I ended up calling weld mount and asking them, they said not to waste the money on the larger ones for this given the maximum weight will be under 75lbs, and spread over 4 mounts. They did say to use the other, faster setting and thinner epoxy though, as it is a little more flexible.

I ordered everything through Jamestown, and it arrived the next day.

 

[Chris Patterson]

You're not "breaking any rules" of any kind. Feel free to jump in with a thought, or idea any time. That's what this forum is all about. Welcome.

 

[TENACITY CS36T]

Thanks, I ended up calling weld mount and asking them, they said not to waste the money on the larger ones for this given the maximum weight will be under 75lbs, and spread over 4 mounts. They did say to use the other, faster setting and thinner epoxy though, as it is a little more flexible.

I ordered everything through Jamestown, and it arrived the next day.

Pm'd you regarding you're install, hope you can respond when you have time, thanks.