Silly roof-rack question

[langer1]

Thanks for the tips. I only want to fill it to make it just a little bit harder than it already is, I don't want to crimp down on it with my spare mount and have it bend or deform.

I'm really thinking about bondo because I know it dries nice and hard, will it dry if it's not in direct contact with air?

Yes it's uses hardner it don't air dry.
I know you’re proud of your son but copper is a problem.
You can’t keep paint on it for one thing.
But very important is you can allow it to contact Iron or Steel not even Stainless Steel.
Because of “galvanic” action it will eat a hole through any thing that’s not Copper, Brass, Bronze or plastic. To mount it you need to use copper screws and insolate it from contacting anything steel.

 

[motorcityxj]

Yes it's uses hardner it don't air dry.
I know you’re proud of your son but copper is a problem.
You can’t keep paint on it for one thing.
But very important is you can allow it to contact Iron or Steel not even Stainless Steel.
Because of “galvanic” action it will eat a hole through any thing that’s not Copper, Brass, Bronze or plastic. To mount it you need to use copper screws and insolate it from contacting anything steel.

I thought that was the case but did not want to chim ein if i was wrong. I am bad at chemistry. I would build one very similar in steel to honor his design and intentions and make him feel good. Give lots of thanks. Is he a young guy ? If so its not his fault he did not know about the reaction, no biggie just tell him i am sure he wanted to do good but does not want to wreck your roof or make extra work for you.

Maybe you can make it into a conversation piece of sorts, like a coffee table for the rec room or try thinking out side of the box. Maybe integrate into a trellace in the yard and grow vines on it. Very artsy fartys foo foo. Just dont pitch it in the trash, and display it i think he will be more proud his old man likes it.

 

[MachineMan]

Completely filling it will be a loosing battle. Maybe put some iron rod down entire length of the side rails? Or just add more ribs to it and use the thicker wall type "L" copper which is used for under ground piping. Also clear coat it unless you like that antique green look... Then take pics for us to see...

 

[gtpolkus]

In order to make the thing stronger you would have to fill the tube with something that would take share the stress with the copper pipe. Foam would take a small amount of stress, but not much. Resin would be better, but it's expensive. Sand wouldn't do anything...it can't support a shear shear stress or a normal stress. Concrete would take some of the stress, but it's very brittle in tension and shear, so as soon as it saw anything but an "axial" load it would just crack up. I would reinforce with some steel, nothing can beat it's price and strength

 

[langer1]

In order to make the thing stronger you would have to fill the tube with something that would take share the stress with the copper pipe. Foam would take a small amount of stress, but not much. Resin would be better, but it's expensive. Sand wouldn't do anything...it can't support a shear shear stress or a normal stress. Concrete would take some of the stress, but it's very brittle in tension and shear, so as soon as it saw anything but an "axial" load it would just crack up. I would reinforce with some steel, nothing can beat it's price and strength

You didn't read my post about steel and copper, or you don't believe me which is it?

 

[OT]

Yes it's uses hardner it don't air dry.
I know you’re proud of your son but copper is a problem.
You can’t keep paint on it for one thing.
But very important is you can allow it to contact Iron or Steel not even Stainless Steel.
Because of “galvanic” action it will eat a hole through any thing that’s not Copper, Brass, Bronze or plastic. To mount it you need to use copper screws and insolate it from contacting anything steel.

I hadn't even thought of that, but you are so right.
I agree with MCXJ, but is it possible to ask him to build another one or another one with you?

 

[scottsxj]

dont know im thinking this far into this, but i looked at your profile and it says you DOB is 1980, making you somewhere around 25. Well how is it that you have a son old enough to make you a roof rack for your jeep. would that make him around 6 or 7. You must have one smart kid.

 

[langer1]

Stepson?

 

[gtpolkus]

You didn't read my post about steel and copper, or you don't believe me which is it?

I'm sorry I missed that, but there are grades of steels that can be used with copper. Any 300 series stainless has a higher nickel content and has a higher corrosion resistance in comparison to the copper and can therefore be used with it . AISI 301,302,303,304,316,321, and 347 can all be used. Anything higher on the galvanic series isn't practical

(Taken from a galvenitic series corrosion compatibility chart)

 

[XJnDixie]

Galvanic reaction....solution....

I design actuators for a living (I'm also an IT manager - long story) - anyway, we see on occasion a galvanic reaction between a bronze bushing and a ENP plated part - lots of things such as environment, salinity, etc. have to be just right - but at worst you can bet that the rack will oxidize and turn green.....

To stop this, you can clear coat the rack. Use a teflon or rubber "washer" or some sort of barrier between it and the bolts and roof and you should be set. I brought up teflon because we designed a teflon bushing to take the place of the bronze bushing and solved the problem.

Also, I was just out in the shop and a possible "cheap" filler alternative was right in front of my eyes.... Liquid Nails. The stuff is cheap - a buck or so a tube, and can be "pressurized" via the caulking gun into the tubing. Do it in steps, allow air to get in and set the compound, then add more....

I still wanna know what u decide to do, and how it all works out....

 

[MaXJohnson]

You didn't read my post about steel and copper, or you don't believe me which is it?

you didn't read langer1's post about steel and copper, you goofball.

or you don't believe him???

which is it???

I once made the mistake of using copper tubing to plumb the hot and cold water in my house. That copper started eating through everything. Before I knew it, it was sinking down through the basement floor; probably close to the center of the earth by now.

Copper is the devil's metal. I guess you didn't know that.

Take my advice. Drill a small pin hole in the tubing and attach a ruby laser to the rack, shining in through the pin hole. Ruby lasers give off red light, the color of the planet Mars. Mars is the god of war, you know.

Give the ruby laser a way to shine in, but don't drill another hole for the light to get out. The laser light will continue to enter the rack, but will be unable to escape. Eventually, your rack will not be able to contain the powerfull red beams(Mars, the god of war). The rack will explode, blasting away from your roof and saving you from the potential destruction of "galvanic" action.

ymmv

 

[FlatLanderHandicap]

In order to make the thing stronger you would have to fill the tube with something that would take share the stress with the copper pipe. Foam would take a small amount of stress, but not much. Resin would be better, but it's expensive. Sand wouldn't do anything...it can't support a shear shear stress or a normal stress. Concrete would take some of the stress, but it's very brittle in tension and shear, so as soon as it saw anything but an "axial" load it would just crack up. I would reinforce with some steel, nothing can beat it's price and strength

Mechanics of Materials....loved that course!

 

[Cowboydoc]

Just to throw my 2 cents in man...I understand the time and effort your son put into the project, but the copper is a hard metal to work with. I used to work on F-14's for the Navy. They had to have mech's like me replace every copper piece on the stupid things just to keep them from destroying themselves. Make it a Friday night project you twop can work on together (Let him teach you how...he'll love that) and fab up another one out of Steel. Much more durable and easy to get to work with other metals....


...Just an idea for ya. Take it easy and good luck.

 

[Phantom]

How about a 2 part resin, the kind used for FRP layups (fiberglass resin).

 

[jeephick85]

Put some Re-Bar inside and put silicone in the tube at the same time to reduce the vibs..

 

[NHextremeXJ]

Helloooooooo....why don't most fabricators use copper tubing for projects requiring strength and durability?.............must be cause they ain't smart like us are..... :doh:

 

[Zoro]

dont know im thinking this far into this, but i looked at your profile and it says you DOB is 1980, making you somewhere around 25. Well how is it that you have a son old enough to make you a roof rack for your jeep. would that make him around 6 or 7. You must have one smart kid.

Sorry it took awhile to get back to you. He's my adopted nephew, his father(my brother) died and to make a LONG story short I'm his legal guardian.

I guess he didn't care for the copper look so he painted it black, ended up filling it with Bondo and it's sturdy enough to hold me & my spare on the roof w/o deforming. One of these day's I'll replace it with steel or something but for now it's good.

 

[scottsxj]

Sorry it took awhile to get back to you. He's my adopted nephew, his father(my brother) died and to make a LONG story short I'm his legal guardian.

woops, didnt mean to bring up that topic, my bad man

 

[Zoro]

woops, didnt mean to bring up that topic, my bad man

That's cool, no harm done