[TowerTalk] welding aluminum

[Martin A Flynn]

John,

Take a look at: 
http://www.dowautomotive.com/capabilities/adhesives/structural/

Martin, W2RWJ

On 1/31/2015 1:47 AM, caraj at cox.net wrote:
> Jim:
> What's the name of this super duper glue in the US.
>
> Thanks,
> John, K2SFS
>
>
> ---- Jim Thomson <jim.thom at telus.net> wrote:
>
> =============
> Date: Fri, 30 Jan 2015 10:02:06 -0700
> From: Bob Tabke <bob at onehorsecreek.com>
> To: towertalk at contesting.com
> Subject: [TowerTalk] welding aluminum
>
> I am building a 6m H-frame (33'x40') and need to connect two 4.5 inch
> pieces of T6 aluminum pipe as well as two sections of 3" al tube. I have
> an al welder. But I am wondering if anyone has experience with welding
> T6 aluminum causing a loss in strength due to lessening the temper? The
> joints will have cradles on either side to reinforce the joint...
>
> Thanks,
>
> Bob, N7IP
>
> ## N6bt told me years ago, the welded joint will drop down to T0.... then
> work harden back to T1.   I find that hard to believe, since  welded AL
> joints are very strong, same deal on welded AL boats, ferries etc.
>
> ##  A local PE  buddy of mine sez you will lose 40% , strength wise,
> with any welded AL joint.
>
> ##  I talked to a business here in town that does Al welding, and also mobile,on site
> al welding.   I believe  Al can be heliarc welded and also tig welded.   Same  local
> business told me that an even stronger method is to just GLUE the pieces together.
> He said the glue was far stronger than any weld.... BUT it cant be used for any type
> of electrical connection.   Say you were joining 2 x 2 inch od pieces of al tubing...
> and had a 3 inch overlap..via swedge, or outer or inner sleeve,  etc .   Say the
> overlap was aprx 3 inchs.   2 inch OD = 6 inch circumference..... X  3 inch overlap
> .... =   18  square inchs of glue.  He said this glue is beyond super strong....and only god can get it
> apart.  BUT, you wont have electrical continuity.  You could get that with a short AL strap across
> each glued connection.   Bikes using AL frames are glued and not welded.   Apparently you can
> also do a tiny weld on the circumference of the glued joint, to retain the electrical continuity.
>
> ##  Its just another option.  Bolted joints  will also work.  Short inner and outer sleeves can also be used
> to re-enforce the bolted connections.   IE:  increase wall thickness where the bolts pass through.  If bolts
> are too tight, u just end up crushing the tubing.   .25 inch  rivets will also work..provided u use enough of them,
> like a row of 5 of em...... every 90-120 degrees.
>
> Jim   VE7RF
>