NDC790
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 posted on 1/1/07 at 12:30 PM |
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Bond........Ally Bond (ing) ???
Hi all,
I did ask this in another thred, but I think it got over looked.
Does anyone know about bonding alluminium? ie Type of bound, how to cure, cost, possible for home build?
Any information would be good.
Many thanks
Nick
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NigeEss
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| posted on 1/1/07 at 02:34 PM |
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Sikaflex or similar polyurethane adhesive works well. Air cures like silicone but far
stronger.
I've found Alpha DP2246 to be extremely good. Used to buy it from a local horsebox
builder for a fiver a tube.
Nige
[Edited on 1/1/07 by NigeEss]
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RazMan
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| posted on 1/1/07 at 04:37 PM |
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Depending on your application you can use PU adhesive (I used Tigerseal) as already mentioned but you can get a seriously strong bond with 3M double
sided tape. I used this in the signs industry to bond metal brackets to ally road signs - you rip the ally before you will break the bond. 
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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Zero 7
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| posted on 1/1/07 at 04:49 PM |
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Yeah that 3m stuff is very very very strong you never want to make a mistake with that stuff. Quiet expensive though.
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BenB
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| posted on 1/1/07 at 05:29 PM |
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I did some experiments bonding aluminium. Epoxy works suprisingly well (scrape [don't file] the oxide coating off both bits first and then
quickly apply a slow setting epoxy [araldite non rapid]. I cut a large matchstick type piece of ali (50mm long, 3mm*3mm) and glued it onto the edge of
a piece of thick ali so that half of its length was glued and half was hanging free. After letting it dry I turned over the sheet and hung a piece of
string around the ali stick were it met the sheet (everyone following this!?!?)... I then hung weights off the end of the string (empty bottles of
coke which I slowly filled up)... Managed to get over 6kg before it failed- which for a contact area of
25mm*3mm I thought was quite good...
You can also use stuff like Technoweld (friction brazing) but you need to be able to heat up the part pretty hot (pre-heat in an oven).... Repeated
the same experiment (new metal obviously to avoid contamination)... Got to over 10kg before I chickened out- the thick ali sheet was flexing seriously
and I knew from the first experiment that when the bond gave way things flew around quite a bit... I didn't fancy being around when double the
weight went off without eye protection.....
Obviously Tig is even better....
For most bonds, especially between sheets ( though you can do a technoweld sweat joint) epoxy is fine. Technoweld is good for people without TIG
ability. Sikaflex has the advantage of being flexible so would work better if some flexibility was required (like vibrations being applied across the
joint) not sure how epoxy would handle that- I suspect it would shear...
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macnab
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| posted on 2/1/07 at 12:17 AM |
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Oh good old Technoweld, that brings back memories!
Use to be an old tools technician and was experimenting with low temperature casting of diamonds into aluminium to make offshore drill shoe bits. Hit
upon using Technoweld, great stuff, in fact the v6's manifold is modified with it. Quite brittle stuff though, even used it to stitch back
together torn landy wings.
Failed totally on the drill bit project, we'd cast a blade, then move onto the next only to melt the first one…great when you’ve got four to
do!!
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NDC790
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| posted on 2/1/07 at 10:38 AM |
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I found this info on the Lotus Elise chassis
http://www.sandsmuseum.com/cars/elise/information/technical/asauto.html
I found it interesting (sad, I know)
Regards
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