Calling all epoxy guru's

[loaded]

Hey guys,
I've tried to epoxy up my brake mount 3 times now, all with the same result of the epoxy failing around the aluminium and separating from it cleanly.  Yet I've seen so many successful carbon/alloy epoxy jobs done on this site!!!

What am I doing wrong??? I've filed off all anodizing from the aluminium, roughened the surface etc.....  maybe I should clean it somehow before adding the epoxy to make sure there's no oil/grease residue?

What's a good epoxy to use on aluminium? any suggestions?
Amy help would be greatly appreciated
Cheers,
Luke [smiley=beer.gif]

[will]

JB Weld is some amazing stuff. When properly mixed and cured, it is incredibly strong.
One key to making a good bond is having good surfaces, but more importantly you need a some kind of a 'mechanical locking surface.' Even if you make a few small V cuts with a file, the epoxy likes to have notches, holes, and corners to hold on to.

In metal to epoxy joints, it's good to go with these rules:
Compression is VERY strong.
Shear is okay.
Tension is fairly weak.

Also, point loading can be awfully dangerous on any epoxy joint. Spread out the load any way you can.

[Simon]

I think your best bet is to remove the other canti mount,fill in both canti mount areas for a nice finish then convert to disc.
just my opinion but I feel this is the safest option as well IMHO,
good luck anyway.
Simon.

[junkster]

Hi,
   I second JB Weld defo. [smiley=nod.gif] Use the longer curing one. My mount on the old alloy xlink I had was rock soilid. Just don't get any paint thinner on it. [smiley=doh.gif]

check it (not pretty but did the trick - remember to roughen up the surface - I actually scored a light series of criss crosses and well as using rough sandpaper. Also ensure there are holes for the JBWeld to ooze through, see below) and give it at least 24 hrs ):

Finished article painted:



the stages:








if you need any pointer feel free to ask.  [smiley=nod.gif]

cheers
Dan [smiley=beer.gif]

[Thunderchild]

Check out these epoxy pastes. Three dimensional duct tape

http://www.newpig.com/en_US/main.jhtml;jsessionid=XNY1ZP1J3FLRWCTGIQVSFEQKMZCCWJVC?page=browse%2Flanding1.jhtml&selectedGroup=PIG%AE+Repair+Putties&catId=2LHBPIGREPAIRPUTTIES&ppanalysis=CATBROWSE&_DARGS=%2Fen_US%2Fbrowse%2FcatStageGroup.jhtml.1_A&_DAV=PIG%AE+Repair+Putties

I have used the general one to repair an air line fitting on my truck.  It has been in place for 4 years.  There catalog shows them making a nut to replace one on a bolt.  There is one for aluminum repair also.  I am not sure if they are better than the liquids like JB Weld.  Worth a try though.  We keep them on hand to fix a leaking drum or other item at work.  They are a bit harder to mix.  The core is one part and the second part of the epoxy is wrapped around it and separated by a layer of something.    
You just cut off the amount you need and mix it up.  Use gloves as epoxies are known sensitizers!

This company is great and use to send out free samples of the putties.  That is what I used to fix my truck air line.  

Thunderchild

[loaded]

Thanks for the replies guys, they helped a lot, so I think you  all deserve to see my dodgey handywork.  

This is what the thought of missing the next ride makes you do!!! [smiley=laughing.gif]

[smiley=turtle.gif]iNTRODUCING THE WORLDS DODGIEST BRAKE REPAIR  [smiley=turtle.gif]

Firstly find yourself an 8metric ramset concrete bolt
like so
remove the end and hacksaw off the flared head

Then wander across the road to the local surf board manufacturer for a fibreglass ding repair kit, and go mad [smiley=evil.gif]




Anyway, it lasted out the ride today and is as strong as nais.  As you can see I filed down the old aluminium mount to keep the old locator holes for the brake spring.  The the fibreglass seems very, very strong!!!  I think I'll have dificulty removing it when I go to discs!! [smiley=laughing.gif]

[junkster]

Ahhh, I see, misunderstood - thought you were talking a front disc mod. Ya fix seems to have done the trick. JB Weld would have worked too on that I would imagine.

cheers

Dan

[shovelon]

Very nice! What a clever solution you came up with. I love this forum.

Terry

[Mr.Ed]

I have used Gorilla Glue to glue seat tube back in place, after roughing the aluminum. Took about 2 full days to cure !! Trimmed off the excess from expansion. 6 months later, still rock solid !!

[loaded]

Well I found out I couldn't get JB weld in Australia, and after a yarn with the guy down at the surf shop I thought I'd give fibreglass a try