Bonding steel to aluminum? | GTAMotorcycle.com

Bonding steel to aluminum?

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inreb

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I need to fasten a steel sleeve to aluminum carb body. I have no experience with bonding agents beyond thread locker. Does anybody know of a surefire product so I don't have to rely on product blurbs? Thanks.
 
Loctite 515 is the best gasket maker/flange sealant available.Maybe?
 
Yes,jb weld.But it will never come apart again.
 
JB weld is a fancy epoxy product, as is Loctite Epoxy. Is there any concern of heat / cool cycling? the dissimilar metals will expand and contract at very different rates. And aluminum is always hard to bond. I would consider an RTV, it has a certain elasticity that may be desirable . Throughly clean and and etch the parts first for maximum bond.

If there is no chance of expansion/contraction that WILL crack an epoxy fit, carry on. Where'd I leave my beer?
 
I guess it's time to come clean. This is a Mikuni TM40 flat slide pumper from ProCycle I've been running on a DR650 for 5 years. The steel adapter sleeve at the head side came loose, creating a stumble at one throttle position. ProCycle uses JB Weld. It held 5yrs. I guess that's good. About 30 years ago I glued a wheel bearing into a CB750 hub. It never let go. I wish I could remember what I used. I think it was green. But it might have been pink. I think I'll just go with JB Weld. I might be dead in five years. Maybe the DR will be dead in five years.
 
I had to use loctite (501?) To glue a rear wheel bearing in an 85 goldwing hub. Apparently they wear fast.

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crankcall said:
JB weld is a fancy epoxy product, as is Loctite Epoxy. Is there any concern of heat / cool cycling? the dissimilar metals will expand and contract at very different rates. And aluminum is always hard to bond. I would consider an RTV, it has a certain elasticity that may be desirable . Throughly clean and and etch the parts first for maximum bond.

If there is no chance of expansion/contraction that WILL crack an epoxy fit, carry on. Where'd I leave my beer?
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I've used JB Weld to build up and reshape intake ports - it's commonly used for that - and it has held up for years. The surface that it is bonding to needs to be rough.

Use the old style 24-hour-cure JB Weld, or the "marine" version, which is also a slow-curing variety. It's a lot stronger than the quick-setting type.
 
I'll draw an analogy to wood, then talk to the problem. When bonding wood, the best joints have mechanical interlocking or large face grain surface contact. End grain to face grain joints or ones with no mechanical fixings are weak. As with wood, making a solid mechanical connection between the parts first is important. Try to have as much surface area contact between the metals as possible - threaded connection, flanged or stepped interface are possible mechanical solutions. For example, trying to build a fillet of J-B Weld around an inherently weak mechanical butt joint is doomed to eventual failure.
 
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robmack said:
I'll draw an analogy to wood, then talk to the problem. When bonding wood, the best joints have mechanical interlocking or large face grain surface contact. End grain to face grain joints or ones with no mechanical fixings are weak. As with wood, making a solid mechanical connection between the parts first is important. Try to have as much surface area contact between the metals as possible - threaded connection, flanged or stepped interface are possible mechanical solutions. For example, trying to build a fillet of J-B Weld around an inherently weak mechanical butt joint is doomed to eventual failure.
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Yes, I just watched a you tube video where they compared various metal epoxies, and like you say, fillet/butt joints show weak. This sleeve affair is not perfectly round so I can spin it to a tight spot. As you know the carb is secured front and back by clamps so I'm guessing/hoping the JB Weld will work. There are steps OD carb flange.
 
Went with the JB Marine epoxy. Didn't need much so with the left over I glued some aluminum and mild steel stock together. It really doesn't seem that robust. Once I broke the pieces apart, which took little effort, I dug a boxcutter into remaining beads and it chipped away easily.
 
inreb said:
Went with the JB Marine epoxy. Didn't need much so with the left over I glued some aluminum and mild steel stock together. It really doesn't seem that robust. Once I broke the pieces apart, which took little effort, I dug a boxcutter into remaining beads and it chipped away easily.
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Did you rough up the original parts? The rougher the better to give it a chance to stick to something. Depending on the thickness of the parts involved, you could even drill some holes partway through (or tap in some socket head cap screws or similar) to give the epoxy something to key into.

I know, I know, this comment is too late. Trying to make it better for the next person trying to keep old bikes alive.
 
JB marine doesn't have the benefit of fillers that JB weld has. It also takes 24hrs to reach full cure.
 
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