glue or weld? (brass to cast iron)

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Old 10-30-04, 07:41 PM
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Question glue or weld? (brass to cast iron)

I need to make a strong bond between two small metal pieces: one is brass and the other is cast iron (I think this stuff is also called pot-metal. It's the casing of a small motor.)
I don't know anything about welding. Is it possible for me to glue these pieces together somehow? What should I use? Otherwise, what do I do to weld them together?

Regards,
Joe
 
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Old 10-30-04, 08:05 PM
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What does this small motor go to? The reason I ask is will it be vibrating when running. What caused it to break in the first place? If it broke from excessive vibration, wear, accident, etc. The following MIGHT not hold.

Motors in general should not have excessive heat applied (as in welding or brazing)

You MIGHT be able to use an epoxy type cement(J-B Weld or Gorilla Glue... etc.) to GLUE then together.
I have personally seen the first one used on a pump body that had a chunk GLUED back in and run under pressure. For how long it lasted I have no idea as I am no longer there. It should hold for your needs.

Pot Metal isn't cast iron. Its usually malable iron or cast steel. Its a very low grade metal(as in "bottom of the pot")and isn't NORMALLY weldable. It contains too many impurities.

Good Luck and post back with your results so others may learn from your experience.
 
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Old 10-30-04, 09:11 PM
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Many thanks for the reply. I will try one of the epoxy type glues. I will, of course, clean the surfaces. In addition, do you think it will help to roughen the surfaces with sandpaper?

The motor drives a lift chair (electric recliner). It seems to be pretty smooth and doesn't vibrate very much. The broken piece was part of the mount connecting the motor housing to the chair metal frame. It broke when the mechanism was subjected to excessive stress. (Trying to raise the chair when something had jammed the lift mechanism).

Again, thanks for the advice. I may just have to glue it and try and if it holds it holds. Are any of these glues better than others?

Regards,
Joe
 
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Old 10-31-04, 05:01 AM
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Like I said, I have used JB Weld and it holds under some extreme conditions. Gorilla Glue is the "new kid" on the block and I have not used it yet but it is sold in wholesale only contractor supply places as well as Walmart. I read the directions and it sounds complicated and messy. I guess if it works as good as it claims, it would be worth it though.Good luck and post back with your results.
 
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Old 10-31-04, 05:27 AM
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Joe,

I use a type of epoxy that is labelled as for use on steel.
I can't think of the brand right now but it has metal particles in it for greater strength.

Epoxies will stick to clean metal that has had all traces of paints or varnish removed.
It also helps to sand the surface to rough it up.

Another thing to consider is that the epoxy will never be as strong as the original joint.
If you can fabricate and glue in a small brace of some type that will take stress off the joint, you may increase your chances of success.
 
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