Best glue to bond metal and plastic

Joined
Nov 24, 2013
Messages
416
Location
Rocklin, CA USA
All of my old standing electric fans are loose/wobbly at the base. Would like to just permanently attach the metal pole to the plastic base. Anything better for this than JB Weld?
 
I have not had that great of success with JB weld on plastic. Seems like it won't hang on - too smooth or something. I have had great luck with JB on metal stuff.

I have had good success with Bob Smith Industries 2 part epoxy on plastic, but I have never tried it on metal so not sure on that side?
 
JB Weld is 50 year old tech. Use something that car makers use today like,

StorkAWD-Product-Lord-Fusor-152-And-153-Extreme-Repair-medium-Fusor-Plastic-Repair-491.jpg
 
It very much depends on the specifics of what is going on with it, how it is designed.

How did they get loose/wobbly at the base? Is a fastener stripped out or missing, or a hole in the plastic elongated, or the plastic cracked, and is the plastic solid where the metal shaft goes in? Pictures might (or might not) help.

Do you even *need* the plastic base and/or would plywood instead, or wood reinforcement of the base help?

If all it needs to do is fill up a gap, then JBWeld is not ideal because it is brittle. That does not necessarily mean it wouldn't work well enough if that is what you already have to try. If it is more about filling a gap rather than permanent attachment then it is less important that it achieve great adhesion to both surfaces, rather more important that it not deform itself. Better would be to take fiberglass matting, or any random scraps of cloth/other material, plus a standard clear epoxy (which is not brittle once set) and make a faux-fiberglass reinforcement layered on.

Another potential option if the plastic is hollow, is close up the gap between the pole and base (temporarily seal up the top surface gap between them so nothing leaks out on the next step), and with them upside down, pour some cement in and let that set, not just in the gap between pole and base but also the surrounding structure if it is hollow and that is how the hole for the pole has enlarged.

Another possible option is just wrap some duct tape around the base of the pole, as a shim if the base is still structurally sound and not expected to enlarge or break further, or a shim from plastic or metal sheeting, or since it doesn't get hot, a lot of hot glue.

Another possible option is make a collar that slips over the pole with a flange that you can screw/rivet/whatever attach to the base.

Another possible option is construction adhesive. Probably more cost effective than epoxy but if you need to lay it on thick, might need to build up thin layers and let each cure before adding another layer because if it is too thick, the middle may not cure any time soon.

Another possible option is cut up slivers of plastic milk jug, melt them in a tin can over a stove burner, and pour that all over the fan and the carpet and yourself. ;)
 
Last edited:
JB Weld is 50 year old tech. Use something that car makers use today like,

That is about $60. Would you really (really!) buy that to repair old fans? At that price, I wouldn't even use it if I had some already, rather save it for the applications it was meant for, which aren't reinforcing a fan base... unless it was getting old, shelf life about up and it would get thrown away if not used which happens with epoxy.
 
actually windshield sealer (3m) may work well ,sets up nice and tight and slightly Flexable, really bonds well, maybe lightly sand surfaces.
 
Here’s the fan. The pole sticks into the hole center of the base. Even with the provided single screw underneath, it’s come loose over the years. Can’t even tighten the screw anymore.
IMG_4405.webp
 
I have not had that great of success with JB weld on plastic. Seems like it won't hang on - too smooth or something. I have had great luck with JB on metal stuff.

I have had good success with Bob Smith Industries 2 part epoxy on plastic, but I have never tried it on metal so not sure on that side?
Adhesional wetting, or surface wetting, aka wetability determines how well an adhesive/coating/paint sticks to a particular material. This does not necessarily have to do with how smooth a surface is. For example, glass is very smooth and can be easily glued while Nylon and Teflon are very difficult to bond without first chemically etching.

Another term to google is 'surface energy' which refers to molecular attraction.
 
Last edited:
That is about $60. Would you really (really!) buy that to repair old fans? At that price, I wouldn't even use it if I had some already, rather save it for the applications it was meant for, which aren't reinforcing a fan base... unless it was getting old, shelf life about up and it would get thrown away if not used which happens with epoxy.
They do sell in smaller 50ml size for much less.
 
Here’s the fan. The pole sticks into the hole center of the base. Even with the provided single screw underneath, it’s come loose over the years. Can’t even tighten the screw anymore.
View attachment 219711
That's not really showing the interface in detail, like upside down, and taken apart.

However if the only problem is that the screw threads are stripped out, then a little JDWeld on the screw threads (after chased and cleaned along with the screw) just might work, if you can hold it together tight enough while it sets. Another option might be a new piece of metal that you tap new threads into, to replace what is there, and secure that into the pole with epoxy if not reasonably easy to get a perfect friction fit.

If both are metal, another option might be welding it together. If the threads are plastic and stuck well in the pole, another option might be drill it out and put a threaded insert in.

What materials and methods do you have available? I hate to buy things and then find out they won't work out, so would start with what you already have.
 
I've repaired a similar fan using JB Weld, where the plastic slot holding the small metal plate with the threads for the set screw failed, as well as a slight crack in the circumference that resulted from the added stress from the failed parts.

Basically, the JB Weld was used to re-secure the plate, fill in any voids that the original design had, and "pot" everything in place. For good measure, also added a hose clamp around the circumference of the base to add strength to the whole thing. Might not be as pretty, but it's solid, and held for a couple years.
 
Back
Top Bottom