Can anybody steer me toward a good strong epoxy for bonding metal to metal? I’ve got a few small metal pieces to join (too small to weld and can’t use the heat for fear of burning the finish). I tried Super Glue brand 2 part epoxy and after it set up (I waited a week) I easily snapped it apart.
In case anybody wonders, one is the nut on the back of an Emtek lockset. And the other is a decorative flower to the stud on the back of a towel ring for my daughter. After that, I’ve got various broken toys to mend.
Thanks,
Replies
J-B weld http://www.j-bweld.com/coldweld.html
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations.
If you want to get the most out of the epoxy you need to clean and roughen the surfaces. A fingerprint is enough to substantially weaken the bond, particularly if the cross section being bonded is small.
Lacquer thinner or other solvents are called for. Sandpaper, rough wire brushing or a working over the surfaces with a file helps give the adhesive tooth. If possible adding a fillet, radiusing any corners. The added epoxy serves to increase the cross section and limit stress risers common to sharp junctions.
I have had luck using superglue to hold small parts in place and then flooding the entire area around the nut with epoxy. This greatly increases the contact area. Areas I didn't want the epoxy to bond to, like inside the nut, I covered in a coat of Vaseline.
Hope this helps. Good luck.
I'll try the JB. I've never been particularly impressed by it, but it was in different applications than this. I know my FIL likes JB for repairs.
I didn't know if there was an epoxy around with greater strength or if the SG epoxy I bought was about the norm.
I'll try the JB and see what happens.
Thanks,
John
J.R. Lazaro Builders, Inc.
Indianapolis, In.
http://www.lazarobuilders.com
I'll second the JB Weld.
J.B. Weld seems to be gold standard for small metal to metal jobs around here also...
And it is fairly widely available in auto supply stores and some hardware stores.
Edited 2/9/2004 11:13:15 PM ET by CaseyR
I would suggest finding yourself a hobby shop nearby. Epoxies are used in a lot of model vehicles (cars, planes, boats, rockets), and you can buy them in reasonable quanties. You may need to use a thickener (silica spheres, wood flour, or something like that) to get the viscosity you need.
Make sure you get the mix ratio right, and remember that the epoxy cure rate depends on the temperature and the size of the batch. Mix a large batch in warm weather, and it will get hot enough that you can't hold it in just a few minutes.
Others are right on surface preparation. The surface needs to be very clean and roughed up enough to get some tooth.
If you're doing toy repairs, you might consider reinforcing with some fiberglass. This will improve the strength considerably.
Oh, and make sure to wear gloves.