A note from Kevin Galbraith on...Repairing broken parts.

Kevin Galbraith RedEye

Suppose you received your latest shipment of parts from us and you accidentally drop the box, breaking a piece of the part inside. Or, maybe you are taking your part out of the box and grab it by a thin wall and a piece chips or breaks. Sometimes, despite the strength and durability of thermoplastics, parts get damaged and broken, leaving you with little or no time to send it back to us for repair or rebuild. Through the years, we have tried a number of things to repair customer parts and we thought it was time to share what we’ve learned with you.

If you do, in fact, break a part or receive a broken part, there are several ways you can repair it. First, refit the part before using a bonding agent to ensure that it fits and will correctly fit when you secure it. We use a professional plastic welder that does a great job of bonding the joints without decreasing the mechanical properties or the strength of the part. In fact, in some applications, bonding the part actually strengthens it. If you are using the clear plastic adhesive on an application with PPSF/PPSU material for a high heat application, you will notice that the solvent bubbles at 100 degrees Celsius. We’ve found that your part will maintain its functionality, but may lose some of its cosmetic appeal. However, you can use a super-strength glue, such as a cyanoacrylate adhesive, and baking soda to repair the appearance.

We use instant glue as another bonding agent to repair parts, mostly to fill in gaps and holes. The baking soda acts as an accelerator for the glue, leaving the color of the part unchanged. In addition, we sometimes use instant glue to reapply pieces of a part because the accelerator (baking soda) immediately cures it.

System owners are probably the only customers able to use the third method of restoration. By applying a piece of the thermoplastic material to the damaged part and heating it with the hot air gun, you can weld the two joints back together and maintain the properties of the original part.

All of these methods will help you easily repair your parts, but you will have to perform some cosmetic corrections if appearance is a concern. For example, the professional plastic welder will leave a shine on the part and the instant glue and baking soda method may leave a rough edge. By using a 220 or 330 grit sandpaper, you can gently smooth the surface finish of your part without scratching it. However, make sure to wait an ample amount of time – at least 45 minutes – for the adhesive to dry before sanding it. In addition, mineral oil on a clean rag helps the appearance of your part. However, immediately wipe off the mineral oil to ensure the part abstains from absorbing the oil.

We are always trying new things to repair and mend broken and damaged parts. If you have tried a method we failed to list, please send it to us. We would love to try it here in our finishing shop and share it with other RedEye customers. Send your tips to Tim Thellin in our marketing department at Ruth.Jacques@redeyeondemand.com.

Customer Comments

"I have used MEK (methyl ethyl ketone) with great success. It is inexpensive, works quickly, and makes the part as strong as the original. Also, if brushed over the surface, makes the parts water tight. It dries much faster than super glue and works just as well."

Gregory Wirtel
Operations Manager
Dr. Brooks Innovations
www.walkhealthy.com