The acrylic and plastic parts we use for our projects are very weak, and I’m sure it happened to anyone to have some important pieces broken because of dropping on concrete or unintentional force applied on them and you can’t find a missing part anymore. This happened to me as well with the electrical panel. I was having it in my hands and opssss… it slipped away and I found a corner missing in it I wasn’t able to find the missing piece anymore… so now what? Make such a complex part again would have took me at least 2 days of work.

I then looked around for a good way to repair it and found out that the polyurethane resin used for casting parts in silicon molds is just perfect for the job. What to do then?

1. In the first image you can clearly see the broken corner of my elec panel. If the part has been already painted remove the paint a bit around the junction point with the specific remover and sand a bit to help the resin to attach to the acrylic piece. I had it painted only on front and I did it on that side. Clean thereafter with acetone or generic home usage alcohol.
2. You need to create a frame that will reproduce approximately the missing piece. In my own case as you can see in the image the part to restore was plain and squared, so using Lego blocks I made a wall around the corner where the resin will be casted. Be sure that the base is closed (use some adeshive attached on bottom to prevent flooding). Keep everything ready for cast the resin, because it usually dry very fast (less then 5 minutes) and you don’t want to ruin the part even more.
3. Mix the polyurethane resin. This one I have is 1:1 mix so easy to make in very small doses. I used a syringe to get 1ml of each component and mixed in a glass with a tipped stick. Cast the resin in the frame slowly until it reach the level needed to reproduce the missing part. Don’t mind if you put a bit more, you can sand it later before repaint the part.
4. Wait for it to be dry a bit (5-10 min) and remove the frame. The resin attaches perfectly to the acrylic by actually gluing to it. The specific strength is a bit less of the polycarbonate or cast acrylic but for this job is just perfect.
5. You can now remove the bulk extra with a cutter while it’s still slightly soft and then wait at least 30 minutes so that the resin will reach the final state. During this period pressing with force on it will leave your fingerprints on the part so use with care. Once rock solid sand the new reproduced part to match the old one.
6. Finally paint again following your usual way. To prevent paint signs don’t cover the remaining part of the piece by sticking adhesives on it else paint signs will be seen from different paint timings and thickness. Just put a newspaper sheet covering the part you want to care of and paint with the gun or the spray can  at a fair distance. That will spread the paint enough to give a good result.

Operation completed.

written by l45 captain \\ tags: acrylic, cast, plastic, reconstruct, repair, resin