+- Mach 1 Club (https://mach1club.com)
+-- Forum: Mustang Mach 1 Garage (https://mach1club.com/forumdisplay.php?fid=175)
+--- Forum: Do It Yourself: (https://mach1club.com/forumdisplay.php?fid=132)
+--- Thread: 1971 - 1973 Mach 1, what material is the "front bumper" made of? (/showthread.php?tid=180)
1971 - 1973 Mach 1, what material is the "front bumper" made of? - Mach 1 Club - 10-26-2009
That front bumper cover is not rubber, although it is "rubbery" and people mistakenly call them "rubber bumpers." Your bumper cover is reaction injection molded Polyurethane plastic - or PU for short (sometimes PUR for polyurethane resin - PU and PUR are two different names for the same plastic).
Polyurethane plastic is very adhesive so you won't have any trouble repainting it. (Go to a hardware store and you will find polyurethane glue - two part resin glue is basically the same stuff - that's how adhesive it is.) You don't need to remove the existing paint, just sand it smooth then paint over. It will probably take you 45 minutes with 320 grit sandpaper. Primer paint any places where you cut through the paint to the raw plastic. Make sure that you add a flex additive to the paint (and use a flexible primer too) because the plastic bumper cover is flexible and without the flex additive the new paint will crack. DO NOT put adhesion promoter on the part it will destabilize the bond between the existing paint and the plastic and a month later your new paint job will be flaking off. Adhesion promoter is only used on the newer style (since around 1995 and newer) TPO plastic bumpers (and PP and modified-PP and TPE just to be technically correct). Adhesion promoter is used on the raw TPO (et. al.) plastic as a bonding agent to help the primer paint adhere to the raw plastic because the adhesiveness of the TPO plastic is low compared to PU.
RE: 1971 - 1973 Mach 1, what material is the "front bumper" made of? - chutsonjr@yahoo.com - 05-16-2011
You also have steel inside the front bumper on all 3 years . I just want to know why some one hasn,t mayed some new moulds for these parts . The 73 has alot of weight . But they did work if you hit something . The paint that was used wasn,t a body paint or it wouldn,t have bonded to the surface . C . L .
RE: 1971 - 1973 Mach 1, what material is the "front bumper" made of? - Rare Pony - 05-16-2011
Good info. I know the body shop that did mine on my 73 convertible had a hard time with the front bumper. They had to redo it three times. The finally had the PPG rep come in and help them out!
RE: 1971 - 1973 Mach 1, what material is the "front bumper" made of? - Steven Harris - 05-16-2011
Good information indeed! I need to get some of that polyurethane glue for my truck. A tire tread took off the bottom part of my dually fender and a ditch took off part of my running board. I imagine that glue will work for both repairs.