Fiberglass and glazing putty or just glazing putty to fill holes?

M

mercedesThomas

I'm just about ready, I bought the epoxy and 2k primer from SPI and a grabber blue Prospray single stage. After referencing "The Perfect Paint Job", I'm a little disappointed I won't be able to finish my painting in a full weekend but I guess I'd rather have quality than speed. The only part where I'm still confused is bodywork. I'll be painting my 1978 Yamaha XS750E that has a metal tank and two plastic side covers and a plastic cowl. I don't think the tank will need any bodywork done to it but the plastic parts will. I've got 3 3/8" holes in the seat cowl where an owner installed a tail light. Would these holes best be filled with fiberglass and glazing putty (I have Evercoat Polyester Glazing Putty) or just the glazing putty? What type of plastic are these UJMs, ABS? Being plastic, would I be able to do the bodywork before I epoxy for the first time or should I defiantly epoxy everything first? Thanks.
 
The first step is to figure out what type of plastic it is-that will determine the correct procedure to use.
 
Bob Hollinshead;29030 said:
The first step is to figure out what type of plastic it is-that will determine the correct procedure to use.
Click to expand...

Most of the time, there is a location on the back side of plastic panels identifying the type of plastic they are made of. Look for two or three letters that abbreviate a type of plastic. Example: ABS, PP, etc..
 
I can't seem to find any letters on any of the plastic bits.
 
shave off a hair of a sliver and see if it floats in water.
 
Great idea. Reading elsewhere, I see Polypropylene and Polyethylene float but ABS and PVC do not. How does this effect the patching? Will I epoxy first regardless? If so, it would seem to me that the patching method would be irrelevant to the type of plastic. No?
 
If it floats it's a Thermoplastic polyolefin, if it sinks it's a Thermoset polyolefin. Being it's a 78' model I doubt it could be a polycarbonate. The type of plastic you have is weldable-which is best for large repairs but being they are only 3/8" holes you can do the repairs with two-component repair materials. There's a lot of them available from Fusor, 3M, SEM, and many others. You'll want to taper them holes back to increase the surface area of the bond. SEM has a material that works for numerous problem plastics like most of these: http://www.semproducts.com/product-catalog/repair-materials/mini-max/
I've used this numerous times with good results: http://www.semproducts.com/product-catalog/repair-materials/dual-mix/fillers/problem-plastic-repair-material/
And this:http://www.lord.com/products-and-solutions/adhesives/automotive-repair-adhesives/product.xml/314

Wash well with SPI waterborne wax and grease remover then taper back the repair area at slow speed not to melt the plastic, sand the whole bond area by hand with 80 grit and clean again with SPI then follow the directions of the repair material manufacturer for application.
 
Thanks so much for the help! This sounds like its for doing before epoxy, I thought the SPI guys like to epoxy everything first.
 
JMO...If it was just a cosmetic repair there wouldn't be any issues with properly applying SPI epoxy and doing some fill work over it but with holes right through the plastic I'd want to plug it with a plastic repair material and have the hole tapered on both sides for some good surface area-trying to fill something like that with a polyester would probably show after some heat cycles-but maybe not, let us know!
 
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