I have recently repaired an older fairing that was cracked with some road rash using abs cement. So far my project is going good. I have the crack fixed and the hole filled but I'm trying to get this sanded to a smooth finish and touch up some of the more minor imperfections. The abs weld worked good for the repair but the cement does not sand out real smooth. Now that I have it welded back together what is a good sand able filler to fill in some of the minor imperfections and minor scratches? I've heard bondo does not adhere well to abs. What about fiberglass filler? Any suggestions?

 

There are fillers specifically for plastics go to an auto body supply store and they should be able to help you find the right product.

 

ok first off lets talk about the different types of plastic and how they can be repaired and the repairing process
there are 2 types of plastics made and used on cars and bikes as followed
tpo-tpe-teo-pp-abs and polyurathene
polyurathene is the only plastic that is a non offlien type plastic
the other plastics are offlien based which mean after the molding process the material used remains soft and greasy
a good example of abs plastic is used on saturns, the fenders, the doors skins and the quarter panles are all abs plastic
abs plastic is not meant to be repaired its a one time use once cracked once broken throw it away and buy a new one
but!!!
I have had some success in repairing abs plastic
before I go on lets just clear the air BONDO AND OR DURAGLASS OR A FIBERGLASS WITH RESIN WILL NOT AND DOES NOT STICK!!!!!!!!!!
NOW ABS IS A OFFLIEN BASED PLASTIC, and any offlien based plastic needs a adhesion promoter for anything to stick to it, if it is not applied the repair material will not stick!!!!!
so what you did kind sir has to come all off again, grind it off
cracks and or broken tabs should be lightly ground down on both sides of the plastic, and the crack v-grooved the side we all see then will be sanded down with 80 then cleaned off with a ammonia free plastic cleaner why?? any wax n grease remover even thinner will make the plastic soft and greasy why?? its offlien based
so I use ammonia free glass cleaner yes glass cleaner
now if the crack is hhuge I have a plastic staple gun It melts staple into the plastic and holding it in place, screw plastic welding that tool is payed its self back 10 fold
so then I use a reinforced mesh from the back side, then after the adheshion promoter has dried I use panel bond on both sides, panel bond is the only material that will stick to abs plastic
panel bond is used to bond 2 pieces of metal together but it has more uses then just mating panel together, and it sticks and bonds to plastic,smc,carbon fiber,fiberglass, aluminum all types of steel as well
now panel bond has to cure for 24 hours no more no less
one its dry sand it down with 80 then 120, 180
now it seems easy but its not the stuff you need it costly and then technique is easy for me but not meant for the novice,
the gun for the glue is 70 bucks sometimes more the panel bond is 40 bucks, sand paper is 30 bucks a roll the plastic staple gun I have cost me 400 bucks
anyways........
that's the process that I use on abs plastic and all ooflien based plastic