Bondo, filler wont stick to armor plastic

[THUNDERCAT]

Hi everyone

I have a bit of a problem, myself and a mate have been using bondo, high grade filler to cover the gaps in the armor. 

Nothing seems to stick to the plastic we try sanding and washing it down prior to applying Bondo and the Filler but still nothing sticks. 

Any advice please? 

First Attempt 

Second Attempt 

 

So far no luck.. any advice would be appreciated 

[spike]

use bondo made for plastic bumpers on cars, for extra grip, scuff plastic with  60-36grit grade, I use superglue/crazy glue on this then sprinkle plastic filings for extra grip, then apply your "bondo." to that surface, use 120 grit to finish off before primer

you should be able to the flexible bondo from an auto parts shop that sell parts, paints, oils, bit an pieces for cars, 

good luck

[greenyone]

Like Spike said.  They make body fillers specific to 'biting into' plastic (for urethane car bumpers etc..)  I've used UPOL 706 for actual auto body work.  Have not tried is on costume plastics though.  If you are just filling small cracks why not just use a tube of Tamiya or Squadron hobby putty?  Those are specifically made to bite into plastics also.

[THUNDERCAT]

Thanks everyone 

I'll try it out and post some updated pics 

[KOtrooper]

Can also try ABS slurry. Mix your scrap plastic (that you from the armor) and a little acetone in a glass jar. The acetone will melt the plastic and, if you have the right ratio, you'll get a thick goo. Use that to fill in the gaps. If the slurry is too thin - add more plastic. Too thick - add more acetone. 

I prefer a thickness you can brush on so you don't melt the armor itself.

[762s]

alot good tips above .. esp, the abs slurry ...

once the part is sanded with a real rough grit i use an all purpose bondo(its white w/white cream) ... i never used a flexible bondo or specialty bondo

i do use a bondo glazing putty to spread over the all purpose bondo to cover the tiny holes and scratches

looks like you may not have the mixture correct ... you could be using either to much hardener or not enough, or the plastic is not roughed/scratched up enough



 

[ferra]

On 4/18/2019 at 10:11 PM, 762s said:

looks like you may not have the mixture correct ... you could be using either to much hardener or not enough, or the plastic is not roughed/scratched up enough



 

My thoughts too...