• Advertisement
 

filling with polystyrene or melted bumper

Anything goes in the world of fiberglass and plastic



Non-Lurker
Posts: 7
Joined: Mon Jul 16, 2012 8:42 am

Country:
USA
PostPosted: Mon Jul 16, 2012 8:49 am
I wonder how important it is to know exactly the type of plastic my car bumper has to be in order to fill cracks by melting a used bumper or placing polystyrene foam into acetone to produce the filler.

User avatar

Fully Engaged
Posts: 129
Joined: Sun Jan 02, 2011 5:01 pm
PostPosted: Tue Jul 17, 2012 10:38 am
if it is a rigid bumper basically its can not be welded with a high return of success you need a soft bumper best was to tell is to either cut a chunk off and throw in a bucket of water if it floats go for it if it sinks buy a new one.... also if you take a grinder to it and it smears instead of sanding you can fill it.... if it sands move on.....
MissouriPaintSlinger

Do it right the first time.
Enjoy it for twice as long



Non-Lurker
Posts: 7
Joined: Mon Jul 16, 2012 8:42 am

Country:
USA
PostPosted: Tue Jul 17, 2012 11:02 am
So you're saying if the bumper is soft the polystyrene will work..? Is what I'm planning to do actually called a weld? I didn't think so since I'm not melting the bumper.

My mechanical plan is to drill holes on either side of the crack, apply mesh, then pour filler over all, basically.

User avatar

Site Admin
Posts: 1912
Joined: Tue Jun 17, 2003 3:02 am
Location: New York
Country:
USA
PostPosted: Tue Jul 17, 2012 12:54 pm
If just cracks needing repair, why not use one of the 3M two-part epoxy repair kits? If you are really filling a big hole or have a chunk missing then find a replacement in a salvage yard...



Non-Lurker
Posts: 7
Joined: Mon Jul 16, 2012 8:42 am

Country:
USA
PostPosted: Tue Jul 17, 2012 1:43 pm
3M too expensive.

User avatar

No Turning Back
Posts: 599
Joined: Fri Feb 11, 2011 3:49 pm
Location: England
Country:
United Kingdom
PostPosted: Tue Jul 17, 2012 3:12 pm
I repair hard plastic bumpers on a regular basis by 'welding' with a soldering iron.
Haven't had any come backs so far



Non-Lurker
Posts: 7
Joined: Mon Jul 16, 2012 8:42 am

Country:
USA
PostPosted: Tue Jul 17, 2012 4:07 pm
Daz_England What steps do you follow for welding hard plastic? I have cracks with severe separation.

User avatar

Fully Engaged
Posts: 129
Joined: Sun Jan 02, 2011 5:01 pm
PostPosted: Wed Jul 18, 2012 9:53 am
Daz_England wrote:I repair hard plastic bumpers on a regular basis by 'welding' with a soldering iron.
Haven't had any come backs so far




probally looked good after it was done but down the road if a basketball hits it in the driveway or you drop a bag on it the chances of crack back occuring is high in my opinion cause the bumper has no stretch to it if it's a rigid bumper. since i do not enjoy doing things 4 or 5 times i would get a bumper featheredge some rockchips prime it and paint and then roll on. but to each their own. I've tried everythign from cross drilling and stiching damage back with welding wire to hold it then slowly filling each end to build stability to just notching and smearing.... it all seems to come back the same way ....

In school I remember actually a week of what bumpers to repair and what bumpers not too, they gave us several ways to tell, ie sand and smear, or chunk in water if it floats, the color smoke it puts off...... also a works to tell you if you need to use a adhesion promotor on the bumper.
MissouriPaintSlinger

Do it right the first time.
Enjoy it for twice as long



Non-Lurker
Posts: 7
Joined: Mon Jul 16, 2012 8:42 am

Country:
USA
PostPosted: Wed Jul 18, 2012 10:34 am
Missouri may be right. But my timeline for my used car only 3 years.. then I get another. Damage is on the bottom half of front bumper. I'm 58. I have never damaged a bumper in my entire life. My daughter showed me how, about 3 mos ago, with MY car. I will test for hardness, whatever, soon. If it's hard I will drill holes on either side of cracks, melt a metal screen into it, and apply a filler I have not yet determined. The screen should do the dirty work. If rigidity is my only problem I'll take my chances.

I'm more worried about adhesion, and I can not spend $38 or more for a 2-part canister because I anticipate screwing up and doing over, and anyway it's a lot of small projects in this deal. Probably need 2-3 canisters. Plus all the other sprays and baloney they sell with it. I may buy an exact model-matched used bumper for $50 and melt it down, needing only touch-up painting afterwards. This would give me a heck of a lot of filler.

She ran over a pipe in the road. No the car's clearance is NOT 3 feet.

User avatar

No Turning Back
Posts: 599
Joined: Fri Feb 11, 2011 3:49 pm
Location: England
Country:
United Kingdom
PostPosted: Wed Jul 18, 2012 2:20 pm
Here's a general guide to how I repair a crack in a plastic bumper cover.

D/A the affected are with 80's....don't go too far into the surrounding area as 80's cuts up the plastic to much
Align the sides of the crack so they butt up,a bit of force or prising with a blade or small screwdriver may be needed
Weld with soldering iron,adding extra plastic where needed.....I save off cuts of old bumpers which I cut down into thin strips to act as filler rods
D/A any high spots
Layer of bridging filler then onto body filler and primer
If I have access to the rear I will roughen with 80 grit paper and use bridging filler to reinforce.

Like I said I haven't had any come backs andI've done hundreds this way.
Of course if you run into something after I've repaired it and it cracks again that's hardly my fault is it :splat:

Return to Fiberglass and Plastic

Who is online

Users browsing this forum: No registered users and 7 guests