filler not adhearing to door panel

ok ive ran into my first big issue with this. My filler is "lifting" off the door panel in some spots. door panel consists of vinyl and plastic (as all door panels do). what can i do to get it to adhere better and not lift? sand the plastic/vinyl in those areas better and add more filler over the problem spots and hope it all adheres?

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Hustle, Loyalty, Respect

One way is to really rough sand the area, so the vinal is very rough. Also if you drill small holes all through it and pack the bondo into the holes and smoth it out on the back it acts as rivits almost.

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ERIC ANDERSON-NOSREDNA CIRE

Heat  some staples red hot and sink them into the plastic, secure the staples on the backside of the doorpanel with some CA glue, this gives the bondo something to adhere to on the front side. On larger surfaces that might have deep bondo areas, run some 1/2" screws through the panel from the backside.

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Top Secret, I can tell you but then my wife will kill me.

and then just bondo over the screws? or grind the ends off when its cured..what would i use to grind it off with? also, i have some excess fiberglass that i need to cut off of the panel, i have cutting disks and was wondering if there was an attachment i could get for my drill that i could use my disks for.

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Hustle, Loyalty, Respect

primal impulse wrote:

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and then just bondo over the screws? or grind the ends off when its cured..what would i use to grind it off with? also, i have some excess fiberglass that i need to cut off of the panel, i have cutting disks and was wondering if there was an attachment i could get for my drill that i could use my disks for.

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If you are working and trying to save what you have already find some spots to where you can drill some 1/8" holes from the backside of the door panel through it and into the part on the frontside. Then come back with a slightly larger drill bit to enlarge just the holes in the door panel. This way when the screws are run in they will pull the part on the frontside down tight. I would also concentrate making the holes and adding screws where it has come apart. Once you have it drilled and ready really rough up both mating surfaces and then mix up some tiger hair or bondoglass and while holding the pieces apart put some of that in between the two and then come back before it kicks and tighten the screws and let the excess ooze out. Once it's cured sand the excess off but leave the screws in place.

I too have just drilled holes to let the excess filler ooze through the holes but I also try and add countersunk area on the backside to where it locks it in more solid than just an even through hole. I've also added too screws poking outward from the backside while fabricating and if it's a removable panel remove it and then come back and enlarge the holes in the panel it's attached to so later when it's wrapped it can be pulled back down tight. 

Jim  

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1968 Chevy II Nova Garage Find 2012
1973 Nova Custom
1974 Spirit of America Nova
1973 Nova Pro-Street

The number one way to rid yourself of this problem is to remove the vinyl. underneath or if you look at the backside you can see that door panels are made of a form of mdf wood.

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I AM THE END