Sanding epoxy primer prior to body fill - Moparts Forums

Register Log In Moparts Forums Moparts Question and Answer Sanding epoxy primer prior to body fill

Print Thread

Sanding epoxy primer prior to body fill #1080758 09/23/11 09:30 AM 09/23/11 09:30 AM
Joined: Oct 2004 Posts: 330 Frederiction. New Brunswick ,C... R RTshaker OP enthusiast
RTshaker OP enthusiast R Joined: Oct 2004 Posts: 330 Frederiction. New Brunswick ,C...	I have an epoxy primer that has been on the car a month plus. What grit should if be sanded with ,for adhesion of a thin shim of filler? What about areas being topped with HB urethane surfacer ?Doesn`t state in the manufactures info. sheet.

Re: Sanding epoxy primer prior to body fill [Re: RTshaker] #1080759 09/23/11 09:38 AM 09/23/11 09:38 AM
Joined: May 2011 Posts: 340 Alaska 7 73rrak enthusiast
73rrak enthusiast 7 Joined: May 2011 Posts: 340 Alaska	I always sand the epoxy off with 80 grit paper ( on a D/A ) and put my filler on bare metal then epoxy over the repair when it's done. If you call the tech # on the filler can I'm sure they will tell you the same thing.

Re: Sanding epoxy primer prior to body fill [Re: 73rrak] #1080760 09/23/11 10:40 AM 09/23/11 10:40 AM
Joined: Dec 2007 Posts: 18,157 Mass DAYCLONA I Live Here
DAYCLONA I Live Here Joined: Dec 2007 Posts: 18,157 Mass	Quote: I always sand the epoxy off with 80 grit paper ( on a D/A ) and put my filler on bare metal then epoxy over the repair when it's done. If you call the tech # on the filler can I'm sure they will tell you the same thing. ....Most fillers/puttys/etc are polyester based, and don't adhere well to epoxy pased products, primer included, where as epoxy will bond to cured polyester, so do the filler work(bondo) on bare metal, then Epoxy coat/primer Mike

Re: Sanding epoxy primer prior to body fill [Re: DAYCLONA] #1080761 09/23/11 10:59 AM 09/23/11 10:59 AM
Joined: Oct 2004 Posts: 330 Frederiction. New Brunswick ,C... R RTshaker OP enthusiast
RTshaker OP enthusiast R Joined: Oct 2004 Posts: 330 Frederiction. New Brunswick ,C...	I`m confused now..I had always used the plastic over bare metal but I thought/heard .. NOW the idea was epoxy on metal then body filler work ,epoxy again then HB and blocking ????

Re: Sanding epoxy primer prior to body fill [Re: 73rrak] #1080762 09/23/11 11:47 AM 09/23/11 11:47 AM
Joined: Jan 2007 Posts: 1,039 Redwood City Ca. B B1arno super stock
B1arno super stock B Joined: Jan 2007 Posts: 1,039 Redwood City Ca.	Quote: I always sand the epoxy off with 80 grit paper ( on a D/A ) and put my filler on bare metal then epoxy over the repair when it's done. If you call the tech # on the filler can I'm sure they will tell you the same thing.

Re: Sanding epoxy primer prior to body fill [Re: RTshaker] #1080763 09/23/11 01:07 PM 09/23/11 01:07 PM
Joined: May 2011 Posts: 340 Alaska 7 73rrak enthusiast
73rrak enthusiast 7 Joined: May 2011 Posts: 340 Alaska	Most people I've talked to epoxy the whole bare metal car then sand off the epoxy in just the areas that need filler then epoxy over the repaired filled areas then hi build. I use Featherfill G2 which is a polyester based primer same as filler (Bondo) and I put it on top of my epoxy and never had any problems.

Re: Sanding epoxy primer prior to body fill [Re: 73rrak] #1080764 09/23/11 10:38 PM 09/23/11 10:38 PM
Joined: Jan 2003 Posts: 8,499 Candler,NC / Myrtle Beach, SC J JDMopar master
JDMopar master J Joined: Jan 2003 Posts: 8,499 Candler,NC / Myrtle Beach, SC	I use PPG DP90LF over bare metal, then let it sit for a few weeks. I then scuff any areas that need filler with 120, but not back to the metal. Then apply and work the filler. Get it slick and then back over the filler with DP90LF. Then begins the K38 and blocking. I did my 71 GY3 Challenger using that process, and it looks as good today as it did 5 years ago when it was painted. No lifting,shrinking or any other problems.

Re: Sanding epoxy primer prior to body fill [Re: JDMopar] #1080765 09/23/11 11:20 PM 09/23/11 11:20 PM
Joined: Aug 2003 Posts: 2,506 Northern Pa G GLR master
GLR master G Joined: Aug 2003 Posts: 2,506 Northern Pa	I have used PPG's epoxy for years...I apply the epoxy over top of the bare steel...let dry for at least 24 hrs and scuff sand with a scuff pad well, clean with cleaner and apply fillers over top of the epoxy. I have been doing it that way for 30+ years..no problems ever and I have also had to repair accident damage after 10 years after the car was restored and the adheasion was great, no rust under any of the filler work either and the owner drove the car a lot, he put 88,000 miles on it since the restoration and it was always outside on nice days all day long in a parking lot.

Re: Sanding epoxy primer prior to body fill [Re: GLR] #1080766 09/24/11 02:51 AM 09/24/11 02:51 AM
Joined: Feb 2003 Posts: 21,318 Manitoba, Canada DaytonaTurbo Too Many Posts
DaytonaTurbo Too Many Posts Joined: Feb 2003 Posts: 21,318 Manitoba, Canada	I always thought putting the epoxy under your filler was supposed to do a better job at complete keeping any moisture away from your metal because the filler can absorb moisture.

Re: Sanding epoxy primer prior to body fill [Re: DaytonaTurbo] #1080767 09/24/11 04:01 AM 09/24/11 04:01 AM
Joined: Jan 2010 Posts: 27 N newem member
newem member N Joined: Jan 2010 Posts: 27	Quote: I always thought putting the epoxy under your filler was supposed to do a better job at complete keeping any moisture away from your metal because the filler can absorb moisture. Seems from all the positive testimonies out there that either method works out alright. The guy that taught me has been a bodyman for 35 years and he prefers to put the filler on bare steel.

Re: Sanding epoxy primer prior to body fill [Re: newem] #1080768 09/24/11 09:16 AM 09/24/11 09:16 AM
Joined: Dec 2008 Posts: 16 North Carolina P pullinpw member
pullinpw member P Joined: Dec 2008 Posts: 16 North Carolina	If your epoxy has chromate in it then dont put body filler over it, otherwise put it over it. Just scuff it with 180 grit,and use a quality body filler.

Re: Sanding epoxy primer prior to body fill [Re: GLR] #1080769 09/24/11 10:21 AM 09/24/11 10:21 AM
Joined: Jan 2003 Posts: 8,499 Candler,NC / Myrtle Beach, SC J JDMopar master
JDMopar master J Joined: Jan 2003 Posts: 8,499 Candler,NC / Myrtle Beach, SC	Quote: I have used PPG's epoxy for years...I apply the epoxy over top of the bare steel...let dry for at least 24 hrs and scuff sand with a scuff pad well, clean with cleaner and apply fillers over top of the epoxy. I have been doing it that way for 30+ years..no problems ever and I have also had to repair accident damage after 10 years after the car was restored and the adheasion was great, no rust under any of the filler work either and the owner drove the car a lot, he put 88,000 miles on it since the restoration and it was always outside on nice days all day long in a parking lot. You and I do it the same way.....but you explained it better than I did.

Re: Sanding epoxy primer prior to body fill [Re: RTshaker] #1080770 09/30/11 11:16 AM 09/30/11 11:16 AM
Joined: May 2003 Posts: 961 . T TMP66 super stock
TMP66 super stock T Joined: May 2003 Posts: 961 .	I never was a fan of filler over anything but bare metal. This is a post from another website that confirms my thoughts on the subject... OK--Here's the gospel on body filler/bondo over primer. I used to work as a technical/sales rep for the company that makes rage filler. I know the guys (chemists) that developed the resin for rage filler. I've been a bodyman/painter,sales rep and technical rep for 30 years. The resin in rage and other body fillers is fiberglass (polyester) resin. Today's resin technology makes the adhesion of these new resins as good or better than most epoxy adhesives (glue). They are designed to really stick! Also they are somewhat flexible when used properly. Most or probably all filler manufacturers design and reccommend them to be used over clean and prepped (grinding with course-36 grit) and rust free (sandblasted)and dry (free from moisture) BARE metal . They will stick to epoxy primers with mechanical adhesion-they DO NOT chemically bond with epoxies. If you put filler over epoxy primer it has to be fully cured with no solvents (thinner-reducer) left in the primer and still should be sanded with a course grit and cleaned. In other words- It's a wasted step that may or may not cause adhesion problems later on. Most critical is to be clean and moisture free. Body filler resin is a thermal set plastic-it cures with heat.

Moderated by Al_Alguire, Hotwheelsjr, moparts, not_a_charger, RangerDan440, tboomer

Hop To

Powered by UBB.threads™ PHP Forum Software 7.7.1