Hot Rod Forum : Hotrodders Bulletin Board - Reply to Topic -- Hot Rod Forum

Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans Advertise
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Body - Exterior> Trying to understand filler work
User Name
lost password?   |   register now

Thread: Trying to understand filler work Reply to Thread
Send Trackbacks to (Separate multiple URLs with spaces) :

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:


Additional Options
Miscellaneous Options

Topic Review (Newest First)
04-23-2014 02:48 AM
glhx Well I did it again. I scuffed my new bumpers with a red scotch Brite pad. Was going to put a coat of epoxy primer on there as it had some cheap gray primer on there.

I barely went through in some spots and knew the primer was thin...Not a big deal. The epoxy would have stuck fine to it because it was barely through..just transparent. So I break out the dx103 for cleaning plastic parts. It smeared the primer and broke through in large spots. AFTER reading the tech sheet on dx103....I read that it is not to be used on primer. After cleaning what was left with jx101 I noticed the static coming through the primer......which is why I didn't want to use it the first time

Now that I have this mess, how can I prepare this bumper for a coat or 2 of epoxy primer.

I could sand it all off and scuff the tight areas.....or just use the dx103 and wipe it off

what grit do I sand this with?
Should I take the rest of the primer off?
Can I use regular wax and grease remover? What a mess....but I'm glad it's just the bumper this time.
Plastic paint aircraft stripper.....this primer is so thin it would take it right off

Also.....can I use a regular spi urethane reducer and clear coat activator in my
dupont chromabase when spraying a solid color?

Using a devilbiss finishline4 with 1.3 tip to spray base and either sealer
,,,,,,lor another coat of epoxy with a 1.5 tip.....what settings should I use?
Using the sata jet 90 conventional for the clear.....settings on this? 1.4 tip
04-15-2014 12:50 AM
glhx I ended up using both epoxy and high build. I didn't have enough of either to do two good coats so I did a coat of epoxy and topped that 4 hours later with a coat of high build I had left. Now I'm almost out of primer....just enough epoxy left to do some patch work if that happens.

The instructions on gun set up helped a lot. I got almost no orange peel in the epoxy and very little in the high build. This should be the last time i prime the car. I noticed that when I tack ragged often it eliminated a lot of texture. The high build and epoxy over sprayed a lot. I tack ragged after doing 4 panels.

I noticed with the black epoxy.....the way it sands and turns a white-ish color.
When you don't change the sand paper often or clean it often......the dust or grit can make deeper scratches. Is this why you wet sand the primer for the finish continually clean the primer and make an even scratch?

The black epoxy also shows any deeper than normal scratches. When it goes on it looks like a shiny black....cleared car...then after a while dries flat black. While it's shiny you can see as if you painted your car black. You can also see your reflection and eliminate using wax and grease remover for checking straightness and waves. I've never used black primer before...obviously.

And now that it's primed and the 180 scratches are filled. Can I just start off with 400 wet or even 600 wet. There's still some orange peel in there....some of its heavy but not too many spots.

I also noticed the high build sands much better after several hours than if I wait a week. About what time frame does it get harder to sand? I wish I could sand it tomorrow but I have to wait 5 days.
04-07-2014 09:56 PM
glhx In looking at how much orange peel and runs I got in the high build.......I was going to block all this out with 180 to get it straight.

I was them going to bury the 180 scratches with another coat and sand that with 320 or 400.

But what happens if that last coat goes on uneven or dry or runny..Then sanding with 320 will smooth it back out but it won't cut out any new build waves. I'm not good enough at spraying to get it perfect spraying 1 coat... I will probably have to cut that coat wih 180 as well. I have 2 coats on there now which the can says will give me 3 mills. It's got orange peel and runs but it went on fairly uniform.......not like last time where it barely went on at all. I will say this about the build. At this point with 2 coats I've got half a gallon of high build on there.

How can I keep it straight after block sanding with 180.
04-07-2014 01:50 PM
glhx I think he's saying they used to use resin before polyester putties.

Fiberglass is strong stuff......I just used polyester
The skim coat is glazing putty which is like a thinner easier to sand version of polyester filler. Still builds well though.
04-07-2014 01:42 PM
glhx I tried the new gun out.
The primer sprayed texture dry like the last time. I shot some on paper to get the pattern right. Read the specs on the gun.....all the adjustments were right

I tried 23psi as recommended by a painter....and 30 as recommended by devilbiss. Fan was all the way out and fluid was almost all the way out. I only had 8 ounces left in the can. The can was 4 or 5 years old.

Checked distance 6-8" and angle as well as speed. Nothing worked.....I sprayed a door panel to test it more and see if I could get it right. If I didn't get it right I was going to stop there. It sprayed texture dry.

I went to the store and bought more primer. Still used marhyde.....would have liked to switch to something else but I had it on there and figured I might as well finish with


The primer was too old or feathered and sanded fine but would not lay down smooth. New primer layed smooth

I over compensated for the dry pattern and had to relearn the gun.....needless to say I got some big runs and a lot of orange peel. By the time I was done I was getting very little. I think I like the orange peel better than the dry sand paper texture.

Here's the dry sprayed door. I went back over it with the new stuff

Here's the worst run I got
I was learning the distance and I wasn't relaxed

Here's where the filler went. That's just one coat on there. All the advice paid off.

I did get some dry spots because of moving too fast......and runs from being too close.

the nooks and tight areas in this tail light housing. Can I just hit that with a red scotch Brite pad if I'm going to top coat it with more 2k just so if anything does get in there like overspray it will still stick?

What sort of coating is this and how do I prep it for epoxy sealer?
04-07-2014 01:25 PM
Originally Posted by MARTINSR View Post
Ok, here is a "Basics of Basics" on filler work that others have found useful.

Bondo Basics - Autobodystore

Something not mentioned in the "Basics" I don't remember but I don't think so is how you need to remove the paint back aways from the filler work. And of course you don't know how far sometimes when you start but lets just say it's most always further than you think. You want the paint removed back away from your work so when you feel the filler you aren't having to figure out what is filler and what is paint. Because YES just the thickness of the paint can be felt and it can be confusing.

But print out that "Basics" and sit down on the couch and read it a few times. And clean up your spreader with a thinner soaked rag when you get done.

I have a question on something mentioned in the article linked here on final skim coats. About 2/3rds of the way down the page it says:

"You can add fiberglass resin(“A” coat if you have a choice) adding the resin was exactly how I learned from the great Emery Robinson (my personal hero in the auto body world). But remember there was no products like polyester putties back then. When you add resin, that resin comes to the top of the film of filler. It is then something you have to deal with. The whole purpose of the SKIM COAT is to put a layer offiller over the top that is easy to block out with as little effort as possible. You want to be able to concentrate on making the panel FLAT not fighting with gummy resin, sand scratches and the like. "

He seems to advise against it but is he saying it is possible to use fiberglass resin to thin bondo as a final skim coat? If not is it possible to thin duraglass with a little resin to do the job?
04-06-2014 11:58 AM
glhx I painted a motorcycle......paint job came out great. Lots of research. Nailed it first time out. Made no equipment failures......

And I didn't learn a damn thing. Success truly is a poor teacher.
This car has been nothing but mistakes.

And I'm not even out of the blocking stage yet
04-06-2014 11:23 AM
glhx Anyway.....what I was intending on posting was something else that is a problem. I've danced with this before but it wasn't addressed well enough for me to understand. A mistake I made a while back.

I shot the high build very dry.......and ended up with this texture all over the car.
I then put dry guide coat on it. I used a 1.4 tip and didn't reduce it. Use a 1.8. Tip....the spot that is circled comes from compressed air being shot over the dry primer. That spot is deep and the compressed air basically blew that hole into the primer. The hole was not there before I shot air into it. I sanded and sanded.....but it would not go away.

"Keep in mind.....from my understanding......if I point my big toe north, wink 5 times and jump up and down on one foot while chanting to the paint gods. The paint might stick "'s said that paintin dry like that you might have adhesion problems.....see above quote.

And if you sand on it and it feathers out it should be fine. So here's what it looks like.
Is this feathering properly? I think so but I don't know and while is make mistakes I don't like to take chances on this.
Look closely. You can see the texture with dry guide coat. I have a problem just primering over this with a fresh nicely layed out coat. I don't want adhesion problems and I don't want shrinking problems......and by the way. How long does it take to shrink anyway. And will it sink Ito that texture? I really want to know.

Problem 2
When taking all that texture out......which I did with a da and 120...I noticed a very faint solvent smell. Not a wet solvent smell. Just a faint on in the places where I broke through the high build into the epoxy. The epoxy was sprayed on with metal temp 80 and let sit for 5 hours before the high build was sprayed on top of it. I was told by the manufacturer that this was ok and I actually needed 4 hours. I left the heat at 80 for and other 12 hours and left. He told me that epoxy takes a while to dry. I can see that and I don't think it's a problem. But.....if the epoxy wasnt dry after a month under there. How will it ever. How will the solvents escape with a coat of high build on top of them? Every place I broke thru I got a faint smell. Most of that high build was taken off anyway because of the problem above. Can epoxy dry under that high build. I should have waited 12 hours like the can said....but.....the guy said I could do it in 4 hours and he puts that on the can for people who don't keep their shop at 80 with a high metal temp.....I turned my heat to 90. Once the post is exposed the smell takes a while but it does go away.

With these products. Explain this to me. Let's say I paint a spot that's 6" .....and I have a spot that's 2" with solvent there.
Will the solvent escape in the area surrounding the 2" or do I have to expose the 2" to get the solvent to escape. If that's the case I should take all that high build off of there. Am I over thinking this.......NO. There isn't such a thing in body work. If you have a guy teaching you hands on then maybe. Of you don't know what the result is going to give might wake up wih a shrunk trashed paint job because of the questions you forgot to ask or the questions you didn't ask because the other guy calls you an idiot because you should know. I'm trying to figure out how much extra work I should put into fixing my mistake.....

Problem 3
Durablock vs rigid block.
I talked of the texture I had above. The texture was hidden by sand dust. The sand dust filled in the texture and the whole thing looked smooth and done. I had the whole car blocked before I found out. It took some good air pressure to expose it. When block sanding with the durablock I noticed it seemed to sand uneven or maybe it didn't.
At this point all that high build is gone anyway. I took a da to it
The area built up un the middle of the trunk is low. I know that for a fact.
I blocked it to that point. The sides of the trunk are flat like the middle. The durablock would get rid of the low spots that showed up on the sides of the trunk. The rigid block took them right out.
With the durablock......I could hit metal and the low spot still wasn't gone. With the rigid block it was gone right away. This happened on multiple panels. My doors were fairly straight.....but I had a build up of hight build in the middle of the door. Again I could go down to metal in other spots and the middle of the door would be still built up......take a rigid block to it and the middle disappeared without the rest going to metal.......

It's like the durablock won't block but the rigid block will. And keep in mind.....I'm only testing both out on flat spots. The rigid block cuts the center of a curve and not the rest if you don't follow the panel. You've seen the cAr....can I use a rigid block on the car or stick with durablock. How I caught this was......I was going to put more high build on there anyway and I wanted tomes what happened. I took a paint stick and did an x pattern on a door wedge that wouldn't flatten. The paint stick knocked the spot right out.....and it didn't follow the low spot. It cut through and made it flat. I still had a bunch of high build in that spot. So I took a 11" hard block to it after guide coat and sure was flat. The durablock was going to metal before that spot would have been flat. I re did the door with the rigid block. It wasn't going to metal and was cutting through everything. Am I using the durablock wrong. I'm letting the sand paper do the work.....I'm using light pressure
........even when I took the da to it to get rid of what I thought was bad high build it seemed to cut off the high build and left the low spots.....I sanded it with light pressure in an x pattern. I was going to redo the high build anyway with 3 good coats. And spend a a lot more time adjusting the gun.

For those who are new and reading this after my car is done and the mistakes are behind me.....spend more time learning how to adjust your gun. At this point i still haven't messed with it. It's a new gun and I've never shot primer out of an Hvlp. I don't even know what good primer looks like. But after today I will. An hour adjusting the gun is better than sanding for 12. I would waste a gallon of high build.....go back and buy another gallon....waste another gallon and get it right before I sprayed a bad coat that I had to sand like this again. AND I DONT EVEN MIND SANDING. Some of you hate sanding.....I bought a devilbiss finishline 4. Only because I saw a lot of people on here use the finishline 3. Some switched to the sagola line and after seeing their you tube video on how well it sprayed primer....I wanted one too. But that was probably years of spraying primer and a well set up gun. I think he finishline will be fine.
04-06-2014 09:54 AM
glhx Dry guide coat.....wet guide coat......and it's epoxy with a shine to it that acts like guide coat. The guide coat is why I'm tripped up. I sand it all off. Or hit metal and stop.

The last time I sanded it off and found a low spot. I said,,,,,,how can that be low. I built it up too much for it to be low. Oh well, I'll just fill that spot with some glaze and it should be good. I waited a while and had a hard block in my hand. I thought.....with this ...or a soft flexible wet or dry pad I could feel much better what was going on instead of just trusting the guide coat and the durablock. I was surprised but it worked. I sanded it slowly by feel and put more epoxy on it. Then re guid coated it and it sanded smooth and even. I used the metal far away from the dent as a guide. I started 1 foot back where it was not messed up. Then hit a high spot. That's when in knew that .....the low spot I was going to fill in ......wasn't low. There was a mound of filler on there. Also keep in mind.
This isn't a flat panel by and means. It's not as compound as the other area on the sail panel but it's still not ideal. The sail panel was the same issue. And in a way. I tackled it the same way.

My whole car is a series of curves. There almost no flat panels on there. In those pictures. All of that is slightly curved and unless you get the durablocks curve and sand paper locked in It is useless, because even if you did get it locked in. The curve changes at the fender flare. This whole mess it's built into that fender flare. Only at the top is it even close to flat. And then you have 4" to work with before it compounds.

I picked one hell of a car to start this learning process. And it's going to be black.
Then I look over at the 69 dart with all of its flat smooth large panels panels with envy
04-06-2014 06:14 AM
Originally Posted by glhx View Post
I ended up filling that dent. It took me about.......don't laugh.....36 hours to get it right. I was block sanding with an 11" Block across the dent. It worked and it didn't.

I used glazing putty to finish it up. I've decided I like glazing putty a lot. It fills more than I thought and sands easy. It's like expensive evercoat rage.
What I learned about evercoat rage is that it has less pin holes than the evercoat gold......but the gold is thicker and fills better. So I'm sanding and sanding and applying and sanding over and over and over. Just couldn't get it right. I was messing around with a 4" rigid plastic block with some 180 on it. So I decided to slowly run it back and forth over the area. Usually I was going in an x pattern. Not this time. I noticed that if I paid close attention to the way the block felt as it ran over the high spots. I could feel the area become more perfect. I ran it back and forth......and I found I could sense more what was going on. Had i not stumbled on this. I would still be using the 11" durablock. Doing it like that worked. So that's fixed
are you using guidecoat, and if not, why not? Takes a lot of the guesswork out.
04-06-2014 05:24 AM
charchri4 Dam 50 bucks in durablocks and the old walmart 1/4 sheet block I have used for years is the way to go after all... Not laughing at 36 hours but understand it well! Glad it worked out for you after all.
04-06-2014 03:28 AM
glhx I ended up filling that dent. It took me about.......don't laugh.....36 hours to get it right. I was block sanding with an 11" Block across the dent. It worked and it didn't.

I used glazing putty to finish it up. I've decided I like glazing putty a lot. It fills more than I thought and sands easy. It's like expensive evercoat rage.
What I learned about evercoat rage is that it has less pin holes than the evercoat gold......but the gold is thicker and fills better. So I'm sanding and sanding and applying and sanding over and over and over. Just couldn't get it right. I was messing around with a 4" rigid plastic block with some 180 on it. So I decided to slowly run it back and forth over the area. Usually I was going in an x pattern. Not this time. I noticed that if I paid close attention to the way the block felt as it ran over the high spots. I could feel the area become more perfect. I ran it back and forth......and I found I could sense more what was going on. Had i not stumbled on this. I would still be using the 11" durablock. Doing it like that worked. So that's fixed
04-06-2014 03:09 AM
glhx Good.....maybe you will learn from the mistakes I made.....

And the mess I'm about to post that I've been fighting from doing something stupid.

See next post for said stupid mistake
04-04-2014 05:17 PM
charchri4 Subscribed - excellent thread guys!!! I'm going out right now to try what I learned here.
03-19-2014 06:34 PM
glhx In the first picture. The body line is above the ruler. The body line is perfect. I don't know how but it is. It seems as though whatever hit the car must not have hit very hard. But enough to either stretch the metal or mess with the body line on the fender flare.

It did mess up the fender flare slightly. It's not like a basketball was thrown at it. More like a baseball. It's hard to tell if the fender flare was damaged from something hitting it or the way it was prepared by the previous guy. Whoever did this car the way they was a body shop.....but doing this stuff every day for a living, not taking out the back window and welding down the quarter panel, not letting the primer or paint flash, not scuffing the original part properly, and using this much filler......I don't get it. The only reason I filled it is lack of knowledge. A pro could have this worked in way less time than it took to fill and perfect it with that much bondo.

They broke the back seat and did not put back in any insulation. Then spray painted the door panel to match.
This thread has more than 15 replies. Click here to review the whole thread.

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

All times are GMT -6. The time now is 08:18 AM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright 1999 - 2012. All Rights Reserved.