I've been working on the body of my 95 dx for a while now, just a simple project that has turned into a big hassle. The passenger rear quarter panel was caved in. So i decided to pull it and fill with bondo. i've got the majority of it filled, now, but i can't get the body line right below the rear window. any ideas on how to catch the body line? AND i have rust around the edges of the bondo. i've sanded and sanded till my arms almost fell off. but i can't get in the ridges of the metal. how do i get the rust out so i can primer and get ready for paint? thanks....

 

sand blasting or an electric sander works wonders on getting the rust out.. as far as forming a body line with bondo, this is a fine art but the general way i have done it in the past was to apply way more bondo than needed and sand it down until i get the body line i want.

I generally follow from one point to another and if your new to it, try drawing it with a ruler and magic marker to create a false line to follow.

 

the tools can also be the key. look into the proper sanding block, im sure you arent doing it with your hand but they sell such things that work better than others for certain parts of the car

 

im in to get details too, because im probably about to venture this route of self body work with bondo to fix some body damage i have.

thanks for the input fellas! This is a great board!

 

Thanks guys, i'm going to go with applying more bondo then needed. i've tried an electric sander to get the rust out, but it can't get in the grooves that i made when i grinded the metal for the bondo to stick better (the body shop i took it to suggested this idea).

 

*after i wrote all of this i discovered this: https://honda-tech.com/forums/paint-body-84/everything-you-need-know-about-autobody-repair-1962364/ *

quick body work tutorial since someone said they were in it to learn for a project they were starting.

Please feel free to edit or modify as needed. These are my own experiences from doing my Trans Am. (I will start working on my Del Sol once I get the front end repaired.

Step one is surface prep.

Some find it easier to work on the car and other find it easier to work with the panel on a work bench (which ever provides you comforter while working) you will be in what ever position for a while.

Define the surface area you want to work on (is it surface rust or is the rust actually though the metal in certain spots?)

if it is just surface rust then sanding will be needed, if it is through the metal anywhere you will need to take it to a body shop to have a patch panel welded into place.

outline the defined area you will need to work making sure to give yourself between 1 and 3 inches of extra space

sand the entire area with rough grit sand paper (I use 80 grit but there may be a better one) you have to cut through the entire clear coat, paint, and primer. The metal should be a scored shiny metal if it is dull anywhere then you are at primer only and need to sand more.

once through all the paint layer you need to treat the metal with some type of rust removing agent. (I went out and purchased a sand plaster in order to remove the paint and rust at the same time) there are chemical treatments but I cannot vouch for any of their quality.

Once down to bare metal and the rust is removed completely it is time to start applying bondo (follow the instructions for mixing on the box/can)

I genearlly mix on to a 4-6 inch piece of cardboard square so i can hold it in my hand and only apply enough bondo for a 3-6 inch square at a time. you should apply one layer of bondo over the working surface leaving about .5-1 inch away from any other paint that is still on the car.

let the first layer dry and then apply a second (make sure you pack the bondo tightly so as to remove any bubbles that maybe in it.) this is very important to remove these bubbles as you go along because if you don't it will leave huge marks in your finish before you start painting.

I have heard of people sanding the surface to give it a rougher texture for the next layer to stick to (i would think this would require drying the first layer of bondo and that doesn't make sense to me) (i have never found this to be true and tends to actually cause bondo to chip over time)

make sure you do not let the previous layer dry completely before applying the second layer (if you do the second layer will just come off) it should instead be a tacky surface to work from.

upon completing the layers of bondo you need to let it dry

Your car or panel should be located indoors in a humidity controlled environment to allow drying to avoid any other exposed metal from rusting. Your bondo should also rise above the surface of the regular metal you are trying to match it up to because you will be sanding to try to get it to become one flat smooth surface.

upon completion of the drying (i generally wait 48 hours before I ever touch something recently bondoed) you are going to begin the sanding process. I recommend that you do this part by hand as to avoid any mistakes. I warn in advance that you will be doing many many hours of sanding because this is where the art of body work comes from. The objective of the sanding process is to have the entire bondo section be smooth with the rest of the metal that has been sanded to. if you run your hand over the entire section of metal and feel the bondo as a raised section or not smooth in any way you are not finished. If you have a few bubbles pop up or if you go down too far don't fret ( you can always reapply a thin layer on top of the dried bondo) when doing this make sure the surface you apply the bondo to is a rough scored surface so it has something to stick to.

upon completing the sanding process your arms will be tired and you will have one smooth surface to work with. If you find that there isn't at least an inch of buffer zone between the bondo and the paint this would be a good time to create it. you need that inch to help blend the paint together with the new paint you will be applying.

upon completing the surface and the scoring of the original paint you have two options. You can either pain the section of bondo or you can paint the entire body panel/car. If you go with painting the entire car that is a whole different subject and I think there are some body forums on here somewhere for that.

If you want to just paint the patched piece then you need to prime it with some type of primmer (generally I use a flat grey primer because it is sold almost anywhere)

After a coat or two for coverage of primer you should sand that down lightly with a mid grade sand paper for scoring and to smooth out any deficient surfaces. (I generally use around a 200-500 grit sand paper here) (this whole process should be done by hand, electric sanders are too harsh and will mess up all of your hard work up to this point)

After the layer of primer you should spray a layer of touch up paint (most auto stores carry spray cans of touch up paint) it is important to go slow and let it go on smoothly this will take a few layers ( my minimum has always been 3 layers of touch up paint)

After the touch up paint dries you should apply some clear coat (i believe the standard is 1 or 2 coats of clear coat) If you want a show quality finish they use a lot more clear coat that gives it that glassy look but be warned that the paint will chip a lot more often, the general happy middle ground is something like 2 or 3 coats.

upon completing this step you need to let the clear coat completely dry (another 24-48 hours here)

once the clear coat is dry you can either buff or wet sand the part down

wet sanding is done with extremely high grit sand paper above 1000 grit and a copious amount of water (the easiest way is with a hose flowing over the surface) go very slow in this process because you are removing the clear coat you just applied. use a softish touch (don't put your body weight into it) and start from the sides and move in one direction.

you will know when you are finished because the original paint and the bondoed section should be almost unnoticeable to the touch and should be extremely smooth.

I will give you a warning that the paint may not match 100% because the sun will have bleached the previous paint slightly if this is a major concern I would recommend sanding and painting the entire piece or the entire car once the bondo is where you want it. The choice as always is 100% yours.

Go slow and use a steady hand and the entire process should take about a week if done right. If you rush something will not work somewhere and will create issues.

(this is my personal experiences and I am not a professional body man, if a professional would like to step in and edit my tutorial please feel free)

I hope this answered a few questions

 

i've sanded and sanded till my arms almost fell off.


lol i have had that happen many times

 

as far as the body line is concerned i use masking tape to mark one side of the body line and i sand on the other side of the tape (block sanding) then when i get a good line. i will switch the tap to the other side of the body line and sand on the other side till i get a good line. then go back over and touch it all up.