Auto Bodywork experts

[Milquetoast]

Don't sand in between coats of primer. I won't be around on the weekend to answer questions so if you have to stop then at least primer what you have done before it goes outside (bare metal or bondo parts). I am not so sure you should expect to drive it that soon on your first try.

Also, when I say "sand to 220" i mean that you start with as rough of a sandpaper that you want and then go finer and finer until it is smooth with the 220 grit paper. If you are trying to rush, you better just sand it dry because primer needs a day or so to be really dry enough to wet sand. A scotch-brite pad can be substituted for the 400 paper.

By the way, like JP said it may just be alot easier to go to maaco and maybe even less expensive but that's just no fun if you ask me, and next time you can get even better by learning from your mistakes.

 

[JuliusPleaser]

Can you post some pics of the rust? If it's not too bad, you might be able to forego the Bondo. I have no idea what Canadian rust looks like. We don't get that stuff down here. Ours is more of a light surface-only variety. Are you going to try spray-bomb or real automotive paint? I'd prolly just go with spray-bomb if you're looking for a 20-footer. Dupli-Color is available in Wal-Mart, and they should have your color in stock. It's not half bad for spray can paint. There should be a rack with small cans in the automotive section.

 

[CanadianRidr]

Ok so Milque what grit should I start with?

JP I don't have any pics right now but I you have to imagine some of the paint flaked off then just a circle of rust, not the kind where you can pick it off, I will try and find a pic of a car with rust like it.
As for the paint Napa auto parts is mixing it for me in a spray can. I think I have all the supplies so far and I think I have only spent about 60 bucks:)

 

[Milquetoast]

You'll see what I mean when you try to start sanding, I would have some 100 around as well to scratch the "glossy layer" off the bondo at first.

If you want to skip the bondo then you'll need to learn how to feather out the edge of the existing paint where it meets the bare metal. This is, imho, much much harder to do well than just to fill that dug out area with a skim coat of bondo. A bad feathering job will look awful and can be seen easily once the paint has dried.

 

[CanadianRidr]

I think I will have to use the bondo, but hopefully just a light layer. I just want it be all smooth :)
So I will sand hopefully I won't need to grind the rust (if it's that deep) then spray the rust killer on (it says 24 hours to dry :( then bondo, sand it with ...grit
then sand the whole roof with ....grit
then prime the roof, 3 coats and sand with with ..... up to 220?

 

[JuliusPleaser]

If you're going to apply Bondo, start with 80 grit. Remove all the loose paint surrounding the rust spots first. You'll need to grind ALL the rust out, so if it's really heavy rust, you might need a grinder with a 36 grit disc attached. Do you have any bodywork tools, or can you borrow some? Take your time grinding on the panel--you don't want to warp it from excess heat. The area should be nice and shiny, and the old paint should be ground as well. If you look at the roof from the side, the old paint should taper down into the freshly-ground area. That's what Milque meant by "feather-edging". You'll need to feather the paint a few inches from the bare metal areas. Bondo will not adhere to smooth old paint.

You'll need some Bondo spreaders and some hardener, too. (Insert standard Viagra joke here) Follow the directions on the Bondo can explicitly. If you mix too much hardener, it will make the Bondo shrink and crack down the road. If you use too little hardener, the Bondo will never cure. Use as little Bondo as you can. If you pile a lot on the roof, you'll spend forever taking it off. You can always add more. Once you are satisfied with the height of the Bondo, use 80 grit to shape it. Then you can go down (up?) the sandpaper order until you are happy with the shape of the filler. 220 is a good point apply primer. You can also use putty that's available in a squeeze tube to fill minor nick and gouges before applying primer.

Milque pretty much covered the rest. Just make sure that you tape EVERYTHING that you don't want paint on.

 

[CanadianRidr]

Okay sounds good :) I do have the hardner (I feel so dirty lol) But I am not to sure on how much to mix with it. I use it on diecast models to make rollpans and shave tailgates etc..(Lowrider stuff) and the bondo is grey and the hardner is red so I mix it until the bondo resembles a very light reddish tinge to it. I don't think the rust is that heavy to need a grinder (crossing fingers)
But ill let you know:D

 

[JuliusPleaser]

You may not need to grind the rust out. We always do it down here cuz our rust is so light. Your rust killer may work well without removing all the rust. It sounds like you have the Bondo routine down already. That's a major plus.

 

[Milquetoast]

Sounds like you've got the color right on the bondo.

JP and I are suggesting to take different approaches with the bondo though and you should know the difference. He suggests that you will do the feather edge on existing good paint and try to get it smooth with the bare metal. This is what I feel is so difficult and should be avoided.
I would leave an abrupt line between metal and the original paint and fill the bondo right up to that line, no further. Sand the bondo down to the level that the original paint is at. I have done it many times and there is no problem with the bondo sticking to paint as you are not putting bondo on top of any paint at all, you are only going to use the bondo right up to the edge of the original paint. I'm not sure JP was getting what I was saying so I thought I would clarify just so you don't get confused. :-)

 

[CanadianRidr]

Milque your way is the only way I know so that's how it will be done lol :)


Now should I sand to bare shiny metal for primer? Or just sand it down till it's flat, smooth and scuffed up?

Once again thanks to the both of you for your help

 

[Milquetoast]

Sand what to bare shiny metal for primer?

The existing good paint does not need primer so sand that to 400 and paint.
Is that what you meant?

 

[CanadianRidr]

WOW, so for the exsisting paint I just need to get it all roughed up to 400 then paint! Yes that's what I meant, wow you just saved me more time :) Thanks!!!!

 

[JuliusPleaser]

You can apply primer to paint if it's scuffed. Spend a lot of time on your Bondo. You don't want the roof to look like Igor in Young Frankenstein. "What hump?"

If you have a library handy, see if there's a book on bodywork there. Can't hurt.

 

[CanadianRidr]

LOL thanks JP, well it's not my car:p
So what's the final choice, should I prime the good paint on the car and repaint it, or just scuff it up?

ps, Bondo is my expertise lol,

 

[JuliusPleaser]

You don't have to prime the old paint. You DO have to scuff any area that you want new paint to stick to.

 

[Milquetoast]

There is absolutely no need to prime over already good paint. Primer is to help paint stick to bare metal so just sand the good painted part with 400 and paint.

 

[CanadianRidr]

Allright that was all very good, I know I learned a few things. I will ask later in the week if anything comes up, but I think I got it covered/ I will try and get pics too :)

thanks

 

[CanadianRidr]

Hmm I just noticed I have black 1000grit microfine sandpaper, should I be using this? Or just stick with everything up to 220 and 400?

 

[a454elk]

Are we still working on this project? Come on man, finish it and go riding! :)
Let your girlfriend drive your lowered truck already!
Elk

 

[Howser03]

If you do the body work yourself, get it all prepped up and ready to be primed.. take it to an auto body shop. It would be better quality than maaco, and shouldn't be too expensive. I brought my moms saturn in to maaco, and the guy wanted to charge me up the a$@ with every little scratch, like a key mark or something. On the hood there were a few spots where it wore through the top coat, but primer was still visible and the guy wanted to charge me an extra $150 for extra work for them. That pissed me off because they were going to be sanding off the top coat anyways. I said I would do all the "extra" prepping myself to fix these minor imperfections. ... he was telling me that there is no warranty on the paint job if I do that...grrrr...yep, I hate companies like Maaco. (By the way I never did get the car painted :confused: )

 

[Milquetoast]

Forget the 1000 grit. You could use it for toilet paper if you run out! That is for sanding a finished paint job before you buff it out. (not necessary in your case)

 

[CanadianRidr]

Thanks Milque, umm Elk the girlfriend WILL NOT touch my truck, she doesn't understand the concept of low trucks don't do well over curbs etc..:p She was warned lol, hey does the wife drive the elk :scream:

Milque so far I have
220 grit sandpaper
400 sand paper
80 grit
1000 grit
and what other grits should I have on hand?

This project will undergo on Friday night and I hope to be done on Monday :) I will let you all know how in went with pics etc...

 

[Milquetoast]

You probably won't need much of the 80, considering how thin you are going to apply the bondo. Make sure you have a good spreader for the bondo. 100 might be necessary but you may be able to jump straight from the 80 for knocking off the high spots of bondo, to the 220.

 

[CanadianRidr]

Sounds good :D
I have some flat plastic sheets I usally use to spread on models etc...
I also have the standard spatula. I think this will work to get it on smooth and flat.

thanks!
ps,you are on here as much as me :)

 

[a454elk]

That's funny, I thought you asked if the wife touches the elk! Very funny. She DOESN'T understand the concept of horsepower! LOL:) No power steering, no power brakes, no power windows, no power door locks, no power seats, no power mirrors, no air conditioning, just pure power! She drove it once and when she got out, she was covered in sweat. Not that it was a bad thing but for the wrong reasons. :):)
Elk