paint thickness?

[Guest msthaiii]

i recently bought a 260z and there are minor [in my opinion] rust spots.. a friend of mine broke off a chunk on the roof.. i don't know why he did so in the first place..

 

now it looks like this:

 

i am planning on sanding it down later before i get a paint job but i want to know is the thickness right? it's about the width of 2 pennies maybe..

 

1] should i apply bondo into the missing area then sand it off evenly as well as the top layer of the paint?

 

or

2] should i sand it down to the metal?

 

thank you

[78280z]

Unfortunately, it looks as if the roof was dented/uneven at some point in your Z's life and one of its previous owners used bondo to repair that dent. The bondo gives the thickness to the chunk that's missing. I would recommend sanding the entire thing down to the metal, fix the rust, get the panel as straight as possible, and then repaint.

[brokebolt]

I agree with 78280z, if you can break of the bondo than you have bad adhesion, in this case looks like rust compromised the repair (and a poor one I might add). Now you need to strip, prep, clean, bondo, primer, paint, and color sand. Obviously that is an over simplified order of events, but the concept is the same.

 

The blue color is the bondo layer and the color layer is very thin on top of that bondo layer. The bondo should never be more than the width of your fingernail (in my opinion) if it is any thicker than your are masking the problem with the metal underneath. Also if you can flick it off than the bondo doesn't have a good adhesion and needs to be stripped off and reapplied. Bondo is a mechanical adhesion not a fusion process, hence the name "Bond-O".

 

Best of luck on the project.

[AK-Z]

Unfortunately, it looks as if the roof was dented/uneven at some point in your Z's life and one of its previous owners used bondo to repair that dent. The bondo gives the thickness to the chunk that's missing. I would recommend sanding the entire thing down to the metal, fix the rust, get the panel as straight as possible, and then repaint.

 

I would only sand down only that spot untill you hit some clean metal. Then spray it with some por15 and then bondo/repair it. Redoing the whole roof because of one spot is a waste of time (trust me, I know )

[Guest Zfixxer]

I would only sand down only that spot untill you hit some clean metal. Then spray it with some por15 and then bondo/repair it. Redoing the whole roof because of one spot is a waste of time (trust me, I know )

 

 

I disagree, not a waste of time at all, obviously it wasn't repaired properly in the first place so why put a band-aid on something that needs surgery? If fixed properly it will last for years and this wont happen again. It is not a fun job but by the looks of it you might find more problems once you get into it so fix it once and than you don't have to worry about it anymore.

[doohopark]

Yes it is indeed a repair job, I would Sand not grind off all the old filler untill rust is not visable, then go 3-4 inches past the end. Fix much of the sheetmetal as possible, prime with epoxy or por15 then reskim the roof. Much harder then it is written. The roof has to be the hardest panel to repair on a Z. Althoe the poster above mentioned filler not being thicker then your finger nail. Why would you say that?? if it wasnt thicker then your finger nail, why use filler?(unles you have some really thick nails) Wouldent you be better off useing a high build surfacer primer? Modern fillers can be used up to 1/4 inch (not recommended) with out any problems, as long as the substrate was properly prepared. In my opinion anything up 1/16 is a good reapir and up to a 1/8 inch can be used in a pickle.

Oh forgot to add, Bondo is a Brand name, there are much better fillers on the market, evercoat rage extreme is awesome.

[brokebolt]

Althoe the poster above mentioned filler not being thicker then your finger nail. Why would you say that?? if it wasnt thicker then your finger nail, why use filler?(unles you have some really thick nails) Wouldent you be better off useing a high build surfacer primer? Modern fillers can be used up to 1/4 inch (not recommended) with out any problems, as long as the substrate was properly prepared. In my opinion anything up 1/16 is a good reapir and up to a 1/8 inch can be used in a pickle.

Oh forgot to add, Bondo is a Brand name

 

Bond-O...that was a joke. Bonding filler, not fusing = Bond-O.

 

We used to skim the entire car and than sand it smooth. It left a lot of small thin areas where the metal had small imperfections. We did use high build primer when needed, high quality needed more work than others. We produced quality work, show quality and it cost $$$. And yes you can slather it on; up to 4 inches (stripped a rear quarter once..). Sloppy sheet metal workmanship uses more filler/primer. That's just the way I roll.

[AK-Z]

I disagree, not a waste of time at all, obviously it wasn't repaired properly in the first place so why put a band-aid on something that needs surgery? If fixed properly it will last for years and this wont happen again. It is not a fun job but by the looks of it you might find more problems once you get into it so fix it once and than you don't have to worry about it anymore.

 

 

If there isn't any more noticable rust, that means that other areas of the roof are fine. If you try to redo the WHOLE roof, there is a chance that you will cause more rust problems down the road.

 

If there is any more rust that hasn't presented it self, then you just repeat what I said before again. And if you want to go ahead and redo the whole roof

then go ahead, yo see how difficult it is to even the roof.

[brokebolt]

The Z roof is a turtle shell and very difficult to get nice and straight (that is to say properly shape), it also lacks a good strong support structure. With that said any good quality body work done in that area will be difficult. Yes, you can mud it and do the same type of repair that was done before and it will look OK for a daily driver and that is fine. I have done those repairs before, why sink $5000.00 into body work on a car you want to value at no more than 6k or 7k, but that is my opinion. Body work is like fine wine, the more you spend the smoother the finish, just in a different bottle (again that was a joke so no need to bash on the wine sentence). It rivals engine work in theory in some reguards, the more you spend (in both time and materials), the nicer it is.

 

Anytime you see that type of rust, formed under the filler layer (or paint bubbles) you have to ask yourself if more maybe present. Has a worm hole formed and run all the way down the back to the rear hatch, or over to the side by the 1/4 window? Dose another spot exist that I can't see yet. Any body work will always pose a risk of potential rust unless done professionally by professionals. doohopark makes a good point about cutting the area out until you confirm that a good clean repair can be made. Knowledge of proper technic and experience play a role here.

 

I strongly suggest you seek out a good book for reference or a body guy in your area or Z club for advice. Hands on is worth more than anything else in my opinion, especially for items like this.

 

If you do the body work yourself in your garage and you are willing to risk the unknown (I assume your are a fist time body guy?), I say have at it msthaiii. I am one that would support your decision, but the flip side of the coin is the gamble of future repairs. But this small repair maybe good experience to see if you would like to tackle more repairs on your car, or another car later.

 

I say all this as both advice on bodywork and warning of the work that is needed and knowledge of tools and technics. I can't stand to see what would be a nice car cruising the yard with primer spots and unfinished body work. I say get on it and finish it, I want to see that thing put back together and looking nice (even it isn't show car nice!).

 

Best of luck on the project, and keep us posted on the progress.

[Guest msthaiii]

Do you have an estimate of the cost tor repair the roof? not including paint or any other sections of the car.. Because if I can't seem to get it right, as hard as I try, then I'll take into consideration of handing it to a prof.

 

Though I do know a lot of people who specialize in cars, in different areas. I do plan on working on it myself because my main goal it to actually learn about the car instead of going through life not knowing anything and relying on others or my boyfriend to solve problems or do an oil change.

 

For the bondo material [i only know it as "bondo"], I can get a professional quality one. I can't remember the exact name right now though. As for technique, my boyfriend has worked for a design company [Asuka Design] for a while but his work was trashed because the owner of the car got into an argument with the owner of the company. He worked with bondo plenty of times so he has brief experience, not an expert for I think enough to learn off of.

 

The reason why I want to sand is to save some money from the paint job. Also I do plan on driving around in black primer for a while. First I want to take off the yellow paint instead of having blotches here and there because of me trying to remove the rust previous there. Then apply black primer [bf has experience with spray paint, learned from designer place] then apply the rust preventer spray paint thing [or are you suppose to apply that first then primer?]. So after a while of figuring out what color I want and going around for estimates, I will then paint the car. During that time, I plan on getting an rb25 or sr20, I don't know yet but a different engine that is fuel injected and slowly disassemble it and reassemble it so that by the time I do swap engines, it will look clean and shiny like the car.

 

That's a brief statement of my plans. Any suggestions or comments are welcomed. Hmm, since I'm not too familiar with all the car lingo.. well I'm a beginner and if anyone has any suggections of what I should look into as I slowly continue, I would greatly appreciate it! And thank you so much for all your input.

[zgeezer]

Do you have an estimate of the cost tor repair the roof? not including paint or any other sections of the car.. Because if I can't seem to get it right, as hard as I try, then I'll take into consideration of handing it to a prof.

 

Though I do know a lot of people who specialize in cars, in different areas. I do plan on working on it myself because my main goal it to actually learn about the car instead of going through life not knowing anything and relying on others or my boyfriend to solve problems or do an oil change.

 

For the bondo material [i only know it as "bondo"], I can get a professional quality one. I can't remember the exact name right now though. As for technique, my boyfriend has worked for a design company [Asuka Design] for a while but his work was trashed because the owner of the car got into an argument with the owner of the company. He worked with bondo plenty of times so he has brief experience, not an expert for I think enough to learn off of.

 

The reason why I want to sand is to save some money from the paint job. Also I do plan on driving around in black primer for a while. First I want to take off the yellow paint instead of having blotches here and there because of me trying to remove the rust previous there. Then apply black primer [bf has experience with spray paint, learned from designer place] then apply the rust preventer spray paint thing [or are you suppose to apply that first then primer?]. So after a while of figuring out what color I want and going around for estimates, I will then paint the car. During that time, I plan on getting an rb25 or sr20, I don't know yet but a different engine that is fuel injected and slowly disassemble it and reassemble it so that by the time I do swap engines, it will look clean and shiny like the car.

 

That's a brief statement of my plans. Any suggestions or comments are welcomed. Hmm, since I'm not too familiar with all the car lingo.. well I'm a beginner and if anyone has any suggections of what I should look into as I slowly continue, I would greatly appreciate it! And thank you so much for all your input.

 

If your filler is that thick, I would think that, at some time, your Z's roof was tin canned. Mine was because the previous owner had stored a bag of Z parts on the roof. The rust is a problem because you don't know how extensive it is. Some fillers and primers absorb water from the atmosphere (rain/washing) unless protected with a "sealer" of some sort. There are a number of "right" repairs that you might consider: all of which labor intensive. I addressed the same problem -rust and all- by removing paint, primer, and bondo off the roof down to bare metal. I treated the metal with POR 15 metal prep to remove all rust and then "shrunk" the metal using a torch and wet rag [i traded services with an old school led sled kind of guy, who oversaw and helped correct my errors). I skimmed the roof with "bondo" and worked it down until there were no low spots. Covered it with POR 15 and I will paint it in another year. Some separation of the POR 15 because of incorrect preparation, but no more rust in the last two years.

 

If this is going to be a learning exercise for you then a stop gap measure would be to simply sand to metal, feather edge the existing paint out three or four inches, bondo and spray a seal primer.

 

I worked 9 months part time on my roof, learned new swear words, and developed a real respect for the skills of old school bodymen. After all the work, would I do it again? You betcha.

 

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