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Thinking of buying a 240z with loads of surface rust. Best way to sand?

2K views 13 replies 9 participants last post by  Greg Reid 
#1 · (Edited)
Hey guys, first post here but I've been lurking for the last 6 months. I finally have the opportunity to buy a 73 240z but it's got a bunch of surface rust on the roof and a but on the hatch and hood. I asked the owner and he said it's just on the surface even though it's been sitting for the last 8 years. I'll go and take a look at it soon but the price is definitely right as long as it's just surface rust.

My question for y'all, what's the best way to sand a whole car? This will be my first ever project car and my research here says I should hand sand using a block sander. What's the best technique to do that and how long do you all think it'll take to do the whole car? I'd plan on priming it after as well then taking it to a professional paint shop to get repainted since I don't trust the cleanliness of my garage.

Here's a link to pictures imgur com/a/u5x6Nlc
 
#3 ·
I don't know anyone in the area that knows about Zs. I could probably reach out to someone in a local car-meet group but I've been doing research on 240zs and 280zs for the last few years in anticipation of having enough money to buy one so I generally know where to look for major rust.
 
#5 ·
My account is too new to embed pictures in the post but there's a broken imgur link at the bottom of it. I live in Idaho so it's pretty dry here, which means hopefully further rust won't be too bad. I'll definitely check it when I drive out to see it, though.
 
#10 ·
I’ll post the images in here for others to see. I got them from the link you provided.

I’m not expert, but the general consensus is find a rust free car because rust repairs are costly. If you can see rust then there’s probably a bunch more your can’t see. It really depends on how much he wants for the car. It sounds like you don’t have a lot of body repair or rust repair expertise so you’ll be paying someone to do the repairs if you want them don’t right
and not have a Frankenstein job.
So media blasting is a great approach to rust repair and probably the fastest. You need to get under the car and look yourself. Especially the frame rails. Look behind the front wheels, deep in where the body is. It’s a classic rust area. The floor boards too.

Good luck.



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#12 · (Edited)
I've done quite a bit of rust repair on different cars and actually, that doesn't look terrible. The main thing is that it doesn't appear to be badly pitted. It looks almost like the paint peeled and allowed the rust rather than the way it usually happens; rust starts and causes the paint to peel.
Having said that though, it's tough to tell from a couple of pics. You have to look closely at the car. The worst rust will usually hide under the paint. Look for blisters. If you see that, try to poke a screwdriver though it. If it goes straight through, that metal will need to be cut out and replaced. That gets expensive in a hurry and even if you can do it yourself, very time consuming.
What I see there looks more like something you could dissolve with phos. acid or the like.
Get underneath, pull some carpet up, check the framerails, especially on the battery side, check the lower corners of the doors, the doglegs behind the doors and down into the rockers etc. These cars rust terribly. They are pretty hard to find even as solid as that one looks.
As for paint removal, you have options- Abrasive or chemical. I prefer abrasive as chemical paint strippers are hard to neutralize in cracks and crevices which can cause adhesion problems down the road.
I like to use a variable speed angle grinder, 6" preferred, with 80 grit. I have also used a razor blade. It removes paint without the dust.
From what I see in the pics, it wouldn't scare me off...what's not seen in the pics is another story. Looks good enough to warrant a closer look in my opinion, especially being a 240 as opposed to a ZX.
 
#13 · (Edited)
I agree the car doesn't look bad from the pics. It does look like it has etched the metal but probably not that bad. Even if you blast the car to get rid of the rust and paint you still need to treat it with phosphoric acid like a product called Rust Mort. Once a car is blasted or sanded down and the metal looks clean, there still could be rust on a molecular level and it will come back unless you treat it with RM.
As far as the variable speed grinder you have to be very careful with them and operate them at lower speeds. Otherwise, you can warp the metal severely. I usually recommend using a device called a DA sander after using the orbital unit. Before using those sanders you must either remove any chrome or stainless items from the car or else tape them off with duct tape. The sanders will ruin them otherwise.
Good luck on your potential purchase. Z man of Washington
www.zspecialties.com
www.datsunstore.com
 
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