jkelly Posted October 21, 2017 Share Posted October 21, 2017 (edited) Hey guys, I'm looking for some advice on what to do for the next step of my 240z project. I have the car stripped down to a rolling shell with the engine bay primered and the underside undercoated already. I'm debating between sanding down the exterior and interior to factory primer, repairing any trouble spots in the process, and then shooting paint OR having the interior and exterior media blasting with fine crushed glass (hopefully less likely to warp) and then shooting paint. The factory paint looks okay. There are few spots that have cracked and are peeling but overall it's not bad. Some spots will have to come down to bare metal anyway for repairing. Which route do you guys think I should take? I have a large compressor and the tools to do the sanding. Media blasting would make the following easier, though: One big issue is rust. There are several rust spots that I'm concerned about and am not sure what to do about. There's rust around the inside perimeter of the roof. There's rust inside the passenger and driver side vent plenums that run to the engine bay. There's rust inside the cowl area. There's some rust in the rockers (not too bad) and the dog legs are pretty rusty. I boroscoped most of these places and have some pictures below. The worst of it all is in the dog legs. In the other spots there rest seems to be bubbling a little but mostly on the surface -- some pitting. I'lllet the pictures do the talking. The car: Dog legs: I will most likely be replacing these. Inside the rear wheel-well area above the dog legs: Around the the inner perimeter of the roof: It's rusted most of the way around and the rust goes into the recessed area all the way around. This is perhaps only surface rust and would come off with a wire wheel, but the issue is accessing this area. This is where blasting would be nice and this is one of my biggest concern areas. Inside the driver and passenger vent air plenums: Some other rust around the hatch sill: What do you guys think I should do about the rust areas? Should I get everything blasted as best they can do then seal it? Should I sand/wire brush everything I can and treat it with some ospho or other converter then seal it and use cavity wax? I have these products on hand. I've already put a lot of money into this project so I'm all in and want this to be near show quality and last a long time. I don't know if it's worth it to split the seams on some of that rust or not. How hard is it to remove the roof? I did my own floor pans, battery box, and frame rails. Edited October 21, 2017 by jkelly Quote Link to comment Share on other sites More sharing options...
grannyknot Posted October 21, 2017 Share Posted October 21, 2017 Get it sand blasted while it is still solid. Quote Link to comment Share on other sites More sharing options...
jkelly Posted October 21, 2017 Author Share Posted October 21, 2017 28 minutes ago, grannyknot said: Get it sand blasted while it is still solid. So you would sand blast the best they can then shoot paint? Would you try to get a rust converter into any of the places that can't be blasted (seams, laps, rockers, vent plenums)? I'm a little hesitant to get it blasted because the guy can't do soda and I'm worried aboit warping panels. He will use 40/70 fine crushed glass. Which he said he's done for body shops before and they like it. Quote Link to comment Share on other sites More sharing options...
Nelsonian Posted October 21, 2017 Share Posted October 21, 2017 (edited) If I had the chance to strip my car again and the circumstances were not what they were at the time, (immediate place needed to house the car after as well as find a body/paint guy), I would have brought my car to a dipper in LA or checked out these guys in Oregon. http://www.metaldipping.com/faq.php Read the Common Questions section and see how many myths that are spread by people. Edited October 21, 2017 by Nelsonian Quote Link to comment Share on other sites More sharing options...
jkelly Posted October 22, 2017 Author Share Posted October 22, 2017 (edited) 55 minutes ago, Nelsonian said: If I had the chance to strip my car again and the circumstances were not what they were at the time, (immediate place needed to house the car after as well as find a body/paint guy), I would have brought my car to a dipper in LA or checked out these guys in Oregon. http://www.metaldipping.com/faq.php Read the Common Questions section and see how many myths that are spread by people. I thought about that. The only thing is my underside is already done (epoxy primed, seam sealed, and truck bed lined). I would be taking a few steps back and eating about $800 and hours and hours of work, but it may still be worth it to have the peace of mind there is zero rust, and they can prime the entire thing for me. I'm not sure. Attached a picture of underside. You think it's worth it? $800 in the grand scheme of things isn't a ton i guess. Id have to pay $500 more to get the rest of it blasted. $1890 for dipping the Z shell, doors, hood, fenders, and deck lid isn't too bad. I saved more than that doing my own battery box, floor pans, and frame rails. 🙄 Has rust come back to bite you since you didn't dip it? Mine is a California car but seems a bit rusty. Edited October 22, 2017 by jkelly Quote Link to comment Share on other sites More sharing options...
Nelsonian Posted October 22, 2017 Share Posted October 22, 2017 (edited) It would be a tough pill to swallow going back on what you have already achieved, however all metal would be rid of rust. I know all too well about one step forward and three steps back as I have made a few costly mistakes along the way on my build, er, um Z build education. I had my car immediately epoxy primered by Bob the blaster using Endura epoxy primer. The car was on his car port in Jamul with body repair started for roughly 4 months with only a blue tarp and bungee cords holding it on. I then moved the car to my body/paint guys garage in El Cajon for a long while then had to move it to a rental garage in Chula Vista close to the San Diego harbor/ocean where it has been for at least 2 years. I have not had any re-rust issues I am happy to say so far. I have had alot of sand come out of the hidden cracks however as the car has been flat bed or moved on a car hauler from south SD to North county SD no less than 4 times n the highway. Hopefully most has shaken itself loose by now. I had an older gentleman who has been blasting for most of his life do the work and still had minor signs of warping. My body guy was not that pleased with the work ahead of him to get all straightened. It would be a tough decision to make to dip then epoxy, undercoat seam seal, but without a doubt will have eliminated all internal rust without warping any panels in the process. Edited October 22, 2017 by Nelsonian Quote Link to comment Share on other sites More sharing options...
grannyknot Posted October 22, 2017 Share Posted October 22, 2017 23 hours ago, jkelly said: So you would sand blast the best they can then shoot paint? Would you try to get a rust converter into any of the places that can't be blasted (seams, laps, rockers, vent plenums)? I'm a little hesitant to get it blasted because the guy can't do soda and I'm worried aboit warping panels. He will use 40/70 fine crushed glass. Which he said he's done for body shops before and they like it. Actually I suggested blasting because you had already done the bottom, I had my Z dipped, the shell and the hood. If I were to do it again I would have done as much as I could of the body work and rust patching BEFORE the dip. The car was sprayed with a water soluble rust inhibitor immediately after the dip which is good for a week maybe two then it starts to rust so you have to be fast. I used the Eastwood inner frame spray to coat all of the areas you can't see or get to then 2 part epoxy primmer for the rest of the car. These pics were taken hours after it came out of the neutralizing tank. Quote Link to comment Share on other sites More sharing options...
jkelly Posted October 22, 2017 Author Share Posted October 22, 2017 (edited) 21 hours ago, Nelsonian said: It would be a tough pill to swallow going back on what you have already achieved, however all metal would be rid of rust. I know all too well about one step forward and three steps back as I have made a few costly mistakes along the way on my build, er, um Z build education. I had my car immediately epoxy primered by Bob the blaster using Endura epoxy primer. The car was on his car port in Jamul with body repair started for roughly 4 months with only a blue tarp and bungee cords holding it on. I then moved the car to my body/paint guys garage in El Cajon for a long while then had to move it to a rental garage in Chula Vista close to the San Diego harbor/ocean where it has been for at least 2 years. I have not had any re-rust issues I am happy to say so far. I have had alot of sand come out of the hidden cracks however as the car has been flat bed or moved on a car hauler from south SD to North county SD no less than 4 times n the highway. Hopefully most has shaken itself loose by now. I had an older gentleman who has been blasting for most of his life do the work and still had minor signs of warping. My body guy was not that pleased with the work ahead of him to get all straightened. It would be a tough decision to make to dip then epoxy, undercoat seam seal, but without a doubt will have eliminated all internal rust without warping any panels in the process. The car looks great! It is a tough pill to swallow. I'm still considering it, but also considering other options like shooting Ospho into every nook and cranny, washing it out with water and a pressure washer and then spraying Eastwood Frame Coating into the cavities. 1 hour ago, grannyknot said: Actually I suggested blasting because you had already done the bottom, I had my Z dipped, the shell and the hood. If I were to do it again I would have done as much as I could of the body work and rust patching BEFORE the dip. The car was sprayed with a water soluble rust inhibitor immediately after the dip which is good for a week maybe two then it starts to rust so you have to be fast. I used the Eastwood inner frame spray to coat all of the areas you can't see or get to then 2 part epoxy primmer for the rest of the car. These pics were taken hours after it came out of the neutralizing tank. Just got done reading your entire build thread. Very impressive timeline and the car looks great. I saw the crap you pulled out of the passenger and driver vent holes. I removed a comparable amount of leaves and probably rat shit from the passenger and driver vent plenums -- 45 years worth of debri, I'm sure. Nasty I'm considering going back and getting it dipped, but a big part of me wants to just push through with what I have and get this thing on the road. There will be more restoration projects in my future, I'm sure. Ill sandblast what i can but after much research I'm thinking about getting a flexible drill attachment with a brush, knocking down what loose rust I can in the rusty boxed in areas, shooting Ospho into all of the boxed in areas, letting it sit for a couple days, cleaning it out with water, and then shooting Eastwoods Frame Coat in there. Then cavity wax on top of that. I figure that should slow the rust rate down a bit. Maybe for another 45 years? I really have no idea. I never really hear of anyone coming back 5 years later and saying "Oh yeah, that rust that I just covered up with rust encapsulating paint still looks great and my rocker panels (or other part) are still solid!" Edited October 22, 2017 by jkelly Quote Link to comment Share on other sites More sharing options...
Greeko Posted October 23, 2017 Share Posted October 23, 2017 I guess it depends on how hardcore you want to go with her... I am doing a resto mod so i stripped it and sanded most areas and blasted the hard to reach areas to make sure... I am very happy with the result and was able to do the work mostly myself.. Quote Link to comment Share on other sites More sharing options...
seattlejester Posted October 23, 2017 Share Posted October 23, 2017 Hard to tell, but some of those spots look awfully pitted, some look like just discolored/surface rust. Downfalls to blasting are the expense and the chance of warping, but blasting definitely will tell you if the panel or area is able to withstand regular use. For me it would be a mindset kind of thing, just encapsulating rust is a bandaid, something that I will have to remember and always plan on addressing sometime in the future. If you lived by the ocean and it was going to rust anyway, then it might be fighting a losing battle, but having pictures and being able to show receipts may be useful in the future when or if you even sell the car or have a claim on it. Quote Link to comment Share on other sites More sharing options...
jkelly Posted October 23, 2017 Author Share Posted October 23, 2017 (edited) 3 hours ago, Greeko said: I guess it depends on how hardcore you want to go with her... I am doing a resto mod so i stripped it and sanded most areas and blasted the hard to reach areas to make sure... I am very happy with the result and was able to do the work mostly myself.. How did you get into the hard to access areas? Like the passenger/driver air ducts that run up the engine bay sides, and the inner fenders above the dog legs, and other areas? Were those areas just not rusted? 3 hours ago, seattlejester said: Hard to tell, but some of those spots look awfully pitted, some look like just discolored/surface rust. Downfalls to blasting are the expense and the chance of warping, but blasting definitely will tell you if the panel or area is able to withstand regular use. For me it would be a mindset kind of thing, just encapsulating rust is a bandaid, something that I will have to remember and always plan on addressing sometime in the future. If you lived by the ocean and it was going to rust anyway, then it might be fighting a losing battle, but having pictures and being able to show receipts may be useful in the future when or if you even sell the car or have a claim on it. It is a mindset thing. I'm to the point where I'm pretty OCD about things. Even if I can clean out most of the rust in those pictures, there's still going to be rust in the seams and lap joints that I'll wonder what the state of it is. I dunno, maybe if I put enough work into the engine and make enough horsepower I'll forget about the lap joint rust Also, you can't even acid dip/chemical dip a car in California any more without paying for it with your left testicle. Jeez. I was quote $2600 for just the shell today. I did get a $1500 quote for the whole car in Phoenix AZ. Pretty good price and only 10 hours away rather than 12 hours to Eugene Oregon! Edited October 23, 2017 by jkelly Quote Link to comment Share on other sites More sharing options...
seattlejester Posted October 23, 2017 Share Posted October 23, 2017 Dipping is quite the challenge if you don't have a high volume shop and a transport method. It is one of the most sure fire ways for sure. You could have someone blast the hard to reach places, I think the local rate is about a dollar a minute for spot jobs. Blasting will definitely test the metal, if it is corroded it will have holes blown in it. Dipping would be more telling as the weak panels would no longer be there and any rust would be neutralized for the most part. You could alternatively either get a sand blaster for the harder to reach areas and spot blast them (sandblasting is super messy, I would suggest doing this outside/in the backyard/ a neighbors dirt lot etc), or cut to give yourself better access and replace the panels down the road. A little blasting setup is not too bad. You can get a setup for about $200 compressor and blaster from harbor freight. Trying to get a flex brush all the way in there would be quite a challenge without good access. Quote Link to comment Share on other sites More sharing options...
jkelly Posted October 23, 2017 Author Share Posted October 23, 2017 Yeah, I'm not sure I want to go to all the trouble of trailering the car out to Phoenix. I'm leaning towards blasting what I can and cutting out some access panels to those hard to reach spots. You sure aren't lying about it being messy. I've done a good bit of spot blasting with my 60 gal compressor and something like this: It works pretty well for smaller stuff and the price. I had the bottom of the car sand blasted by a mobile blasting company. It made a huge mess and I wouldn't do that at my house again. A dirt road or a field somewhere is a much better idea. Quote Link to comment Share on other sites More sharing options...
seattlejester Posted October 23, 2017 Share Posted October 23, 2017 For sure, I blasted in my garage, spent the rest of the weekend cleaning up. I did find they make special heavy duty vinyl that you can stack weights on, pull them up to the rafters, then you just vent at the top, all the sand is heavy so it stays inside, sweep and re-use. I still wouldn't want to do it indoors though. Also just a word of advice fine silicate particles are extremely hazardous to your health. Use a quality respirator under the blasting hood if you value your lungs in any way. A needle scaler is also quite nice if you have room to get it on the surfaces. Much less of a mess. The panels do take a beating so maybe on floors and unseen spots, I wouldn't use one on the outside panels. Quote Link to comment Share on other sites More sharing options...
rturbo 930 Posted October 24, 2017 Share Posted October 24, 2017 2 hours ago, seattlejester said: Also just a word of advice fine silicate particles are extremely hazardous to your health. From what I've read, you shouldn't be using sand anyway. Health hazards aside, it's too abrasive, prone to warping the metal, and some have said that it will work harden the metal. If I were blasting, I'd use something a bit gentler. There's plenty of options. Quote Link to comment Share on other sites More sharing options...
jkelly Posted October 24, 2017 Author Share Posted October 24, 2017 3 hours ago, seattlejester said: For sure, I blasted in my garage, spent the rest of the weekend cleaning up. I did find they make special heavy duty vinyl that you can stack weights on, pull them up to the rafters, then you just vent at the top, all the sand is heavy so it stays inside, sweep and re-use. I still wouldn't want to do it indoors though. Also just a word of advice fine silicate particles are extremely hazardous to your health. Use a quality respirator under the blasting hood if you value your lungs in any way. A needle scaler is also quite nice if you have room to get it on the surfaces. Much less of a mess. The panels do take a beating so maybe on floors and unseen spots, I wouldn't use one on the outside panels. I might try putting in some drop cloth or something similar in the garage to contain it. I blasted in the driveway/yard at my old rental house and the landlord had a little fit about the sand in the yard, if you could even call it a yard -- more like a dirt lot. So, I'm not going to try that again being that I'm still renting. I'll have to clean up whatever I do and it'll be easier in the garage. I've seen those needle guns. They look really effective, especially for undercoatings. 1 hour ago, rturbo 930 said: From what I've read, you shouldn't be using sand anyway. Health hazards aside, it's too abrasive, prone to warping the metal, and some have said that it will work harden the metal. If I were blasting, I'd use something a bit gentler. There's plenty of options. I've read the same during my research. I think it comes down to the person doing the blasting, type of sand used, pressure, technique, etc. The safest route is to use walnut shells, plastic, or soda blast it which all have their downsides, so I've read. I might just get some walnut shells for doing the blasting spot blasting I'm doing or just take it easy with the sand and not doing any outer panels. I don't mind sanding. I just have to do something about those rusty inside panels. Quote Link to comment Share on other sites More sharing options...
Greeko Posted October 24, 2017 Share Posted October 24, 2017 17 hours ago, jkelly said: How did you get into the hard to access areas? Like the passenger/driver air ducts that run up the engine bay sides, and the inner fenders above the dog legs, and other areas? Were those areas just not rusted? It is a mindset thing. I'm to the point where I'm pretty OCD about things. Even if I can clean out most of the rust in those pictures, there's still going to be rust in the seams and lap joints that I'll wonder what the state of it is. I dunno, maybe if I put enough work into the engine and make enough horsepower I'll forget about the lap joint rust Also, you can't even acid dip/chemical dip a car in California any more without paying for it with your left testicle. Jeez. I was quote $2600 for just the shell today. I did get a $1500 quote for the whole car in Phoenix AZ. Pretty good price and only 10 hours away rather than 12 hours to Eugene Oregon! I didn't have rust in most of those areas. I did however spray some rust converter in gaps and crevices to make sure.. Quote Link to comment Share on other sites More sharing options...
seattlejester Posted October 24, 2017 Share Posted October 24, 2017 15 hours ago, rturbo 930 said: From what I've read, you shouldn't be using sand anyway. Health hazards aside, it's too abrasive, prone to warping the metal, and some have said that it will work harden the metal. If I were blasting, I'd use something a bit gentler. There's plenty of options. I agree, if one had the money I think having it dry ice blasted would be pretty neat, no moisture involved really, cools as it blasts. All the other bits I couldn't find locally which killed the price in shipping. Financially I don't think you could beat the price of sifted sand. I did find and try baking soda. That is way too soft to really get at surfaces. It would leave things like rubber and gasket intact, probably why it was suggested for things like aluminum. I've heard similar things for walnut, a bit too much on the soft side. I do agree with big thin panels sand might be a bit too abrasive though. Make sure to get a regulator to control pressure and apply at an angle for any spots of that nature, but those might be better suited for a wire brush anyway over blasting. Regardless if you have decided to blast inside the garage, make sure you have a kill room so to say setup with air flow out controlled. I still had sand in the rafters and stuff, that stuff really does get everywhere, you really don't want to think about having to pay for replacement heaters and stuff because you stuff up the intake and stuff. Quote Link to comment Share on other sites More sharing options...
LLave Posted October 24, 2017 Share Posted October 24, 2017 I really dig this discussion, I have been doing chassis repairs/reinforcements and I am at the point where I am considering blasting or dipping. My biggest trouble spot is in the interior of my cowl. It has some rust, some difficult to remove paint (looks like the P.O. applied POR15). I am considering getting a little spot blaster for just the hard to reach spots. Most of larger rusted sections I just cut out and replaced. A couple of notes on the methods I have tried: Doing it area by area with wire wheels/rolloc discs, convoluted discs. This is time consuming and surprisingly expensive. The 3M bodyman's bristle discs (purple) are amazing. They work really well, they don't catch edges, they don't remove hardly any base metal, and don't fling wire wheel bits. However they are really expensive. You are going to go through a fair amount of consumables. Good grinders and a big compressor are a must for me. This works for most of what I have run into. Sandblasting yourself (I did a 70' challenger chassis), again surprisingly costly, and a pain in the ass. You go through way more media than expected, more tips and consumables. I bought a cheap Harbor Freight pressure blaster and had to fix it over and over. It took a long time and made a huge mess. I even constructed a wood and tarp booth to contain it. I used a supplied air respirator (which I already had). You are probably money ahead to pay a shop to blast and epoxy primer it. If I saved the materials expenses and spent half the hours I had into blasting at work picking up some overtime, I could have just paid to have it done. Home chemical stripping, Aircraft remover for paint and acid (Ospho) for rust. Chemicals and fumes are nasty, aircraft remover will burn you. This method can be pretty effective. Get some plastic sheets to contain the mess, use good quality gloves, be careful. Also note epoxy primer does not play well with Ospho, you need to have a really solid procedure to wash and neutralize or you will have paint failure. Ospho must be re-wet with Opsho then flushed with water and a little dawn dish soap, then water born was and grease remover, dried very well, then painted. Quote Link to comment Share on other sites More sharing options...
seattlejester Posted October 24, 2017 Share Posted October 24, 2017 You do bring up a good point. I had to run tandem air compressors to keep up with the demand, the energy bill was kind of nuts with a couple days of blasting in. Harborfreight had a better style blaster (not a propane tank looking one) that worked a lot better in my opinion, if you sifted sand you could get through the whole thing. V-fib went all out in there. It was surprisingly gone in his car. He took out all the spot welds and we fabricated a new floor and cabin intake to weld in. Honestly really over kill unless you can really see a lot of rot in that area, I can't imagine how much work it will be to fit the cowl panel again and seal the windshield in. I just ospho'd mine on the sides. They do sell ospho paint/rust converter that works ok on light rust. Aircraft stripper will not only burn you, but the fumes or toxic and a nerve agent, really really bad stuff. Quote Link to comment Share on other sites More sharing options...
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