Jeff Posted October 28, 2002 Share Posted October 28, 2002 I know we have touched on this before but I wanted to share my experience on this so far. Had a pretty good weekend and got a fair amount of the car completed. Here is a pic of what she looks like naked My rust free body shell ended up having a couple of rust through spots that I didn't find until I removed the undercoating. This was the reason for going through this process in the first place. Here is the worst rust I found, minor but still needs to be repaired. The process I have been using to strip the undercoating goes something like this. 1. Saturate an area with carb cleaner and let it soak in a minute. Start attacking the heavy stuff using a stiff scraper and reapply the carb cleaner as needed. I have used a combination of tools thus far including a stiff scraper, putty knife, stiff plastic bondo applicator and an assortment of wire brushes. 2. Once you have gotten all the heavy stuff off you can attack the lighter coating that is left with a spray bottle full of acrylic enamel reducer and a scotch brite pad. You will create a thin coating that can be wiped clean with disposable paper rags. I bought the kind that dispenses out of a box. The enamel reducer works great and you can buy it in a five gallon drum inexpensively. I bought mine from the local Keystone Automotive distributor. I believe they have something like 150 locations nationwide. The enamel reducer evaporates quickly and can therefore be applied heavily in tight spots to literally wash the undercoating away. 3. You can spray one final application of the enamel reducer and wipe clean, then you are done. You can either sand the surface or go with a light sandblasting if you prefer. I used a layer of visqueen topped with a layer of 15# roofing felt to protect my garage floor. This is a very messy job and always wear quality gloves and eye protection as you are doing this. Just thought I would share my experiences thus far and I am sure there are many other methods to accomplish the same end result. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted October 28, 2002 Share Posted October 28, 2002 Jeff, That's amazing. You got almost 100% of that dang undercoating off. Thanks for the info. Tim Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted October 28, 2002 Share Posted October 28, 2002 Progress Jeffy!! Progress!! Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 28, 2002 Share Posted October 28, 2002 Looks good. That rust is not bad at all. I used the propane torch to heat the heavy stuff up and then scrape. I just went over the residue with a rag with mineral spirits on it. A rotisserie makes it so much easier! Quote Link to comment Share on other sites More sharing options...
RPMS Posted October 28, 2002 Share Posted October 28, 2002 I'm VERY impressed that you got it so clean! You must have looked like a tar baby when it was all over and done with. Out of curiosity, at the bottom of the second picture I see a dark line running left to right along the box section of the door sill, touching the seatbelt pocket. Is that absent metal? Quote Link to comment Share on other sites More sharing options...
Jeff Posted October 28, 2002 Author Share Posted October 28, 2002 Out of curiosity, at the bottom of the second picture I see a dark line running left to right along the box section of the door sill, touching the seatbelt pocket. Is that absent metal? No that is a stripe of black paint. Looks like somebody painted the wheel wells and the area below the rocker at some point. Quote Link to comment Share on other sites More sharing options...
Guest jdllaugh Posted October 28, 2002 Share Posted October 28, 2002 Nice job! I'm doing the same project using kerosene and a scraper. VERY tedious. I have most of the thick stuff off, but now I have to get that last nasty film off, and clean out the tight spots. I'm curious about the color of your underbody. When I removed the underbody coating, what I have left is bare metal. Yours looks like it's coated with something, like paint. Was there a paint layer under your underbody coating? Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 28, 2002 Share Posted October 28, 2002 I think there's paint there, but the steel has a very light zinc coat on it. Too light - it gets eaten up by moisture very easily. Quote Link to comment Share on other sites More sharing options...
Jeff Posted October 28, 2002 Author Share Posted October 28, 2002 I'm curious about the color of your underbody. When I removed the underbody coating, what I have left is bare metal. Yours looks like it's coated with something, like paint. Was there a paint layer under your underbody coating? There is a layer of paint or primer there beneath the undercoating. My 72 240 that I started with did not have the paint, it was just bare steel. I gave up on the 240 just too much rust. Quote Link to comment Share on other sites More sharing options...
PETEW Posted October 29, 2002 Share Posted October 29, 2002 That is a really nice job you are doing. I am in the process of do;ing this job myself so I know how you feel. I used a slightly different method. I have been using a scaler attachment on my air hammer. If you have air tools, I would reccomend getting this one. It does a nice job of cleaning of the undercoating, it's cheap, and no messy clean up of toxic chemicals. It doesn't make it look quite as clean but after a good coat of POR-15 it looks real nice. Good luck eith the car. Quote Link to comment Share on other sites More sharing options...
TomoHawk Posted October 29, 2002 Share Posted October 29, 2002 I used a HEAT GUN the last time i stripped a car bottom. You can scrape it as clean as you want, then wash the rest off with mineral spirits or K1. Quote Link to comment Share on other sites More sharing options...
Guest Zachb55 Posted October 29, 2002 Share Posted October 29, 2002 i had to remove some undercoating from a section under the floorboard, who hasnt?, i just used i torch, i didnt even think of some laquer thinner, i got a five gallon thing of that too, running on about 2 gallons at this point though... ill use that for sure to clean up the rest of it, it seems like there is a coat of something under my undercoating but it comes off along with it leaving mostly bare metal. well i do sortof wish i could take it to the point of removing all of the undercoating, but i have to get it running by my 16th birthday!!! and thats at the end of december, oh well, i figure doing the work is easy, getting the license, maybe not as.... -Zach Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 29, 2002 Share Posted October 29, 2002 track down your nearest snapon dealer..... buy a crud thug. it cuts undercoating like warm butter as long as you keep the belt sharp. takes it right down to bare metal. thats how i did mine. took me about 2 days to do the whole bottom and wheel wells. i only have to scrape some corners and nooks in the trunk area and its finished. good thing is it will also strip paint, rust, body filler..... basically anything off metal. nic Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted October 29, 2002 Share Posted October 29, 2002 Some one once posted they used a pressure washer that had a built in heater to remove undercoating. High pressure hot water sure sounds a lot less painful than 5 gallons of solvent and a trash can of solvent soaked rags. Quote Link to comment Share on other sites More sharing options...
Guest silverbullet Posted October 29, 2002 Share Posted October 29, 2002 I absolutely LOVE seeing old Zs being brought back to life and given a lot of TLC, good job Jeff Quote Link to comment Share on other sites More sharing options...
Jeff Posted October 29, 2002 Author Share Posted October 29, 2002 Thanks for the kind words guys. The reason I am getting it so clean is because I am not going back with undercoating. Going to go either the truck bedliner route or chip guard with a urethane paint. The guy who sold me the car is a painter and also a good friend. He wants to do the chip guard but I am not sold on having a paint finish under the car. I'm sure it would look sharp at first but I don't think it would hold up. After all of this I am probably still going to sandblast the entire bottom of the car. The more I think about it I don't think I want to reuse a primer that has been covered with a petroleum based product for 28 years. Thanks again and any opinions on what to coat the bottom of the car with are welcome. Quote Link to comment Share on other sites More sharing options...
TomoHawk Posted October 29, 2002 Share Posted October 29, 2002 If you fitst coated the whole underside with a good layer of an epoxy coating, the paint that goes on over that will look nice & flat, like on metal. The epoxy shouldn't chip off like paint and I think you can get in a brush-on formula. Quote Link to comment Share on other sites More sharing options...
Sam280Z Posted October 29, 2002 Share Posted October 29, 2002 First I have to say thanks for the reducer idea. Not only does it work well but you get a nice buzz as well. I am doing the exact same thing to my car. And I am in about the same place as you, except for the small nooks and crannies. I was fighting those pretty hard, but the reducer works awesome. I wouldn't sandblast. Been there done that (on another car). Sand gets everywhere. You will never get it out of everything. I recommend using a chemical stripper to remove the primer and get it down to bare metal. I noticed that the reducer softened the primer quite a bit. On places that had stripper applied it even would wash the primer away. I too haven't decided what the finnal coating will be. I do know that it will be primed with an etching primer and then an epoxy primer (after treating with some sort of metal prep). I guess I should tell y'all what Ive tried so far: Easy Off oven cleaner: apply thickly and cover with a plastic garbage bag, let sit 24 hours. Undercoating and primer sluff off easily. Do not allow to dry because it only seems to work once. Charcoal lighter fluid: soak a rag in it and lay over undercoating, cover with plastic and let it sit. The undercoating gets real soft and scrapes up easily. Heat gun: just heat and scrape. Chemical stripper: tried quite a few. Some didn't work worth a damn. The sprayable (comes with a squirt bottle) works really well, but the spray bottles don't last long enough and the only other spray bottles I could find only lasted a few squirts. Finaly, I have been washing with mineral spirits in a spray bottle and lots of shop rags (from teh big box). All of these worked well for large smooth areas. Its the nooks and crannies that kill you. Another thing that worked well was a cheap set of wood chisels. They come in various widths, and are sharp and plenty stiff. Quote Link to comment Share on other sites More sharing options...
Sam280Z Posted October 30, 2002 Share Posted October 30, 2002 I forgot to mention... Get 3M stripping pads instead of scotchbrite. They don't fill up as easily, even with gooey undercoating. Sam Quote Link to comment Share on other sites More sharing options...
Jeff Posted October 30, 2002 Author Share Posted October 30, 2002 Thanks for all the tips Sam. I'm glad the reducer is working for you. It's all those nooks and crannies that were killing me as well. I played around with quite a few methods myself, but I never tried oven cleaner. Might have to give it a try on my spare tire well. The stuff on there has a coat of white paint or primer on it and it seems harder than the rest. Thanks again and good luck with yours. Quote Link to comment Share on other sites More sharing options...
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