I've got to paint my inner fenders they are just surface rusted and corners are hard to get to. What is your suggestions for protecting the surface from further rust? Some people seem to have a bad opinion of POR. Not too sure if Rustoleum is any better. Rust converters like Rust Mort or ?? What about being able to weld on it later? Any suggestions are appreciated. Thanks -Erik
I use rust mort rust converter, then paint in places like that. Turns the rust hard and black. To weld later you just sand or grind down to shiney metal and proceed as normal. If you can't get to the shiny metal, you would have had to patch it anyway.
I'm assuming you don't want to take them off of the car to paint? If that is the case, you can get Ok results if you prep them by wet sanding with 320, prime using rustoleum. I'd allow them plenty of time to cure before top coating. You'll probably want to break the surface with 600 before top coating. This can all be done with a brush and properly thinned paint. I'd also add 1-shot hardner or Japan dryer. That's just what I'd do, if i was trying to paint inner fenders on the vehicle. Saves alot of masking time. Do some prep work before starting, like a good thurough steam cleaning under the hood! That and use compressed air to blow everything off before starting to apply the paint. Dan Stevens dba, Steelsmith
having previously done the floor and having good results i have done my boot, under guards and sprayed inside the chassis rails, sills and doors with POR-15 i first gave everything a good blasting with the water blaster, hit everything i could reach with a wirebrush on a drill, another waterblasting and then blew everything out with compressed air. Anything i could reach was given 3 coats with a brush. The sills etc were given 3 coats using an engine cleaning gun to spray the por-15 (dont breathe it in, use a respirator). Follow the instructions and por-15 is great (i.e. dont go putting it over primer)
These parts are off- hood and fenders. I'm using epoxy primer on the exterior surfaces and that seems to protect the metal well even outside in the North West. Some areas like behind the hood inner panel are impossible to get to by hand. What can I pour and slosh around there to stop the rust process? Thanks for the advice! -Erik
I like POR15, it covers well and gives you a tough finish. Any pinholes can be covered with glass cloth and painted over with POR15.
i just put a rear end in a 37 buick coupe - the frame had been painted with por-15, 10 years ago - not a hint of any rust, but had to grind a bit for good welds - that por is TOUGH stuff - need to GRIND not just sand!...just did my tbird floor with it and some leaked thru a weep hole to the floor...can't get it up from the cement without a chisel...good stuff!...rustoleum is much thinner, but is ok too with less trouble in the breathing dept!
oh yeah, POR LOVES rust - don't grind the areas to be covered so they are shinney and smooth or the por will NOT stick well
my thoughts are ........ is it possible to do a bit of sandblast there ....... and there is an epoxy compound that is used to coat the inside of older steel motorcycle gas tanks that is pretty impervious to solvents might try that one ...... for the tank you mix the epoxy and hardner together dump in slush around dump the excess and let harden hope this helps
The Rust Mort people have a new product called Rust Seal that doesn't have to be top coated. I use it as a slosh in impossible to reach areas. It can be top coated if you wish however.
For a converter, I use Permatex's "Extend". Brush it on and it turns the rust to Black Zink Oxide. Also used Rust Mort. Works quite well. I've also used POR-15 on frame rails as well as flat beds. Had very good results with that also.... HTH Steve in NJ
I really like POR15. It goes on smooth with a brush. I have never had rust problems on the areas that I have used this stuff on. Somebody earlier spoke about spraying POR. I'm not sure how good of an idea that is. POR is potent stuff even when spraying the proper equiptment (mask, etc.).
Not to make things more confusing, but I heard of another product called RustSeal from KBS coatings. Supose to be like POR15 but easier to use and stands up to UV better. I was thinking about buying there Frame Coater kit to do a frame I am working on. Anyone have any knowledge on this stuff?
Great advice everyone. I've used Rust Mort and POR before. POR seems thicker than the converters. I've patched the front edge of my hood but the inner panel is just about 1/8" away from the outer so I can't do much but pour something in there. I painted the back side of the patch with a weldable primer but now I want to seal the whole thing. One thing I am concerned about is in case I have a small rust bubble surface later and need to weld a new patch in that I don't want something too flammable or toxic if I weld there again. I'm kind of thinking of using converter where I don't have access and something like POR on the big open areas. Any experiences with welding later with these coatings?
I thought this was an old thread that had been revived....there are a number just like this, do a search.
I used to work for Rust-Oleum. Ever wonder why their red oxide primer smells funny? It has fish oil in it. Not kidding - that's how Rust-Oleum got started in 1921. The guy who invented it noticed that the steel decks on fishing trawlers never rusted. So for a paint type protection, you can't do better. That said, I still favor one of the rust convertors (like "Extend"), which truly changes the rust to a neutral material. Also, for under the fenders additional protection on my '29, I used Lizard Skin, the stuff for insulation and sound deadener. Helps prevent starring.
You're going to need to grind the coating back about 2" from the weld area. I then use a propane torch to flame the remaining coating enough to allow its removal with a wire brush. I do this in a well ventilated area or outside, before any welding is performed. An old stand-by product for rust treatment is 'Navel Jelly'. It's fairly inexpensive and does a good job of treating a surface for painting as well as cooking any remaining rust. Dan Stevens dba, Steelsmith
I think it comes down to your budget and where you live climate wise. If you can afford POR-15, use it! If you live in a dry climate with no humidity, Rustoleum will last for years just fine, and cost less.
Good advise but this is the front of a F100 hood and the rust out was between panels. I can't get access to the underside in case I need to weld there again. It's totally hidden so all I can do there is pour something in from the top gap and swish it around. I just worry that if I get a small bubble there later I don't have something too nasty cooking on the inner side. Hopefully it won't but just in case...
I totally agree, you can get some great results with a brush. Unless you are looking for a 100 point resto finish,brushing is more than adequate. Spraying POR is just plain nasty! Here's my floor earlier on in my build.(Brushed)
just to throw another one in there ive had great results from eastwoods rust encapsulator , worked best for me
More specifically what can be used in the inaccessible areas that won't be too bad if some spot welding needed to happen again? They make a UV proof POR and that would be fine for the fenders but the hood inner panel is my concern right now. I won't be able to clean it off before welding.
On an inner fender where it might get rocks and dirt and stuff bounced off it now and then, I'd lean towards the POR-15. It seems to be pretty tough stuff.
Ospho may be your best bet , its water thin and will get into tight spaces on its own , you may end up needing to re-apply it in the future , as I don`t know how long it will last without a top coat to protect it , maybe someone else has some experience using it without a top coat and will chime in.
I used a engine cleaning gun/cavity wax gun to get it in the ends of the sills, chassis rails and hard to reach bits in the doors -"squirts" put rather than a fine spray. Worked great for those areas. The rest was brushed and you would be hard pressed to find any brush marks
You guys who have used POR-15 lately, is the metal prep stuff really necessary? I know when I used it on my '50 Chevy, it seemed to stick best on the inside of the doors - which at that point I was just using up what I had poured out without doing the prep or anything. But I put some on my beater at the time and it didn't seem to work very well, it rusted through later on. I forget if I did anything to the spots on that but at most I wire brushed them.
The Jalopy Journal
