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Inner fender rust

Slantscamp

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hi guys. Just when I thought I was done fixing rust, I found a little more. I plan on cutting out the rust below my battery tray and patching it, but my question is about the light pitting on the top of the inner fender. Do you guys this I can just treat this area and then prime and paint. Thanks for any tips you have.

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That’s doesn’t look bad enough to cut out. Sandblast or chemically treat the rust, use glazing putty to smooth it out and be done.
 
I agree, I don't think its bad enough to be worth patching it. Use some acid on it (rust remover or converter) + good primer and it should be fine. I'm kind of a perfectionist so I don't like to cut corners but IMHO your probably better off just leaving that section above the battery tray intact and doing the same treatment.

Sometimes just leaving the light pitting on an original piece gives a better final result (and is just as long lasting) as opposed to patching. When you start cutting and welding small patches sometimes it wont look as good in the end vs. just leaving the original metal intact.
 
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I am a perfectionist as well. The first thing I thought was “I better put a whole new inner fender in. But the rust really isn’t too bad, I was just kind of bummed to find it. Previous owner put filler over it an rattle canned the engine compartment. Even the floors in this car weren’t too bad, but I ended up doing all new floor pans for piece of mind.
 
Don't waste your time with the over priced rust BS products they sell out there.
Phosphoric acid from Home Depot, $6 a gallon. Put it in a spray bottle, mist it down, let it set overnight then wire wheel it the next day. Make sure you clean it very, very well. Get all the acid off.
Skim coat of filler, sand and prime. :thumbsup:
 
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Thanks again for the advice guys. I will blast it, what primer would you guys recommend. I don’t have a paint gun or compressor set-up to do it. I was going to buy epoxy primer, paint and a 2k clear in spray cans from my local paint supplier. I’m not sure how it will turn out, I don’t want to wast my time. But don’t really want to trailer it to a paint shop just to get the engine bay painted.
 
Thanks again for the advice guys. I will blast it, what primer would you guys recommend. I don’t have a paint gun or compressor set-up to do it. I was going to buy epoxy primer, paint and a 2k clear in spray cans from my local paint supplier. I’m not sure how it will turn out, I don’t want to wast my time. But don’t really want to trailer it to a paint shop just to get the engine bay painted.
At this point it's probably a worthwhile investment to buy a paint gun if possible. I don't think there are any good rattle can options as far as paint goes.

In that case I recommend SPI brand primers, most people like the epoxy because its more durable but I like to use urethane a lot of the time.

For paint I use the restoration shop line that tcpglobal sells.

Both cheap and work well in my opinion.

Check out my cowl rust repair thread (https://www.forbbodiesonly.com/moparforum/threads/cowl-rust-repair.163953/) I used that primer and paint

For the gun, I hear the harbor freight one isn't that bad actually.

If spraying isn't do-able then you might consider brushing or rolling paint on. Then wet sanding and buffing out

the two part stuff that you mix together is much better than the 2k primers and paints in a can, imo
 
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I agree. Buy a small spray gun to shoot the primer on with. A rattle can has very little solids in it, it's all solvents. Look at the size of the pin hole nozzle. You can't put product on with a hole that size. These little guns work great for the small areas your touching up, and they are $29 at walmart and probably cheaper at HF.
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Ok. You guys have talked me into it. I will end up blasting the rust and using a bit of filler. I will have to go talk with the guys at my local paint shop to make sure I get everything I need that is compatible and a good fit for my project.
 
Ok. Sorry to bring back an old thread. But I finally went and got the paint to do my engine bay. I basically went to the paint supply store by me and told them what I was doing. I attached a photo of what they sold me. I also got the paperwork for the products. So my questions are. Do I have to sand the primer surfaced before I topcoat with paint. And what grit should it be. 400? It doesn’t mention in the paperwork, it just says 1-2 hours before sanding and topcoat. My other question is should I do all my filler on the bare metal or should I prime, do filler, sand and then prime again? Sorry but I just don’t want to mess it up and googling it just gets me even more confused haha. If someone can break down the steps that would be awesome.

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I do the major filler under the primer to give it some bite (rage extreme)
then expoy prime over it then go back over the smaller parts with filler (rage ultra) and prime it again with 2k primer (rage ultra and 2k are easier to sand)
wet sand with 400 (would be what I would use)
then topcoat
you have the jist of it.
 
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Thanks for the reply, ok so here is my plan. Sine it’s an engine bay, I’m not doing a lot of body work.
1. I will strip the engine bay to bare metal with wire wheels, then scuff up the metal with 180-220 per the primers instructions.
2. Then I will apply filler on spots with a little pitting and where I did some welding. I will sand the filler with the same 220.
3. Wipe everything down with wax and grease remover and spray 2-4 coats of primer surfacer per the primers instructions.
4. Wait 1-2 hours and then sand with 400 grit.
5. Topcoat.
Not to beat a dead horse, but does that sound like a good plan?
 
Where you apply the filler I would personally use 80 grit on the bare metal to start. It will help adhesion. The primer will fill up those scratches easily just don't go crazy. When you block out and sand the primer and filler avoid creating grooves when sanding with bare hands finger tips, consider small blocks and chunks of hard foam to stick the sandpaper to, those will help keep the surface uniform. Also I would start with 150 on the filler, and finish with 220. You could do it all with 220 it would just take a little longer.


What topcoat are you using? Single stage ?
 
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No problem, it is good to ask questions first. Sorry this ended up a bit long, but seemed necessary. This worked well for me many times. YMMV

I’d use wax and grease remover before wire wheeling and again after wire wheeling.

The engine compartments of mopars have many ripples and waves in the stamped metal. We don’t want to try and fill all of these details, we just want to avoid seeing sand scratches, weld seams, and pinholes from our repairs in the finish, but smoothing It like the outside of the car is not factory.

Do you have filler primer? I can’t read what your products are. I’d not use that on the entire compartment, it will start filling in around bolt heads and tight areas. I would only use filler primer where you did filler work, if necessary. I would use a light coat of sealer on the whole thing before painting. Filler primer is great on the outside where it will be block sanded down. You cant easily block sand filler primer in all the nooks and crannies of an engine compartment.

I would like to see you sand the filler down close with 220. Then finish the sanding of the filler with 400 before applying the primer.

I would recommend sanding with 80-120 on the rough pitted areas that will have filler. Sand the rest of it with 400 grit. I’d skip the 220.

This will make it smoother with less for the primer to fill. Reduces the chances of shrinkage and showing scratches under your paint.

(A friend has his entire 1968 charger body shrink back after painting, now the whole car shines great and shows sand scratches everywhere. It’s really a horrid sight.)

PS: did you get the product information sheet? It says how many coats to apply and how thick it will be, how long to let it before sanding, top coating, etc. you can find it online if needed.
 
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They sold me a primer surfacer. Is that the same as a filler. I asked about if I needed epoxy and he said no. The topcoat is single stage. I’m not trying to smooth out too much. You can just see where I welded in the inner fender braces and the light pitting under the battery tray.
 
I would go back and get some Shopline epoxy primer. It has a sealer in it, so if you don't have to do any bodywork, you can paint right over the top of it. Do it within 3 days and you don't have to scuff. I really like using epoxy on everything.
 
They sold me a primer surfacer. Is that the same as a filler. I asked about if I needed epoxy and he said no. The topcoat is single stage. I’m not trying to smooth out too much. You can just see where I welded in the inner fender braces and the light pitting under the battery tray.
You don't need epoxy, no. Is it slightly more protective against the elements? yes. The bad thing about epoxy is it has to be in a 60 + degree environment to cure properly if it's too cold it will never work. Also is more expensive. Its probabaly overkill here.

If your doing a whole car, floor plan, or another large area that needs protection and has been blasted or dipped to bare metal then I would reccomend epoxy. but for this, what you got is more than fine.

A primer surfacer, also known as a high build primer is meant to be block sanded. It is meant to have some thickness to it so you can sand it down perfectly smooth. You could reduce it or just shoot it thin surrounding the main area. Sort of feather it out. Just don't crazy with it on your engine bay especially in the creases and around bolts as mentioned. It does build up thickness.

Surfacer achieves the same thing as filler but to a lesser degree. They are different. Filler is meant to go on thicker and has more strength to it so it can be left up to 1/4 thick. It's almost like soft cream cheese consistancy and you spread it on like putty. Surfacer is sort of a spray on filler that isn't as strong. You can't put it on as thick so it will only remove small imperfections. You don't need filler for what your doing. The surfacer will work fine
 
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