Dash & Under-hood Bodywork & Paint help

[Mr. Notorious]

I suppose there's no better time to cleanup some things that have been bothering me while I am taking out the entire wire harness. I am far from a body guy so I'm having a hard time figuring out the best plan. I tend to want to try to do the "best" thing I can the first time around, with the goal of not having to re-do something again in a few years. I am not doing a full restoration that I'm expecting to win awards for. Would be interested if there's another forum y'all would recommend for this kind of stuff, I checked out our paint & body section and it was a little quiet in there.

Back to my project, I think I have 3 unique scenarios I'm trying to work on. Under dash rust that can't really get sanded, engine bay that can kind of get sanded, and the dash which can easily get properly prepped and done "right".

1) Under dash I have alot of surface rust. It's obviously not an area that can get proper surface prep and prime and paint it right. Should I just get a wire brush where I can, maybe a wipe down, and get a basic rust convertor rattle can and go to town under there? Any brand suggestions or better ideas? Do you then paint over the rust convertor, or just leave it as is? Are the brush-on rust convertors better performing than the rattle can? Does it really pay off to get the surface prepping in, or does the rust converter stuff work pretty good afterall?

2) When I finally pull the last bit of wire harness out, I am considering freshening up the engine bay too. I can def surface prep better than under the dash, but it's still not going to be great access with the engine still in. Frankly I am also not interested in spending 10 hours of surface prep time to do this since you can see it's all kind of an embarrassing mess in general. Do I just get those sanding sponges (80 grit?) and scuff up where I can, wipe down, and then do the basic paint and primer? Is there a big difference in performance between rattle can and a spray gun for this application? Is there certain paints/brands I should be looking for? Any tips or suggestions?

3) I welded about a dozen patches in the dash from who knows how many previous owner's adding old switches, indicators, and whatnot. I would like to spend a little bit of time here to test my skills here.

I kind of got overwhelmed watching some of the Eastwood company's youtube videos talking about high build primer, body filler, glazer's etc. For my level of detail to this project, I think here is what I gathered I need to do, please correct where wrong.

1. Ideally get it down to bare metal, 80grit-ish. I have some old filler to get rid of under the dash still. (Do I need to go nuts here getting it down to 100% bare metal, or can coatings stick to these other coatings ok?)
2. Work out any remaining dings/dents with hammer and dolly (I think I did 90% of this already, but need to go over it again with a straight edge).
3. Spray Epoxy Primer. (I assume if it's been a few days since I did the sanding I should hit it again quick?)
4. I believe I read that within 72 hours of epoxy primer, I need to apply body filler. I guess I'll pick something off of eastwood's website? Any particular recommendations?
5. Smooth down the filler so it's all flat. (80-120 grit?)
6. Spray a high build primer, sand down again as needed (120-240 grit?)
7. Spray base color, 1-3 coats. Then do I still do a clear coat over it? I don't think there is much clear on this vehicle to begin with, so I don't want to end up with super glossy dash board with the rest of it being some early 90's paint job. For this type of project, is there a decent different between rattle can and spraying?

I already have a compressor, DA sander, buffer, etc. After writing this, I am thinking about rolling it outside and just getting a Harbor Freight sand blaster to help with the under dash problem and the engine bay. Trying to avoid making a big project out of it, but like I said I do like to challenge myself and see how "right" I can do something, and see if it's something that I'd like to do more or less of in the future. If anyone wants to make a suggested list of things to get I would definitely be appreciative!

 

[sggoat]

your choice to get the thing outside and blast away on the under-dash, etc. is prob good--Buy a lot of sand!!--Don't use the glass beads HF hypes--it won't clean off that rust very soon. if you elect to use some of Tractor Supply or Northern tool black diamond blast media get the medium grit(be aware this stuff may be regulated as a hazardous substance in your area)--so make sure you have some containment--AND be sure to protect yourself--blast hood and suit.
my experience says don't try to put ANY coating over an old one--get the old off--all of it--it's like using a wire brush on a rusted surface--you are just 'polishing' the rust--you gotta get it off--
Keep at it, you are going in the right direction---and keep the pics coming!~

 

[macdaddy59]

I built my own sandblaster and use fine grade contractor sand, It is $6 for 50 lbs. It does make a mess so you need to do this in an area where you can let the sand accumulate without worrying about it. I have sandblasted the entire fj40 frame, body, every part and then used epoxy paint to seal the metal. I hate rust.

 

[wimberosa]

Perhaps I'll just chime in with a minimum suggestion since this isn't a body off and you are wanting to just
protect certain areas.

1. Am somewhat uncertain but I doubt you'll see much love on here for "rust converters". There are many reasons but the
thing you really want to do is to get rid of as much rust as you can to start off with.
Minimally thats wire wheeling it and using products like evapo-rust
(which @Malleus likes) and/or krud-kutter rust remover (which I like). Obviously there are other types of stripping wheels
and other rust removers.
2. Protect / seal it as best you can. Thats probably an epoxy primer. Since you aren't shooting a whole lot on here..you could
get something like the eastwood epoxy primer in a can. If you go that route....get the version that you actually have to actuate
and mix via breaking an internal membrane in the can. There is a different version that supposedly mixes on the fly...but I'm
not a fan of it as I'm not really sure its doing what it says it does. The "version I prefer" has a short can
life after its mixed.

POR 15 could potentially be another sealer type....but I don't want talk about that as there are very strong opinions there
from some.

3. You may want to just rattle can on top of it. When you start talking about 2 stage painting....you are using an hvlp gun and
learning a whole process to get a clear coat on top without running. Obviously you can go with single stage or 2 stage
with a paint gun but you are buying into a good bit with both time and money.

Get it back together and enjoy the ride. I'm sure it will last quite a long time if you even do the minimal as suggested.

 

[Malleus]

Actually, in this case, I'd use Ospho; EvapoRust only works if you can immerse the part. I've had no luck painting it on anything. Ospho, on the other hand, actually chemically changes the iron oxide to iron phosphate, but in order for it to work in your situation, you have to get the rust down to a really thin layer.

It looks like you're already there in the dash area. Be careful about what you spray it onto - it's a mild acid and it will burn your skin if it's left on there long enough (several minutes) and it loves to eat rubber.

Any acid will "convert" rust; phosphoric acid (Ospho) creates a molecular layer that is especially good to paint onto. The only better first layer is zirconium phosphate, like Houghto-Prep ZP4.

 

[MOTOV8R]

My experience with blasting behind the dash of an FJ40 was that I could never get all the sand back out. Even after it was painted sand would find it’s way out of my dash. I used air to try to blow it all out several times before painting. On my current build I removed as much as I could with wire wheels and scratch brites then used rust converter.

 

[South Texas 97]

From my limited experience take a look at the seam sealer below the front window, firewall area, that is what was driving the water ingress in glovebox and under the dash.
I have several friends who use ospho, I have had success with the CRC rust converter gel product.