Tackling rust, need some assistance

Hi! So I’m currently in the middle of tackling some rust repair on my Miata. Im currently in the process of grinding down the old rusty metal. There are some tight spaces that I am having trouble reaching. I was wondering if any of you had any tips on getting rust removed from very tight to reach spaces? The only tools I have are:

• 4.5 inch angle grinder

• Handheld drill

• Electric drill

On a side note, are there any solvents that can help "dissolve" the rust as well that may work in those hard to reach spots? I would like to find a way to remove the rust, and if a solvent would work just as well as removing it manually, then I'd consider it. I plan on coating it all with POR-15 after its all said and done.

Thanks!

Por15 Has to have rust to stick. If you're planning on using that as a topcoat just follow their recommended procedure of marine clean metal ready and top coat. If you want to grind all the rust out or rust converter it for use with a different product. Or welding I'd recommend something like ospho or one of the other commercially available parts store rust remediation chemicals.

You can also try a dremel/rotary tool with grinding stones of different sizes. You can get wire style extensions to get into very tight places. Wire wheels/grinding stones for your drill. 

What exactly are you doing?

Pete

Interested as I need to fix the lower quarter on tubey. No welding skills though. 

bobzilla said:

Interested as I need to fix the lower quarter on tubey. No welding skills though. 

Check out the panel adhesives. 3M is good but $$$

Pete

Thanks everyone! I didn't know POR-15 needed rust to stick...I thought it would stick fine even after most of the rust was removed. I can look for some grinding stones for the dremel, I forgot that I even had one!

I'm trying to get some rust off of the front frame rails...to my horror I saw some up front there when crawling around under the car and decided to tackle it as best I can. I also have almost no welding skills (I can do it, but it comes out very, VERY bad).

Can I use a very course grit sandpaper on the metal to allow the POR-15 to adhere? Or maybe anything cheaper than the POR-15 branded etch?

POR will adhere to non-rusty metal.  I have used it on sandblasted metal and it's sticks very well.  I would suggest ruffing up the surface as you are suggesting though.  As noted POR wants you to acid prep the metal first.  It will discolor to a grayish color if exposed to sunlight, but if not, it does not need to be top coated. 

Oh, I guess I should note, regarding POR-15.... don't get it on your hootus...

In reply to aircooled :

Thanks! Yeah I've been reading about getting it on skin...definitely gonna use gloves, haha! So do you think I can just use something like a 60 grit (or maybe lower grit) sandpaper and be fine, or do I absolutely need to use an acid prep?

Best bet for getting rust out is a wire wheel followed by something like OSPHO to convert what you miss.

POR does not adhere clean new metal, but will stick fine to rust-free pitted metal like you get after wire-wheeling the panel.Wheter this is due to the remaining oxide or the mechanical bond of the rough surface, I do not know.

While I have the experts on line, have any of y'all had experience with "Hydrate 80"? Seems more like a Euro solution to this game but would like to know how effective it is.

I think one the prime reason POR wants you to acid prep is that is doesn't actually "convert" any rust, it just traps it, so that acid neutralizes the rust before covering it.  E.g. if you remove old POR that was put over rusty metal, it's still rusty.  The danger of using acid in your situation, is getting it all off. You are supposed to wash it off with water (so it doesn't keep eating the metal)... which... makes the metal rusty if you don't get IT all off...  The danger of not using it is that you might still have active rust under it.  If it's in a tight, or closed space, clearing out acid and water could be difficult (a hair dryer or heat gun might be useful in those cases)

POR is also flows GREAT, so it will even out rough surfaces, so don't worry about going to rough, just use rough enough to score the surface well.  Sand blasting doesn't make a surface super rough, and it works with that for me.

In reply to aircooled :

Thanks! Since this is on a frame rail for a Miata, do you recommend I don't use the acid, and just score the surface well after removing all or most of the rust manually?

Evaporust works quite well for removing rust, and it's available in gel form for use in areas like frame rails.

Using the acid is best, unless you don't think you can remove it, e.g. it will flow down inside the frame.

stuart in mn said:

Evaporust works quite well for removing rust, and it's available in gel form for use in areas like frame rails.

Nice, looks like evaporust is available locally too! Thanks! 

aircooled said:

Using the acid is best, unless you don't think you can remove it, e.g. it will flow down inside the frame.

Thanks, I'll have to see after I work the surface a little more and make a decision then.

I have a question for all of you. I decided to tackle the little bit of rocker rust I had as well. I grinded it all down, and this is what I found underneath. When I push on it, it definitely feels like theres still solid metal behind it all. Do you guys think I can get away with maybe POR-15 it and put some body filler over it, or should I cut out the rusty section and weld in a new piece? Just wondering because I do want these repairs to last, since this is a car I would like to keep for a very, very long time. I'm not a very good welder, but I do have a harbor freight welder on which I could possibly practice a little more.

https://imgur.com/a/3WYWPp1

Theres a few photos at that link, I don't know how to get them to embed here.

In reply to Japspec :

Miatas rust from the inside at that location. If it were me, I'd cut that dogleg area out and weld in a new piece. You will find rust behind the outer skin.

DeadSkunk (Warren) said:

In reply to Japspec :

Miatas rust from the inside at that location. If it were me, I'd cut that dogleg area out and weld in a new piece. You will find rust behind the outer skin.

Gotcha, thanks!

If that's an NB, and you are fixing from frame rail rust... Warren knows more about this than I. But it usually requires welding. 

joey48442 said:

If that's an NB, and you are fixing from frame rail rust... Warren knows more about this than I. But it usually requires welding. 

I tackled the frame rail by cleaning up the rust and then putting some POR-15 over it, so I'm hoping that the rust out front wasn't too bad. To me, it didn't seem like it, as when I would push on the metal after cleaning up the rust, it was still solid. The driver's side had a lot more than the passenger. Passenger was not too bad at all. The rocker, however, I think I'm going to try cutting and welding. I'm just not very good at all with welding, so thats why I didn't want to mess too much with welding the frame rail. I was afraid I'd just ruin the structural integrity of the front of the car. My welds for the rocker are probably going to be below average, at best.

In reply to Japspec : I feel like the rocker is much more cosmetic than the frame rail part up front.  So if it looks good that's good enough!

NOHOME said:

While I have the experts on line, have any of y'all had experience with "Hydrate 80"? Seems more like a Euro solution to this game but would like to know how effective it is.

 

I have experience with Hydrate 80. It's just Naval Jelly. Nothing you can't get on shelves here.

If you want a unique British solution for your rust problems, you want deox gel. It's made by the same manufacturer (Bilt Hamber) and is basically like a gel-ified version of Evapo-rust. It's very great stuff. My only gripe with it is that you have to import it yourself via online retailers.