Advice on cleaning up / painting battery area?

[fpvga]

The front corner of my 82's trunk/frunk is looking pretty shabby. No real significant rust issues, but definitely some surface rust and corrosion, on the hood as well, and the whole area is pretty dingy. I am wondering how best to treat it as I clean up the whole trunk. This is a driver but I am picky so want something a little cleaner looking. I have read a ton here but can't really decide if I should do por-15, just some satin rustoleum brushed on, or something else. And also I am nervous about painting without totally stripping it down, but it's not worth the time. Any suggestions on whether just doing a little sanding/stripping of the worst rust and corrosion spots, then hitting it with some brush on rustoleum, is going to cause problems later? Thanks in advance!

[HarryD]

I would wire brush what I can, hit it with an spray on rust neutralizer (Extend or similar), and paint with satin black. Keep doing this every 6-8 months to keep the rust at bay.

[fpvga]

Thanks much. Do you think I need to try and do anything to get under the battery mount plate? Is there a way to do anything besides cut it out?

[Discseven]

Drilled holes and removed the odd perf plates to get access to that area. Scratched & scraped around inside the "caves"... blew them out... then hosed in good volume of rust reformer swabbing up the flow out. Certainly anything done to preserve that area is better than nothing.
.

[fpvga]

Ah that’s a good idea...agree better than nothing.

[4flyboy]

Caves Karl?

Now terrified and donning my spelunking gear.....good advice!

Happy New Year guys.

[ian c2]

Here’s how I tackled it on a later car

Originally Posted by ian c2

Today was a working day , but relaxed and easy .
Ramping up slightly for the modifications stage , as when that happens it will be a little less relaxed and easy ....

Remember I busted off the pressed-in captive nut for the battery clamp due to a rusted thread ?

I had a plan , and we get this weekend off so I borrowed a tiny tig set from work (has to fit in the passenger seat of my daily boxster) and I also borrowed one of our appprentices Tyler as he has a gas bottle and truck and happens to love working on cars in his spare time ..

I have him a couple of m8 nuts and he took the zinc plating off while I went to Home Depot looking for the longest 8mm bolt I could find .

The nut was put on the end of the bolt and coerced through the hole before I flattened the metal that had “exploded” outwards as I fought to get the spinning captive nut out then started to tightening down the bolt so it hit the trunk floor so the nut raised to the metal before finishing the are to a standard Tyler was happy to weld .

The welding was done , weld flattened slightly with a flapper-disc, then the area was masked ready for primer .

I was wary of whatever caused the rust on the nut/bolt causing unseen damage within the cavity between the battery-tray and trunk floor so had previously masked and poured in rust remover .
Now it was time to do the same again with bare-metal primer , but instead of making a “bath-tub” of the area and pouring it in like I had done with rust remover and flush , I was going to use a cavity wand .

Once it was masked I simply inserted the wand wherever it would fit and hoped for capillary action.
If I didn’t see black primer coming from the seams between the spotwelds everywhere , I simply added more .
Then masked/stuffed with rags the obvious leaking areas , and added more .
Then added more .
Then ran the can dry and brushed around the seams with a 1/4” brush .
Then used rags to mop up the mess .
Needless to say , I’m confident there is no more rust and no bare metal anywhere in that area !!!

In the next few days I’ll be applying Shultz and finishing off the trunk .

[ian c2]

More pics

Originally Posted by ian c2

[ian c2]

Probably easier to just link to the thread ..

Originally Posted by ian c2

Just been Out and removed the masking and wiped off any seepage still coming from the seams.

I think I am happy with this repair . ( And it is a repair not a restoration.. )
Things like this play on my mind and I normally end up taking it all apart a few weeks , if not days, down the line to replace the repair with factory parts.
But that would mean completely stripping the trunk and underside to spot weld in a new battery tray and then even then I would have to reinforce the nut with weld in case it seized again in the future ....

It’s a good sign , that looking at the pictures my eyes are drawn to the yellowing plastic on the fluid reservoir , the wrinkles in the tank hold-down strap , and the oxidized copper on the batter/chassis ground instead of the repair

[ian c2]

Excuse the train wreck of that thread .
I’ll go back and clean it up in the new year when I’m working on the car again ..

Finally got my car back !!!

[Locker537]

Here's a thread I started on this topic.

https://forums.pelicanparts.com/porsche-911-technical-forum/1042110-cleaning-battery-area-concerned-about-drainage.html

I cleaned the area with baking soda and water, as well as NoCo battery acid cleaner, and then flushed the area out very well. An inspection camera / boroscope let's you poke around a bit and see how extensive the corrosion is or is not.

[HarryD]

The only reason I do not want to acid wash the area is the difficulty in making sure all traces are gone from the nooks and crannies of this area.

[T77911S]

wash it with baking soda and water. let dry

pour osphoric acid in there to kill the rust.
it wont hurt anything.
wire brush it clean
then paint with something like POR 15
you can even put a cost of extend on first, then the POR.
or paint with WURTHs

[bkreigsr]

There is a lot of 'extra' sheet metal around the mounting platform.
I'm still getting a small amount of rust flakes out of the corners of the platform so my next step is to drill holes like Discseven did and do the peek-a-boo repair.
Bill K

[T77911S]

use
osphoric acid first

[ClickClickBoom]

I use muriatic acic(hydrochloric acid, to remove rust and primarilary zinc and cadmium from steel prior to welding. I store mine outside in a Nalgene bottle, in a plastic bag, the fumes are pervasive. Hydrochloric acid is also a strong degreaser the fumes travel quite aways. You had best douche the surrounding area with a mild alkali solution. The zinc coating on Porsche body panels is very thin and hydrochloric dissolves it almost instantly.
For those not familiar with harsh chemicals be very wary about using anything this aggressive on your car. This is what we use in the aircraft world:

https://www.aircraftspruce.com/catalog/cspages/blkfloatbtm.php?clickkey=10765

Originally Posted by ian c2

More pics

[schoward]

Wire brush the rust best you can, vacuum out, brush some Por-15 and be done. Only thing I kind of wish I did was put one of those $2 'battery mats' under the monster battery when it went back in, but no way i am wresting that thing out until it dies.

[darrin]

replace your battery with an AGM battery (which is very resistant to leakage) once done fixing to minimize the possibility of another acid leak