Corrosion How To Deal With It..?

Anything at all relating to the cockpit area of a B-26K.

Unfortunately due to export permits etc required for getting stuff shipped across the pond, i doubt i’ll be getting anything bigger than what will fit in an airmail envelope.

Is there a budget in place?

I tackled another piece today. Fortunately it only had minor rust in the latch holders and a couple of good dings which were easy to hammer back out. There was no apparent corrosion on it from what I can see but I will monitor it just in case…

Permits shouldnt be too much of a problem – depends who you are dealing with.

Let me know if I can help

Bruce

Anything at all relating to the cockpit area of a B-26K.

Unfortunately due to export permits etc required for getting stuff shipped across the pond, i doubt i’ll be getting anything bigger than what will fit in an airmail envelope.

.

Timely question that i’d like some answers also please. The Invader is covered in pockets of corrosion small, large & huge and the ally’ is delaminating.

The underside is especially bad having been sat outdoors in water & vegetation for 20+ years. Blasting it isn’t an option due to the size, what else can i do ?
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I’m fairly familiar with A26’s, what parts are we looking at there? At least one looks like the spar…

Sorry, no.

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Timely question that i’d like some answers also please. The Invader is covered in pockets of corrosion small, large & huge and the ally’ is delaminating.

The underside is especially bad having been sat outdoors in water & vegetation for 20+ years. Blasting it isn’t an option due to the size, what else can i do ?
.

Have you worked out how you’re going to tackle it Dave and have you got any more photos of progress?

John

ZRX61 this will help you. just do not use stripper on Mag as it will turn your nice Magnesium into a 60 year old field find. As above use Celeneous Acid,

I was just curious if it was still available in the UK is all. Here in LA we just drop the parts off at the shop & go back the next day to pick them up all sorted 🙂 Altho it’s been a while since we needed any done.

If you want to turn Magnesium into cookie dough give it to someone who does anodizing 😉

& just a heads up: Filler over etch prime is a no-no. The acid prevents the mud from kicking off so somewhere down the road it parts company with whatever you stuck it to.

Hello Tony.
In case I havent said it, I value your advice and opinions and I will read through the attached I promise. Thanks very much!

Does anyone in the UK still offer Dow7/Dow9 coating for Mag?

I have to admit I walked away from this thread after getting stalked on it….

Either people want professional help or not, I do not need it. Anyway, that aside

ZRX61 this will help you. just do not use stripper on Mag as it will turn your nice Magnesium into a 60 year old field find. As above use Celeneous Acid, also

So what did you end up doing?

I ended up grind out the corrosion down to bare metal. Some areas I had to use small amounts of body filler as some of the corrosion went fairly deep. Once I had cleaned the areas down to bright metal again and the filler had dried, I lightly sanded the whole panel with finer grits of sandpaper. A quick wash and degrease and it was ready for primer. Two coats of primer two coats of paint and voila!

very nice Peter, top job:D

Alu prep or metal prep is completely different, they are simply surface cleaning/prep products using phosphoric acid, after which a normal etch primer should be put on. The clear etch is actually and etch primer, acid chromate I think. You can tell where you have sprayed it, because it turns the metal a uniform dull finish. granted its not the easiest stuff to use, when you can’t see so well where you are applying it. I would suspect that it’s usually applied with an electrostatic spraying kit to make sure it’s covered.

Dow thwmselves still do it. you want Mil-M-3171 Type I and III. The proper way to treat it first before Dow#7 dichromating, is with Celeneous Acid, but at approx £50 per 150grams at last check, phosphoric acid solution is just fine! Dow #7 is expensive and I dont believe much more effective that a good allochrome or Alodine treatment. we etch ours by submerging the parts in Allodine, until they have turned gold. Then a good few coats of non etc primer, followed by several top coats, then laquer. no corrosion has returned yet.

If you want to know about magnesium treatments, Dow themselves do a very good book. “Operations in Magnesium Finishing”, 1990 The Dow Company

the books will tell you NEVER EVER user phosphoric solutions on Magnesium based parts. Well you can take that with a pinch of salt. We treat Mag parts often with phosphoric based methods. So long as you thoroughly wash off the solution afterward, there really is no problem at all. blasting won’t always remove the corrosion in deeply pitted areas, magnesium parts being a prime example, and chemical is then the only way to get at it.

Does anyone in the UK still offer Dow7/Dow9 coating for Mag?

So what did you end up doing?

MRJ et all.
Here are some pictures of the work and the finished article.

How do you know where you’ve sprayed it?

Sounds like what we call “metal prep” which is basically phosphoric acid diluted enough so it doesn’t turn the air yellow & dissolve your eyelids. Spray it on & it etchs the surface with a slight rainbowy/yellow tint.

You can see where it is because the metal reacts. I’ve got some steel car parts I used it on 5 years ago that I haven’t got around to painting yet & there’s no sign of corrosion.. however, I live in the Mojave Desert which is drier than a popcorn fart. I even have some steel engine mounts that I bead blasted 12 years ago that haven’t gone rusty yet.:p

I suggest you read some of the early posts again, I believe garnet was mentioned, that’s definately grit. 😉

Missed the reference to Alf, he was fairly coarse. 🙂

You’ll have to forgive me, but I shall have to bow to your obviously great experience in boat anchors and getting your supplies from pet shops, I speak from experience of decorroding aircraft structures on an almost daily basis in job I’ve been doing for quite a few years.

Actually we get out supplies from McMaster Carr in 5 gallon buckets or 50lb bags. The pet shop comment was aimed at people who only need enough to do a few parts, not 50lb at a time.

I also speak from a couple of decades of dealing with warbirds on a daily basis, including one of the Wildcats that came out of Lake Michigan. Current list covers an F7F, 3 Staggerwings, a Stearman, a few T28’s, about 8 Mustangs, 2 DC3s, a DC2 & a halfdozen T6/Harvards… It’s how I make my living.

& my only experience with boat anchors came during my 4 yr apprenticeship with Jaguar :diablo:

“Clear etch prime?
Cellulose laquer (what people often just call *laquer*) certainly doesn’t etch so what product is clear & etchs?”

not a cellulose laquer. cellulose is frowned upon in the UK now, its nasty stuff. A pigmentless acid etch primer. You can get it at any car paint specialists in the UK. It’s used to provide a base for such vehicles as bare aluminium panel land Rovers etc. It’s simply a metal etch primer with no pigment in it. ever seen a bare aluminium Audi A8 or a6 is it? the aluminium panels are etched with clear, then covered over with acrylic laquer layers, to bring the shine back. its clever stuff.

How do you know where you’ve sprayed it?

No one is talking grit blasting & the only media that could possibly qualify as “expensive” is plastic & thats only because it;s twice the price of the others.
I’ve found that for small quantities of walnut media that the local pet shop is the place as they sell it for parrots

We’re talking about aircraft parts here, not boat anchors.. 😉

I suggest you read some of the early posts again, I believe garnet was mentioned, that’s definately grit. 😉

You’ll have to forgive me, but I shall have to bow to your obviously great experience in boat anchors and getting your supplies from pet shops, I speak from experience of decorroding aircraft structures on an almost daily basis in job I’ve been doing for quite a few years.

“Clear etch prime?
Cellulose laquer (what people often just call *laquer*) certainly doesn’t etch so what product is clear & etchs?”

not a cellulose laquer. cellulose is frowned upon in the UK now, its nasty stuff. A pigmentless acid etch primer. You can get it at any car paint specialists in the UK. It’s used to provide a base for such vehicles as bare aluminium panel land Rovers etc. It’s simply a metal etch primer with no pigment in it. ever seen a bare aluminium Audi A8 or a6 is it? the aluminium panels are etched with clear, then covered over with acrylic laquer layers, to bring the shine back. its clever stuff.