Neutralising Mag Rot

[farmhard]

Welding galvanized or other processes that release zinc is the main issue with products containing zinc. Zinc phosphate primer is all I've ever used on galvanized panels, spray bomb style or in gallons, aluminum cast or billet, magnesium or other non ferrous alloys like the stuff. It even sticks to copper. Remove the grease and oils with soap or metal conditioner then dry it for a day. Sand or scotchbright. Once that zinc primer sets it won't come off. One coat only transparent. Biggest mistake is two coats or one heavy coat. No need to bake it like some epoxy primers. It just sticks to everything that was well prepared. JB sticks to it. So does silicone and gorilla snot. Pig putty and gastank sealer won't come off.

Using that two part chromate takes too long but does lock down corrosion pits and prior issues. I feel zinc primer does the same thing in a dry environment. Burning out the cases over a 350°F bbq or outdoor oven helps a bunch. We couldn't do that with stuff containing rubbers, plastic or gaskets. Galvanized cowl panels can't be baked either, opps. They twist badly. Cast aluminum stuff can be cooked near 400°F no sweat like intake manifolds or exhaust manifolds.

What I was alluding to is the mixture of Alodine and dipping or neutralizing with water. Flushing it down the drain or your driveway in solution is extremely nasty.
Our old school trick for flux was to dissolve zinc in muriatic acid. You could make a pickle, electroplate or anodize for that matter.
The spray primers IMO are much safer to use, I will post pictures tonight of aerosol etch primers that lifted off the metal and washed off with lacquer thinners so beware the Plastikote and Dominion Sure Seal products.

 

[Lightning Performance]

What I was alluding to is the mixture of Alodine and dipping or neutralizing with water. Flushing it down the drain or your driveway in solution is extremely nasty.
Our old school trick for flux was to dissolve zinc in muriatic acid. You could make a pickle, electroplate or anodize for that matter.
The spray primers IMO are much safer to use, I will post pictures tonight of aerosol etch primers that lifted off the metal and washed off with lacquer thinners so beware the Plastikote and Dominion Sure Seal products.

That's my references to "acid wash" old school dangerous but it works. You can let the water evaporate. Solids go to hazmat recycling.

 

[Lightning Performance]

What I was alluding to is the mixture of Alodine and dipping or neutralizing with water. Flushing it down the drain or your driveway in solution is extremely nasty.
Our old school trick for flux was to dissolve zinc in muriatic acid. You could make a pickle, electroplate or anodize for that matter.
The spray primers IMO are much safer to use, I will post pictures tonight of aerosol etch primers that lifted off the metal and washed off with lacquer thinners so beware the Plastikote and Dominion Sure Seal products.

We peeled a 71 Chevelle with two coats of primer with zinc in it. The roof literally blew off with air pressure. Been there decades ago and did all that separated stuff until we learned not to recoat anything. The paint in the 1980s was well north of 400 plus all the stuff to redo the job. I grew up in a collision shop that also did restoration and hot rods or drag cars. Street rods and stock cars were done there back when I was into 4x4 trucks and cars. Later was mostly late model hard hits.

 

[farmhard]

We peeled a 71 Chevelle with two coats of primer with zinc in it. The roof literally blew off with air pressure. Been there decades ago and did all that separated stuff until we learned not to recoat anything. The paint in the 1980s was well north of 400 plus all the stuff to redo the job. I grew up in a collision shop that also did restoration and hit rods or drag cars. Street rods and stock cars were done there back when I was into 4x4 trucks and cars. Later was most late model hard hits.

Having primer with zinc in it does not necessarily mean it is etch primer. The zinc is added for corrosion. The early automotive zinc primers would sometimes cause the paint to discolor before we had epoxies.

 

[farmhard]

That's my references to "acid wash" old school dangerous but it works. You can let the water evaporate. Solids go to hazmat recycling.

Depending on the process, you need to rinse the acid off. I don't think too many people would go through the trouble to capture and evaporate the water off. On the flip side it is good for killing tree roots in septics.

 

[Lightning Performance]

Having primer with zinc in it does not necessarily mean it is etch primer. The zinc is added for corrosion. The early automotive zinc primers would sometimes cause the paint to discolor before we had epoxies.

They also crack when layered on like fillers. Reminds me of nitrostain.

 

[farmhard]

One way I did this years ago was to sandblast and electroplate a flash coat of a sacrificial metal like zinc or cad. You could solder up holes and then do another flash coat. This would be similar to how carbs were coated with Zmax. I still have the crystals here for the GM carbs. We laid down the softer metals so the acids in the copper didn't attack pot metals. The solder is then a mechanical bond.

Below is the gearcase from a 1989 Johnson that was removed, stripped, sanded and primed with Transtar 2k gallon kit. Then it peeled and was stripped, sanded, primed with self etch and Transtar 2k.
Every 2-3 years the paint shrinks and lifts off in sheets. This was built from 2 motors, cleaned in diesel, steam cleaned, washed with prime wipe, stripped to bare metal and water sanded with 180.
Initially, the paint rep blamed gear oil (case was empty), then not using etch primer. I thought it was the Transtar product but when the self etch lifted off the metal I was confused. Last summer I had some self etch wash off with thinners so it's not doing it's job.
I'm hesitant to do this a 3rd time vs just put another gearcase on.

 

[HansFranz]

It doesn't have to be in chromate form, zinc itself it one of the most toxic elements.

...except in zinc tablets for the flu...or zinc oxide cream as a sunscreen ...

 

[dboyd351]

...except in zinc tablets for the flu...or zinc oxide cream as a sunscreen ...

I forsee another round of Camp LeJune/Roundup lawsuits in the works.

 

[farmhard]

...except in zinc tablets for the flu...or zinc oxide cream as a sunscreen .

I was totally expecting this comment.
That's not exactly true on the supplements and definitely isn't true on the sunscreen either but if you require zinc which is a heavy metal in your diet and on your face that's your choice.
I wouldn't suggest licking a piece of iron either if you are B12 deficient.
I personally won't be hosing these metal conditioners down next to my garden.
Google zinc toxicity in sunscreen, zinc toxicity in vitamins.

 

[HansFranz]

So...zinc is not only "one of the most toxic elements" ... but also an essential nutrient that is found throughout your body and is "a major player in the creation of DNA, growth of cells, building proteins, healing damaged tissue, and supporting a healthy immune system."

Got it! Almost as dangerous as dihydrogen monoxide!

 

[farmhard]

So..."one of the most toxic elements" ... is also an essential nutrient. Got it!

You can cherry pick my comment if you like, then have the debate on eco system vs human consumption and break it down further if you like.

 

[HansFranz]

Better rid your house of every penny made after 1981 ... you're carrying "one of the most toxic elements" ... (gasp) in your pocket.
I bet it's also in your kitchen faucet, bathroom faucets...you're probably drinking the stuff!

 

[farmhard]

Better rid your house of every penny made after 1981 ... you're carrying "one of the most toxic elements" ... (gasp) in your pocket!

I would encourage you to go study up before you make ignorant comments.

 

[huskihl]

Brush it off
Degrease/clean it
JB weld over it

Not rocket surgery

This is like an oil thread except I don’t care to know much about neutralizing mag rot. Clean it and cover wif JB

 

[HansFranz]

Brush it off
Degrease/clean it
JB weld over it

Not rocket surgery

This is like an oil thread except I don’t care to know much about neutralizing mag rot. Clean it and cover wif JB

Yep, I had a Skil worm gear saw that got mag rot after the previous owner stored in on a concrete floor. The lime in concrete will attack aluminum, magnesium, zinc, Zamak, pot metal, etc. (Bases like lime, lye, ammonia, etc., react with these metals.)

I just wire-brush the rot scale, degrease/wash it with Dawn detergent and hot water, brake cleaner, etc., then let it dry real well (a heat gun can help here), then coat it with either thinned-down epoxy or drain oil...

I think the main thing you want to do is seal up all the pores. Otherwise, dew will condense in all the tiny nooks and crannies, and the galvanic corrosion will continue between the dissimilar metals ... if not regular corrosion from lime, etc., being in there.

 

[Lightning Performance]

One way I did this years ago was to sandblast and electroplate a flash coat of a sacrificial metal like zinc or cad. You could solder up holes and then do another flash coat. This would be similar to how carbs were coated with Zmax. I still have the crystals here for the GM carbs. We laid down the softer metals so the acids in the copper didn't attack pot metals. The solder is then a mechanical bond.

Below is the gearcase from a 1989 Johnson that was removed, stripped, sanded and primed with Transtar 2k gallon kit. Then it peeled and was stripped, sanded, primed with self etch and Transtar 2k.
Every 2-3 years the paint shrinks and lifts off in sheets. This was built from 2 motors, cleaned in diesel, steam cleaned, washed with prime wipe, stripped to bare metal and water sanded with 180.
Initially, the paint rep blamed gear oil (case was empty), then not using etch primer. I thought it was the Transtar product but when the self etch lifted off the metal I was confused. Last summer I had some self etch wash off with thinners so it's not doing it's job.
I'm hesitant to do this a 3rd time vs just put another gearcase on.

Sand it with 80 grit. Prepsol before and after. Use some POR 15 over Zinc phosphate primer and don't wait but an hour between them. It won't shrink and it won't crack or lift. I have gear cases well over ten years with no POR 15 just zinc and good prep with Marnier spray bomb cold. We run salt water here all the way upto fresh.

 

[TRTermite]

This thread was a good read..Thanks everybody.