Hot Tanking

[Smokey Eddy]

I don't know anything about hot tanking a block.
I have a bare aaz that i'd like to really clean up. It came from the east coast of canada so it's got some hefty surface rust.
Is there anything i have to be aware of? like ... hot tanking will then require every surface to be re-machined?

I have a very small solvent tank for cleaning parts - definately not suitable for a block but i guess i could find a derelict spot somewhere and just unload a few cans of brake cleaner on it?

I want to make this block look re surfaced and paint it black.
I can post pics if needed.

Hot tanking like this...

[Smokey Eddy]

Would i be better off to pressure wash it in the sun and then dry it really well?
I really don't want to have to hand sand it. blech.
I attacked it with a wire brush yesterday but it still would have taken ages.

Thanks for reading.

[the caveman]

Do you have a food whole sale shop near you? Buy a couple buckets [20l] of malt vinegar. Then a big plastic tub big enough for the block. Soak it in the vinegar for a couple of days, remove and wire brush it. Then repeat. You should be able to get it clean enough to rinse  well and paint.

[Baron VonZeppelin]

Vinegar works good, any kind of vinegar.
The type i buy in gallon jugs at grocery store is only 5%.
Works great on stuff. Never done anything with it the size of a block though.

Best thing would be to have it furnace cleaned since rust is main issue. A lot of automotive machine shops have that now. And its way better than hot tanking.

if you have any rusty brackets etc... have them done too.

The old school hot tanks aim more for degreasing.
Its hit and miss on rust.

Either way you go, no re-machining is necessary.
But all the bearings will need to be removed prior, and of course any plugs.

[Smokey Eddy]

okay. My main concern was the bearing surfaces (not the bearings them selves but where they sit) and the bores, gasket mating surfaces and what have you. I'll try the vinegar since i have a big blue tote that will fit the bare block.
Thanks guys! It should be soaking by the time i go to bed tonight

[Smokey Eddy]

its soaking on one side right now
4 gallons of vinegar later. we'll see how it looks tomorrow.
I also got a gal of Varsol.

[rs899]

Why vinegar?  Why not something that's made to handle rust like phosphoric acid?  I buy the stuff at the big box home stores for around $15/gallon.  Either way, you will need to degrease well before you use an acid or it won't work very well, I would think.

[theman53]

http://www.fullsizebronco.com/forum/showthread.php?t=175550

I don't know about this, but have always wanted to try. Seems all you need is steel that is not stainless, pool ph balancer, and a battery charger. Might work for you.

They also said even with regular steel don't do it under a roof as there are fumes. 2 amp to 10 amp was the settings IIRC

[Smokey Eddy]

Why vinegar?  Why not something that's made to handle rust like phosphoric acid?  I buy the stuff at the big box home stores for around $15/gallon.  Either way, you will need to degrease well before you use an acid or it won't work very well, I would think.

the vinegar was $2.50 CAD gallon at walmart we'll see how well it worked.
I'm not concerned about the grease. it's not that greasy and i have varsol to take care of that.

http://www.fullsizebronco.com/forum/showthread.php?t=175550

I don't know about this, but have always wanted to try. Seems all you need is steel that is not stainless, pool ph balancer, and a battery charger. Might work for you.

They also said even with regular steel don't do it under a roof as there are fumes. 2 amp to 10 amp was the settings IIRC

I really appreciate the info but after reading it i think that's more work that just grabbing some emery cloth or a wire wheel on a drill and going to town on the block which i will likely do afterwards anyways.

[burn_your_money]

I hope you are taking before and after pics

[rs899]

Oh, I see now that you are soaking it in vinegar.  Yeah, too expensive to do that with phosphoric acid, but it works so well that you normally just spray it on and wire brush a few times.  Shouldn't take more than a pint or quart, maybe.  See if the vinegar works.  You can also try muriatic acid (carefully) but have to figure out a way to neutralize it....and don't spray that stuff if you want to keep your lungs...

[the caveman]

Oh, I see now that you are soaking it in vinegar.  Yeah, too expensive to do that with phosphoric acid, but it works so well that you normally just spray it on and wire brush a few times.  Shouldn't take more than a pint or quart, maybe.  See if the vinegar works.  You can also try muriatic acid (carefully) but have to figure out a way to neutralize it....and don't spray that stuff if you want to keep your lungs...

That is one reason i mentioned using vinegar. It's not toxic , and will do a lot of the work without you having to anything other than watch the tube and drink beers while it's at it. Using a wire brush wheel can be almost as toxic as acid if you don't use a good mask, messy also.

[Baron VonZeppelin]

Yep, the vinegar should do 90-100% of the job.

The varsol degreasing probly should have been done first.

I don't neutralize anything after the vinegar.
It leaves a treated looking finish on metal that temporarily resists rusting. Seems to be no need. I go strait to paint after its dried off.

If you rinse/neutral with water = it will orange residue rust when its dried. Especially in pits and crevices.

maybe just run an oily rag through the cylinders when its dry.

I also prefer to paint engines with a brush and oil base paint.
Versus aerosal. A quart will do 2 coats on about 6-8 shortblocks with oilpans. No overspray, better film build, seems to hold up better for longer.

[Baron VonZeppelin]

Get a pic of the half that soaked - versus the half that hasn't soaked yet. I'm with Burn, pix would be interesting.

[rs899]

I wouldn't consider phosphoric acid particularly toxic.  It's in Coke...