Exhaust manifold cleanup

[oldcarnut]

While replacing my exhaust I decided to try and dip my exhaust manifolds while they were off. They didn't have any gaskets under them and I had to redo a broken stud.  I had bought some muriatic acid from Lowes for an earlier project and wanted to see how it worked on my manifolds.  Pics are before, during, and after.

[oldcarnut]

After removing from the acid I wash it off with water, dried it,  then wire wheeled any powered residue.

[oldcarnut]

It also loosened up a lot of carbon deposits inside that washed out.  All that was needed next was some VHT very high temp header paint.  Thought it was going to be a darker gray but maybe after the heat cure it will go darker.  Worked good for me and seemed to knock out the rust.  This can't be done in a closed area-needs good ventilation.  Puts off a lot of fumes for which a respirator needs worn and of course safety glasses, and water hose while your handling it.    
David

[resq302]

VHT makes a Nu Cast cast iron paint that is good up to 1200 degrees.  Duplicates the raw cast iron exactly.

[TylerCharger69]

Yep....Muriatic acid is what I use in instances like that. A very costic material but it does loosen up rust, carbon, and anything else under the sun

[Just 6T9 CHGR]

Looks great!  Color looks a lot like my Jet-Hot coated ones....

[dstryr]

That looks great.   I'd add that I wouldn't leave anything soaking in an enclosed space or the vapors could affect exposed metal. 

[Chatt69chgr]

Your manifolds really came out nice.  Thanks for documenting the procedure.  I may try it out on some myself.  And yes, the fumes will float around and corrode everything in the area.  Best to leave the bucket outside with a ventilated lid on to keep the local neighborhood pets out.  If there are any kids in the area, that would be another worry as the acid is nasty stuff.  After finishing, you can neutralize the acid with baking soda and then just pour out and hose down with water.

[oldcarnut]

I think it wasn't much more than around 30-45 mins + or - that I left them soaking doing one at a time.  Definitely the best place was outside but even with an occasional light breeze every now and then, a whiff of the fume smell would creep in the garage and it could not be missed. Should have had a cover but I didn't have one for the containor I used  .  Next time I will.  Trust me when I tell you not to breathe in over the acid with no respirator when your moving the parts around or stirring the solution  .  No kids or pets were around and I told the wifey to keep away.  You can pour it back in the original Plastic containor or leave it in the new plastic one for reuse later.  I have used this batch several times.  Works great but keep it safe.

[Nacho-RT74]

mmmm NOW thinking on get it on muriatic acid myself instead take my heads and intakes to a machine shop to make that.

do you say less than hour is enough for each piece ?

[hemi68charger]

That looks great...... 

[62 Max]

 I don't want to sound negative but wouldn't glass beading with fine glass accomplish the same thing with less effort and cost ?

[oldcarnut]

I don't want to sound negative but wouldn't glass beading with fine glass accomplish the same thing with less effort and cost ?

Well for me I didn't have a good blaster.  The one I do have from Harbor Freight leaks dust all over the place and works not too good anymore and would have taken a longer time.  Also I wouldn't have been able to get inside the cavities like the acid did.  When I hosed it off, a lot of carbon buildup came out with it.  While it was soaking I used the time to work on putting in the motor mounts.  Blasting may have been a safer way to go but if you take precautions I feel like this was more effective in my circumstance. I guess it's a matter of whats available to use or have to pay to have someone do it for you.  I think it was around $6 gal when I got it.
http://www.lowes.com/lowes/lkn?action=productList&N=4294961544&Ne=4294967294&Ntk=i_products&Ntt=muriatic  Mine was the 1st blue container.

mmmm NOW thinking on get it on muriatic acid myself instead take my heads and intakes to a machine shop to make that.

do you say less than hour is enough for each piece ?

It was for me and I would say it depends on how fresh the acid is and how bad the surface is.  If you look at the pic it's pretty black looking from contamination lifting off and of previous uses.  Some of it started boiling up right away and other heavier rust areas took a little longer.  I also didn't have enough to completely submerge it.  I did take a piece of pvc tube to stir it around occasionally.  You can see it turn black when it's done most of the work.  If you try it just monitor it but should be less than an hour and maybe less than 1/2hr if it's fresh.  Try a junk piece first to get an idea  I'm going to do my intake also.  I have some extra intakes and may try it out a little later and post a pic.  Not so sure what effect it would have on the valve seats in the head.  I haven't done that.