Hot Citric Acid Bath

[Onoff]

Why are some thinking it has to be a box shaped tank?
If you excuse the pun, think outside the box.

Think along side the idea of a BIG plastic bag.

Place the item in a sealed bag, fill with the solution. Seal wait.

A good idea about the bag. I wonder, does excluding air from the process hasten or slow derusting?

 

[The_Yellow_Ardvark]

If the item is fully covered any air in the bag will have no effect.

But if any part is exposed it will rust.

 

[Dcal]

Thinking to mount the bath up on 4 bits of slot together scaffold. Maybe a couple of bits of Unistrut lengthways if the bath feet don't sit right. Fill it up with 160L water. Then a quick homemade solar thermal panel o/of some leftover Pex-Al-Pex. Got a scrap OSB board I can mount it on and paint black. I could really go to town and frame it, glaze it and even insulate! Let it do its thing and thermosyphon. All out of scrap of course

The first worry is maintaining 65degC?

Now I'm the last person to talk when it comes to over complicating things but do you really need to set all that up for a one off job?

Heat won't do any harm but if you aren't in a rush it's not needed.
Having a container / bag that can take the complete subframe is worthwhile I think, as if it's done in half's the treated half will start rusting while the other half is being dipped.

Some good tips in this thread that I will certainly use in the future.
Especially like @cheb tip of adding containers of water to displace the citric solution (archimedes would be proud)
Also like @The_Yellow_Ardvark plastic bags but I'd be worried about getting a puncture.

 

[The_Yellow_Ardvark]

plastic bags but I'd be worried about getting a puncture.

Duct tape works.
But careful prep will stop that.

 

[cheb]

A body bag would do it very nicely. How easy they are to get I don't know, an ebay search just came back with lots of handbags.

 

[eSCHEn]

A body bag would do it very nicely. How easy they are to get I don't know, an ebay search just came back with lots of handbags.

Try a search for "survival sack" - first one on eBay. They're basically a massive long heavy duty plastic sack for holding a person and not breaking.

 

[Turbo]

Try a search for "survival sack" - first one on eBay. They're basically a massive long heavy duty plastic sack for holding a person and not breaking.

A bivvy bag or a wheelie bin liner could also be used.

 

[Onoff]

A bivvy bag or a wheelie bin liner could also be used.

Good shout on the wheelie bin full stop. I reckon my cross member would fit in one. Pity we don't have them where I live!

 

[Turbo]

Good shout on the wheelie bin full stop. I reckon my cross member would fit in one. Pity we don't have them where I live!

They would make a great cleaning tank, built in wheels & a lid plus they're quite cheap to buy from your council! I've seen them used as mobile water butts by folk that do commercial pressure washing.

 

[Onoff]

Continuing the learning curve...

I left my collection of bits in the strong citric acid mix for a week...big mistake!

What I assume are the bits with high carbon content like the plane blade ends have narrowed, thinned and in the case of 4 circlips for the mower they've disappeared!

Got an old bath ready to put the cross member in. Removed the waste as the Deox-C instructions say not to get near lead, tin or zinc or their alloys and pretty sure that's some sort of zinc alloy. Got to blank it off somehow.

 

[Turbo]

I like using electrolysis but I'm going to give this citric acid a go now.

I have acquired an old but working electric chip pan to do this with a s/s tank & removable element. Is it ok to put the citric acid in the s/s tank, does it affect the tank? The alternative is to hang the element unit in a plastic header tank but that's more work!

 

[Onoff]

I like using electrolysis but I'm going to give this citric acid a go now.

I have acquired an old but working electric chip pan to do this with a s/s tank & removable element. Is it ok to put the citric acid in the s/s tank, does it affect the tank? The alternative is to hang the element unit in a plastic header tank but that's more work!

Stainless steel is fine as container.

Read here/see attached PDF:

http://www.bilthamber.com/media/dow...FjABegQIBBAI&usg=AOvVaw0d1VS89s9wJBTMapI-viQy

I'd try and keep it to 65degC and don't leave in there too long.

 

[Turbo]

Stainless steel is fine as container.

Read here/see attached PDF:

http://www.bilthamber.com/media/dow...FjABegQIBBAI&usg=AOvVaw0d1VS89s9wJBTMapI-viQy

I'd try and keep it to 65degC and don't leave in there too long.

Thanks for the pdf, a lot of useful info in that including dilution rates.

BTW, how do you attach a pdf to a post. I tried before & it wouldn't let me attach anything but photos.

 

[Onoff]

Thanks for the pdf, a lot of useful info in that including dilution rates.

BTW, how do you attach a pdf to a post. I tried before & it wouldn't let me attach anything but photos.

You click Upload A File and it appears but with no option for Thumbnail or Full Image then just click Post Reply. It'll be attached at the bottom of your post.

 

[Onoff]

So, got an old bath set up here ready to fill with citric acid at 19:1 and drop this cross member and a couple of other suspension bits in.

Learning as I have that you perhaps can't leave steel in indefinitely, I'll drop it in and keep a close eye on the process. But what to paint it with when I haul it out? It won't be going on the car straight away so some sort of (cheap) holding coat. Thinking maybe this?

 

[Dcal]

Don't put anything on just because it cheap and you think it's only short term.
The first coat is by far the most important and if you put rubbish on you will have the extra bother of taking it off again to do a proper job.
Why do you want to get your parts to a stage where they are perfect for rusting and then store them?

If it was me I would paint them with an epoxy primer, Jotun 87a would be my choice, but any good epoxy would be OK, then apply your preferred top coat over the epoxy keeping to the manufactures application recommendations.

You will probably cause more issues and create more work for yourself by leaving parts in any holding primer as they have a recommended overcoat time and the dirt and grease picked up during storage will need to be sorted.

Just consider the life your suspension parts will have on the car, if your worried about getting them damaged in storage you are not putting the right coatings on them.

If you can't do the above because of circumstances just forget about starting the job until you are in a position to finish it.

 

[Onoff]

If you can't do the above because of circumstances just forget about starting the job until you are in a position to finish it.

That Jotun costs more than the car is worth!

It's really just something to stop further rust after the citric acid treatment and allow storage in a cold garage where metal surfaces tend to get some condensation forming.

 

[Dcal]

Why are you spending the time on something worth £50 plus vat?

Might as leave as is and just spray used engine oil on it.

The existing rust will protect the steel somewhat, removing it just exposes the good steel to the atmosphere so it can rust even quicker.

 

[RaceDiagnostics]

If you don't wipe off the citric acid solution and just let it dry, that will protect till you need it, wash anf dry just before you do need it.

I used that AutoTek primer once, it was terrible, seemed to have silicon contamination in it that showed up when top coated.

 

[MG David]

That is interesting. So just allowing the part to air dry with no rinsing works ok?

I have never tried it and I have been impressed by the work you have shown on here. I always rinse and they wipe over with a dilute phosphoric acid solution to prevent flash rusting and to phosphate the surface of the steel. Do you think I am wasting my time?