one shot drain cleaner - de-rusting

[JonE]

I'd been using this for derusting baths with added water - 91% Hydrochloric - but it's not available from hardware store anymore without licence apparently.
Can anyone recommend something as good - Sulfamic crystals seem to be available on ebay, but not sure if will have as much oomph. Or does anyone know where its still for sale?

[Spex]

Concentrated Hydrochloric acid is used to change the pH in swimming pools.
Try a pool supplies shop.
Cheers, Peter

[JonE]

excellent - thankyou.

[Davemayle]

'Brick acid' from builders merchants is another option Jon. Also called 'patio cleaner'

Dave

[Bob Culver]

Plumbers used to  use hydrochloric extensively. Was their spirits of salts for soldering, usually "killed" with zinc.

[Parazine]

I find de-rusting by electrolysis is very effective.

Get a large bucket and a sheet of 20 gauge steel. Cut the steel to make a plate that goes around the inside of the bucket with a lead connected to it.

Connect another lead to the item to be de-rusted, fill the bucket with a solution of washing soda (sodium carbonate). Put the item to be de-rusted, attached to its lead, in the centre of the bucket, immersed in the solution, make sure it can't touch the sheet round the edges.
Now connect the lead going to the 20 gauge sheet to the positive pole of a 6V battery. Connect the item to be de-rusted to the negative pole. You'll need to connect a charger to hold up the battery...
Leave for between 2 and 24 hours. You should see bubbles rising. Beware, they are bubbles containing hydrogen, so no naked lights! At the end of the time, you can then remove the item, wash it carefully with clean water and wire brush it, the rust will fall off! If there's still stubborn rust, return to the bath for another few hours. Only parts with "line of sight" to the 20 gauge sheet will get cleaned so you may need to reposition the item several times.

Note: DO NOT ALLOW Stainless Steel into the bath, don't use Stainless bolts or nuts. The chromium leaches into the solution and forms some nasty, poisonous compounds.

You can use a 12V battery to speed up the process but you'll need a heavy duty charger as the current flow will be quite high, perhaps 10A.

Just finished doing the block, head and con-rods for the Top Hat engine.....Photo's to follow.

[Bob Olive]

There is a very cheap, very efficient, very safe (non-acid),and very eco-friendly way of derusting which requires only washing soda, a 12v source of power (an old-type battery charger will do), a plastic washing up bowl, or water butt or similar, and a six inch nail!! If anyone wants the recipe and MO please PM me, or I can post the details on the forum if any interest...

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Just read Parazine's electrolytic process which is pretty much the same is as mine... I have not used mine on any large items, but I have not used any stainless steel plates, (just the items aforementioned) - or the like and had excellent results. I meant to say you will also need a wooden batten to straddle the bath, bucket or basin!

[Bob Culver]

Note that acids and eloctroplauing are regarded as dangerous applied to ferrous parts of reasonable strength (ie spokes, springs, steering, engine internals). Promote hydrogen embrittlement and fatigue sensitivity. (Some major modern very tall London building was plagued by hydrogen problems)

[Chris KC]

I tend to find that a good scrub with a wire brush does the job as well as most potions and generally faster. Not much good inside things of course.

[Howard Wright]

Hi All

I’m a fan of using molasses to de-rust  Takes a long time but the results are surprising AND you don’t have any nasty toxic or harmful chemicals to deal with!

Cheers

Howard