concrete dissolver

[ferguson_tom]

Hi Everyone,

I recently purchased a trailer which was an old builders trailer so has the normal layer of concrete built up over the years. Any recommendations for stuff to remove it that wont damage the metalwork underneath. Found a few things online but a lot is for cleaning off bricks etc rather than what I am doing. 

Cheers in advance

[Centrepin]

Hydraulic acid, washed off thoroughly afterwards, before it eats the metal.

The stronger the acid the quicker it works.

Very dangerous stuff to work with. 

[Modafinale]

Hydrochloric acid

[The Heron]

1 hour ago, Modafinale said:

Hydrochloric acid

I would not recommend this I spent many years working with this type of material it is highly dangerous and not to be treated with contempt 

[Centrepin]

1 hour ago, Centrepin said:

Hydraulic acid, washed off thoroughly afterwards, before it eats the metal.

The stronger the acid the quicker it works.

Very dangerous stuff to work with. 

Sorry I meant hydrochloric, its the auto spell thingy.

[Scully]

We wore full breathing apparatus when using hydrochloric at work, so be very wary of those fumes if you go down this route, and whatever you do don’t let any chlorine anywhere near it! 😀

[millrace]

Blowtorch and hammer!!....

[Modafinale]

1 hour ago, Centrepin said:

Sorry I meant hydrochloric, its the auto spell thingy.

I know, my reply was a correction.

we used to put this and sulphuric onto each other’s bags at school as our form rooms where Science labs for two years.

probably not accessible to school kids now, we had access to lots of fun ! Lithium/ phosphorus  school friend was a bit of a chemist and we got him supplies to make explosive devices in the woods next to school .

how times have changed 

[miki]

3 hours ago, ferguson_tom said:

Hi Everyone,

I recently purchased a trailer which was an old builders trailer so has the normal layer of concrete built up over the years. Any recommendations for stuff to remove it that wont damage the metalwork underneath. Found a few things online but a lot is for cleaning off bricks etc rather than what I am doing. 

Cheers in advance

That works, it's 10% hydrochloric acid, I think you can get 15% too, like @Centrepin said, the stronger the faster it works. Wear a mask, eye protection and gloves.

It's also excellent stuff for cleaning up Galvanized metal, have a hose ready as water neutralises it.

[Jim Neal]

Hydrochloric acid will corrode any metal parts it comes into contact with.  I would strongly advise against its use.

Phosphoric acid will soften or dissolve cement-based substances, albeit with less speed , but shouldn't harm any metallic parts.  I would try to physically remove as much as you can first, then maybe use a 4" grinder with a flap disc before trying any chemical approach which will really only work on a thin layer of residue - it won't take off an inch thick covering of cement.

If you search for a product called Phos made by Clover Products, that's a fairly strong phosphoric acid solution for de-scaling purposes but it will have a decent effect on cement residue.  You'll need to dilute it about 1:10 with hot water, apply and let it soak in.  start to give it a bit of an agitation with a scraper or stiff brush, maybe wire brush, see how it's loosening up, probably have to keep re-applying the solution and allowing it to soak for some time, possibly overnight.

It'll be a tough old job though!