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Re: Descalers

A point which doesn't appear to have been made on the use of acid descalers is that they must contain an appropriate inhibitor. Neat acid will do serious damage as so far described. Proprietory descalers should have in them an organic compound which inhibits attack on the bare metal once the scale has been removed. The compound forms a passive layer to protect the metal.
At one time I regularly used contractors to descale the tubes in heat exchangers including steam raising waste heat boilers. A rig was set up which circulated hot inhibited 5% hydrochloric acid for several hours. Control was by frequent chemical analysis to determine the end point. Inhibited sulphamic acid is a good cleaner of copper items as is ethyl diamine tetra acetic acid (EDTA).
If you know of a reputable chemical cleaning outfit they may be the ones to approach if you want some help.
Ron

Location: Thornbury

Re: Descalers

Well my (cheaper) Dynamic Descaler arrived yesterday and I put an old cast iron brake drum in a neat solution of it for an hour this morning...

 photo DSC_0593_zps587eb2ff.jpg

 photo DSC_0594_zps5631844c.jpg

The wheel location lugs, presumably made of steel (?), have not really changed in any way...

 photo DSC_0595_zpsfcd0a77a.jpg

Thanks for all the advice and pointers on this, very pleased!

Re: Descalers

Interesting Ruairidh, thanks. I wonder why the rust on the steel is apparently untouched by the solution??

I also have to ask, why the extra hole in the drum?

Ian Mc.

Location: Shropshire

Re: Descalers

Snail cam adjuster hole for hydraulics Ian.

Re: Descalers

Location: Shropshire

Re: Descalers

Slightly off topic I know but I'm seriously thinking of sousing the boiler in my traction engine in this stuff to remove what little scale there is in it, in advance of replacing the smoke tubes this winter.

Basically I know the stuff HSS sell is designed for the purpose, and has inhibitors as described to prevent corrosion of the steel.

Ruairidh, the stuff you bought does look awfull like the same product at a more agreeable price, and your result is what I would expect. Does any of the 'guff' sent with the product confirm inhibitors are included and is there a dosing rate for the product?.

I've priced up the HSS stuff and am keen to see if a saving can be made, HSS are well known for a heavy mark up (though their customer service is second to none).

Re: Descalers

Data sheet for the stuff I bought is here: http://www.hitek-ltd.co.uk/media/downloads/3/Dynamic%20Descaler.pdf

No other paperwork came with it.

Re: Descalers

hmm, it seems I need a 45 gallon drum of that stuff too.

Better start saving!