Flushing the system; overkill??
 

This week I decided to take the afternoon off at work so I could get to some maintenance. I reread Joe's article on using hydrogen peroxide for flushing. Got some of that at the local drugstore at 3% dilution. I had to dilute it even more with distilled water because I simply didn't have enough. Now, this already brought out a good amount of little crap. But I was thinking that with my dilution I wasn't getting the most out of my little cleaning session. I found some hydrochloric acid that the previous tenant had left behind for cleaning dirty toilets etc. That got me thinking; what kind of componentry can be found in toilets: plastic tubes, ceramic, and some metal tubes. I know from the long gone chemistry lessons that hydrochloric acid also eats away metal. But the original bottle had a 30% dilution that i mixed at +/- 9 parts distilled water , 1 part of 30% hydrochloric acid. I pumped this nasty stuff through my system (don't even think of inhaling some of those fumes, it is absolutely nasty, even at that 'mild' solution) switched off the pump for a minute, and started to see some pretty large gunks of black crap floating through the water. Thought that that couldn't be too good, and pumped the solution out again. Now you should have seen the debris that waq collected at the bottom of the cooking pot I was using as a res. The debris I can most easily describe as 1-3mm diameter pieces. They looked like when u dremel into black plastic, the black rocky shrapnel u get as the plastic burns.

What I am trying to get to is this. If the hydrochloric acid , as stated on the bottle, is used to clean plumbing systems: it cannot be that corrosive to metal or plastic, as both of those components are used in plumbing. It looks though that that nasty acid ate away pieces of the black plastic on my second rad.

The other possibility is that the acid dislodged alot of crap from WB and rad.

I have been using only demineralised water and generic radiator additive for about a year now. As distilled water and water wetter can be hard to come by where I live (found out that distilled water can be had cheap from drugstores), it could very well be that WB and rad were getting pretty clogged up. Although my temps were not increasing, like joe's temps made him flush his system.

Sooooo, plz chemists, what happened, did I eat away some good componentry or did I kill the crap?

Thx for sticking with me on this long post,

I dont think that HCl can eat plastics, it is packed and sold in plastic bottles here, so IMHO dont worry about plastic from the rad being eaten by it.

Was the rad brand new when you bought it or is it the used one?
If it is used one, that crap could be sitting in there for a long time, and acid just freed it...

now that u mention it, indeed it is in a plastic bottle. what i also meant was that the crap that came out, looks like burnt plastic, but prolly isn't.

so, would that acid be strong enough to eat such amounts of metal, in such a short notice.

if indeed it is dirt and other residue that flushed out because of the acid. then it is a great method.

You were using very weak concetration of HCl, if I'm not wrong, 3.33 %. That cannot eat metal fast. (good)

I think that you cannot have little chunks of metal because of acid, couse acid would eat metal 'in layers' (dissolve kinda) not making chunks, except if you have metal posts that can be removed from somewhere (not likely), but the only thing that comes to my mind are the turbulators inside heater core tubes, they are small enough... (also not likely)

When I was flushing/testing my system I also got small black chunks coming out from the system, and I found that that were little pieces of black sealing silicone (I used that for sealing the parts of the heater core.

IMO, you should be careful putting acid into the system, you don't want damaged heater core/rad tubes, they are really thin, also, the pump rotor axis, holding the impeller is also metas (in my pump). If you put it, just make sure it won't stay too long in the system...

As for clogged blocks, somebody with more experience is needed here...:D
To be honest, I have no more ideas what are and where from are coming those black chunks...:cool:

thx m8. u took the time to read the post and comment as far as your experience goes. thats further than my experience on the subject, so i learned a couple of things. cool.

NP ! :)

Not all polymers react to acids the same way. I am far from a chemical expert, but deal with plastics and chemical resistance in some of our products. I would recommend either DuPont's chemical resistance guide (online, but must register) or a google search for chemical resistance. Yeah, the stuff comes in a plastic bottle or jug, but your system isn't made of the same stuff as that jug.

FWIW, there are plenty of alternatives to HCl, such as limeaway, vinegar, and muriatic acid. All will eat mineral deposits that are a common result of all but the purest of distilled water. Also, even though an acid may not "eat" a plastic, that doesn't mean that it has no effect. Some plastics become embrittled and may fail later. Something to think about. . .

u probably have a good point there myv65. but the said stuff is used as stated on the bottle to 'remove chalk / cement from ceramic, or used to deblock toilets and drainage pipes. the last part interested me the most. if they use general description of toilets and drainage pipes; then i would hope they mean that almost any pvc type of plastic is not deteriorated. dunno if there is alot of diff between pvc tubing/watercooling and hard tubes.

hope someone can clear this out, because if it didn't eat away my hardware, then it is a mighty good way of flushing the system.

Your HCL (hydrochloric) solution might have reacted with a substance (Water Wetter?), causing the black residue: it might not necessarily be a black substance from any of your watercooling rig components.

A mild acid, like vinegar might be best, dunno.

i think i will indeed use a little less drastic method next time.

The part I'd worry most about is the pump, the rubber seals and such. strip it down and have a peek for your own (and mine! :D ) peace of mind...

well. i would have liked a pure chemists opinion, but from what i remember HCI is corrosive to metal, not plastic. the fluid is contained in an ordinary weak plastic bottle. it is said on the bottle it is good for cleaning toilet and plumbing systems. i was thinking that in those systems roughly the same gaskets and piping is used. so in a mild solution i though it couldn't be too harmfull to my metal parts.

anyway; it is now 5 days ago, and i have absolutely no indication of any leaks. the next time i do a large maintenance i will check the pump, but not now. just did the whole maintenance thingy.