An answer as to Evapo-rust and springs breaking

[J Tiers]

Posted over on PM.

The poster had 4 out of 11 springs break while in evapo-rust. That's a pretty high failure rate for springs that have been sitting there stressed for maybe 30+ years, and then they quickly break in Evapo-rust. Caliper springs, almost surely left in the stressed condition when trying to de-rust them.

Sounds like pretty good proof that Evapo-rust WILL do the stress corrosion routine, and springs or other types of stressed metal are not safe in it.

http://www.practicalmachinist.com/vb...prings-342009/

[johnnyd]

From what I've read, it's a problem of hydrogen embrittlement. They need to be treated without any load/tension on them & baked afterwards.

[J Tiers]

From what I've read, it's a problem of hydrogen embrittlement. They need to be treated without any load/tension on them & baked afterwards.

I do not think so. In fact I can guarantee that is not the problem.

The problem described, which is also a problem I have seen, is direct corrosion that is accelerated 100 times or more by the presence of stress in the material, and a corrosive agent in the solution. The corrosive agent does not need to be some obvious problem like hydrochloric acid (muriatic), it can be something that would not normally be highly corrosive.

While your idea of baking may be reasonable in general, embrittlement is not the primary issue with the parts. They come out of the solution damaged or destroyed. They do not "crack", they get a fairly obvious corroded path across them, obviously in a direction which follows the stress. Internally stressed material, like case hardened steel, may corrode along the lines of stress, and not crack at all.

Your advice of soaking them in an unstressed condition is good, I do recommend that, but it is not 100% protective.

[Forrest Addy]

I'm confused. People are immersing assembled items in a EvapoRust? Seems to me that only individual parts should be so treated.

How long were the springs immersed? Half hour? All day? Jerry is right: stressed parts corrode many time faster than unloaded parts. Sensitive parts should be monitored then pulled and scrubbed as soon as the rust loosens. Read the efffin' label!

Evapo-Rust is not a perfect de-rusting agent. It will attack work left in the solution for too long a time. There is always residue that needs to be scrubbed off. Immersing assembled items ensures pockets of mystery crud lurk in crevices to float into lubricants or wick into paint and blemish it. Loaded springs left for long periods in chemical baths of any type? Felony stupid and never done in competent shops.

[lakeside53]

I immerse assembled parts all the times - Often it's the only way to get them all apart!

[CCWKen]

Springs that are cleaned when NOT under stress are safer.

I'm not sure this is a valid statement. How can this be? There are stresses present in springs at rest by the very nature of there manufacture. There must be some complicated physics and/or chemistry going on and a point where the problem begins. That or the springs had a problem before going into the solution. And why only four of the eleven broke? Why didn't all of them break?

[JCHannum]

That is not really a valid test of Evaporust. Without knowing the extent of the rusting to begin with, the springs may well have failed prior to immersion in the solution, or would have failed regardless of the derusting method employed.

Had all 11 failed, I would say it had some credibility, but since the majority did not, I would say the evidence is in the other direction.

[Joe Rogers]

The process of de-rusting may be a player. It is well known that a part left partially submerged will have an etched line at the fluid/atmosphere border. If the spring was partially submerged this etched spot would be a stress riser.
Joe

[J Tiers]

.......

Had all 11 failed, I would say it had some credibility, but since the majority did not, I would say the evidence is in the other direction.

When almost half broke in a short time in the Evaporust, although they had been fine for decades..... so you say it is better proof that Evaporust does NOT have any such effect of having things corrode and break?

Well, then, I suppose that being wet is better proof that you have had NO contact with water in any form.... I simply do not understand the logic.

There are Evaporust proponents who are unwilling to credit anything that could possibly be considered negative about it. Personally, I do not care, but the question had been raised before.

You can lead a horse to water......

[QSIMDO]

Interesting.
I was not aware of this phenomenon.
The PM post however doesn't say the springs were all in good condition prior to immersion.
Is there more info from the OP elsewhere?

[JCHannum]

Well, slightly more than 36% failed after exposure to Evaporust. This tells me that, if this is a valid test, your chances of not failing after exposure to Evaporust are better than 60%.

I have no particular preference for Evaporust, only giving it a try after seeing it extolled here, It does work, no better or worse than several other methods. I have no idea if it does or does not cause springs to fail, nor do I really care one way or the other. I frequently encounter rust in one form or another and, for the most part, use mechanical means to remove it. That can be scraping, wire brush or abrasives depending on the amount of rust and the value of the object being de-rusted. For large, complex, shapes, I prefer electrolysis. That does cause hydrogen embrittlement, which can be dealt with. I do not use or encourage the use of acids.

The only way to prove or disprove whether Evaporust has an effect on springs is with a valid, controlled test. The PM thread does not meet any of the criterea of such a test and can be considered nothing more than anectdotal evidence if even that.

[dan s]

I agree trying to draw any kind of conclusions from what was posted is a fool's errand.

For all we know, the springs could have been so corroded that the rust was the only thing holding them together.

[elf]

When almost half broke in a short time in the Evaporust, although they had been fine for decades..... so you say it is better proof that Evaporust does NOT have any such effect of having things corrode and break?

Well, then, I suppose that being wet is better proof that you have had NO contact with water in any form.... I simply do not understand the logic.

There are Evaporust proponents who are unwilling to credit anything that could possibly be considered negative about it. Personally, I do not care, but the question had been raised before.

You can lead a horse to water......

It's the Internet. You can believe whatever you want from an uncontrolled test

[J Tiers]

It's the Internet. You can believe whatever you want from an uncontrolled test

Hey there, my man.....

EVERY test or circumstance reported here is uncontrolled.

The reports that Evaporust, or vinegar, phosphoric or molasses cleaned the rust off are ALL uncontrolled tests, so why would you believe Evaporust or any of the others actually cleans metal?

Even if you try it yourself and see that it apparently (as far as you know) cleaned the metal to spotless perfection, THAT is an uncontrolled test, and so, per your logic,, should NOI be believed.

You are simply chopping logic there, and can be safely ignored.

The post I referred to is simply another report, not a "test". Apparently he did not expect the result, and had no reason to believe that the things were broken almost all the way through, which would have, in any case, been VERY obvious. It can be taken at face value as a "datapoint", and something to watch out for.

I find it more likely that there was an effect than that coincidentally, 4 of 11 springs were already broken and cemented by (non-springy!!) rust, but that they still acted like springs, and that they coincidentally all failed while in the Evaporust, when they had been fine for decades before.....

I prefer cheaper and effective rust removers, but I have no dog in your fight. Purely presenting what turned up, in hopes that it helps someone who, like the poster, may not be expecting that.

I have already pointed out that phosphoric will do that, and folks have mentioned that electrolysis will also. Others have basically likened Evaporust to baby formula, as far as safety and risks, and it seemed good to point out a person who had an adverse outcome, so that others can hopefully avoid that.

But I see that the Evaporust users union will try to shout it down, as is usual on this forum. We surely do have open minds here, yessir.

[JCHannum]

I see no one supporting Evaporust. I do see several saying that the PM poster's experience does not offer any proof that Evaporust has a deleterious effect on springs. I do see one poster in the anti-Evaporust contingent wildly proclaiming that this is irrefutable proof that Evaporust will destroy springs. (Even though the majority of springs were not affected.)