Dry fertilizer - would grade 5 bolts be better than grade 2

andy r · Mar 18, 2015

When it comes to corrosion from dry fertilizer would grade 5 bolts have more corrosion resistance than grade 2 bolts, or does it matter? Seems like no matter how much you clean and wash the fertilizer out bolts just rust away. I am thinking I should hit metal components with some spray can rubberized undercoating.

Ken Macfarlane · Mar 18, 2015

No grade 5 doesn't help corrosion. Stainless and plated help.

ypop · Mar 18, 2015

I agree with Ken Stainless will not rust, plated helps but still will rust over time!
Ypop

flying belgian · Mar 18, 2015

stainless.

jeffcat · Mar 18, 2015

Stainless, also wash it out and then a light spray coat of drain oil. Made things on our broadcast spreder last quite a bit longer.

Weldcase · Mar 18, 2015

Always use stainless in fertilizer, or any type of liquid as well, especially pig manure. If you cant get them locally, we should have it.

Bob Harvey · Mar 18, 2015

SS, BUT, there are more than one grade. Spend the $$ and get 'top of the line'. Done.

RodinNS · Mar 18, 2015

Define 'better'... They're harder to snap off after they seize, the same as a gr 2 bolt does.

Rod

ss55 · Mar 18, 2015

I'd stay with the same material and coating that the rest of the hopper is made of i.e. stainless with stainless or painted steel with painted steel.

Machnegative · Mar 18, 2015

Stainless is best choice in fertilizer. It will eventually degrade, but will last longer than gr 5, 3, or 8. Stainless seems prone to galling and sometimes stretching, so I always use lots of anti seize when assembling.

ObsoElitist · Mar 18, 2015

(quoted from post at 18:54:17 03/18/15) Define 'better'... They're harder to snap off after they seize, the same as a gr 2 bolt does.

Rod

You are supposed to use anti sieze compound with stainless, i use it with most hardware to save time and trouble.

Machnegative · Mar 18, 2015

[/quote]

Well said.

jimg.allentown · Mar 18, 2015

The grade of the bolt has no direct relationship to its resistance to corrosion (rust). The grade of a bolt is an indicator of its tensile strength, toughness, and shear strength.
As previously posted, stainless is your best bet for corrosion resistance. Be warned though, stainless is prone to galling. Lubrication of the threads is recommended with an anti-seize lubricant. Also note that stainless is attacked by chlorides.

MarkB_MI · Mar 19, 2015

See if you can get 316 stainless. Hardware store bolts are 304, and often of questionable quality.

The most corrosion-resistant fasteners are silicon bronze or monel. However, they aren't very compatible with steel.

Here's one source of 316 stainless steel bolts.
316 bolts at Jamestown Distributors

showcrop · Mar 19, 2015

Don't apply any coating. As soon as it gets a scratch along with some moisture you will have corrosion under it and spreading fast because the coating retains the moisture.

gene bender · Mar 19, 2015

Thats why you save used oil paint a good coat after blowing and cleaning.

Dry fertilizer - would grade 5 bolts be better than grade 2

andy r

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Ken Macfarlane

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ypop

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flying belgian

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jeffcat

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Weldcase

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Bob Harvey

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RodinNS

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ss55

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Machnegative

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ObsoElitist

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Machnegative

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jimg.allentown

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MarkB_MI

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showcrop

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gene bender

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