Metal spraying advice needed for farm machinery sheet metal

[Clodbuster]

I'm trying to extend wear life on various farm equipment that handles grain or runs in fresh harvested wheat stubble. Our equipment is just getting absolutely killed with abrasive wear. On the inside from grain, chaff, dust, etc. And on the outside, the underside of the machinery, from straw rubbing it as it drives through the field.

This is serious wear. The straw will cut the heads off of bolts that stick out, wear the bottom out of a transmission in a couple seasons. And mild steel seems to take it the worst of all materials. So I'm looking for a relatively easy way to put material back on large surfaces.

I know flame and arc spraying, etc. are out there, but haven't done either. What processes are best for primarily sheet metal work? Ideally something cool enough not to warp thin parts, that will stick well to highly polished surfaces (the bottom and inside of my header are shined like a mirror). A process that deposits long-wearing alloys, etc. on to steel, stainless, even aluminum. If it comes off, I want it to come off in little bits, not peel off in big chunks that will wreck machinery.

Whether this is a machine I can buy and use ourselves, or hire a shop locally to do is fine, but share what you know please!

 

[gbent]

I have never heard of significant abrasive wear on the underside of a combine from straw. I'm not going to doubt you, but I would find some pictures very informative.

There are no thermal processes that won't warp sheet metal severely. Your best bet will be an easily replaced sacrificial layer to absorb the abrasion. Either plastic or stainless steel. There are plastic resellers that stock plastics that are near the factory color of your combine, although I don't recall seeing galvanized.

 

[cyanidekid]

there is no process known to humankind that meets your criteria outside of Hogwarts academy. basic understanding of material science would enlighten you on the difficulties of what you seem to be calling for. a magic wand is the only tool of choice. you might want to head to platform 9 3/4 for that.

 

[Flail]

I would think it would be cheaper and easier to make a skid plate for a transmission rather than building up its thickness. The skid plate could have exchangeable surfaces such as plastic, armor plate, rubber sheet. Let us know what holds up best.

 

[EPAIII]

I am using some spray can truck bed liner on some spring clamps I am installing, mainly to prevent excessive scoring of the aluminum tube they will attach to. No results yet, but it seems to me that it could be considered for this. But you will have to go over the mirror surface with some sand paper first. And a wipe down with some alcohol or other solvent that leaves little residue would also be advisable.

Of course, you could always have an auto paint shop apply it.

 

[true temper]

When I worked in the sand pit we would line the sand handling equipment with old conveyor belting, it lasted way longer than steel and we always had plenty laying around.
A good friend of mine told. Me he had seen small pieces of ceramic tile glued inside of grain handling equipment. I thought that was an excellent idea.

 

[Limy Sami]

+ another on the old conveyor belting.

And UHMWPE is incredibly abrasion resistant - try attacking it with an angle grinder if you don't believe me

 

[Billtodd]

Not much to add other than to confirm the OP's statement about straw and grain.

I was asked to write some software for a local farmer's grain business - when I first saw the grain handling equipment I was impressed how clean and polished he kept them :-)

 

[dian]

im sure there is some "ceramic" coating for steel that is abrasion resistant. might be price prohibitive, though. (e.g. casting equipment gets coated with some zirkonia based compounds, etc.)

 

[john.k]

Ceramic tile might be a goer.....Ive seen ceramic tile epoxied onto coal slurry handling equipment to cut abrasive wear......Provided it didnt get hit with objects big enough to break the tiles...Tiles are about 6"x4" x 1" thick,epoxied onto a grit blasted steel surface.

 

[Clodbuster]

I would think it would be cheaper and easier to make a skid plate for a transmission rather than building up its thickness. The skid plate could have exchangeable surfaces such as plastic, armor plate, rubber sheet. Let us know what holds up best.

That's what we already do for the most vulnerable parts. We install sacrificial armor that deflects the straw and takes the wear rather than the part. I have a row of angle iron under the transmission. It works well for relatively small areas, but the bottom of the header and inside it are too large for that aproach.

UMHW and rubber are by far the best wearing btw.

 

[Clodbuster]

there is no process known to humankind that meets your criteria outside of Hogwarts academy. basic understanding of material science would enlighten you on the difficulties of what you seem to be calling for. a magic wand is the only tool of choice. you might want to head to platform 9 3/4 for that.

"Any significantly advanced technology is indistinguishable from magic" - Arthur C Clarke.

 

[DDoug]

That's what we already do for the most vulnerable parts. We install sacrificial armor that deflects the straw and takes the wear rather than the part. I have a row of angle iron under the transmission. It works well for relatively small areas, but the bottom of the header and inside it are too large for that aproach.

UMHW and rubber are by far the best wearing btw.

How about the commercially applied bedliner material ?
The local dealer was doing all kinds of stuff,
I recall him doing the underside of lawnmowers.

I saw a tow behind woodchipper came into the garage for work, the owner had his crew
clean it over the winter, had all the sheetmetal covered with the bedliner
material.

It did help the wear and vibration cracking problems.

 

[Clodbuster]

When I worked in the sand pit we would line the sand handling equipment with old conveyor belting, it lasted way longer than steel and we always had plenty laying around.
A good friend of mine told. Me he had seen small pieces of ceramic tile glued inside of grain handling equipment. I thought that was an excellent idea.

This is on the track of what we are doing right now. Both applications have very similar wear load. We are on sandy, volcanically young soils here. Which are very sharp, embed themselves in the straw and cause much more wear than machines run in grain elsewhere in the world. We have a neverending problem convincing the big ag machine manufacturers, headquartered in the midwest on much mellower, rounded soil types, that this wear can even happen.

A typical conversation when we order parts "What do you mean that wore out in a season??!! Those last for the life of the machine here!"

 

[Illinoyance]

I am trying to recall Metco information from many years ago. First, sandblast to get the metal clean and give it some tooth. Second, spraay with nickel aluminide as a bonding coat. Third, spray with hardfacing material.

 

[Clodbuster]

So...

Can anyone add what metal spraying/deposition processes *might* work for this? I know there's no such thing as a perfect process, and it might not do everything I want. But I'm looking for help shortening my search based on others' experience.

My knowledge of using other approaches to help wear is very good... because we've tried them all over the years! Coatings like bedliner are ok for straw. Not good for grain as the stream gets under them and lifts the sheet off the metal.

Flame spraying works very good on relatively small and thick parts that can withstand the heat. That's what I'm hoping to duplicate.

Rubber sheet is good, and UMHW is excellent... except you have to have a way to secure them in place. If you lose a piece under the machine it's not a problem. Not the case when you lose one INSIDE the machine and attempt to thresh it. Rubber doesn't glue well, and UMHW not at all. If you bolt or rivet it through, the grain wears the heads off first (even if countersunk), and the whole sheet pops lose and gets eaten.

I've learned to be very strategic about how things are attached in wear areas. I do a lot of welded patches, and they all get numerous plug welds in addition to fillets around the patch. Fillets alone get worn through quickly on the upstream side where the flow hits it. Then the sides. Eventually the grain wedges under the patch, peels it up using the thinned downstream weld as a hinge, where it can pivot up and get caught by an auger or conveyor.

The goal is to have the wear material come off in little bits that won't hurt anything as they pass through.

 

[DrHook]

My spraywelding experience was 30 years ago, but unless someone has come up with a newer method, it ain't gonna work on sheet metal. If the commercially applied bedliner doesn't hold up well enough, maybe HPC (Jet Hot) has a ceramic that is cold applied. I have installed the ceramic tile in material handling equipment moving Manganese and stainless steel slag, and that lasts a long while, but I don't see that being a reasonable option for the inside of a combine...

 

[DDoug]

So...



My knowledge of using other approaches to help wear is very good... because we've tried them all over the years! Coatings like bedliner are ok for straw. Not good for grain as the stream gets under them and lifts the sheet off the metal.



The goal is to have the wear material come off in little bits that won't hurt anything as they pass through.

What kind of bedliner ?
What did you doo for surface prep ?

 

[Billtodd]

It will be important to ensure any coatings will not damage the grain and lead to an increased susceptibility to moisture, drying is expensive!

 

[akajun]

Maybe have the parts melonited?