Metal spraying advice needed for farm machinery sheet metal

[Clodbuster]

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

I think the bedliner/undercoat was a rattle can product. Have also used various caulk tube products, which seem to adhere better. We didn't do any prep on the surface. It was the usual wavy mirror finish that grain leaves. You can see your distorted reflection in it, it's polished, but unevenly grooved. Roughing would certainly help, but we were attempting a fast fix.

 

[BT Fabrication]

I dont think there is much option, other then recessed bolt heads and plastic sheeting to protect or rebuild full panels at dedicated intervals based on wear. I doubt all this wear happens in a day, thats why you inspect your machine every couple hrs.

 

[DDoug]

I think the bedliner/undercoat was a rattle can product. Have also used various caulk tube products, which seem to adhere better. We didn't do any prep on the surface. It was the usual wavy mirror finish that grain leaves. You can see your distorted reflection in it, it's polished, but unevenly grooved. Roughing would certainly help, but we were attempting a fast fix.

Before you give up on a spray applied plastic product, make a test with a proper prepared surface, and a professionally applied (2 part heated hoses, etc.) vendor.
The stuff is really tenacious if applied properly.

IIRC the sandblasting supply places have some prep info listed on line.

I would go for some fine sand (sharp) to leave a very flat surface.
Not glass bead, that leaves rounded/smooth surface.
Might try recycled (crushed) glass media, or black beauty.
Unless otherwise
recommended.

"Fast fix".....so your not doing a pre-harvest inspection of the machine ?
with enough time (like over the winter) to remove affected parts, and send them
out for spraying ?

 

[Mud]

I did spraying as a service once upon a time. I have my Metco O/A rig for sale if you'd like to try it yourself. There are more exotic processes since then, you can now spray things like carbide, but the equipment is costly. I could spray things like steels and ceramics and still keep the base metal under 300°F, because of the exothermic reaction of the material combinations. My process was not tolerant of shock and impact, newer ones are better. Here's a link to Oerlikon/Metco - Thermal Spraying Processes << Oerlikon Metco

 

[gusmadison]

You should buy Mud's Metco setup, if for no other reason, just to experience using one. They are really kind of exciting to use, the whirl of the air turbine spooling up on the wire feed I found to make me smile every time I used mine.

You can use it for some experimenting and amuse the kids and/or grand kids as well.

 

[DDoug]

You should buy Mud's Metco setup, if for no other reason, just to experience using one. They are really kind of exciting to use, the whirl of the air turbine spooling up on the wire feed I found to make me smile every time I used mine.

You can use it for some experimenting and amuse the kids and/or grand kids as well.

"While crawled under a header....filled with chaff".....yup a "Thrill-A-Minute".

 

[true temper]

I would like to see some photos of the damage too. Here in Kansas a combine will rust out long before it wears out

 

[Clodbuster]

Here's what the wear looks like. This is on a 42 ft wide stripper header. Similar things happen in and under the combine, tractors pulling other equipment during and post harvest, etc.

Bolt heads on height sensor mounts:


Sensor bracket and floor pan of header. The "serrated knife" look is typical for straw wear, as once a groove is started it deepens continually. We will weld these thick parts. I'd like to use a spray coating on the underside of the header since it is only 1/8 thick.


Wear on the skid plates. They were skinned with 1/4" hardox 2 years ago and are now worn through. We will patch and hard face.



The inside of the header. This is primarily what I want to coat. The auger, floor, sides, teeth, cover, etc. And none of this is easy to remove, so I'd like to do it in place as much as possible.

 

[DDoug]

Have you looked into what the rotoblast people doo for the cabinets and other wear parts ?

your wear looks allot like that, only shiny-er.

As far as "In place" I think your beyond that point. Nothing sold over the counter
as a single spray can is going to doo.

Headers come off daily, everyone around here uses a "xport cart" as the fields are small.
so at least remove the header, get it in the shop, and up end it with a crane if needed.

 

[gbent]

Thanks for the pictures. It was difficult to visualize the damage without them.

To me it looks like the cheapest solution would be to buy new equipment every year and then trade it off somewhere where such wear isn't a problem. Your used equipment would probably last forever anywhere else.

I just talked to a millwright yesterday about combating wear in grain handling equipment. You might find a local millwright company and ask about some of their wear mitigation techniques. They often use large ceramic wear plates, but are to thick for usage in your combine grain flow. They do have some techniques for covering the heads of fasteners that may be useful.

There are also white iron wear plates to add life or repair of earth engaging tools, so you might look to heavy equipment suppliers as well.

 

[DDoug]

With plastic parts bonding problems....did you talk with Lord Corp ?
Along with "fusor" glue, they have always done rubber to steel bonding.
From What I Hear, the Fusor glue is almost like a room temp bonding.

 

[Mike C.]

I run a Metco gun regularly. This is a really poor application for metal spray. The coating is almost more a sintered/ cast product and is extremely brittle. It sticks well to shafts because it is sprayed on the OD and shrinks as ut cools, grabbing tighter (in fact, if you spray it too close and get it too hot, it'll split when it cools). To get the excess spray off the metal shield on the wall behind the lathe, I either tap it with a hammer or slide a screwdriver under a lifted corner (it peels up at the edges) and it comes loose in a nearly entire sheet.

 

[EPAIII]

I was wondering what those black chunks in my breakfast cereal last week were.

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.

 

[EPAIII]

Duhhhhhh! I know it is total heresy, but

READ THE INSTRUCTIONS!

I think the bedliner/undercoat was a rattle can product. Have also used various caulk tube products, which seem to adhere better. We didn't do any prep on the surface. It was the usual wavy mirror finish that grain leaves. You can see your distorted reflection in it, it's polished, but unevenly grooved. Roughing would certainly help, but we were attempting a fast fix.

 

[Mud]

I run a Metco gun regularly. This is a really poor application for metal spray. The coating is almost more a sintered/ cast product and is extremely brittle. It sticks well to shafts because it is sprayed on the OD and shrinks as ut cools, grabbing tighter (in fact, if you spray it too close and get it too hot, it'll split when it cools). To get the excess spray off the metal shield on the wall behind the lathe, I either tap it with a hammer or slide a screwdriver under a lifted corner (it peels up at the edges) and it comes loose in a nearly entire sheet.

The newer technology sticks a lot better, the plasma guns etc., but it's still not up to what's in those photos. I think it needs plated with something like AR500.

 

[gbent]

Belzona makes epoxy products that are specifically for abrasion resistance. Bonding is always a problem, as you have discovered. They are Belzona products, so they are stupid expensive. In the right usage they work very well. They have products with ceramic and tungsten carbide particles to resist the abrasion.

 

[HuFlungDung]

Maybe on the outside of the machine, you could attach a layer of Astroturf. The idea being that the turf will load up with the same dust as is doing the abrading, and they can wear against one another. Maybe even spray adhesive on the turf so that the dust will stick to it.

 

[Flail]

Is it possible to case harden the bolts to decrease wear? I know they make ceramic coated screws, so I expect there are ceramic coated bolts.

Edit, maybe use hardware used in excavator buckets.

 

[Mud]

Is it possible to case harden the bolts to decrease wear? I know they make ceramic coated screws, so I expect there are ceramic coated bolts.

Edit, maybe use hardware used in excavator buckets.

Excavator bolts aren't any harder than any other high strength bolts. The builders protect them by keeping them away from abrasion somewhat. For example, the heads might be flathead and the nuts might be recessed, so that dirt packs around the nut in the recess. that way the hex stays intact and only the very end is exposed to dirt.

 

[stephen thomas]

Devcon makes trowlable urethanes for similar anti-wear apps in process equipment.

My experience is with the castable stuff, for feed rollers & such. Also for for bonding nonmetallic parts to steel & bronze. If the trowlable is as good, they have well designed systems including necessary metal primers and modfiers for the urethane. There may be cheaper alternatives ; Devcon does seem to care that their products are well engineered & work.

If you decide to try it or a similar product, don’t take short cuts on metal prep, primer/activators, or mix ratio.

Also don’t let the advertised cost of various retail kits put you off if the products look interesting - prices are never cheap with them, but in larger quantities they might start to look cost effective.

smt