Mild Steel Finishing

[Jason Lister]

Ok, so I need some help finding the right tool to buy. I dont mind paying some money if it is going to help my efficiency.

My wife and I sell these coasters: https://www.etsy.com/shop/ApocalypseFab?ref=si_shop

I'll describe the process I do to finish them to a sellable state:

They start as 3/16" thick P&O Hot Rolled Sheet and then we cut them up with the CNC plasma.

I then take them to a 8" wire wheel on a grinder and deburr/clean all the edges.

Then I stick them in a holding jig I have and use both 36 grit and finally 80 grit fiber discs on 4.5" angle grinders to clean and grind the finish on them.

Then they are washed with soap and water. Dried with a towel and then clear coated.

My wife handles the felt gluing and waxing.

My question...

What tool should I be using to surface these coasters? I doubt very much that the angle grinders are the most efficient.

I'd like to use something like the drum sanders that woodworkers use, but I have no idea how it would like sanding metal and the hardened plasma dross pieces.

My current idea is a holding jig with a magnet to use either:

http://www.grizzly.com/products/Combination-Sander-6-x-48-Belt-12-Disc-3450-RPM/G1183

or

http://www.use-enco.com/CGI/INSRIT?...MKANO=354&PMKBNO=3110&PMPAGE=18&PARTPG=INLMPI

or would some sort of surface grinder be best?

It doesnt need a mirror finish, but I do need to get down to bare metal.

Thanks, any input would be appreciated.

Jason

 

[Givl Reggin]

The belt/disc sander will be more useful. But, the finish you get off of it will be completely different than what you're getting now.

FYI- I hope you have licensing agreements with the owners of some of those logos!

 

[thebeekeeper1]

No help from me, but a comment--you are going to get dinged for the various trademarked images sooner or later. That could end up expensive as all get out.

 

[Jason Lister]

The belt/disc sander will be more useful. But, the finish you get off of it will be completely different than what you're getting now.

Yes, I know the finish will be straight grained. I dont think that will be a big deal.

I have a disc sander already... so that's kind of a moot advantage.

 

[mossyboy6]

If you use a time saver, you need to send the metal through in sheet form, so, you can get all of the inside cutting done, pull it off the plasma, run it through the time saver, and then cut out the coaster outside shape.

Short of that, I can't really think of a batch finishing process for what you do.

 

[Joe B.]

For the clean up part you might be better served with a vibratory deburing machine. Either that our sending them out to a metal finisher. Your current process can't be a good use of your time! I think it would then be quicker to lightly etch the texture onto them.

 

[Zrexxer]

If you're looking to save time, cutting them out of stainless and doing away with the clearcoating process would help...

 

[LXCam]

Your best bet IMO would be a 4 X 60 belt grinder like this with a scotch bright belt. I do a ton of metal finish where it must be absolutely perfect prior to powder coating. The magnetic jig is a great idea btw.

http://www.burrking.com/catalog/p-100006/model-960-401-4-x-60-two-wheel-wet-belt-grinder

I also have a dedicated 48" belt sander I use with a scotchbright belt for final finish before polishing on aluminum parts that works pretty damn good too.

 

[Jason Lister]

If you use a time saver, you need to send the metal through in sheet form, so, you can get all of the inside cutting done, pull it off the plasma, run it through the time saver, and then cut out the coaster outside shape.

Short of that, I can't really think of a batch finishing process for what you do.

I assume a drum sander is a "timesaver"? That's an option, but the plasma cutting is pretty messy, especially with the water table.

For the clean up part you might be better served with a vibratory deburing machine. Either that our sending them out to a metal finisher. Your current process can't be a good use of your time! I think it would then be quicker to lightly etch the texture onto them.

Hrm.... I didnt really think of a vibratory deburring machine.... that's definitely an option, but it would still need to be ground.

If you're looking to save time, cutting them out of stainless and doing away with the clearcoating process would help...

I am getting a quote from my supplier for the price difference going up to 304 ss. We'll see. I definitely agree that would save a lot of time!

Your best bet IMO would be a 4 X 60 belt grinder like this with a scotch bright belt. I do a ton of metal finish where it must be absolutely perfect prior to powder coating. The magnetic jig is a great idea btw.

http://www.burrking.com/catalog/p-100006/model-960-401-4-x-60-two-wheel-wet-belt-grinder

I also have a dedicated 48" belt sander I use with a scotchbright belt for final finish before polishing on aluminum parts that works pretty damn good too.

I'd love to use a burr-king, but I dont think the 4" wide is going to work with our 4" wide coasters. Not efficiently, anyway. How does the scotchbrite pad hold up to dross? Ive used them on small 2-3" rolocs, but never used a full size belt of it.

Thanks for all the input guys!

 

[LXCam]

I would do a three step process. 120 then 180 grit, then a red belt and yes they hold up very well. I have a burrking and love the fricking thing. The only reason I run the 6" wide belt on the 48 is some of the pieces I make are too large to get a good flat surface prep off the 2" belt I run on my BK.

 

[Jason Lister]

I would do a three step process. 120 then 180 grit, then a red belt and yes they hold up very well. I have a burrking and love the fricking thing. The only reason I run the 6" wide belt on the 48 is some of the pieces I make are too large to get a good flat surface prep off the 2" belt I run on my BK.

What are your thoughts on the 3900 sfpm on the edge sander vs the 5000 sfpm on the grizzly? I'm really only cleaning the surface, not taking a lot of material, so...

Is there an advantage to the edge sander with the 89" long belt vs 48"? (cooling, I would think?)

Burr Kings are like 8k sfpm right? (nevermind... they are 5k and 6.6k respectively) and they dont make a 6" wide; that I have seen.

 

[LXCam]

The major advantage to a longer belt is just that, much more abrasive area so belt changes are minimized. On some machines a belt change is a very time consuming effort, where as on a BK, it's 15 seconds and done!. That's what makes working your stages of abrasive worth while. I cringe when I have to change belts on one of my 48's, all kinds of **** to take apart. The other one has a quick release lever and that's not so bad. My suggestion is to take that into account while you're deciding on a machine, just what has to come off to change the belt.

As to sfpm, be careful you may not want that much surface tension going that fast, could make for a hell of a nice projectile in the right circumstances.

 

[Monte]

<iframe width="640" height="480" src="//www.youtube.com/embed/m6GVQIGFS4E" frameborder="0" allowfullscreen></iframe>

 

[A_Pmech]

A wide belt sander will do the job on the finished parts, but you'll need to build a jig from plastic to hold them tightly when you run them though the machine.

Timesaver offers a machine specification service and can help you with your application if you give them a call.

 

[mattamd_xp]

Stainless turns black where you use a plasma cutter on it unless you have a high-end oxy plasma setup.

 

[zkling]

but you'll need to build a jig from plastic to hold them tightly when you run them though the machine.

Small metal parts and a drum sander could turn into a projectile launcher.

Depending on the size of the coasters. I would try to find an old worn out, yet still running surface grinder. OR look up "knife making surface grinder". Knife makers build all sorts of low budget surface grinders that do exactly what you are looking to do. Usually run on 2x72 or wider belts so your finish range is very open from brushed to mirror.

 

[Heavy Metal Doctor]

For the clean up part you might be better served with a vibratory deburing machine. Either that our sending them out to a metal finisher. Your current process can't be a good use of your time! I think it would then be quicker to lightly etch the texture onto them.

This was also my first thought, as well - when I worked in production machining, nearly all small parts we made went through one of the tumblers....when I first started, I was amazed at what a nice finish those smooth stones could create just by throwing the parts in and turning it on for a while.

 

[thundermug]

Sell your plasma cutter and buy a water jet cutter. You can send a sheet of metal through a sander and then cut it without any plasma scorching.

 

[Jason Lister]

The major advantage to a longer belt is just that, much more abrasive area so belt changes are minimized. On some machines a belt change is a very time consuming effort, where as on a BK, it's 15 seconds and done!. That's what makes working your stages of abrasive worth while. I cringe when I have to change belts on one of my 48's, all kinds of **** to take apart. The other one has a quick release lever and that's not so bad. My suggestion is to take that into account while you're deciding on a machine, just what has to come off to change the belt.

As to sfpm, be careful you may not want that much surface tension going that fast, could make for a hell of a nice projectile in the right circumstances.

It "looks" like the edge sander is easier to change... with the quick release handle, but I will look into that more.

I saw Mick120 using one of those on a stainless project. They look awesome. That may be an option too. I just dont know how much faster that really is than what I am already doing.

A wide belt sander will do the job on the finished parts, but you'll need to build a jig from plastic to hold them tightly when you run them though the machine.

Timesaver offers a machine specification service and can help you with your application if you give them a call.

Just a preliminary check of their website. Their smallest model to handle small parts has a minimum length of 5". The coasters are 4".

Stainless turns black where you use a plasma cutter on it unless you have a high-end oxy plasma setup.

I understand. It would still need grinding, just not clear coating.

Small metal parts and a drum sander could turn into a projectile launcher.

Depending on the size of the coasters. I would try to find an old worn out, yet still running surface grinder. OR look up "knife making surface grinder". Knife makers build all sorts of low budget surface grinders that do exactly what you are looking to do. Usually run on 2x72 or wider belts so your finish range is very open from brushed to mirror.

I was wondering if a surface grinder would work, but again, would it be faster? As a baseline I can go from off the table to clear coated in 10 minutes for a set of coasters.

This was also my first thought, as well - when I worked in production machining, nearly all small parts we made went through one of the tumblers....when I first started, I was amazed at what a nice finish those smooth stones could create just by throwing the parts in and turning it on for a while.

Yeah... I am just not familiar with the finish potential of a tumbler.

 

[Jason Lister]

Sell your plasma cutter and buy a water jet cutter. You can send a sheet of metal through a sander and then cut it without any plasma scorching.

You can send that check to offset the cost to my home address!

 

[PCO6]

Monte - That Metabo burnisher operates a bit like an old Black & Decker work wheel that I have ... but MUCH better. I'm able to put various wheels on it but nothing close to as wide as what is on that one. Very nice.

The speed is non-variable on this. It turns at 3,400 rpm.

 

[A_Pmech]

Just a preliminary check of their website. Their smallest model to handle small parts has a minimum length of 5". The coasters are 4".

Thus the fixture.

You can also plasma the parts and leave them tabbed into the sheet. Then run the whole sheet through and break them out of the sheet after finishing.

Or use a sticky belt:

 

[Steevo]

For the clean up part you might be better served with a vibratory deburing machine. Either that our sending them out to a metal finisher. Your current process can't be a good use of your time! I think it would then be quicker to lightly etch the texture onto them.

I second the vibratory tub as a much lower labor solution.

 

[Jason Lister]

Thus the fixture.

You can also plasma the parts and leave them tabbed into the sheet. Then run the whole sheet through and break them out of the sheet after finishing.

Or use a sticky belt:

Gotcha on the fixture. Tabbed in the sheet is a really good idea too.

I second the vibratory tub as a much lower labor solution.

Yes, I am leaning more and more that way. My main concern is with time. We have a 2 week old baby boy, our 3 year old, and day jobs. Time is my most expensive commodity.

I really like the "automated-ness" of the tumbler. I also like that it wont make a mess and I can run it inside the garage. I need to check on the volume of it; while running.

I am driving through Goleta tomorrow; so I am going to check these out: http://www.candmtopline.com/finishing_tanks.html

or if I can use one of the smaller bowl style tumblers:

http://www.candmtopline.com/vibratory.html