acceptable level of dross

[Cracker Red]

Attached are 2 pictures. One on left is with the THC turned off, one on the right is with it on.

Is the dross on either part acceptable? It's a pain in the ass to remove, and I don't get much on thicker material or larger pieces.

If this can be improved how?

Hyperthermia 85amp machine

Book settings averaged between 10 and 12 gauge

45 amp fine cut consumables

82 volts

[whiskeymike]

Don't see the pics. Can you try to share them again?

[OTHill]

I don't see any picture but with my equipment any dross that doesn't come off in seconds with a stiff cup wheel on an angle grinder is to much.

[exapprentice]

Hi Cracker Red

I would love to look at the Pic's of the dross you are talking about as well, just so I can compare and read the replies to your question

[Cracker Red]

Sorry, let me try this

[steel 35]

Try cutting with 10 gage settings, Works for me on 11G?

[Cracker Red]

I dont think the THC functions correctly and/or consistantly. You can always hear when something is off.. I've witnessed the THC pull the torch up almost 1/2" off the material and seen the voltage go to 110ish on occasion, and have no idea why it does this. I'll typically recut that area and manually turn the THC off then back on.

Sometimes it does like the above right picture, other times not.

Dan from LDR motion advised me to adjust the tip saver to 5 or 6, mine was set at 3 (never touch it, really don't understand a lot of the settings). On a setting of 6 and the THC I'm getting results like the pic on the left...although I'm not sure what changed as I was cutting parts like these a week after getting the table with no issues whatsoever.

Could the tip saver setting change when I upgraded the sheetcam software? (don't see how).

[WyoGreen]

The one on the left is definitely better. Which means the THC on the right has a problem. What voltage did the one on the left cut at vs your set voltage?
The cut voltage of the one on the left should be the set voltage for the THC on the right.

That's the only thoughts I have right now, Steve

[Cracker Red]

Same settings, cut back to back. One with it on, one with it off. This is before I changed the tip saver from 3 to 6 which is what Dan advised me to do.

It worked and now cuts like it did on the left. Question is why....and what changed (as I have never adjusted the tip saver before)

[Cracker Red]

I don't see any picture but with my equipment any dross that doesn't come off in seconds with a stiff cup wheel on an angle grinder is to much.

I've been using 80 grit flap disks but I'm intrigued by this cup wheel....can you elaborate?

[muzza]

I don't see any picture but with my equipment any dross that doesn't come off in seconds with a stiff cup wheel on an angle grinder is to much.

I've been using 80 grit flap disks but I'm intrigued by this cup wheel....can you elaborate?

I use these Pferd Cobitwist wire wheels on a 4 1/2" grinder. I have tested them up against Jobsco ones (cheaper brand) and found that I get better than 10:1 so I don't mind paying a few dollars more. I found they worked much better than the cup ones and for best results I used a variable speed grinder going fairly slow. I have a sign which I cut several hundred a month of and these do each one is less than 30 seconds each. Mind you my dross level is probably comparable to the left pic above at worst most of the time. Where I notice the bigger difference is on Corten which I have never been able to cut dross free, I'm told because of the copper content. These discs have wires twisted clockwise then anti clockwise etc. around the discwhich might be part of the reason they last longer.

As for your original question, the dross on the left I would say is probably quite acceptable for 16 gauge or lighter but on heavier I can get virtually zero unless it's a real busy cut where the torch slows too much.
Murray
https://www.pferdusa.com/products/208b/ ... 0201P.html

[SeanP]

The good thing with wire wheels is it also takes away the sharp edge a little, flap wheels just sharpen it further, good tip about going slower, I have a metabo polisher i'm going to try with the wire wheel now.
Those twisted brushes look hellish savage but it's surprising how well they do work.

[exapprentice]

Hey Sean

what do you use? cheapo wire wheels or do you go for the more expensive option
to date I have only used the cheap M14 wheels, they seem to do a good job, like you have said they take the sharp corner off
Do you find you have to be a little gentle, when I started using them I could put a sharp (very, very sharp)on by brushing the metal off

The dross I get just seems to ping off, when I get real good cuts with little dross I find it harder to clean up strange as the bigger dross comes off far easier

just trying to get a handle on good and bad practice

[SeanP]

Er yes well I did try some cheap Aldi ones once feckin things vibrated so bad I took those back!
I think the last one was only a jefferson make, but balanced well, the first one I used was just a straight cup brush, looked ok but had to be damn careful or it would snatch, the twisted ones seem better for that.
Yes it only takes a quick go to lift off the dross on intricate parts, most straight cuts/plates I tend to just scrape by hand.

[exapprentice]

Hi Sean

I have been doing some experimenting with different bits of kit for dross removal.

I was using just a std 4" grinder with a knotted wire disc which seemed OK a little aggressive if you didn't pay attention when cleaning up parts

I came across this "http://www.screwfix.com/p/titan-ttb602g ... 240v/3278f"
seemed cheap enough to try out so got one in
works a treat as you can slow the rpm down, then tried using a cup knotted wire wheel and it was brilliant, on the slower side of the RPM and holding the cup flat onto the material it leans up and knocks the dross off as well as taking the sharp edges off
the grinder above also has a soft start which makes it a lot more user friendly

the above combo is the best I have used so far