Grinder for polishing

[Waluigi]

PM sent

 

[acaciaguy]

Thank you sir.

 

[Tony73]

Hi. I used to have Flex polished. But it's big and heavy. Paid £260 and it didn't last that long. Now I use Makita polisher (£110) and I am very happy with it. Its lighter, cheaper.

 

[Concrete guy]

POLISHING 101 - The basics.

The cheapest and most versatile way to stick your toe into the world of polishing is with Silicon Carbide discs. They are inexpensive and work on almost anything.

You can attach them to anything variable that has a speed range around 2000 to 4000 rpm.

When you buy a variable speed machine (from any manufacturer) buy something that you're more likely to use towards the top end if it's designed speed range. Variable speed tools tend to have the cooling fan rotating at the same speed as the drive axle. The side effect of this is they can overheat if being used for extended periods of time (extended being upwards of 20-30 minutes of continuous use) at the lower end of their speed range.

I'll use two FLEX machines as an example (but the same principals can be applied to any brand).

L1503VR polisher is a dedicated polisher with a speed range of 1200-3700 rpm. Most polishing is done at the upper end of this range and it can also be used for profiling tools at around 1500 to 2500 rpm.

L1506VR variable speed grinder is the same machine with a different gearbox giving a speed range of 2200 to 6800 rpm. It also has the advantage that you can fit blades and a dust extractor head to it. It's effectively a grinder than that can do a bit of polishing. It will take grinding cups, curved blade and grinding drums. It will polish, but it's going to heat up if being used constantly to polish.

The reality is for tiling either will do and it's unusual that a tiler would be doing extensive polishing work. Just read above and figure out which one is more appropriate for you.

Wet vs Dry, the bottom line here is generally economy.

Wet polishing is mostly done with diamond pads, it really comes into it's own when doing volume. The consumables are more cost efficient per l/m or sq/m but the initial set up cost is higher. It's also messy, very messy and you need to think of how you're going to deal with the slurry created.

Dry polishing, the consumables are more expensive and don't last as long, but the initial set up isn't as expensive as wet polishing. Dry Diamond pads can be very material specific, Silicon carbide discs are very versatile, but have a short lifespan. You need to deal with the dust created.

 

[Concrete guy]

Think of Silicon Carbide as sand paper, you're filing the surface of whatever you're polishing with silicon carbide grains of specific sizes (the grit size). The grit is fully exposed - hence they'll work on pretty much anything.

Diamond pads (excluding electroplated and vacuum brazed types) are generally resins cast in a mould mixed with diamond dust/granules and allowed to cure. When the diamond resin pad is introduced to the product it's polishing, the resin wears on the product, exposing diamond, which does the polishing. It's important the resin is formulated for the product being polished otherwise it just won't work.

A dry diamond pad designed for polishing granite or concrete won't work on Limestone, the limestone simply isn't abrasive enough to wear the resin to expose the diamond, so what tends to happen it it just rubs the surface of the stone, creates heat and eventually starts to melt the resin, that's where you get brown resin transfer stains.

The flip side is a resin diamond pad designed specifically for soft product like marble or limestone will simply wear away in no time when used on something more dense or abrasive.

There's also no such thing as a diamond pad that's truly wet & dry use, it's one or the other.

Manmade quartz is a difficult product to polish dry, really only silicon carbide is appropriate for edge polishing (dry) but then there's the question of if the dust is harmfull. Diamond pads are only really appropriate used wet as the abrasion of the pad can often generate enough heat when used dry to melt the resin content of the quartz (more brown smears).

Don't try to surface polish quartz, it'll generally cause more problems than it will solve, it can be done but it's a specialist operation.

 

[Blunt Tool]

Well @acaciaguy there is a comprehensive and informative answer to your questions, he certainly knows his onions! Thanks @ATSDiamondTools

 

[Flintstone]

Great post from Alan.

Here is what you can achieve using Silicon carbide discs, dry on a bosch variable

 

[Blunt Tool]

Great post from Alan.

Here is what you can achieve using Silicon carbide discs, dry on a bosch variable
View attachment 101581 View attachment 101582

Brilliant example of what can be achieved with them

 

[Tile Shop]

Great post from Alan.

Here is what you can achieve using Silicon carbide discs, dry on a bosch variable
View attachment 101581 View attachment 101582

Nice clean cuts too... slight side step of the topic, but what blade did you use to cut them and did they need any rubbing down?

 

[Flintstone]

No rubbing down needed Paul, I used an old turbo blade from ats, I find it great for stone. Some times I will use a vacuum brazed blade if required

 

[acaciaguy]

Thank you all for taking the time to offer help and advice.

 

[Tile Shop]

No rubbing down needed Paul, I used an old turbo blade from ats, I find it great for stone. Some times I will use a vacuum brazed blade if required

Thanks. Just I tried the Turbo blade on Italian Carrara and Chinese Black Veined marble and both chipped (chinese worse than the italian). Had to undercut by 1-2 mm and polish it down. However have ended up using the Rubi ECD for both cutting and shaping with near perfect cuts every time.

Must have either been my technique or the quality of marble used that made the difference.

But to get back on track, from what I have tested for my personal needs of polishing edges and bull-noses, Sait Pads are top of my list and they last surprisingly well.

 

[Flintstone]

For me Paul I used an old turbo blade which had done many weeks of porcelain use. Straight out of the box the vacuum brazed blade is brilliant