Chipping ceramic tile's glaze as Diamond wheel finishes cut thru. [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile

PDA

View Full Version : Chipping ceramic tile's glaze as Diamond wheel finishes cut thru.


WallyPoP
09-22-2001, 09:38 PM
I have a question related to the tiling I just did. This was the first time I used a rotary diamond saw to make my cuts using an inexpensive ($95) 1/2 hp portable unit available at HD. It has an adjustable guide such as found on small table saws, which I quickly removed, (couldn't arrange guide exactly parallel to blade), in order to manually guide/feed the tile while eyeballing a grease pencil cut line. I was pleasantly surprised at my hand/eye coordination.

For my purposes all worked fine with just one little occasional hitch. As the diamond wheel exited from the tile upon finishing my cut the glazing would sometimes "chip" erratically at the tile's exit edge. Finicky me scrapped several tiles as I tried various schemes to overcome the chipping, ( such as not finishing the cut, backing off the tile and 180 degreeing it, then cutting to meet where I'd left off, eg ) but feel you pros undoubtedly have better tricks up your sleeves.

Do the more expensive saws, on which the tile rests on a carriage that glides on rails for better controlled feeding into the blade, overcome this chipping problem?

Look forward to your shared tips for my next project. Thanks, once again.Thanks.

Sponsored Links


Rob Z
09-22-2001, 10:44 PM
Wally

The problem is most likely the cheap saw and blade. Even my expensive IMER saw will chip along the edge, but that is rare. Try to plan your installation so all the cuts are hidden under other tiles or caulk, or maybe rent a bigger saw for just the cuts that will show.

Z

PS If you are looking for my permission to spend money on a new toy, tell the 1stSGT that I said you really needed to buy a new tile saw. Just think of all the money you are saving doing the work yourself!

John Bridge
09-23-2001, 06:53 AM
Wally,

I have one of the cheap saws like yours. We use it to make repairs -- one or two cuts (not that we need to make repairs very often).

The problem is that the tile is not fully supported as it makes its way through the cut. If you are pushing the tiles through with your thumbs, place them directly in the path of the cut. This will prevent the blade from binding, which I think is the problem.

The blade will not cut you. I sometimes place my thumb or finger right up against it.

Attention woodworkers: Do not try this trick on your table saw! :D

WallyPoP
09-24-2001, 04:47 AM
John & Rob

I'm going to continue to experiment. Will investigate different quality blade designs, ie, I assume the coarseness of the diamond grit, the rpm of the wheel, the dia of the wheel, its thickness all play a part.

I also assume wall tile has thinner, hence more fragile glazing while floor tile is more substantial and may chip less.

The binding John noted occurred only when I had the guide installed, a consequence I feel related to lack of exact parallelism with the wheel. Lack of table flatness resulting in incomplete support of the tile further contributed to the chipping problem.

This will be a long term program so it'll be a while before I get back to the subject.

As ever, thanks for your support.

Jason_Butler
09-24-2001, 09:18 PM
Hi Wally,

I think John and Rob have got you on the right track.

I would like to add one add'l note if I may. I have noticed even with the high end saws that debris on the slide table ( beneath the tile) can cause tiles to break/bind/chip at the ned of the cut. I usually keep an extra sponge available to wipe off the table periodically. Otherwise remnant from prior cuts will build up beneath the tile and cause premature cracking.

For motors with higher torque this is even more of a problem since the blade "grabs" the tile and exerts downward pressure. Of course a dull blade can also be the culprit

Jason

Kirk Downey
09-25-2001, 12:32 AM
Wally

Try cutting about a half inch, or even a third of the overall cut length into the tile then flipping the tile so that you finish the cut in the middle of the tile. The tile chips-out because there is no support for the last bit of brittle tile against the blunt blade. To compound the physics of those saws - the blade is exerting upward force which blows out a flake on the top of the tile. Finishing the cut in the middle of the tile allows the tile to support itself.

Also, Try being more patient with the guide. If you can set it right, you can make relatively fast and uniform cuts.

Kirk
------------------------
God is Love

WallyPoP
09-25-2001, 06:25 AM
Jason & Kirk, Hi

Good thoughts. I do as a matterof practice, wipe off the table after each pass just so my feeding is smooth and the debris exerts no upward pressure on the tile.

I wasn't too brite and was trying Kirk's suggestion in reverse, ie cutting thru tile almost to end and then turning it around to cut from opposite end. However both approaches still resulted in the tile ocasionally chipping only this time it occurred in the interior rather than the edge. The less than perfect support of the tile enables the weight of the tile on either side of the blade to force a fracture rather than await the blades controlled chipping/fracturing action.

Kirk, I think the blade exerts a downward force at the point of cutting; at the rear as the blade comes up the resultant kerf precludes an upward force.

Aside. Perhaps I should make this another subject, but I'll throw this out here.

I now own a 20" professional tile cutter (score via wheel an snap) and and inexpensive diamond blade power saw. I bought the saw in order to make very narrow width cuts, diagonals and ells. I presume the scoring type cutter's main advantage is speed and the fact that replacing worn carbide wheels is cheaper than replacing diamond blades.

How do the pros operate? Just curious. As a DIYer I prefer the cutter since it's less messy and most of my cuts are hidden so that the wheel's smoother edge result is only occasionally needed. I hate the cleanup, too.

Jason_Butler
09-25-2001, 12:48 PM
Wally,

Use the scoring knife where possible. It is definitely a time saver and works well where the cut edges can be placed adjacent to or beneath baseboards

I haven't quite figured out how they do it, but I have seen entire houses tiled without a wet saw

Jason

John Bridge
09-25-2001, 04:26 PM
When I first went into business here in Houston I was so poor I couldn't afford a wet saw. I'd rent one if I had to, but mostly I'd do without. You become very accomplished with the biters. Of course, you break a lot of tiles in the process. They didn't have the little cheapie wet saws back in those days.

You can make an 'L' cut by scoring in both directions with the cutter, and then biting/nipping out the waste (very carefully).

K.
10-23-2009, 10:01 AM
I have probably the same cheap saw from HomeDepot with the fence that isn't quite parallel (workforce brand?) that seemed fine on my first tile job but now I'm in the middle of the second and wondering about a similar chipping question. Not only on the exit edge, but all the way through. The chips aren't really large but it seems like it is worse than when the unit was new, and continuing to get worse still.

I've tried a couple of things not mentioned above.

1. use a piece of scrap tile to support the exit edge as the cut is completed

2. flipped the tile upside down so the blade is cutting inwards against the glaze rather than outwards. This also mitigates the specific problem at the exit edge of the tile since that chip seems to be deeper on whichever side of the tile is facing upwards; ie this way the glaze remains intact even if the clay underneath is chipped.

Neither had much benefit. So my question is, to what extent is chipping a sign of wear and tear issues on the blade like warping or dullness? How do you tell when to replace a diamond blade anyway? I've made probably no more than 500 cuts on it so far.

-Jonathan