Track saw, mfc, chipping.

[cdbe]

as an aside
ffx on ebay will often front load the price a bit to cover all or some ebay costs so worth checking on ffx as well remembering free postage above £25 and clearpay [credit] £10 voucher

I always check, eBay was a tiny bit cheaper this time, the £10 is for a £100 spend - so I might have to do more shopping!

 

[cdbe]

How to cut melamine mfc with a Plunge Saw and rail.

The rail rubber needs to be in mint condition.

When cutting the top edge using the rail, set the plunge saw so it only cuts a depth of 2mm through the board, instead of cutting away from yourself, set the saw at the end of the cut a Plunge 2mm and pull the saw backwards "slowly" effectively scoring the mfc, then set the saw to cut full depth.

To stop the underside chipping, lay the board you are cutting on a sacrificial piece of wood, so you cut through the board you are using and into the board underneath, this stops breakout on the underside.

Lightly sand both cut edges to stop breakout when fitting.

Some MFC just chips, I use 48 tooth Triple Chip blades.

Thanks, rails are new (2 x Makita 1.5m). The saw does have a "score" setting so I'll try that - it doesn't seem to want to slide backwards - there is a spring loaded knob on the plate (not the front one that locks in into the track) that stops the saw sliding backwards - but I can hold it open I suppose:

I don't know what make the sheets are, I think they're actually back panels for breakfast bars.

The job is to build 3 x tall larder type units to fill this space:

The units will built in to studwork with slab doors and Gola true handleless rails - if it goes ok I might have a go at the entire kitchen - this is just a trial to see how I get on - with these cuts, the rails, using the confirmat screws (snappy RTA on its way) and fitting the doors - they're Howdens and pre drilled for hinges so it'll just be the carcass holes, internal drawers etc.

The only other thing, I suppose you could call it a "get out of jail free" card, is that the boards come with some trim sections which actually look pretty good on the visible internal cuts and hide a multitude of sins!

I know it's a cheat but I don't think it's that bad as a detail.

 

[robinbanks]

Be really careful moving any circular saw such that the direction of travel for a tooth cutting the work is the same as the direction the work is travelling (if the work is fixed and the saw is travelling, flip it round in your head and imagine that it is the saw that is fixed and it is the work that is travelling)

Circ saws are only stable when the effect of a blade tooth sinking into the work is to push the work item away from the blade. If the work/saw is moved so that that blade could be a wheel driving itself across the surface it's much more unstable.

You'll be amazed and quite surprised how quickly things go wrong if a blade grabs the work and all the kinetic energy in the blade is put into flinging the saw or work across the room

 

[cdbe]

Today's attempt, the new blade, score and then full pass, second piece underneath, gentle sand down afterwards.

Top of cut:

Underneath of cut:

Top of cut butted against a panel:

So a pretty big improvement, it didn't help that I've run out of offcuts to practice on so it was a small piece and the track wasn't completely stable and the hoover hose got caught, that's my excuse anyway.

 

[aveatry]

As I understand it this will be the inside of the cabinet and at the back so I think you are there with it, you could always run a very thin beed of black silicone down the corner after its built if there are any chips still showing. Same with the outside edge if it shows run a fine bead of silicone at the unit and wall junction.
When doing longer lengths plan out and practice the run and see where the hoover pipe "would of got caught" - it happends all the time when I am cutting - its really anoying when the hover pipe flexable concetina profile decides to not pull past the starting edge when I am half way through the long cut. I need a smooth flexable hoover pipe

 

[big-all]

do you have the blade only 2mm sticking out the bottom??
another option a bit off [sacrificial board]sheet material say 6mm mdf under the cut line preferably the full board your cutting or more then move the work to a bit un-grooved for the next cut you should get zero chipping then but the undercut chipping is shocking with the new blade

 

[aveatry]

I blame the material here now I think.
Try cutting something else that is laminated.

 

[big-all]

I blame the material here now I think.
Try cutting something else that is laminated.

thats exactly my thoughts so was hoping it was a setup or operational error otherwise mass or premature delamination may happen during assembly or in use ??

 

[cdbe]

I blame the material here now I think.
Try cutting something else that is laminated.

I think you're right!

Just tried something else, no scoring or material underneath and it's near perfect on both sides.
Must just be very brittle laminate, no indication that it's delaminating.

Anyway, it's good enough for the job at the price.

 

[robinbanks]

What happens if you heat the cut line with a heat gun before you run the cut? Just curious if it's been kept somewhere low temp and is more brittle as a result..

 

[cdbe]

What happens if you heat the cut line with a heat gun before you run the cut? Just curious if it's been kept somewhere low temp and is more brittle as a result..

Knowing my luck I'd set fire to the sawdust and burn my house down. I did wonder the same, it's in my unheated extension but well above freezing.

 

[robinbanks]

Heat guns are electric, not flame based. You'll struggle to set sawdust on fire with one

It's not really related to the temperature that water freezes at; 273 degrees kelvin isn't some magical number below which all materials are brittle and above are not.. I've broken plenty of plastic things on low temperatures that withstand the same punishment in summer just fine.. Using a nail gun to fix felt support trays for example (and I don't roof if it's freezing!) - in summer it punches through, in cooler temps they shatter

Perhaps even just leaving the boards in the sun for an hour before you run the cut will make a difference