Gluing Burned Wood

[Bob Penoyer]

I'm making a cabinet with shelves made of plywood. Some of the edges of the shelves were burned while being cut on the table saw.

The front edge of each shelf will be banded using solid wood. The sides of the shelves will be held in shallow dados and glued to the plywood sides.

I'm concerned that the burning might have affected the porosity of the wood and, so, might affect gluing. I don't want to sand the edges of the shelves since they're the correct dimension now. Will, say, Titebond II hold the pieces together securely?

[dadiOH]

Yes assuming the edges don't look like you took a blow torch to them.

[Ed Pawlowski]

Depends on how bad the burning is. Cabinet shelves do not require the same accuracy as the trajectory of moon shot so I'd try to clean them up a little. You won't see 1/64 or so.

[Leon]

Unless the edge is charred 1/16" deep sanding will not remove too much wood. Typically burnt wood is superficial and is only a few thousands of an inch deep.

[hubops]

If the table saw burned the wood badly enough to affect the integrity of the joints - I think he has more serious issues to consider ! :-) . John T.

[-MIKE-]

1. I doubt it will be a problem at all.
2. Go ahead and sand some of it off if for no other reason than to open up the grain a bit.
3. Burning it caused by a blade that is either dull or askew. If your blade is nice and sharp, then askew is the culprit. Either the blade is warped (not uncommon) or your table saw needs trued up. The blade trunnions need adjusted so the blade is be perfectly parallel to the miter slots. Google how to check and adjust blade alignment.

[whit3rd]

No. Sand the edges, to get the right surface for glue adhesion. What causes 'burning' is a saw blade that's blunt or misaligned, which rubs on the wood; this will collapse the wood fiber at the cut, which impedes glue.

Coarse sandpaper, just enough to roughen the surface, is good for this. I'd go for 80 grit and do it by hand.

[dpb]

On 07/06/2017 11:17 AM, -MIKE- wrote: ...

_Most_ saws will adjust the table to the trunnions, not vice versa...

[-MIKE-]

Thank you, Semantics Nazi.

[dpb]

You're welcome... :)

In general the trunnions are the "immovable object". There are some that _are_ vice versa, just not the most common so if OP were going to do something figure it's the better bet...

[-MIKE-]

Yeah, I wasn't really thanking you. But thanks for nothing. Typical usenet bullshit.

[Leon]

Kinda hard to say there which is most common for adjustment.

IIRC contractor saws mount the trunion to the table and you loosen the trunion and move the top.

Cabinet saws tend to have the trunion mounted to the cabinet and the top is mounted to the cabinet.

Just saying. ;~)

[Bob Penoyer]

Thanks to everyone who responded. I lightly sanded the problem edges and completed the gluing.

I think the burning happened due to accumulated resin and debris on the saw blade.