Working with ash lumber

[mvettori]

I started cutting out the stems today for my Bob's Special using piece of ash lumber. I've never worked with ash before so I had two questions:

1) I noticed that it burns very easily. There was a considerable amount of smoke and burn marks onthe cut faces of the lumber. Is this normal for ash? I've never experienced burning like that on any other piece of lumber. The burning was significant in that the saw dust under the table was actually dark brown!

2) Since I am cutting out the laminates for the stems and will ultimately be glueing them do I need to sand of the burns or will the glue set through the marks?

[John E]

I haven't worked with Ash yet but did work with Red Oak for the first time just a few weeks ago. I also had some burning mostly when I had to pause to re grip the wood and it had a chance to rub the blade for a second or two. It is imperitive to always use the sharpest of blades, (Carbide tips are a must) when cutting hardwoods, go slow and do not force the cuts, keep the wood moving past the blade and do not let it stop where the blade can heat up where it rubs.

The wood should be sanded where burned for two reasons:
1. It will be much nicer to look at the grain rather than the burn marks, The burn marks should not be too deep unless you really burned it bad.
2. Any finish, epoxy, or glue you plan to put on it needs an equal field to absorb into the wood. The burn marks effectively seal that portion of the wood where burned and you need to remove that area to open up the grain again.

If you have access to a disk sander with a fence you could slip the wood between the disk and the fence (snugly) and get the sander to surface the wood for you. I did this with my Oak and it worked beautiful, removed not only the burn marks but also the cut marks from the blade.

[Glen Smith]

I would add two things to what John said: 1) check the tablesaw fence adjustment. It should be about 1/32" further away from the blade at the rear compared to the front to prevent pinching. 2) if you don't have a splitter installed, put it on to prevent the cut wood from pinching the blade.

[mvettori]

Thanks John and Glen. Those are good suggestions. The strange thing is that I have an 80 tooth crbide finishing blade on my table with a splitter. I've cut a lot of wood on it and I've never had the level of burn that I did today. Maybe the blade is startingto get dull.

Nevertheless, John I'll take your suggestions and sand off the burn marks. Thanks again.

[Glen Smith]

If you are using an 80 tooth blade to rip the wood, that could be the cause of the burning. You would be better off with a 24 or 36 tooth "ripping blade". It won't produce as fine a cut as the 80 tooth blade but it should do just fine. I once tried ripping with my 80 tooth and the wood got burnt also.

[John E]

AN 80 tooth is way too much for ripping strips. That is more of a crosscut blade where finish of the cross cut counts or the rip is such that you have almost no side pressure of the blade against the wood such as when you do a final trim to size.

When ripping you wind up with too many teeth contacting the wood at the same time with an 80 an tthis causes heat to build up hence the burning . Also most 80 teeth blades are not designed with the cooling and vibration dampening (those funny little squiggle cuts in some blades) that Ripping blades are.

Good luck in the project

[mvettori]

GReat info John...much appreciated! I'm done with the stem strips but if I do any other ripping I'll remember to change my blade. Thanks again.

[Bob/PA]

In addition to all the excellent advice already offered, I'd suggest spraying the running blade with silicone lubricant between cuts. It evaporates quickly and in any case will be subjected to steaming or soaking and then drying before you get to the lamination stage, but a slippery sawblade will add to the protection against burns. It does no harm and probably will help.

[John E]

NO on the silicone lubricant. These stirps are to be coated with epoxy and one would have to believe in the strong possibility of silicone contamination. Silicone and Epoxy do not go well together.

[Bob/PA]

Gee, guess I have just had the luck of the ignorant.

I routinely use silicone and have never had the slightest problem, possibly because there is hardly the least chance that any of it will survive to become a contaminant after scraping, sanding, washing with mineral spirits, or (in the case of stems) steaming/sanding, and all the other treatments the wood is subjected to before it ever gets touched by epoxy. But to each his own: I still recommend it.

I have found the silicone to be especially helpful in minmizing sap buildup on the blade when ripping strips, but then...

[JimND]

John is correct, never use silicone for anything in a woodworking area. Mention this topic on a woodworking forum and you will get dozens of horror stories about silicone. Walk into a professional, or even a serious amateur, woodworking shop holding a can of silicone spray and you will be shown the door. Employees in commercial shops get fired for bringing in silicone.

The problem with silicone is that it causes finishes to not adhere, causing what many call "fisheye". Once used in a shop it can persist literally forever, since it is nearly impossible to remove it all. It easily becomes airborne, sometimes by itself, but usually in the form of extremely fine saturated dust. Trying to wash it off with solvent just smears it around more.

On the other hand, Teflon based products work just fine for coating cutting edges and surfaces. There are a number of specialty products made just for woodworking, or you can buy the less expensive brands. Just be sure it has no silicone in it.