Friction burning on a slope with a wire

Re: Friction burning on a slope with a wire

David Walser

That's one way of doing it. My method seems a little simpler: Turn to final profile. Use a skew, point tool, or something similar to cut a v-groove where I want the burn line. The wire will follow the groove and burn a clean line.

Of course, if the slope is too steep, a v-groove will not be sufficient to hold the wire in place. For example, say I'm trying to burn a line on a virtually flat box top. Or, if I'm trying to burn a line inside a bowl or box. In neither case will a v-groove allow me to burn a line with a wire. In such cases, I still cut the v-grove, but instead of wire I use the folded edge of a brown-paper sack, a thin piece of wood, a scrap of plastic laminate, etc.

Excellent description John

Re: Excellent description John

Sam Scalzo

John

I use a piece of formica. Works great

I forgot to mention...

John K Jordan

I have used many methods to put burned lines on sloped surfaces and my mileage varied depending on the slope, the wood, and the quality of the line I wanted. (i.e, some looked terrible, fat and sloppy.)

The stepped finish cut method described is especially useful for very "steep" surfaces. It is difficult to get thin, clean lines on a profile like this one, or steeper, using other methods, and especially in some woods:

I've even used it on surfaces that were almost vertical. It always works and works well (except in lignum vitae!)

Cutting a groove first with a point tool or the tip of a skew works if the profile is not too steep. However, even then, the resulting burned line is generally deeper and "fatter" than I want to see it. When step cut and burned, a skimming cut can leave the lines very thin and very clean.

With the right wood you can hold a thin object such as a piece of sharpened ebony or formica against the spinning surface. This works even if the surface is vertical on the lathe or even concave. However I found two problems with this.

One, some woods are more difficult. It is difficult to burn a line at all in some woods and at some diameters. In fact, with some woods even a "sharpened" wire held at full speed on a horizontal surface will not work well, especially if the diameter is small so the surface speed is slow. In that case, having a step to capture the wire is a big help.

Two, with some woods and circumstances, burning with an object like formica held against the wood gives a poor line. The line can end up fatter and have less crisply defined edges. Burning a clean, thin line on slick wood close to the axis is especially difficult.

Cutting a step and burning with a very thin wire works in all these cases to make a thin, clean line: problem woods, near vertical surfaces, and for circles with very small diameters.

JKJ

PS: For best results, I like to "sharpen" the wire, especially after it has been used for a while and is becomes burnished or slick with carbon deposits. Simply pinch the wire with a piece of coarse sandpaper and pull the wire through to scratch the surface.

PPS: Not much luck with lignum vitae! - too much lubrication in the wood. I thought about using electricity to make a red-hot wire but that might be a fire hazard...

Re: I forgot to mention...

Dick Coers

If I want a finer line with laminate scrap, I sharpen the edge on the disc sander.

great to hear

John K Jordan

>If I want a finer line with laminate scrap, I sharpen the edge on the disc sander.

Can you share some pictures? That might be especially helpful to less experienced turners trying out techniques.

I would especially like to see how your method works to make some very thin, sharp-edged black lines on small diameters, say about 1" or less, on smooth end grain faces of wood like dogwood, hard maple, persimmon, and boxwood.

I found those combinations more troublesome than larger diameters, side grain, softer wood, and rougher surfaces. I've seen in person what some others have done and frankly, it sometimes looked ok if you didn't get too close. :-)

Your sharpened laminate tool in the picture might also be helpful to someone who hasn't tried this before or is having trouble.

JKJ

Funny, Formica is Kraft paper and a resin...

Re: great to hear

Dick Coers

I'll post some info latter in the week. Heavy into the Christmas rush right now.

Putting the last coat of finish on a 12 bowl and 2 vessel heritage wood commision. Glad I have the old freezer kiln to set the finish is this damp weather we are having! Then on to 3 friction lid boxes that were ordered on Saturday, and a wood mount base for a vintage Jaguar hood ornament. Funny, I had to stop typing to answer the phone on the hood ornament. She just dropped it off Thursday! I feel like raising the price, definitely will if she calls again! LOL

Cool!  Thanks, John

Re: Friction burning on a slope with a wire

Jorge

A stick of pitch pine works well too. Any oily wood works.