Burning whist cutting

[Little flower]

Reading the instructions for many projects (SSW&C's latest issue - project Whiskers- sparked off this thread) we are told to cover the pattern with clear adhesive tape to prevent burning. Over here in Kiwi country several of us have tried this method but find that adhseive tape just gums up the blades and dulls them off. Maybe we have superdooper sellotape or superdooper wood but we don't seem to have too much of a problem with burning. Certainly not enough to warrant putting tape over everything before even start. So we've devised a few questions we'd like to run a survey on.

Have you had the experience of 'blade burning' lately? If so, would you reply to the following points

1. Has your machine got variable speed? What speed were you cutting at?

2. What was the timber?

3. How thick?

4. A solid block or were you layer cutting?

5. What type of blade & what size?

6. Were you cutting with the grain or across it?

7. Did you take any prior steps to try to prevent the burning?

8. If you used adhesive tape, what type?

9. Did you experience the blade gumming up?

10. Any other comments?

Cheers and many thanks from the Kiwi Crew.

[jttheclockman]

I am probably not going to be of any help with your survey because I rarely experience burning and do not use any kind of tape. I may occasionally have a problem when using very dense exotic woods then I may go to a different blade and use clear packing tape. Burning is mostly caused by bad scrolling habits. You will get a problem when cutting wood 1" or better or like I mentioned hard exotics but other than that if the saw is set-up right, you use the proper blade for the task and the proper feed technique you should have no problems.

[CanadianScroller]

Burning is caused by a couple of things. Dull blades will heat the wood till it burns, SOmetimes the sawdust gets caught in the gullet of the blade and that increases friction causing burning.
JT summed it up by calling it poor scrolling habits.
The thickness of the wood, species of wood and type of blade all have an affect on the burn. Also the pressure you are applying and the tension of the blade.
I could be wrong but I thing the gumming effect is what prevents the burn, the glue acting as a lubricant.
I have successfuly cut 2" maple on a Delta 16 variable speed saw with no burning. Don't apply too much pressure. Have the blade run at a suitable speed and choose a blade with a lare gullet. ie skiptooth.

Hope this helps

[GrayBeard Phil]

Little Flower:

1. Yes, I have had burning. I have a VS, and was running at somewhere between 1100 to 1400 strokes/min.

2. The wood I was using is what we call 'cherry' in the USA. I doubt it is available in Kiwi land. This wood comes from a tree that does not produce an eatable fruit. The wood has a lot of natural 'oil' that makes the wood a redish color.

3. The wood was about 3/8 inch thick. (call it about 7mm)

4. single cut.

5. Flying dutchman #1 Silver-R design. Check out Mikes site for details on tooth design.

6-10:
I have a bad habit of stopping the cutting with the saw running, and moving my hands one at a time when I need to reposition them. I know I should stop the saw, but as I said I got into a bad habit. Doing fretwork, so the cutting is every which way accross the grain, with the grain and so forth. On an inside tight corner, using cherry wood, if you stop cutting and let the saw idle, many times burning will occur. Also if you cut a tight curve too slowly you may get burning with 'cherry'.

When I do use 'packing tape' the product is technically called 'mailing tape' and is made by 3M (www.3M.com) The tape I use is made to conform with US Postal regulations for package sealing. This product may or may not conform to package sealing tape for international postal shippments. If you search the 3M site, and query for 'package tape' you get a differet product (a more industrial type package tape) than what I sometimes use. You need to query for 'mailing tape' and then select the clear tape to get the product I use.

BTW: I don't use the mailing tape directly on the wood. The adhesive is too strong. I use it only on top of the cutting pattern. I normally use a product by 3M product #2090 'long-mask' masking tape, which everyone calls blue painter's tape. It is a low adhesive masking tape, that leaves little residue on the wood.

If I use the combination of blue tape, then the pattern, with mailing tape on top, no I don't get burning with cherry. I also don't get burning if I take my foot off the foot petal when I reposition my hands. (aside: I don't get burning on long cuts, just in the tight turns.)

Oh, one last thought. This package tape thing, it works on scroll sawing, but I have never heard of it working on a band saw, or table saw, and it does not help on a router cut at all. And it does not help on plastic stock or Corian cutting on a scroll saw either.

Phil

[3_M]

I have to agree with some and not with others. The tape has a chemicle on top, so that it can be un-rolled from it self. That chemical is like a silicon. It releases friction. Very good for cutting plastic, corian etc. You can use a smaller blade and the object will not stick to it self after cutting. I use the 2" clear package tape over the pattern and the glue of the tape is so minimum that it does not bother the blade at all, like glue in plywood what is very hard on blades. In fact it increases the life of the blade. Some put the tape on the wood first. Some like the blue painters tape and they put it on the wood. It is easier to remove after cutting than the package tape.
I know that I will keep using it.

Mike M

[Little flower]

[QUOTE=GrayBeard Phil]Little Flower:

2. The wood I was using is what we call 'cherry' in the USA. I doubt it is available in Kiwi land. This wood comes from a tree that does not produce an eatable fruit. The wood has a lot of natural 'oil' that makes the wood a redish color.

It does sound like the same cherry we have down here though I havn't used it myself for scrolling. My husband uses it in turning.

I have a bad habit of stopping the cutting with the saw running, and moving my hands one at a time when I need to reposition them. I know I should stop the saw, but as I said I got into a bad habit.

I think I do this a bit too as I do get a bit of burning in tight corners when cutting NZ rimu.

We know the blue masking tape talked about but haven't used it in scroling. Its hard to tell just what your clear packaging tape relates to here cause it can come in so many different microns. As a libriarian I use several different grades in book preparation so we will have a play with the different ones - may be a good topic for us for a workshop evening.

Oh, one last thought. This package tape thing, it works on scroll sawing, but I have never heard of it working on a band saw, or table saw, and it does not help on a router cut at all.

Maybe if our mate used it on the drop saw he wouldn't have lost his hand But good can always come out of bad because as a result he's taken up scrollsawing (one handed) and doing pretty good.

Certainly agree with you JT about the right blade and feedrate are key elements.