question for you engineers/scientist

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workinforwood

workinforwood

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I've been reading for years about packing tape being a lubricant for scrolling. People take a stack of thin boards. They glue a pattern on top and then wrap the entire stack with packing tape, drill the starter holes and cut out the images or whatever. I just can't see how this can be possible. Packing tape is plastic and on top of that, it has glue on it. When I cut plastic with my tools, the plastic sticks to the blades and has to eventually be cleaned off. I never heard of a plastic that lubricates, and if the plastic is sticking to my tablesaw blade, that's the opposite in my mind for lubrication. They swear by the tape. I've heard some say it's because of a coating on top of the tape that helps it not stick to itself, but packing tape sticks to itself just fine last I tried some. Otherwise it would be sold as a rats nest, not a nice roll would it not? Others say that masking tape works just as good as packing tape. The main benefit seems to be a reduction in burn marks. I have my own theory. My theory is that the tape with plastic and or glue, leaves a residue on the blade. The residue prevents burning because it slows down the speed of the cut and maybe even lets some air squeek in between the blade and the wood. The reduced blade speed cause by drag will reduce the friction of speed. They say when the leave the taped area to a non tape area, the burning begins shortly after. I believe the residue on the blade has now left, causing the speed of the blade to increase along with the metal on wood direct contact and thus the burning. I rarely encounter burning, but I run my saw slow and I think most people go fast like they are in a race, but can't say for sure that's true. So...what's happening? Is it lubing, or is it the opposite effect which is also a positive effect.:confused:
 
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Jeesh Jeff, there isn't anyone as qualified as you to do some trials with it.
But Keith cuts through stuck on templates when he does his crazy cool stuff, maybe he has noticed a difference??:biggrin:
 
Jeff, I suspect (but don't know for sure) that the slow speeds you mentioned are the answer to your question. I scroll at slow speeds too, and I've never noticed a benefit to using packing tape. I can see how it might help at higher speeds which could cause the tape to melt. I quit using packing tape because it tends to trap saw dust which covers up the pattern lines. For the most part, I just use spray adhesive and touch up any "lifters" with a glue stick.
 
I can see no appreciable lubrication for the cutting blade but I can see how wrapping a stack of sheets in packing tape would hold everything together well and perhaps provide a lower coefficient of friction between the stack and the table. Could that be the "lubrication" that is referred to?

Regarding the melting of the tape, the tape is too thin for the cutting action to generate sufficient heat to cause the tape to melt. It should cut cleanly and perhaps deposit a little residue of plastic and adhesive on the blade. Neither of these would be what I would think of as a lubricant.

JMHO (as an engineer but not a scientist!)

John
 
I don't know why it works but I know it does. It's not really a lubricant but for some reason it really cuts down on the burn marks on wood that is prone to burning.
Give it a try and you may be surprised.
 
No engineer or scientist here just a long time scroller.

Now you surprised me on that one Jeff. I now use blue painters tape under all my patterns for 2 reasons one is easier to peel off than to peel off the pattern with sprayed on masking, and the second reason is it does prevent burning. I may go to the purple tape if it is a huge cutting and will take a few days because the purple has less tack and after a few days we all know what happens to masking tape, it becomes tough to peel off.

The answer to your question is------------------------ the lubricant comes from the top of the masking tape. All tapes are treated with a chemical or material makeup that allows the tape to unroll easily. If it did not have this you would not be able to unroll the tape. So it actually does not matter what type tape you use except how you use it. If you are putting a tape over a pattern then you want a clear packing tape. If you are putting the tape under the pattern like I do then use a blue or purple or the new green painter's tape. Some people like to use both methods in conjunction but I feel there is no need for that. Never use duct tape and if using double sided tape to hold pieces together be sure to use the less tacky one and not carpet tape or you will run the risk of breaking the piece trying to get it apart.

Hope that help and as far as speed goes. full out just about all times here.
 
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That might be true John. It's an answer I've heard before, and not out of the realm of believablility. But, maybe the glue is just dispersing a bit of the heat which helps with the burning, and if you simply slowed down and used a slightly larger blade, the problem wouldn't exist in the first place. I always use the largest blade I can that will still get the job done, I cut slow speeds and pretty much never have burn marks..unless it's purpleheart of course.
 
Well that is some of the golden rules of scrolling. Use the largest blade for the job, let the saw do the cutting and don't force the wood or other material, and no sidward pressure. I think most rookies get caught up in one or two of these things when learning and the sidward pressure is the big one. They are concentrating so much on their hands and watching the lines they have a tendency to push too hard and sideways.

Hey whatever reason the tape helps continue to use it if you feel it necessary. I know I will. Happy Scrolling.
 
I am not a scientist But i am a science Buff and have done many thing that require an understanding of chemistry. here is a simple answer that might just make you go Hmmmm at the very least who knows? Teflon is a lubricant (not a pipe sealer as many DIY Plumbers think it is) it is also technically a Plastic. Plastics in short cover a very wide range of items and cover a wide range of properties. slick is very much one of them.
 
Umm, probably dumb question here from an obvious kindergarten scroller, but do i put the glue side of the tape down on the board I am scroller, or glue side to the pattern..??



jttheclockman said:
..If you are putting the tape under the pattern like I do then use a blue or purple or the new green painter's tape. .
Click to expand...
 
penhead said:
Umm, probably dumb question here from an obvious kindergarten scroller, but do i put the glue side of the tape down on the board I am scroller, or glue side to the pattern..??
Click to expand...

The idea is that the tape goes on the wood, then the pattern goes on top of the tape. You can use spray adhesive to attach the pattern to the tape, or even clear packing tape, or whatever. The blue/green tape comes off the wood easily, or at least easier than spray adhesive. I just use spray adhesive and put the pattern on the wood. Mineral spirits take off the residue from the spray adhesive very easily.
 
penhead said:
Umm, probably dumb question here from an obvious kindergarten scroller, but do i put the glue side of the tape down on the board I am scroller, or glue side to the pattern..??
Click to expand...

Put the glue side of the tape on your board first. Then spray the back of your pattern with an adhesive. I have been using 3M for many years. I use the 3M77 and also the repositionable spray mount you find in craft stores. you can get the 77 in any home center.
Like I said I do not put any clear tape on top of that for I feel that is overkill. I may do this if scrolling a wood like purpleheart or something that will burn very easily. I am then looking for any advantage I can get. Cut my pattern and wipe the piece down with some acetone if need be but most of the times a quick sanding with 220 grit paper and am good to go for finishing. One thiong that is pretty crucial at least i find is that I will sand the blank to 220 grit before applying the pattern. This will save headaches later. Less residue sticks in the grains and less chance of breaking delicate pieces if you have to sand aggressively after it is cut. I can go on and on but unless there is specific questions I might be able to answer than I will shut up now.
 
workinforwood said:
I don't know, don't have the issue yet. Got an article in there though.
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OK, it is in the June issue of Creative Woodworks and Crafts. Anyone in a bookstore that gets this scrollsawing magazine you need to check it out. We have a celebrity amongst us.

I got this magazine last week and I usually first scan the magazine to see if anything jumps out at me that I may want to try and if not I will at a later date read it more thoroughly. Not sure if I would have made the connection. Thanks for pointing it out. Congrads on the article. Did you take the photos or did Wes take them?? He is the magazine photographer. I used to keep in contact with Rob Becker.


Very nice article about intarsia door handles. These happen to be butterflys. Very well done and your description is easily followed. I always felt intarsia is a 3d look into scrolling and it involves some special talent in that you need to be able to see things differently than when scrolling flat pieces. You need to incorporate wood grain to your advantage as well as color weather it be with woods or with stains and dyes. You have "mastered" this technique it sure looks like.

Did you use a high school picture for that photo because you look awful young there lad. HE HE
 
The in progress are me, any others, like the pic of me is from Wes. He photo'd it all here last fall. I heard in the next issue or two is a feature about me! Sure hope that's true..it's good publicity.
 
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