Just wondering

[wombatie]

Just wondering if this has ever happened to anyone else.  A couple of weeks ago I went to buy some more ply and the guy gave me a good deal on a sheet of Poplar ply 2 or 3mm.  Anyway I started the Steve McQueen portrait today and OMG I have never had so many problems before.  It was as if the ply had a mind of its own. First it would not glide in the scroll saw so had the stop to polish it, then It was as if I could not control the blade if I wanted a thin cut I ended up with a thick one. I tried about 4 different types of blades of different sizes (no spirals) but no that did not help.  The more I did the worse it got.  I have been scrolling for about 15 years, I have not shied away from intricate patterns in fact I think there as only ever been one pattern that I have not complete but I would do it now without batting an eyelid. But I have never come across ply with a mind of its own.  I slow the speed down I even made it faster. In the end I gave up and found another piece of ply and I am having no problems at all. Boy am I confused. :huh:

 

Marg

[thumbs]

Marg, I just love those good  "deals" was the second piece the same plywood? I have bought 1/4 inch underlayment  because of a good deal. Ended up using it for backer boards. If I remember right, It even smelled funny when I was cutting it. Hope someone else has a better answer--Richard

[wombatie]

No Richard the second piece of ply was completely different but the same thickness.

Marg

[EIEIO]

I wonder if it had some different type of glue in it. If you use a blade that gives less than one tooth in the thickness of the board you will get a lot of chatter as the blade contacts and releases. But if the thin layer of glue is very hard, and the poplar is soft, then you might be seeing the same thing as the tooth contacts and releases the glue layer. just a thought...

[Marcellarius]

I wonder if it had some different type of glue in it. If you use a blade that gives less than one tooth in the thickness of the board you will get a lot of chatter as the blade contacts and releases. But if the thin layer of glue is very hard, and the poplar is soft, then you might be seeing the same thing as the tooth contacts and releases the glue layer. just a thought...

Hi Marg

Think Ray has a good point,

I use different types of ply and in different sizes, but I think the type of glue does matter.
the effect gets worse if you stack two or three layers....
but to be honest I check things first myself, because I did things wrong .

- isn't the blade mounted upside down?
- try an other new blade from a different dozen, (I've had more then one bad blades in a bundle)
- is the blade tension OK?
- no suspicious sounds from damaged or old bearings?
- if all is OK, I take a piece/blank of an other type plywood or hardwood and make a test cut and see it that goes well, then you know it's the wood.... but then again, you could try that first of course



good luck!

[overfifty]

Could they be mixing species in the veneers?

[wombatie]

Hi guys.  I think it was because it was a soft wood.  The second piece of ply I used was completely different a harder wood altogether and I'm having no trouble what so ever with it.  Unfortunately I have a 4' x 12' sheet of the poplar one. Just hope I can use it for something.

Marg 

[EIEIO]

4x12 feet? that's some big piece of thin plywood. Maybe use it for some big things that can be cut with a circular saw, like the side panels of a toy box.