burn marks

[officialpain]

I have been getting burns marks in cutting 3/4" birch, maple, blood wood which are hardwoods which may be the cause. I run my scroll saw at about 70% and am using # 5 ultra reverse scroll saw blades. Any suggestions? Thanks. Jim in Bend

[Jan]

Those are all very hard woods. The burn marks are not unusual with them. Many of the folks here use either blue painters tape or clear packaging tape between the wood and the pattern because it seems to lubricate the blade and prevents some of the burns. You might consider using the #7 UR's and slowing the saw a bit as well.

Jan

[Janette]

I would suggest using #7 blades and make sure they're new and sharp. Also packing tape will help as Jan suggested. I always run my saw at 100% - seems to give me better cuts - but it's a personal preference. Sometimes the direction you go will make a difference too. Sometimes if I have trouble going one way, reverse and go the opposite way may help. As for bloodwood...it's gonna burn

[3_M]

Jan is correct about the tape.
Most use the blue painters tape on the wood because it is much easier to remove than the 2" clear package tape. I like to put clear package tape on top of the pattern.
The tape has a chemical on top, like silicone, what releases friction.
FD Mike

[sawdust11703]

The last time I cut bloodwood, I thought I had a fire under my saw, even with using tape. That is incredibly hard to cut.

[officialpain]

re:burn marks

thank you all for your tips. I'll give them a try. Now that I have burn marks I guess the only thing to do is sand, sand, sand to try and get them out. Unless you have any other ideas. Jim in Bend

[Jan]

Depends on what you're making. If it's intarsia, the visible burn marks will most likely go away with shaping and the ones that don't will be hidden when the piece is glued together. Otherwise, sand away. Sanding the edges of intarsia pieces is fraught with danger as it will change the shape and ruin the fit. Just saying.

Jan

[officialpain]

JAN, THANKS FOR YOUR INPUT. WITH CURRENT PROJECTS ALREADY CUT i'LL JUST HAVE TO SAND AWAY ON THE EDGES TAHE ARE EXPOSED. ON NEW PROJECTS YOUR SUGGESTED LUBRICATING THE BLADE BY PUTTING BLUE PAINTERS TAPE BETWEEN THE WOOD AND PATTERN. DOING THAT THE PATTERN GLUES DOWN TO THE PAINTERS TAPE. IS THIS CORRECT?? WITH CLEAR TAPE i
'VE READ TO GLUE THE PATTERN DOWN FIRST AND THEN THE CLEAR TAPE ON TOP OF IT?? WHICH METHOD GIVES THE BEST RESULTS. JIM IN BEND.

[dedijerry]

I have used both and I prefer the blue tape as it is so much easier to get off no residue at all. I do find however the blue tape has a tendency to tear on the bottom and bunch up a little was wondering if anyone else has had this problem.I have always glued my pattern to the tape no matter which tape I used.
As for the burn marks I find speed has a lot to do with it on very hard oily woods like bloodwood I slow my yellow saw to about 40% and seem to have had good luck although you will still get some burning. Like Janette says change your blades often to keep them sharp. I have found on 4/4 bloodwood I need to change my blade about every 10-14" of cutting using a #5 FDUR.

[Jim McDonald]

I use blue tape and then spray glue the pattern and cover with clear packing tape.

Having said that, I did some bloodwood for ornaments in 2010 and have just about sworn off the stuff. Very hard to cut and burning no matter speed or blade.

[Janette]

Jim, if you put the clear tape on the wood first, then the pattern on top - not only will you have the tape for lubrication - but the pattern will come off easily with no residue.