scroll saw corian bowl

[kraftsmanmike]

I want to use up some Corian scraps I have and decided to try my hand at making some bowls.  Having trouble finding patterns. I don't want fretwork style, just simple closed bowl.  Also since the Corian is 1/2 inch does that mean that I have to have 1/2 inch rings?  ANY help and suggestions appreciated.

[preprius]

Hi (Mike) ?

I do like to make bowls.  I have not made segmented bowls.   I do use the technique of board to bowls. 

Any shape can be a bowl.

In the board to bowl technique the ring height is based on material thickness.   The bowl wall thickness is based on the angle you choose and the material thickness.

Use the tangent equation.

tan A = opp / adj  .   "opp" is the material thickness.

Here is some pics that might help.

This shows a fixed angled bowl.

As for patterns, pick a shape then add properly calculated offset for each ring.  I suggest you start from the center.  The more the rings the higher the bowl.  Also the corners get bigger.  

You can start with the outside ring and add offsets inward, but you can run out of bowl height. And have bottom too small.  Like I did.  This ellipse now looks like and egyptian boat.

Ok, on the pattern pic a spot to drill tiny holes.   I choose the end. Drill these holes at the same angle as you calculated.

Drill bit size gets tricky.  you want the smallest size of hole. But the drill bit has to be longer than the angled thickness.  The bigger the hole the more sanding.

I hope this helps.  If more info is needed then ask more questions.

Me.

Mark Eason

[kraftsmanmike]

Preprius I hate to sound stupid but I still don't understand.  The Corian is 1/2 in thick.  Does this mean the walls have to be 1/2 in thick?  That is a 1/2 in space between each ring?

[OCtoolguy]

6 minutes ago, kraftsmanmike said:

Preprius I hate to sound stupid but I still don't understand.  The Corian is 1/2 in thick.  Does this mean the walls have to be 1/2 in thick?  That is a 1/2 in space between each ring?

If I'm understanding your question, yes. What you will be doing is cutting concentric circles or elipses from a flat board. You have to experiment a bit to find just the right amount to angle your saw table. For 1/2" material you're going to be roughly 5 degrees. Once you have all the rings cut, turn them all over and start stacking them one atop the latter until you get to the last piece which becomes the bottom of the bowl once it's all stacked and glued. Once you're done with that, the sanding (the no fun part) begins. As mentioned you will be drilling an entry hole for each ring at the same angle as the table tilt for the blade entry hole. Try to use a drill bit as tiny as possible just enough for the blade to pass through. Those holes will leave a line that will have to be sanded off so place the lines all in a row or you'll be having to sand them all in different areas. I usually try to put them on one of the ends if the bowl is oval, on a corner of square or whatever. If it's round just line them all up. Here is a pic of one I made that was cut all from 3/4" stock except the bottom. It was 1/2" because of the inlay. Bowls are fun. There are lots of videos on youtube too.

[kmmcrafts]

32 minutes ago, OCtoolguy said:

If I'm understanding your question, yes. What you will be doing is cutting concentric circles or elipses from a flat board. You have to experiment a bit to find just the right amount to angle your saw table. For 1/2" material you're going to be roughly 5 degrees. Once you have all the rings cut, turn them all over and start stacking them one atop the latter until you get to the last piece which becomes the bottom of the bowl once it's all stacked and glued. Once you're done with that, the sanding (the no fun part) begins. As mentioned you will be drilling an entry hole for each ring at the same angle as the table tilt for the blade entry hole. Try to use a drill bit as tiny as possible just enough for the blade to pass through. Those holes will leave a line that will have to be sanded off so place the lines all in a row or you'll be having to sand them all in different areas. I usually try to put them on one of the ends if the bowl is oval, on a corner of square or whatever. If it's round just line them all up. Here is a pic of one I made that was cut all from 3/4" stock except the bottom. It was 1/2" because of the inlay. Bowls are fun. There are lots of videos on youtube too.

 

Beautiful work there Ray, I have a boatload of spalted maple that just doesn't work well for the things I normally make as all the streaks of dark color wood distracts from fretwork type projects.. Anyway, I might have to try making bowls to use that wood up.. I've never done a bowl before, but did make some coffee cups and boxes out of some of it. 

Won't the size blade also affect the angle you use? In other words if you start out with a #3 blade you should finish cutting with the same number and style blade?

Edited January 6, 2022 by kmmcrafts

[OCtoolguy]

4 minutes ago, kmmcrafts said:

Beautiful work there Ray, I have a boatload of spalted maple that just doesn't work well for the things I normally make as all the streaks of dark color wood distracts from fretwork type projects.. Anyway, I might have to try making bowls to use that wood up.. I've never done a bowl before, but did make some coffee cups and boxes out of some of it. 

Won't the size blade also affect the angle you use? In other words if you start out with a #3 blade you should finish cutting with the same number and style blade?

Yes it does Kevin. The blade's kerf enters into the equation. I was using a #5 Pegas MGT and if I recall I was at about 4.5 degrees. I had to change it  just a smidgeon for the bottom cut. It's been long enough now that I just can't recall all the details. If I make another one, I'll have to go through all the experimental cuts to find out what angle. Bowls are fun to make. This one came out a bit longer and narrower than I had liked so the next one I'll alter the pattern some and make it a bit wider. I'll leave the length alone.

 

[preprius]

2 hours ago, kraftsmanmike said:

Preprius I hate to sound stupid but I still don't understand.  The Corian is 1/2 in thick.  Does this mean the walls have to be 1/2 in thick?  That is a 1/2 in space between each ring?

Mike,

great your asking questions!

If you use the same space between lines you get a 45 deg angle. 

Ok let's go thru some numbers... 

thickness 0.5 inchs

lets say you want 30deg angled side.

tan angle = offset / thick.

tan 30 * thick  

0.577 * 0.5    =   0.288 offset.

so the spaces between circles or (ellipses)  would be 0.288 inches.

The thickness of the blade does not really change the offset but a little. Unless your using a big thick blade.  So consistency is good.  Stay with the same blade thickness.  As others have said. It is not terrible if you have to change blade types. 

The offset between lines 0.288,  is the bowl wall thickness. 

The number of rings times the thickness is the height of the bowl.

The next picture shows the cut rings as they were cut.  The 2nd picture shows reverse stacked rings.

Please note this was an experiment of changing angles. This shows changing wall thicknesses because the angle changes.  

As you reverse stack the rings the wall thicknesses line up on the previous ring.  

If you cut perfectly, there is no sanding.  But expect sanding. As your cutting at an angle it is easy to put pressure left or right on the blade.  This pressure will effect the cut angle a little bit.  Pay attention to the blade pressure left and right to reduce sanding.

Glue the rings together don't  glue to bottom yet.  If there is no bottom it gives easy access to inner rings. Sand the inside rings smooth.  Then glue bottom on. Then sand outside.

Me.

Mark Eason

[preprius]

Mike,

I am in the sanding inner rings step on another bowl right now. 

Here is 2 pics showing a board thickness of 0.3 inches and a wall thickness of 0.125 inchs.  My angle was 26.65 deg. 

I had a too thin blade. I had issues controlling the cut on the line.  So sanding shows lower wall thickness. 

blade #1 on hard oak 0.3 in thick was a bit too small of blade. 

After I am done I will post this project. But for now I dont want to show the shape. 

 

[Roberta Moreton]

Carole Rothman has an article on a type of bowl done in corian in Scrollsaw Woodworking and Crafts magazine. Fall 2020,

issue 80. Page 60. I would love to get some. 

[rustynail]

 Here are two of Carole Rothmans books that are a great source and have plans in them. I checked them out from my local library. I recommend them highly for learning how to make bowels. 

[meflick]

I second the recommendation of Carole Rothman’s books as great resources. She also participates on the magazine’s forum and is always willing to answer ?s there. https://forum.scrollsawer.com 

If you don’t have it, you can order the magazine Roberta mentioned on their website here: https://www.foxchapelpublishing.com/scroll-saw-woodworking-crafts-issue-80-fall-2020.html

[Puzzleguy]

Id check about wether its a good idea to use corian or not -

some materials are not food safe etc.

plus you will need a better than average mask - at least a N-95

for your own health - maybe better if you use wood -

[OCtoolguy]

1 hour ago, Puzzleguy said:

Id check about wether its a good idea to use corian or not -

some materials are not food safe etc.

plus you will need a better than average mask - at least a N-95

for your own health - maybe better if you use wood -

I wonder where a person might find a mask?   lol

[Karl S]

2 hours ago, Puzzleguy said:

Id check about wether its a good idea to use corian or not -

some materials are not food safe etc.

plus you will need a better than average mask - at least a N-95

for your own health - maybe better if you use wood -

Wondering----Do I need to remove our Corion counter tops since they come into contact with food sometimes? Hope Not!

[OCtoolguy]

12 minutes ago, Karl S said:

Wondering----Do I need to remove our Corion counter tops since they come into contact with food sometimes? Hope Not!

I was wondering the same thing. I think they are food safe.