sanding disc

Re: sanding disc

Dick Coers

Have you priced 20" discs? Price bugs me every time! My opinion is that plywood is not flat enough, unless you get high grade and get lucky. If you get a little warp, you can't flatten it on the lathe without going through a layer of veneer. A piece of plastic laminate may help you get a flatter face, but you also have another layer of contact cement in the stack. 2 or 3 layers of a good poly will give you the same surface. I mention the layer of contact cement because it's not unusual to have a little trouble removing an old disc. Not unusual on my steel disc to use a little heat, solvent, or razor blade to remove adhesive residue. Heat or solvent will need to be controlled if you use the contact cement and laminate. Adhesive backed will not stick to bare wood. Adhesive backed works well, but expensive and you still can have residue issues. I bought some old stock paper backed, and use 3M 77 spray contact adhesive.

Re: sanding disc

Bill Tindall, E.Tn.

Consider hook and loop. The advantage is you can easily change grits.

Be wary of a 20" disk. Spun fast enough it could disassemble.

Re: sanding disc

John C Lucas

I made a 16" many years ago a d still.use it. To flatten the plywood, even good stuff you mught need some.wood.filler. i wouldnt go.with the plastic laminate. It will loosen with heat which you will generate with sanding. Dick's advice on the poly is good. I buy the pressure sensitive.discs because i rarely change them until they are worn. Depends a lot on what you tend to do with it.

Re: sanding disc

John C Lucas

Forgot to.say i attached mine permanently to a homemade faceplate so it stays aligned. You can do pretty good if you label a faceplate and the wood so you can install it the same.way everytime. If you use a chuck with a rebate do the same thing. Label jaw #1 s position and the install the wood i. This position every time. Even with a permanent faceplate it will sometimes move over the years but its easy to true up and just apply some more poly.

Re: sanding disc

Don Stephan

Ahhhhh, [brush on] three layers of poly[urethane]. I thought some different type of "poly" sheet good was being recommended in a three layer lamination. My apologies.

Re: sanding disc

AZ in Colorado Springs

I have a 12" disk on my Rikon mini lathe. It's a piece of 1/2" MDF attached to a face plate. I bought a variety pack of PSA self adhesive disks at woodcraft. Works great. I have a rubber eraser type block for cleaning the sanding disks and they last a long time. When I change the abrasive disk, a putty knife helps pry it off and scrapes away and adhesive residue.

Re: sanding disc

Doug Wolf

Here is a 12" one I made from an old computer desk top that was an inch and a quarter thick and covered with Formica. I turned it round on the lathe and sealed the edges with several coats of "poly" so it wouldn't absorb any moisture. It's permanently mounted on a faceplate.

Re: sanding disc

kruizen

I was fortunate enough to find a salvaged piece of corian counter top for $20.00 on Craigslist. I mounted on permanent on a face plate.

I have to say that Corian is not my favorite stuff to work with but it stays flat. Also you DO NOT want to drop it it can chip or break.

I have both PSA and Hook and Loop Versions in 12". Used the hook and loop 95% of time easy to change grits with the heavy grits and the larger motor on the lathe can do free form work very quickly.

I have noticed that when I used to glue segmented rings in halves and sand the final joint on the H&L disc sometimes did not flatten because of the flex of the H&L.

I have a 20" as well do not use very often but it does work for flattening larger segmented rings.

Re: sanding disc

ben d.

Thanks for the reply's and I was going to use a dedicated face plate so that will take care of the alignment. I am planning to make some large segmented pieces and need a large disc to true up the ends of the half circle. As stated hook and loop may not be true for this purpose so I think I need to go with the stick on sanding disc's and because of the glue up's I mentioned I think it is best to stay away from those, so it comes down to if I am reading correctly to use a wood disc and coat with poly to stick the sanding disc to.

Any other comments are welcome.

ben d.