Flexible Sanding Blocks

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Introduction: Flexible Sanding Blocks

About: If its practical, I have no use for it!

This is a really quick and super simple project tip, yet it is really useful for wood working! Make flexible sanding blocks/sanding pads from rigid foam and sandpaper to sand any round, concave, or convex shapes. Because they are flexible they conform to the shape you are sanding. It is also easier on your fingers when you use the foam pad. You use hot glue to attach the sandpaper to the foam pads!

Supplies

  • Polyethylene closed-cell foam, 3/4” to 1-1/2” thick. Recycled packing materials (like sheets or panels) are ok and free! If it's too thin you can glue up a stack to get the desired thickness like shown in step 1.
  • Wall insulation rigid foam (the pink stuff) also works.
  • For round shapes use pipe insulation tubes or pool noodles.
  • I don’t use styrofoam, it’s messy, it breaks, and its not flexible enough to conform to odd shapes!
  • Sandpaper or sanding disks of different grits
  • Hot glue gun
  • 5" plywood disk
  • 1/4" carriage bolt and nut
  • Drill press, band saw

Step 1: Sanding Sponges for Hand Sanding

Cut a piece of foam to fit into the spaces you want to sand. Cut a piece of sandpaper (e.g. 100 grit) a little larger than the foam pad. Use hot glue on the sandpaper, and glue it to the foam pad. Don't use the glue gun tip on the foam, you will probably melt the foam. The sandpaper may extend about a 1/4” beyond the foam pad. Curl the edges slightly upwards.

You can also shape the foam pad (e.g. concave or convex bottom) to match the curvature of your workpiece before gluing on the sandpaper.

After the glue sets, use the sandpaper foam block to sand your workpiece. I have found that the sandpaper does not tear as easily when used this way, and it is a lot easier to use in curved and tight places. When the sandpaper is spend, hot glue on a fresh piece or discard the pad.

I don’t know anything about automotive body repair work, but maybe these flexible sanding blocks will be useful for that as well.

Edit 7/10/22: Well, I am doing some door frame repair and repainting in my workshop right now, and what do you know? The sanding blocks are very useful for that job as well :-)

Step 2: Sanding Disk for Drill Press or Drill Use

Cut a 5 inch diameter plywood disk with a 1/4” center hole. Insert a 1/4” carriage bolt thru the center and fix in place with a couple of nuts. This is your sanding arbor for use in a drill press.

Cut a 5 inch diameter foam disk and hot glue to the arbor disk.

Use a standard 5 inch sanding disk or cut your own sandpaper disk, and hot glue to the foam on the arbor. Mount in the drill press and sand away!

When the sandpaper is used up you can glue on a new piece; or remove the foam pad and reuse the 5 inch arbor.

That's it, really quick and easy!

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    13 Comments

    0
    Threadhead Jude
    Threadhead Jude

    15 days ago

    So useful! Thanks for posting!!

    0
    rschoenm
    rschoenm

    Reply 15 days ago

    Thanks!

    0
    terrefirmax2
    terrefirmax2

    16 days ago on Step 1

    So obvious, yet we continue to throw things away and just buy more stuff? Things have so much packing that is formed around parts it makes me look at it trying to figure out how it can be utilized, as template or mold. Good thinking!

    0
    rschoenm
    rschoenm

    Reply 15 days ago

    Thanks!

    0
    JG49
    JG49

    27 days ago

    Hi,

    Thank you for sharing this, it's amazing just how many things we tend to throw thinking it's of no use, then you come across something like your Instructible and then it hits you what you could have done with the bits and pieces that have been thrown (I hope that makes some kind of sense :-) )...

    Thank you again...

    All the best...

    John...

    0
    rschoenm
    rschoenm

    Reply 26 days ago

    Thank you! It's always a good thing to reuse and recycle. For me these sanding blocks work as well as the store bought ones, plus you can customize them for your specific needs.

    0
    terrefirmax2
    terrefirmax2

    Reply 16 days ago

    Better even. Not as stiff, and size and shape is custom.

    0
    nils2u
    nils2u

    19 days ago

    „That's it, really quick and easy!“
    Those are the things I love the most!
    Thank you very much for reminding me!
    I‘ll fix some up asap, because else I’ll forget, so they‘ll be ready next time I need them….

    0
    rschoenm
    rschoenm

    Reply 19 days ago

    Thanks! They are easy to make and very useful!

    0
    Componenx
    Componenx

    25 days ago

    Last year at one of the set shops I work at I found a bunch of cut offs (blue 1" thick foam with 1/8" luan glued to one side) in the trash and realized they would make great sanding blocks. I cut them into various sizes between 2x2" and 3x6". They also are great for custom shapes.

    0
    rschoenm
    rschoenm

    Reply 25 days ago

    What a great find. You can probably use both sides (the foam side and the luan side) for different sanding tasks! Thanks for sharing!

    0
    ironarmadillo
    ironarmadillo

    Tip 27 days ago

    This is a nice variation on something I've been doing for years. I save the foam packing from mail order purchases, cut it up into something I need then use spray contact adhesive instead of hot glue. When the sandpaper wears out I just use spray contact adhesive to add another layer of sandpaper. This works great for non-hook-and-loop sandpaper. This variation will eventually get so many layers of sandpaper built up that it just gets thrown away and a new sanding block is started.

    Another variation I have good experience with is spraying contact adhesive on a piece of foam and attach a fitted piece of the hook backing part of velcro. Then I can use hook-and-loop sandpaper on the foam block.

    I buy most of my non-5" sanding disks as long rolls of sandpaper - some plain backed, the rest is hook-and-loop backed. This saves a ton of money on buying the packaged sandpaper at the home improvement centers. I also have several large drum sanders that require hook-and-loop sandpaper so, consequently, I occasionally have to replace the velcro backing on the sanding drums. A 50 meter roll of 10 cm velcro (you can buy just the hook backing part of the velcro) lasts a very long time so using velcro backing to attach hook-and-loop sandpaper is a very practical solution for me.

    0
    rschoenm
    rschoenm

    Reply 27 days ago

    Thank you for your great suggestions. I like the approach using velcro and I will try that sometime.

    As you mentioned spray adhesive is a very good option for attaching the sandpaper. I use hot glue since that is what I have in my shop for a variety of tasks; but you have to be careful not to melt the foam.

    I also buy my sandpaper sheets in bulk, it is significantly cheaper!

    Thanks again for sharing your ideas and experience.