long sanding blocks

[Upali]

Quick question: What is everyone using as sanding blocks for flat surfaces like wings or canards?

Can I adopt an aluminum tube similar to the one below? I can make sure it will be flat enough and I am looking for about 36" block.

https://www.ebay.com/itm/284030303143?hash=item4221867ba7:g:1UYAAOSwN2RfdQ6Y

[Kent Ashton]

Serveral discussions on this page

https://www.canardzone.com/forums/topic/18661-kents-long-ez-project/page/13/?tab=comments#comment-62441

IMO 36" is unwieldy and you have to glue long sandpaper to it.  I use pieces of 2X4 about 18" long, round the ends slightly and staple or tack belt-sander belts to them.  However, an aluminum bar is useful as described above.

 

[Upali]

Thanks for the tips Kent. I will see if I can use a 2X4 piece.

[Marc Zeitlin]

9 hours ago, Upali said:

Can I adopt an aluminum tube similar to the one below? I can make sure it will be flat enough and I am looking for about 36" block.

Yes, that would work, _IF_ the extrusion is perfectly straight and flat. There are few 2x4's on the planet that are flat/straight enough to use for a sanding block - you'd never get a really good contour. 3" is a bit narrow, although it would take a 3" roll of paper.

I used a 1/2" thick piece of plexiglass as large as 3 sheets of 3M wetordry sandpaper, and glued a 2" x 2" AL extrusion to the back to keep it straight. With 3 sheets of paper on it, being about 33' - 36" long, you get really good coverage and straightness/flatness on your contours. 18" is marginal for wing/canard contouring, IMO. The larger the sanding block, the better your contour will be.

[Kent Ashton]

11 hours ago, Marc Zeitlin said:

Yes, that would work, _IF_ the extrusion is perfectly straight and flat. There are few 2x4's on the planet that are flat/straight enough to use for a sanding block - you'd never get a really good contour. 3" is a bit narrow,

Well, whatever floats your boat but this block (16") and aluminum bar have finished three airplanes.  "The poor carpenter blames his tools."  🙂

[Marc Zeitlin]

1 hour ago, Kent Ashton said:

Well, whatever floats your boat but this block (16") and aluminum bar have finished three airplanes.  "The poor carpenter blames his tools."  🙂

 

Well, yeah, I could wrap a piece of 80 grit around a ball-peen hammer and contour a plane, but it wouldn't be pretty :-). I'm shooting for optimal, not adequate here :-).

[Upali]

Thanks guys! 

I already bought duragold 2-3/4" (width) sandpaper rolls. Should I go for larger width or will this work?

 

[Kent Ashton]

2 hours ago, Marc Zeitlin said:

Well, yeah, I could wrap a piece of 80 grit around a ball-peen hammer and contour a plane, but it wouldn't be pretty :-). I'm shooting for optimal, not adequate here :-).

Pissch!  I can contour an award-winner with a concrete block!  Usually start with a regular block, then go to a red stepping stone for a finer finish.  Next airplanes we build, we will have to hold a contest  🙂

49 minutes ago, Upali said:

I already bought duragold 2-3/4" (width) sandpaper rolls. Should I go for larger width or will this work?

Those should work but 20 yards is enough for 4 airplanes.  You need various grits though.  36 to get started, then finer.  220-240, 320

[Countach74]

I use a 48" Great Planes Easy Touch aluminum extrusion. They are discontinued at this length, but are found used on EBay or rc airplane classifieds.

[Marc Zeitlin]

3 hours ago, Kent Ashton said:

Pissch!  I can contour an award-winner with a concrete block!  Usually start with a regular block, then go to a red stepping stone for a finer finish.  Next airplanes we build, we will have to hold a contest  🙂

 

Hah! When I was a boy, we'd contour sand with a wet strand of spaghetti, wrapped with hot gravel. You try to tell kids these days, and they won't believe you.

In any case, it'll be a cold day in hell before I build myself another airplane, so this contest will have to occur in another lifetime...

[Upali]

Thanks guys for all the insight! Will be back with tons of questions once I start the project.

[Jon Matcho]

From Nick Ugolini's blog, he builds a copy of an off-the-shelf tool that I'd want to use for long sanding. 

Nick Ugolini's Blog » Search Results » flexisander