Build sanding blocks with blasting media?

I realize there are a few companies out there that build say sanding blocks with the blasting material glued to them. I have a set and think they are great. I use them after I get the stringer down where I want it to be. I am looking for an alternative because I don’t want to ruin the sanding block by having the grit wear down from the stringer. 

What I want is a beater sanding block that when hits the wooden stringer wears out I can easily replace cost effectively. 

 

I cut my own blanks so I want to be able to easily square up the blank with a rigid grit. 

 

I have many blocks with sandpaper attached to the block  and have seen many ideas on sways  

I was thinking of using either a 28" piece of steel or aluminum and pvc pipe to do concaves  

Does anyone have recommendations as to which type of glue is better to attach blasting media or grit to a sanding block that being a 2x4, steel, aluminum and pvc?

Hello; assuming that you are using an electric planer to shape the board (and if you do not; you should) you do not need any special block.

For example: you shape the bottom and rocker curves with the planer, then get rid of the marks etc with a heavy block with a coarser sand paper; is not too much; is a pass from nose to tail and in the concaves from middle to rails and in the V following the V shape. Now, use a wood scraper for the nose area or a japanese curved hand wood planer; then use a hand wood planer for the rest of the stringer.

Then use a finer grit sandpaper on the same block and pass from nose to tail; repeat the process with the hand planers. Only one pass.

Smooth out with a finer grit and a bit softer pad and repeat the use of the hand planes.

The bottom lime is that after every sandpaper complete pass, you go down with the stringer/s with the other hand tools. That is the way to do it by the great shapers.

Remember to have sharp tools and more than one small hand plane (they are cheap) with different angles of attack. As mentioned, the first one that you would use is the bigger and heavy one to have a nice flat surface and avoid bumps; if you obtain (depends on the foam and how sharp are the blades) some gouges besides the stringer, with the next finer sandpaper should be eliminate them.

Of course, you can do it your way and use whatever you have in hands but I show you the right way to have a clean smooth professional surface.

Thank you reverb. That was very informative. 

 

I do use a planner. I was just thinking that an aggressive 28" block would sand down my rectangular blank faster than using my planer. 

 

I will adjust my techniques. 

 

I agree with you. You definitely need to have sharp tools. Last weekend I took all my hand planes and sharpened them all. Made a huge difference. 

Square up the blank using the planer, use surforms if you want to turn the rails by hand.  Most blocks for concaves are the size of full sheets of sandpaper; I’ve never seen one longer than 12" or so. Longer than this would make it difficult to feather back into the normal bottom.    You can make custom blocks from polyfoam or balsa depending on how long you wanted it to last.  I’ve also seen blocks made from large diameter PVC, metal duct pieces, all manner of bottles and cans.  On making your own abrasives, really not worth the effort and blasting media is not the same as the material on sandpaper (lacks sharp edges).  A sheet of 80 grit white will last for several boards and after that it gets retired into the 100-120 drawer. Stringers are planed - never sanded except for the nose and tail which are done using a 2" power grinder or maybe a Dremel on swallow tails.

There used to have been a couple of blocks you could buy that were wider than twelve and took Velcro backed sandpaper the width of belt sander paper.  I have one in storage.  Tried to use it a few times, but realized it wasn’t that handy.  It was originally a fairing tool for boats etc.   There are a couple of blocks these days manufactured for concave work.  The “Varirad” being one.  I tried the “grit” sanding tools and wound up with grit material all over my blank.  I also made a few tools that use sandpaper that worked as well.  The best tool that uses grit is a rail square that I bought from Surf Source.  It will also take a pencil and mark rails.  36–40–60&80 grit abrasive will do everything I require.  New guys and beginners are always looking for some sure fire way to do concaves, but the easiest way I have ever seen was done by Minchinton doing one of those sweet spot nose concaves on an RA.  One or two widths of tape out from the rail in the shape of the concave.  Mark it with a pencil and pull the tape.  Take tour Skil 100 to it and then a sander and a pad.  Finish it off with sandpaper and screen.

Thank you PeteC and McDing for the reply’s and veteran experience. 

 

My idea was after I cut the rocker profile out of the eps block and glue a stringer in to take a 28" sanding block/beam to take out any high spots caused by the Hotwire. At this point the blank is just a long rectangle. 

 

I do use a planner to knock down the high spots and stringer. I do find that I get nervous with eps and skil 100 that the skil gets clogged with beads. I am a fanatic and blow out the skil with my compressor. I have a beater hitachi that I built an adjustable “on the fly knob” but I limited it to 1/16 to 1/8 cuts so it does take a little time with cutting rail bands etc. 

McDing I do like the Varirad  I have seen a handful of people using it  it is an interesting concept  

For the nose concaves I use a template I designed for my longboards and make adjustments from there  I typically create an outline with tape, use a planner to take out some of the concave and then use a soft sanding block with 60-80 grit to do the work  Sharpened my block planes to help take down the stringer  

Since travel is limited right now I used 1/2 ply that I had laying around on a few of the blanks  looks really cool but is a bitch to plane  

Keeping these boards thick  Could possibly use them for SUPs for the right person