Monday, February 3, 2020

Detail Sanding – The Arsenal

Bosch - Modified Chinese - Hutchins - B&D Mouse and  2"

It is always best to use the biggest sanding pad possible to minimize the amount of ripple in the surface.   The 8” sanding/buffing grinder works well for this.

When the surface gets more intricate and curvy, a smaller disc has to be used otherwise the edge of the sander will cut too deep into the gelcoat.  I have 5” and 6” pads in both stick-on (Velcro) and glue-on pads that can be put on either my electric or pneumatic sanders.

One thing about post-sanding the gelcoat is the amount of dust created.  I really like to wet sand since it minimizes the airborne dust and also washes the dust out of the sandpaper, making it last longer and work better.
Hutchins 7544
As explained in a prior post, using an electric sander with water is not such a big deal because of our power setup.  However, since now have an air compressor, the pneumatic sanders are lighter and definitely  the way to go.

Water Injection Adapter
I bought a Hutchins 7544 water injected pneumatic sander since it seemed like a good way to go.  These cost $350 on Amazon but I got a used one on ebay for around $100.   It worked well and can be used with all pad combinations 5”/6”/Stick-on/Glue-on.  After seeing how it was designed, I felt that and random orbital with vacuum extraction could be used as a water injection sander. 

The Hutchins has a small tube that injects the water through the holes in the sandpaper.  Most of the time, I use sheets of sandpaper cut and glued on to the disc so the water just runs out from around the disc and onto the surface anyway which works fine.
Internals of the Chinese Sander

My hack was to connect the water hose to the vacuum port and pump water into the sander.  I bought a $35 Chinese sander for the modification.  It worked well but works better if you sand with the water tube up so the water runs down onto the surface.

2" Pneumatic with velcro and glue discs
Sometimes a 5” disc doesn’t quite cut it so I bought a 2” pneumatic sander.  This is ideal for most small radius corners and close in edging.  This sander doesn’t have any real way to inject the water so I tried attaching the water hose to the frame but in the end, it was much easier to just hold the water hose and dribble it on the surface.   

These sanders come with Velcro pads which are fine but since I also need glue-on, I took a razor blade and cut off all the Velcro,and melted the remaining bits with a torch to make a glue-on pad.  Both pads have worked great except for some cheesy sandpaper from Amazon that just gets destroyed within a minute from the vibration.

No comments:

Post a Comment