I have a Dewalt sander I am using for wet sanding on a boat hull. I have already burned one sander out do to moisture I figure is there a way to protect the new sander from this happening again I am sanding surfaces above my head so the sander is upside down 90percent of the time

I would suggest giving our Service Center so we can get your unit looked at. DEWALT com

That sounds right. It is probably the type that uses adhesive backed paper. You stick the paper to the rubber pad.

this sander appears to use the hook and loop system, you can download an instruction manual by going to dewaltservicenet.com and typing in your model number.

I'm not sure I understand your question, but I'll give it a go.

The DW421 is a sander already. If you want to change it to a polisher, you can buy polishing pads to go on it.
If you have a Dewalt polisher and want to convert to a sander, you can buy sanding disks to fit your polisher. They are installed on the spindle and I believe you can get a backing pad for it also.

Hope that helps

go to here this link is for a dewalt manual


http://service.dewalt.co.uk/PDMSDocuments/EU/Docs//docpdf/d26441_eur.pdf


hope this helps


john

I think your model holds the paper with glue that is on the sand paper.Just take apart the back cover of the sand paper to expose the glue.

The velcro pads wear out and need to be replaced periodically. You can buy new pads on-line at any Dewalt parts seller.

Check the brushes for the motor they may have gone bad or broken, I have seen this happen before on dewalt tools.

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/sean_54c3a3dc48a7773c

This info may help;

Features: DeWalt D26451K 5" Random Orbit Sander Kit

• 3.0 Amp motor operates at 12,000 opm providing ideal sanding speed for smooth finish
• Textured anti-slip top & body grip provides ultimate comfort and control during prolonged use
• Controlled Finishing System maintains pad speed and minimizes gouging during start up
• Dust-sealed switch prevents contamination
• Sealed 100 percent ball-bearing construction provides longer life
• High capacity dust bag with built in vacuum adapter provides maximum dust collection with or without vacuum
• Dual-plane counter-balanced fan reduces user fatigue
• Accepts 5", 8-hole hook & loop paper allows sanding discs to be switched back and forth quickly and easily
• The sanding discs mate to the sander plate similar to Velcro, and this particular sander uses a 5" disc with 8 holes in it. Can be purchased in Home Depot, Lowes, etc....

Hope this helps!

have you checked the fuse first.
possibly worn brushes on the motor, remove the brushes and check the length of them , also look to see if they are pitted or burned.