Orbital vs Duel Action

[Nochain]

I have both and am wondering which tool to use for what. Is the DA meant for final finish sanding due to its more random performance and the Orbital for taking more material off like rough filler work?

What is the difference in the actual patterns? Seems like my Orbital makes a lot of swirls?

I am at initial 150 grit rough up on my epoxy primer getting ready to lay down my final 3 layers of SPI primer. Whats best to use for this rough up?
Thanks in advance for your reply…..

 

[Lizer]

I use DA for everything. Orbital basically amounts to a grinder and doesn't sand evenly like a DA does. Orbital is ok if you need to strip something off but I leave it at that.

 

[MJM]

3/16 throw DA sander for metal prep. I would advise not using the DA for sanding filler. Filler should be sanded by hand using a block.

 

[Chris_Hamilton]

Orbital basically amounts to a grinder

That would be rotary not orbital. Orbital or random orbit is an elliptical pattern used on both DA's and orbital sanders. The main difference between a DA ( duel action) and an Orbital sander is that a DA can be locked in position to have a rotary sanding effect along with the orbital sanding effect. Orbital sanders do not have a locking mechanism and sand in one pattern only.

Orbital sander example:
https://www.amazon.com/Dynabrade-21061-6-Inch-Dynorbital-Spirit-Orbital/dp/B008E35ZZU

DA sander example:
https://www.amazon.com/Sunex-SX203N...ocphy=9008896&hvtargid=pla-617562952483&psc=1

 

[Nochain]

So I need to prepare my surface (which has a 2 coates of epoxy primer for more 3 coats epoxy primer. The current coats are not SPI and does not sand well ie clogs paper easily. I paln to block by hand the final 3 coats of SPI primer. Much of the car is already blocked out. So will a DA with 150 mess up the current blocking? Blocking the current primer by hand is difficult due to the fact that it clogs paper.
What about using coarse scotchbrite? The coarse scotchbrite works well but not sure the tooth structure is coarse enough for the next coat of primer…..

 

[crashtech]

DA with 150 will most certainly "mess up" the straightness of the finished product. It's hard to decide on the best course of action without being there, but some kind of hand blocking is usually best if a nice outcome is desired. You might need to try wet sanding if the clogging is that bad. Typically I can use compressed air to unload my sandpaper and I'm not afraid to go through a bunch of paper if a goal needs to be achieved. You have to weigh your options.

 

[Nochain]

Funny thing. I tried both my DA and Orbital with the same interface pad and my DA was signimore aggressive! Albeit the DA is heavier…. Il block it and use my super coarse scotchbrite pad where needed. Thanks for all your input guys!

 

[OJ86]

I generally use a DA for prepping bare metal and roughing in body work.