# DA or Orbital -- Sander of Choice for Auto Painters?



## Tooled (Jul 25, 2012)

I'm looking at stripping the paint off my car and going with a different color. I've done quite a bit of research over the past few months to make this kind of a "winter project". I'm having issues trying to pick a good sander that's going to save me time, but more so one that's going to give me the luxury's of paint stripping, sanding in all stages(minus hand sanding corners) including wet sanding if its mandatory...I've been looking at the Hutchins brands and a couple Ingersolls -- but i've heard to stay away from them, except I've heard mixed opinions on people who sand with a DA vs. a "Random orbital" 

I'm not entirely sure if I should get a "all in one" sander that can do wet sanding with a vacuum ready attachment. So I'm seeing if any members on NASIOC have experience with this brand/models. I guess the question I have is which one do you think would be best suited for doing Auto Restoration short of buying other sanders like jitter bug sanders, etc. 

And yes I do have a good quality air compressor... 

Hutchins - RO Sander 
Amazon.com: Hutchins 3500 Super III Random Orbit Sander: Home Improvement 


Hutchins Super VAC Sander 
Amazon.com: Hutchins 3950 6-Inch Light Weight Super Sander VAC: Home Improvement 


Hutchins - Water Bug 
Hutchins 7544 6-Inch Water Bug Sander III with 20-Foot Hose - Amazon.com 


Ingersoll 
Amazon.com: Ingersoll-Rand 4151 Ultra Duty 6-Inch Vacuum Ready Random Orbit Pnuematic Sander: Home Improvement


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## teejaybee (Apr 16, 2011)

I use a snap on palm da sander, but if your stripping down to metal just use air craft stripper will save time


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## Tooled (Jul 25, 2012)

I've heard good things about the air craft stripper solution. 

Is this ideal for a car that has still a good paint job or is just taking some 220-320 on it good enough with a DA. I've always heard DA's leave swirl marks, which is why Random Orbital were optimal; I just wanted to know if this is true in that case. Is there a set time of brushing the aircraft solution on, I heard it practically starts to flake off easily. Is this a safe solution to sanding down the plastic trim too? i.e. bumpers, skirts, wing, etc.


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## teejaybee (Apr 16, 2011)

well if your stripping it to raw metal, air craft stripper is the most ideal just use a paint brush to apply it let it crack and scrap it off


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## Boo5st3dPmkn (Mar 13, 2009)

First thing's first.. a D/A and a random orbital are the same thing.
Out of the links you provided, I'd suggest going with the Hutchins 3500. I personally use Hutchins 4500 series, pretty much all day everyday, and they keep going without a problem. And if you ever do have a problem, remove a few screws and the entire thing comes apart so you can clean it out. I prefer the Hutchins over other brands due to the ease of changing pads (you dont need a wrench to pull a pad off) and I just like the way they balance out in my hand. They seem to work nicer when wetsanding as well. 
If your looking to save a few bucks, then go with the Ingersoll-rand. It'll get the job done.

Next, DO NOT use paint stripper on your car. There is no need for it, your just going to make a huge mess, and open up all the bare metal on your car to moisture and rust. And no, regular aircraft stripper is not safe to use on plastic parts, it will soften it and begin to melt through it. They sell plastic safe paint stripper for those jobs, IF you need it.

To try to keep this short, here's a really brief list of suggestions:
-Wash your car with dish soap a few times between now and winter, just to start removing the wax and other contaminents on the surface.
- I also like to give a car one last "good" wash before I pull it in to start work. Get some degreaser and some brushes. Clean out your engine bay, all the jambs, wheel wells. Just make the car as clean as possible.
-Buy yourself some wax/grease remover, and before you even think about picking up a piece of sandpaper, wipe the entire car down first, 2 times wouldnt hurt either.
-Walk around the car and look for damage, in different light, at different angles. Make a note of where all the damaged areas are.
-Then come up with your game plan. Since your doing a color change, I'd start by stripping all lights, markers, and anything else off that is easily removable.

Now, rather than going crazy with your D/A and ending up having to spray primer on the entire car, start off with Scotch-brite pads. I prefer red, its an agressive cut. You can also use gray, a medium cut. I would scuff the entire car from top to bottom, you can do this either wet or dry. I prefer to do this wet, using some SEM 38338 soap during this process to help aid cutting/cleaning.

After the outside of the car is completely scuffed up, then begin your body work (if you have any). Try to keep your repairs as small as possible, and after the repair is complete, try to keep your primer area as small as necessary. After the primer is dry, wetsand the primered areas with 600 grit.

Then the real fun begins, you'll need to pull off all exterior panels (bumpers, doors, etc) since your doing a different color. Make sure that you now go around the car again and scuff up all the edges and jambs that are now exposed, as well as any areas you may have missed the first time.

Wipe everything down with wax/grease remover again, tape tape tape, mask , tape some more. And after wax/grease removing again, and tacking everything off, your pretty much ready to start blowing on some color.

Long post, I know. 
Paint work isnt easy, or cheap. It takes time, and the prep work is key to success. Make sure you do a lot of research, make sure you buy the "correct" products (not bondo and spray bomb primer from walmart!), ask questions even if it makes you sound like a retard. Might as well do things right the first time, otherwise you'll be starting from scratch all over again.


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## JCCLARK (Dec 1, 2011)

Boo5st3dPmkn said:


> First thing's first.. a D/A and a random orbital are the same thing.


That's not true.
A DA is dual action, measured in RPM's which spins quite fast but is 
on a slow eccentric.
A random orbital (RO) is measured in orbits per minute, it spins real slow and orbits real fast, like 10,000 per min. It's more like a vibator sander.
Most woodworkers use a RO, they are way to slow for
most car work, they work good for featheredging or polishing (not buffing).
but can't compare to the power of a DA which is air driven and claims way more
horsepower than any electric RO.
When you buy a DA check the rpm and the offset.
When you buy a RO check the amps and the orbits per minute.


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## Tooled (Jul 25, 2012)

Boo5st3dPmkn said:


> First thing's first.. a D/A and a random orbital are the same thing.
> Out of the links you provided, I'd suggest going with the Hutchins 3500. I personally use Hutchins 4500 series, pretty much all day everyday, and they keep going without a problem. And if you ever do have a problem, remove a few screws and the entire thing comes apart so you can clean it out. I prefer the Hutchins over other brands due to the ease of changing pads (you dont need a wrench to pull a pad off) and I just like the way they balance out in my hand. They seem to work nicer when wetsanding as well.
> If your looking to save a few bucks, then go with the Ingersoll-rand. It'll get the job done.
> 
> ...


All good info, I've been trying to find experience based story's, because your absolutely right..I've never done a job this big, or this detailed; but I absolutely want to get it right the first time. The info, thats pretty much what i've done as far as research goes on the methods used...short of using sandpaper instead of a scotts pad. I guess if you go that route, is priming the whole car still necessary/more beneficial? It sounded like a quick method, but I was under the assumption of starting out with scuffing it with 220-320, then following up by possible 400-600 wet or dry. Then priming, and repeating the process with 400-600 wet/dry. Followed by the base and clear with the same rinse and repeat process..

The Hutchins all seem good, I didn't know if I could wetsand with the 3500 instead of paying 300 bucks for the wet sander one, but I suppose it wouldn't be a problem since its air.



JCCLARK said:


> That's not true.
> A DA is dual action, measured in RPM's which spins quite fast but is
> on a slow eccentric.
> A random orbital (RO) is measured in orbits per minute, it spins real slow and orbits real fast, like 10,000 per min. It's more like a vibator sander.
> ...


good info too thanks!

I appreciate the detailed post, I know repeatability dumb questions get stale so that's why I've tried to do as much research as possible.



thanks guys


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## JCCLARK (Dec 1, 2011)

If you want to strip a car with sanding, look at the National Detroit
brand air sander. It's called a grinder instead of a DA because it only spins,
no dual action. That's what makes it way more aggressive and it'll remove paint
quicker than anything I've used. It's a very good tool.
Next to that you can use a buffer, it too only spins and will remove paint pretty fast.
You just have to buy a backing pad for it, but they're easy to find.
Stripper is an option, and has one advantage, it doesn't scratch the metal like sanding does.
Most cars panels have a coating, it's like galvanizing, if you strip all the paint off with 
stripper, this coating stays intact and you'll notice it doesn't rust even after you wash it
with soap and water. I always liked that. If you sand the paint off, you loose that coating and
it'll start to rust immediately.
Both have pluses and minuses, I usually sand it off because it's so much faster.
But some items that are hard to get sanding to, stripper works best.
Good luck, either way!!


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## Boo5st3dPmkn (Mar 13, 2009)

Tooled said:


> short of using sandpaper instead of a scotts pad. I guess if you go that route, is priming the whole car still necessary/more beneficial? It sounded like a quick method, but I was under the assumption of starting out with scuffing it with 220-320, then following up by possible 400-600 wet or dry. Then priming, and repeating the process with 400-600 wet/dry. Followed by the base and clear with the same rinse and repeat process..


You stated that your car still has a decent paint job.. so there is absolutely no need to sand the whole car down (or strip it) and then re-prime. The only time this would be neccessary would be when you are doing body work to / block sanding the entire car, or the previous paint job is bad or flaking. 
If you go the Scotch-Brite route, you'll only need to re-prime the areas that were repaired (any area that you had to sand more aggressively to remove filler or surface defects). Only the primer will then need to be wetsanded smooth (with 600)......
However... After priming, you can go around the car and wetsand it smooth if you prefer (600grit). The smoother the surface, the smoother your paint job has the potential to be. Also, more the surface is cut, the better the paint will adhere. I like this step also because it gives you another chance to check all the panels for flaws you may have missed.
As far as sandpaper grit goes, I would suggest talking to whoever you buy your paint from. Most paint manufacturers have a different preferance for surface prep. The basecoat I like to buy will cover up scratches better than most others. If you spray some bases over (say 400grit) the base might not be able to cover up the scratches. If you finish sand your primer (or car) with 600grit wet, you should be pretty safe with any paint though. 

Depending on what color your car is, and what color you want to change it to, it may not be a bad idea to spray your car in a primer sealer before you spray the base/clear. Most sealers are a wet/wet application, meaning you spray on your sealer, let it tack, then continue to spray your base and clear with no sanding in between the primer and color coats. 

And yes, you can definately wetsand with the Hutchins 3500, you'll just need to buy a different backing plate. Just be sure to keep it clean and dry it out after use, as well as keeping it oiled.

Check out www.autobodytoolmart.com I get a lot of my supplies from there, even with shipping costs they tend to be a little bit cheaper than my local supplier.


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## Tooled (Jul 25, 2012)

I'm familiar with that site, would this be a good prime/sealer, they make a Catalyst version too. I think I was looking at this a while back are these like those "2 in 1's" or whatever; this said no sanding. 
http://www.autobodytoolmart.com/kirker-enduro-prime-epoxy-primer-p-12620.aspx

I'm debating on making it easy on myself, car is yellow, probably going to a gloss or flat black. I was planning on going to Sherwin Williams and picking up some Deltron 2000, it seemed like a reliable paint brand, but I'm open for suggestions, price isn't an issue, like I said, I want to get it right the first time.


> If you spray some bases over (say 400grit) the base might not be able to cover up the scratches.


You mean sanding the primer/overrall surface with just 400 right? I was planning on going at least 600/wet all over the car after the scratch pads and possibly a dry 800? or wet. I'm not entirely sure, the sanding phases is the last thing I need to layout, I do have a good set of blocks though, but my beginning question was if a hutchins orbital would save time and be safe to do the final stages. Is there anything specific as far as the bumpers/wing plastic parts go? I didn't know if there's a specific way to spray plastic with these paints-- as well as just doing the same steps with the scotch pads, wet sanding, everything will be off the vehicle.

Any treatment after the base is on? no sanding, etc. just hit it with 3-5 coats of clear?


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## Boo5st3dPmkn (Mar 13, 2009)

Kirker Enduro Prime is an epoxy primer.. good for sealing up bare metal, or can be used as a sealer before basecoat. Epoxy is not easy to sand,and its not really designed to be either.
I would suggest http://www.autobodytoolmart.com/kirker-black-diamond-low-voc-2k-urethane-primers-p-17644.aspx . I think this is going to be the next primer I try out. If mixed properly, this can be used as a high build primer surfacer over top of your body work, then blocked smooth for a seamless repair. It also can be reduced and sprayed as a sealer. If a primer designed like this is sprayed over your repairs, then blocked out with 600, it does not need to be sealed but can be if you want to.

Flat black- if you decide to go this route, I would suggest just using a single stage product such as Kirker's hot rod black. Since your not spraying the car in a booth, you'd end up with all kinds of dirt in a basecoat/matte clearcoat job, and defects cannot be fixed with matte products.

Gloss black- I dont have any experience with Sherwin Williams products, but I'm sure they would work fine. I would even suggest trying the Kirker base and clear. A nice quality paint for the price. Very user friendly for beginners.

Sanding- Yes, you'll be fine sanding the car with 600 as a final step. And I would do this wet, not dry.

Use your blocks, they'll be your new best friend. A D/A definately helps speed up productivity, but isnt completely neccesary. You can do the same job by hand, it just takes longer. A lot of beginners tend to sand with the edges of D/A pads anyways, and end up with a more wavy panel than when they started. If you do go that route, try to keep it as flat as possible and move around, dont stay in one place. 

Plastic- Unless your working with raw plastic, or need to repair a large bare area, most of your prep will be the same as the rest of the car. There are so many variables that can factor in here, but to keep things simple, scotch brite and wetsand and that'll work out fine. If a part is pretty flexible, they make additives for that, as well as adhesion promoters.

Base/Clear- When you buy your paint, ask for a tech sheet. This will tell you how long to wait between coats of base, how long to wait between spraying base and clear, and how long to wait between the coats of clear. Just be sure to wait the proper flash time for the temperature you are spraying in. No sanding is needed between base & clear, just be sure to use a tack rag between to make sure there is no dirt on the surface. Usually 3 coats is enough, 4 if you are planning to wetsand/buff, 5 is typically overkill. Also kind of depends on if you are spraying a thick or a thin clear.


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## Boo5st3dPmkn (Mar 13, 2009)

What kind of car is it that you plan to work on?


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## Tooled (Jul 25, 2012)

I have some damage on my 03' WRX so it's the first to go, I'm planning on re painting my MKIII at a later point in time(the same color; red)

I figured their was something with the plastic painting, as in additives and how these paints would react with the material. I figured most paints would chip once it was flexed on the plastic. I guess I'm still surpiresed that I can take just a scratch pad to my car to get a good base primer/color to adhere to it. I figured it would be a little more in-depth. Sounds like it might be a "peaceful" (yea right...) winter project.

I think that pretty much covers it, other then the plastic painting, I take it I should probably just stick with the blocks versus going around the whole car with an orbital sander and trying to smooth it out with 600/800wet? I might use it for the smaller pieces possibly the roof as well...again all good information from what it sounds like, appreciate it. :thumbup:


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## JCCLARK (Dec 1, 2011)

The important thing about plastics is using a good adhesion promoter
on any new or exposed bare plastic first. And new plastics should be
scrubbed real good first to remove any "mold release" agents.
I like to use a red Scotch pad with Dawn dish detergent.
I do a lot of bumpers and have learned if I use an epoxy primer after
the adhesion promoter I reduce the road rash tremendously.
It has to be a flexible epoxy, I use SPI brand, it stays flexible.
If it's been painted already then I just scuff and use the epoxy before repainting.
Either way, the epoxy makes the paint adhere much better.


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## vdubmike2 (Sep 21, 2004)

if your doing a complete color change i would just buzz the whole car with 320, red scuff, seal and paint. dont kill yourself scuffing the whole damn car if your going to seal it all anyways. just dont put a bunch of waves in it with the da and you should be fine. you could go to 600 if you want but if your using a decent sealer it will cover 320 no problem.


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## VenaGTi (Mar 19, 2006)

> Most cars panels have a coating, it's like galvanizing, if you strip all the paint off with
> stripper, this coating stays intact and you'll notice it doesn't rust even after you wash it
> with soap and water.


I have found this to be true. I have stripped the outside of my car to bare metal because of a lot of crazing and cracking. Afterwards, only the areas of the car that were repaired previously and had the coating sanded off were rusting immediately. For collision work, you can't beat the speed of the sander. A paint and rust remover pad on a grinder works super fast too. But for restoration work, stripper is the way to go.


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