Is 3x4" orbital sander good for clear sanding?

K

Klein E

Promoted Users
Hello everyone, new to the forum.

I have a question about clear coat sanding. Normally, I use a DA sander, works not bad but it leaves some swirl marks sometimes. So I wonder if 3x4" orbital sander can work better or not. I can't find any info about a comparsion between DA and 3x4 sander, so I came here to know what you experts say.

It seems very less people use them, but I find a vid of Kovax, they show their super assilex sandpaper by a 3x4" orbital sander. I guess it may be slower than DA? But how about swirl marks? Much or less? Mainly I want to use it just before polishing, so just for 1000-3000 grit sanding.

Please share some experience if you use it.

Appreciate your thoughts.

K
 
If you are talking about a flat 3x4 sander then I can say that I tried that several years ago and the results were far less pleasing than a da.
 
Those sanders make straight sand marks that are harder to get buffed out, A da will do much better and faster. I always flatten my clear with 1000 on a da then wet sand by hand at 2000 then on to 3000 wet and the buff comes right out. If you want to try the flat sander just work on a small area and see what you think, good luck with whatever you do.
 
JC Daniel said:
Those sanders make straight sand marks that are harder to get buffed out, A da will do much better and faster. I always flatten my clear with 1000 on a da then wet sand by hand at 2000 then on to 3000 wet and the buff comes right out. If you want to try the flat sander just work on a small area and see what you think, good luck with whatever you do.
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Are you referring to a board sander?

Sounds like OP is talking about a rectangular orbital sander. I have several I use for woodworking, my favorite being a half sheet (4.5x10 pad size) Bosch, 3/16" orbit, 11,000 OPM variable speed. I have used it to and primer, and it is pretty fast and does a good job of flattening. I have yet to try it on clear, so I haven't any idea how it would work. I don't even know if I can get the finer grits in that sheet size (4.5x11), other than in wet/dry silicon carbide.
I just checked and I can get Klingspor green film up to 2000. I have used the green film, but only up to 400.
 
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I have a rectangular dynabrade orbital, I tried it several years ago with 2000 grit on clear and all I can say is that it was much slower and the sand marks are harder to remove with a buffer.
 
i dont see any reason to use a square sander over a da. you are really locking yourself in sandpaper wise. no one really makes paper to fit it that is designed for color sanding clear. if your seeing sanding marks then you need to find out why. if your getting marks with a da then your going to get them with a 3x4. the shape and dimensions of the paper arent going to cure sanding marks.
 
Jim C said:
i dont see any reason to use a square sander over a da. you are really locking yourself in sandpaper wise. no one really makes paper to fit it that is designed for color sanding clear. if your seeing sanding marks then you need to find out why. if your getting marks with a da then your going to get them with a 3x4. the shape and dimensions of the paper arent going to cure sanding marks.
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My experience is on wood and wood finishing, so I can't speak to how it works on automotive finishes. However, a 5" disc covers 19.625" square and a half sheet sander covers 40.5" square. 5" Dynabrade at 3/32" x 12,000 OPM; Bosch 1/2 sheet sander at 3/32" x 11,000 OPM. 1/2 Sheet is more than twice the surface area, so should be much faster. Of course, a 3/16" Dynabrade is now pretty equal to the 1/2 sheet. So a 3x4 is going to be 12" square and 3/32" OPM, so way slower than the Dynabrade.

Again, I haven't tried the 1/2 sheet with the finer grits. That experiment will have to wait a while until I've got something to try it on.

Found a Makita with 5mm orbit diameter; so far the only one I've found.
 
Eagle has Kovax square orbital sander for use with Assilex and Buflex sheets. Big money, around $400. They offer firm and soft interface pads for it.
eagleguys.com

Kovax BA Finishing Sander

Lightweight, precision-made mini-orbital sander designed to provide a smooth action and to save labor time by 50% or more. This sander is specifically designed for all topcoat fine finishing sanding so you can achieve a consistent, shallow scratch pattern that will result in a beautiful finish...
eagleguys.com eagleguys.com

I’ve never really seen an advantage of using this sander but maybe there is one…
 
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Thanks everyone, really appreciate all comment!

I'm just curious about this sander. For now, I'm 100% satisfied of my 3/32" DA for very fine sanding, but still want to know if something better. Especially I found this vid by Kovax:

QQ截图20240403183829.png


They use sheet sander for all around sanding, from removing old coat to final fine sanding. Also, they use this for all curves with soft interface pad. I wonder if they can provide a better control than DA.
 
dhutton01 said:
Eagle has Kovax square orbital sander for use with Assilex and Buflex sheets. Big money, around $400. They offer firm and soft interface pads for it.
eagleguys.com

Kovax BA Finishing Sander

Lightweight, precision-made mini-orbital sander designed to provide a smooth action and to save labor time by 50% or more. This sander is specifically designed for all topcoat fine finishing sanding so you can achieve a consistent, shallow scratch pattern that will result in a beautiful finish...
eagleguys.com eagleguys.com

I’ve never really seen an advantage of using this sander but maybe there is one…
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Yes buddy, I saw this one then be interested in. I heard people say this one is slower than a DA, but wonder if it has a better control. Especially for blending work. And what I really cared about is if it provides more/deeper scratches and pigtails.
 
uggg, 3/32. if you want something better then just get a regular da but in the normal 3/16" orbit. 3/32 is a complete waste of time and offers nothing in return. most color sanding paper or systems arent even meant for 3/32. 3m for example doesnt even recommend them.
 
Klein E said:
Yes buddy, I saw this one then be interested in. I heard people say this one is slower than a DA, but wonder if it has a better control. Especially for blending work. And what I really cared about is if it provides more/deeper scratches and pigtails.
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I think the real difference is using Assilex and Buflex, even with 6” discs. The scratches are shallow and easier to remove. Give them a try.

I use 1000 Eagle yellow, 1500 Assilex, 2500 Buflex and 8000 Trizact. 3/16 orbit. The original Jim C method. Give it a try, you might like it…

Don
 
Jim C said:
uggg, 3/32. if you want something better then just get a regular da but in the normal 3/16" orbit. 3/32 is a complete waste of time and offers nothing in return. most color sanding paper or systems arent even meant for 3/32. 3m for example doesnt even recommend them.
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Hmmm, maybe I didn't try a good 3/16 sander, from my experience 3/16" orbit always bring more marks than 3/32", though it works faster, I use a 3/16" for primer sanding, 3/32" for final fine sanding.
 
dhutton01 said:
I think the real difference is using Assilex and Buflex, even with 6” discs. The scratches are shallow and easier to remove. Give them a try.

I use 1000 Eagle yellow, 1500 Assilex, 2500 Buflex and 8000 Trizact. 3/16 orbit. The original Jim C method. Give it a try, you might like it…

Don
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Thanks Don, I use them now with DA. But maybe I still prefer 3m purple film 260L for 1000 and 1500. I think it flatten the surface a little better than kovax, super assilex is very soft so it followed the texture more, though the difference is subtle. I usually use buflex 2000 and 3000 before buffing and polishing.
 
The 3m finishing film cuts fast but doesnt last. Plus its super expensive. Try the sunmight film for 1000 and 1500 step. Last way longer and its 1/3 the price. The film is much more rigid than eagle yellow so it cuts flatter.
 
Jim C said:
The 3m finishing film cuts fast but doesnt last. Plus its super expensive. Try the sunmight film for 1000 and 1500 step. Last way longer and its 1/3 the price. The film is much more rigid than eagle yellow so it cuts flatter.
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Thanks Jim! I'll check out Sunmight brand sandpaper, are they suitable for dry sanding?
 
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