Rotary or Random Orbital

TOGWT · #1 05-22-2009, 01:18 AM

There is a place for both a random orbital buffer and a high speed polisher in a detailer’s toolkit, once you are proficient with an orbital all that is required to ‘step-up' to the polisher is practice, practice and then more practice, which should be done on a scrap vehicle panel as opposed to your own or someone else’s vehicle
Sometimes a dual-action polisher just isn’t enough for really tough scratches and swirls. You need the cutting power of a rotary polisher to penetrate the clear coat and smooth over rough edges to restore your paint to its original flawless finish.
Rotary polishers are a powerful tool and should not be used by a novice detailer; these polishers are for experienced detailers or professionals. The purpose of circular polishers is to remove layers of paint or clear coat down to the lowest point of the scratch until it is completely level with the surrounding surface. An inexperienced user can easily produce new swirls and / or burn the paint by holding the polisher in one place too long. These polishers are for experienced detailers or professionals.
Pros- used mainly by body repair / paint shops or professional or very experienced detailers due to its ability to both quickly and efficiently rectify more serious paint film surface imperfections; paint renovation / correction. It has the ability to produce the friction necessary to break-down diminishing abrasive polishes, it will also correct paint defects much faster than an orbital buffer and hence is the machine of choice for professionals.
Cons- due to the high speeds available it has the ability to burn paint if too high a speed is selected or the machine is held on one spot for too long or at paint surface edge
Rotary Polishers- a high-speed polishing machine, the high-end machines have a direct-drive with selectable electronic speed control that maintains a constant speed under varying loads conditions regardless of pressure applied.
· Porter-Cable 7428 - reliable , 10-amp motor, variable speed 0- 3,000 RPM, 9 Lbs weight
· Metabo PE12-175 – ergonomically sound , on / off switch, feathering variable speed 700 – 2200 RPM, 10-amp motor, 6 Lbs weight
· Makita 9227C –a reliable workhorse, ‘soft start’ trigger switch and variable speed 600-3000 RPM
10-amp motor, 6 Lbs weight
· DeWalt DW849– a reliable machine, 8 Lbs weight, 1000 – 3000 RPM,8-amp motor

Used mainly by body repair / paint shops or very experienced detailers to rectify more serious paint film surface imperfections using a Velcro baking plate, foam or wool pads of varying coarseness and an abrasive compound or polish to remove swirl marks, scratches and paint defects, using their high (revolution) speed and friction (heat) to enable compounds to abrade the paint film surface that require more power /speed than a random orbital buffer can provide.
1. Nearly every rotary on the US market today uses a 5/8 - inch / 11pi arbour spindle for backing plates. (non-US M14) I would recommend getting a hook and loop (Velcro™) backing plate and a 5.5-inch pad to start with as they are more easily controlled.
2. Practice control of the rotary polisher, on different panels, different orientations (i.e. flat –hood roof and trunk, vertical - doors and fenders) as differing techniques of machine movement must be adopted.
3. Clean your pads before you use them, or start out with a new pad; use a soft toothbrush for foam, and a spur for wool. As a general rule, the more aggressive the polish, the more often you'll need to clean out your pads. I clean out my pad after every panel when compounding.
4. Clean (or replace) you pads frequently – a clean or fresh pad will restore the intended abrasive ability, were as a saturated foam pads abrasive ability will decrease (note dried or caked on polish will increase risk of surface scratches) clean often with a soft fairly stiff brush or pad spur (Duospur). It is very important that you keep your working pad clean; as you go over the surface the removed polish and oxidation is being absorbed, which will become large abrasive fragments and will interfere with the cutting ability of the diminishing abrasives as the old polish debris will not breakdown a will affect the desired surface and may also be the cause of surface hazing.
5. Practice cantering the pad on the rotary; spin it at a low speed to ensure it is properly centred. Higher RPM speeds can give the illusion that it is centred as the centrifugal forces push the foam out slightly making it appear more centralized
6. Before commencing polishing do a test panel on the car, once you have achieved the desired results with the chosen polish / pad combination proceed
7. Diminishing abrasives- you need to allow the abrasives to break down (become progressively smaller) to create a great finish or you may impart surface marring, holograms or worse. When a polish "flashes" from a liquid paste to a light semi-dry haze; its colour changes from the polish colour to almost transparent; the polish has then broken down and is ready for removal. It is important to know when a polish has broken down because if you take it too far you (dry polishing) will re-introduce surface marring.
8. Conversely if you don’t work diminishing abrasives sufficiently they will cause surface marring; this is due to the size of the abrasive and its cutting ability, once an abrasive has broken down it becomes very fine and will burnish the surface as opposed to cutting it
9. Ensure a ‘wet’ polishing film is always present between your pad and the surface. Swirls are usually caused by using an aggressive polish without breaking down the diminishing abrasives properly, or you may have used too much polish or it may have dried. To remove, spritz the pad with distilled water (un-primed pads can cause marring) do not add further polish) and re-polish using the polish left on the pad.
10. Holograms - A pattern of small scratches left in a finished paint surface by the pad or sander during the sanding compounding and/or polishing operation;
a) Are caused by not allowing a diminishing polish to fully break-down i.e. insufficient work time, the product should become somewhat transparent (i.e looks like thin cover of Vaseline)
b) Dry buffing
c) Using too much polish
d) Not working a product long enough
e) Using an overly aggressive pad
f) RPM speed too high
g) Pad angle (keep the foam pads flat) etc.
h) A finishing foam pad and polish should remove them
11. Some professionals prefer to polish the surface first in a side-to-side motion and then in an up-and-down motion. I was taught (many years ago) to polish in a firgure-8 movement and it's now second nature to me. Side-to-side and up-and-down motions seem awkward to me now. Try both motions and stick with the method that is comfortable for you.
12. Edge (spin off) – a light sensitive approach is essential, using only the weight of the machine, on vertical panels just enough pressure to maintain contact with the surface (without applied pressure) tilt the contact edge of the pad a few degrees so that only the leading edge of the pad is in contact with the paint surface.
13. A smaller pad surface contact area will increase friction heat so adjust machine speed accordingly As far as the edging goes; normally you aren't going to find excess marring and scratching over the edges. So if you machine in steps (and you definitely should be) save the edges for you last stage of polishing. This way you’re using a least aggressive product with a less aggressive pad.
14. Knowing when a polish is fully broken down comes with experience but a good yard stick is when the polish has gone clear and is very easy to wipe off. Holograms or micro marring are again imparted due to polish that hasn’t been properly broken down or too high speeds. Following the advice above or below should cure these.
15. Intermediate polishing horizontally, final polishing vertically, so if there are buffer trails, they will be able to tell which process created them.
16. ‘Buffer hop’ is when the rotary jumps across the paints surface usually due to insufficient polish/lubrication and as the foam pad grips the paint it jumps. Try spreading the polish more evenly across the pad, add more polish, distilled water or quick detailer (QD) This can also be caused by a bogged down pad – clean / spur / replace pads often.
17. For the neophyte user I would suggest starting out by using a smaller pad, 6.5 – inch I have even found 4- inch pads to be very useful for polishing small tight spaces and smaller panels.
18. High RPM i.e. >1700 will cause high surface temperatures (should be limited to 1000F / 300 C)
19. 13.1150F / 450 C < will damage clear coat to the point that it requires repainting.
20. A rotary requires no more pressure than that required to ‘hold’ it on the paint surface
21. Always tape pinstripes; it doesn't take much to wipe them right off the paint, or thin them out
22. Inspect your work under full sun (or use a 3M Sun Gun®) Holograms, fine marring hooks, etc. are very difficult to see under man made light. There's nothing more frustrating than having to strip off your LSP and re-do.
23. Remove all polish residue and oils before applying your LSP. This is a general rule of thumb for best results across all product lines, and you will notice an overall improvement in the clarity, gloss, and overall 'look' of your finish.
24. If you're new to rotary polishing start off by only using finishing pads and do not exceed 1500 RPM < faster is not better and it may cause you problems. Let the rotary do the work, you'll be surprised at what you can correct with a finishing pad and a mildly abrasive polish.
25. When you shut down the machine never let the pad stop on the surface. Bring the machine to the closest edge of the panel and slowly let it roll off with an angle facing inward to the panel, this will help prevent marring.
26. One of the biggest problems when using a rotary is product sling. However when using highly lubricated polishes sling is a sign that you’ve used too much polish or you have turned the speed up to too fast, too soon. No matter how much you try and avoid it you’re still going to see it. Cover areas you don’t want covered in product and mask off trim with blue painter’s tape if necessary and cover windshields or other vehicle parts with towels. Be careful around mouldings, antennas (aerial’s to us Brits ) and other trim pieces
27. Do not to put the chemical on the pad as the product will sling. The rotary should be in constant motion, if you're putting the chemical on the pad, then that means you are starting from a standstill. That also means that the rotary isn't spinning when it touches the paint, rather you are accelerating up to speed while already on the paint. Another reason you want to put the chemical on the paint, is that the chemical is acting as a lubricant between the pad and the paint.
28. Do not remove compound or polish grit / dust with a dry towel; as this will cause surface marring. Use a damp Micro fibre towel with minimum downward pressure and a no-rinse type product (Optimum No Rinse) that contains surfactants to encapsulate the debris
29. Moisten the pad with distilled water as it stops the pad absorbing to much product and provides a longer ‘working’ time.
30. A smaller pad on the PC has more cutting power than a smaller pad on the rotary An 8- inch pad on the rotary will have more cut than a 6- inch
Using a Sliding Scale 600-900-1200 RPM- commence by spreading the product and then start polishing by setting the speed to 600 RPM, then adjust to 900 RPM culminating at 1200 RPM then descend to 900 RPM and finish at 600 RPM; linear speed should be 2 – 3 inch per second (IPS) 1200 RPM is where most of the paint surface defects will be removed. There probably will be some polishing defects (holograms, etc) by descending the sliding scale (1200-900-600 RPM) you will remove these and any other minor defects