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Location:
Perth
Registered:
March 2005
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Correct Motions to use when sanding back a car ?
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Wed, 03 August 2005 14:33
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Hey guys,
I couldnt find topic on this, So wondering what are correct motions when sanding back a car ? like flat surfaces and round surfaces etc ? any tips are welcome aswell.
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Location:
Adelaide
Registered:
May 2002
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Re: Correct Motions to use when sanding back a car ?
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Wed, 03 August 2005 15:17
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always sand in a straight line. do not swirl
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Location:
NSW
Registered:
July 2005
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Re: Correct Motions to use when sanding back a car ?
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Thu, 04 August 2005 00:01
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Rule #1: Make sure you use the right grade paper.
Rule #2: Never, ever use your finger tips, as this will leave little groove marks in the primmer, and you won't see or feel them until you paint.
Rule#3: Always use water, never rub dry.
Rule #4: Try not to rub in the one direction. Use a cross hatch pattern.
Rule #5: Use a block where possible, if unable to use a block use your hand, but FLAT. Why ? refer rule #2.
Rule #6: Use a guide coat, every time you rub the car down.
I've been a Panel beater for the last 5-6 years.
We usually rub down in 2 stages, first we use 600 wet & dry, then wash it down with clean water, dry off well, and guide coat again (not a heavy coat), then rub down with 800 wet & dry. after you have finished (sounds weird) get an old sponge and a bucket, with a tiny bit of car wash and wash the entire car, dry it off properly. Last thing you want is to be painting and a bead of water comes from no where and you start all over again. Lastly before you paint, use prepsol (wax & greese remover)wash it down and wipe it off with clean rags, and don't touch it, if you need to touch it, when you move it where ever you are painting, Prepsol it again. Oil from your skin and paint don't mix to good.
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Location:
sydney
Registered:
March 2003
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Re: Correct Motions to use when sanding back a car ?
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Thu, 04 August 2005 10:06
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havnt u watchd karate kid 1 2 and 3
wax on wax off
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Location:
brisbane
Registered:
October 2004
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Re: Correct Motions to use when sanding back a car ?
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Thu, 04 August 2005 10:07
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hey this is what i need to hear! i am doing a sprayjob too,
keep the tech coming!
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Location:
Perth
Registered:
March 2005
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Re: Correct Motions to use when sanding back a car ?
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Thu, 04 August 2005 10:16
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Thanks alot Rob  ,
What about rubbing down round surfaces like doors, also is it ok to fill bumper scratches and dings with putty ?
Yeh i'll be sure to watch the karate kid 
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Location:
Forster NSW
Registered:
September 2004
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Re: Correct Motions to use when sanding back a car ?
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Thu, 04 August 2005 12:43
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Try and use the palm of your hand, and go very lightly around the edges as it will wear through really easily.
Bumper scratches would depend on how deep they are, if it's just stop putty you should have primer on before applying stop putty. Stop putty only fills very light scratches, and stone chips, any gouges or significant dents will need body filler (bog).
Also are they plastic bumpers? If so there's a couple of tricks if you're painting them off the car.
Rubbing them back makes them become statically charged, so when you start to paint it draws fibres and bits of dust particles etc off clothes or anything on you/ around the object being painted. The end result being bits and pieces in your paint and you wondering where they came from.
The two options to avoid this are to just go very lightly when rubbing back (probably hard to avoid). And running a hose and watering down the panel is supposed to discharge the static from it.
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Location:
NSW
Registered:
July 2005
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Re: Correct Motions to use when sanding back a car ?
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Thu, 04 August 2005 23:04
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Just as dale said. Be careful of edges, Use the flat of your hand to rub down, rounded panels, but try and use a hard block as much as possible. Reason for this is, if you have a low spot somewhere on the panel and you use a soft block or your hand, it will follow the dent and it not show with the guide coat.
As for filler in plastic bars, you don't just use a normal bog. Use 'fine filler'. This filler is water proof, and pretty flexible, which is why we use it in bars, grilles, door handles. It's pretty easy stuff to use, but as always, don't use to much hardener, as it will bleach the paint. You do however, need a plastic primmer for the bars, and make sure that the repair is rubbed back properly or it will show.
Only happy to help 
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Location:
Adelaide
Registered:
May 2003
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Re: Correct Motions to use when sanding back a car ?
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Fri, 05 August 2005 00:13
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Just a quick one, what do you mean by guide coat.
I have an idea in my mind which im 99% sure it is, and is what i do currently, but its good to hear from a 3rd party to ensure im not all crazy.
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Location:
NSW
Registered:
July 2005
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Re: Correct Motions to use when sanding back a car ?
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Fri, 05 August 2005 00:47
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Guide coat is when you have a panel/car in primmer and you have like a light dusty coat of paint (usually black).
When you rub the panel down the black disappears and leaves black marks where there is a dent or a low spot. It's a pretty sure way of finding dents before painting. Bare metal is a whole other can of worms.
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I supported Toymods
Location:
Epping, Sydney
Registered:
May 2002
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Re: Correct Motions to use when sanding back a car ?
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Fri, 05 August 2005 00:50
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so Rob - how much for a respray from you?
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Location:
NSW
Registered:
July 2005
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Re: Correct Motions to use when sanding back a car ?
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Fri, 05 August 2005 00:50
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Maybe if a mod, reads this it might be a good idea to turn this into a tech doc. Would be happy to assist/ do it.
Could do the same thing for some panel beating, provide pics etc... What do you all think ??? I got nothing better to do...
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Location:
Adelaide
Registered:
May 2003
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Re: Correct Motions to use when sanding back a car ?
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Fri, 05 August 2005 00:52
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thanks for that Rob, its what i thought it was.
A couple of times ive been ridiculed for doing it, but meh, it works heaps better that way.
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Location:
NSW
Registered:
July 2005
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Re: Correct Motions to use when sanding back a car ?
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Fri, 05 August 2005 01:23
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I don't spray cars sorry. I have done a couple, but yeah, i'll prime them and prep them, even build them, but the actual painting side i leave to a pro.
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Location:
Pilbara
Registered:
November 2004
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Re: Correct Motions to use when sanding back a car ?
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Fri, 05 August 2005 01:57
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I reckon that it would be great to do a tech doc on panel prep and priming.
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Location:
Lost in the K hole
Registered:
May 2002
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Re: Correct Motions to use when sanding back a car ?
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Fri, 05 August 2005 03:59
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also worth a read: do a search for "bog tips"
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