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Old 13th July 2006, 10:22 PM   #1
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Default A 'how to' for High Gloss Finishing

Paint Finishing Technique

I've had a few emails about the finish technique I used on the Percieves so I've decided to try and capture the finishing process again and also add some useful commentary on what I do throughout. The last time I tried this it was on a silver basecoat and you could hardly tell the difference between each step. This time its on a black basecoat and the differences are very apparent.

What I use:

You don't need hundreds of pounds worth of kit and product to get a very nice looking finish. I use a Makita palm sander which cost around 45, I know some will look on in horror as I mention I use this to flat back all the orange peel left over after spraying but it works great and does the job in quarter of the time it takes to sand by hand, this is absolutely indispensable if your A. lazy or B. have large cabinets - I fit both of those I find that a decent quality 1/4 sheet palm sander is more preferable to a larger and heavier 1/2 or 1/3 sheet sander, the obvious reasons being more lightweight and you will appreciate that after holding it for a couple of hours! And it also provides more finesse and less vibration both of which make the final finish that bit better.

After the palm sander comes the sanding paper and I'd highly recommend you buy the very best you can find. For me that's 3M silicon carbide 2000grit, this stuff provides a brilliant cutting action but only leaves very light scratching of the surface which makes the rubbing compound and polishing steps that much easier. Its also rather forgiving and only takes off a very small amount of paint material providing you don't do something daft like stand on the sander whilst flating out the finish, so what this means is you can easily control where to take more paint off whilst avoiding going too far and pushing through the paint, which you absolutely don't want because it means you just wrecked all your hardwork and you'll need to re-spray.
Just another quick note, the better the paper the better the cutting action, buy cheap and you'll likely get a naff and scratched to hell finish that takes twice as much rubbing compound to fix. Better sand paper means less work and a better finish. Cheap sand paper also tends to fall apart or becomes ineffectual after a few minutes of sanding. I can't stress enough about the decent sand paper thing, one of the very best there is would have to be 3M 'purple' line, which are easily identified as they're purple.

Here's the sand paper I use: http://www.paints4u.com/ProductDetai...productID=6030

All sanding is done wet and all I do is use a softish cloth peroidically soaked in water and apply this to the cabinet and then sand with the palm sander. Regularly wet the surface to keep it both clean and also not to allow the removed paint material to start to gather and clog, you'll know when this happens because the sander doesn't glide so easily and starts to dig into the work.

Click the image to open in full size.

The rest of the stuff that I use is as follows:

Cutting compound - Farecla G3: http://www.paints4u.com/ProductDetai...productID=2789

Ultra Fine Cutting Polish - National Grade-A: http://www.paints4u.com/ProductDetai...?productID=536

And these: http://www.paints4u.com/ProductDetai...productID=5577

Be sure to buy/use at least 4 of these finishing cloths. You'll need one for applying the G3 cutting compound, another to rub off the dry residue, one for the ultra fine cutting polish and another to wipe off and buff after using that. Last thing you want is to start using a cloth that has been used to wipe G3 rubbing compound off the work only to use it to 'try' and buff after polishing, all you'll do is scratch the work to hell. Keep them seperate and you'll get a much better finish. Again, be sure to get some decent soft and lint-free finishing cloths, the best ones leave no swirl marks, those linked to above are in this catagory and I recommend them.
Another important note is make sure they're clean with no dried on cr@p, dust or grit before you start, most are machine washable too.

Step1:

You'll start off with something that looks like this:

Click the image to open in full size.

Notice all that orange peel, it has a decent gloss but the reflection is very distorted by the surface imperfections cause by the orange peel. You can get a *much* better looking finish than this with a little work.

First thing to do is get the palm sander, your decent quality 2000grit sanding paper and wet sand like I mentioned above. Go light with the sander and move in horizontal full length strokes until you've covered the work and then move in vertical strokes, keep alternating between these - the reason for doing this is to keep the surface more uniform as a high gloss finish will highlight even the smallest surface level imperfections. You don't have to get it perfect, or maybe you do but providing you take reasonable care you'll get a better looking piece.

After you've made your first couple of passes you'll notice the dull sanded surface and the glossy untouched pits. Ideally we want rid of every single one of those glossy pits, so keep sanding (carefully!) until all you can see is a dull surface with no gloss pits, when you get to this stage you'll know you have a 'flat' surface and the orange peel has been removed. Be sure to switch to wet sanding by hand on tricky bits like the bevels you see on the example photo's and only use the palm sander for larger surfaces.

Replace your sandpaper when you notice its not really doing much and always take more care with fresh sand paper.

After you've done all that you'll have something that looks like this:

Click the image to open in full size.

IMPORTANT: Be sure to sand the entire cabinet in this manner before moving onto step2! This ensures that you don't undo work done by rubbing compound etc. with a slip of the sand paper. Complete each step for the entire cabinet first and then move onto the next.

Step2:

Clean down the work using soapy water to remove any sandpaper grit and then wipe dry.

Now its time for the rubbing compound. I use the Farecla G3 stuff and it works well, there are others so choose a good quality one if this isn't available.

The first thing to do here is wet one of the finishing cloths mention above and wring it out so its just damp. Apply a *small* amount of cutting compound and get to work. I use use horizontal and vertical motions but anything works here so do whatever feels most natural to you. When you first start working the compound into the paint you'll notice its quite gritty and then after some rubbing you'll see it turns to a fine paste and it becomes harder to work the surface - this is good! Keep at it until the rubbing compound virtually dissappears from the surface of the paint and is instead, a dry residue on the finishing cloth - this is the correct way to apply rubbing compound and NOT how I and most others did when we first started with all this ie. apply loads of rubbing compound and then just scratch the hell out of the surface because it never really brakes down into the fine paste/dry residue I mentioned above. Remember that rubbing compound starts out coarse but gets finer as you work it more.
Once you get to the point where you're working just the dry residue then apply more rubbing compound to a clean part of the finishing cloth.

IMPORTANT: Cutting compound is quite harsh when freshly applied, be sure to exercise extra care when dealing with corners or sharp angles as you can push through the paint and ruin all the hardwork you've done so far

After the first pass my work looks like this:

Click the image to open in full size.

You can clearly see a reflection now but the surface is still very scratched leaving a misty reflection that looks pretty poor.



This is after 4 passes:

Click the image to open in full size.

You can clearly see the reflection now and the scratches remaining are light and only visable up close, its at this stage that the rubbing compound has done its job and we must move onto something with a very fine cutting action such as the Grade-A polish if we want to better the shine and contrast of the reflection and also fully remove the scratches.

Step3:

This is the where we apply the very fine cutting action polish. I use National Grade-A polish and again I highly recommend it but as always there's tons of different brands so just pick something well respect and that is described as having a mild or fine cutting action on the label.

The procedure here is very much the same as with the cutting compound ie. apply in small amount and work in thoroughly - read step 2 for a little more info.

This is the result after 2 passes:

Click the image to open in full size.

Now its really looking well with lots of contrast to the reflection. Still some very fine swirl marks but these get less and less with each pass.



And finally this is the end result after 6 passes:

Click the image to open in full size.

The end result is a pretty awesome gloss finish that looks every bit as good as you'd see on an expensive car. Virtually all the swirl marks have gone and there's definitely no scratches.

In the end this is about 95% close to what a proffesional would produce and all it took was some time, care and enthusiasm.

I hope this is of some help to folks and if you have any more questions please feel free to ask.
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Old 13th July 2006, 10:44 PM   #2
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Very informative and nice article!
Good finish and nice work, i hope your speakers sound as good as they shine.
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Old 14th July 2006, 07:10 AM   #3
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You're truly an inspiration for me.

I WILL get there, one of these days.
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Old 14th July 2006, 07:44 AM   #4
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Beautiful.

Liked the John Peel quote too. He must have heard my fridge...
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Old 14th July 2006, 12:53 PM   #5
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This has my vote for a sticky thread. Thanks Shin.

A couple of comments (variations on a theme)

Let the finish fully harden before attempting to bring up the gloss. Rushing will only cause the sandpaper to gum up, making scratches. Lacquer could take a few weeks to fully harden.

I like to work up through the grits - with a power sander I'd start at no coarser than 400, maybe 600 depending on your level of clutziness. With the higher grits you are less likely to sand through the finish, though. I usually go 320 (hand sanding), 400, 600, 800, 1000, 1200 then rubbing compound, polish, wax. If you sand to 1500 grit you can probably go straight to polish.

It takes me less time to get the surface flat (eliminate the orange peel) starting with a coarser grit than 2000. Thoroughly cleaning the work and work area between grits is very important.

Another tip gleaned from a piano finisher: if you use a random orbit sander do a light sanding in a straight line using a hand block with the same grit before going finer. This helps eliminate swirls.

I use a couple drops of dish detergent in my water to help prevent clogging the paper and forming the lumps Shin mentioned.
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Old 14th July 2006, 02:02 PM   #6
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did you spray the black ? -- HVLP -- if so the orange peel might result from using the wrong air pressure or the wrong ratio of solvent to solids.

this was a big problem for US car manufacturers in the 1980's (as if they didn't have enough problems of their own design) -- the environmental regs in the US reduced the amount of VOCs and as a result considerable time was spent buffing out the problems.
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Old 14th July 2006, 02:28 PM   #7
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There will always be a bit of orange peel. Good guns and proper adjustments (gun and finish viscosity) will minimize it, but it will be there.

No sprayed finish will look as good as what Shin showed us without a proper rubout. It's just a matter of where you start. You can get worse orange peel from a spray can and with elbow grease and patience end up with a nice mirror finish. Balance the cost of equipment needed (and likely further use) against the value of your time.
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Old 14th July 2006, 03:16 PM   #8
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Quote:
Originally posted by BobEllis
Let the finish fully harden before attempting to bring up the gloss. Rushing will only cause the sandpaper to gum up, making scratches. Lacquer could take a few weeks to fully harden.
Yep, I agree. The laquer/clearcoat I used in the above photo's is 2 part stuff and I always leave it for about a week before doing the finishing.

If your using single pack laquer then I'd recommend 2-4 weeks to allow it to fully harden and shrink back.

Quote:
Another tip gleaned from a piano finisher: if you use a random orbit sander do a light sanding in a straight line using a hand block with the same grit before going finer. This helps eliminate swirls.
I can get a better finish by hand sanding using a decent block but the problem is the amount of time it takes and especially when dealing with anything larger than a small standmount design. The sander gets around 80% of the quality and consistancy of the reflection results you get from block sanding but in around 25% of the time, for me the maths make sense and my arm thanks me for it

Quote:
I use a couple drops of dish detergent in my water to help prevent clogging the paper and forming the lumps Shin mentioned.
Yep, after reading about that from you in another thread I tried it for the very first time on this one and noticed it made things that bit easier. So cheers for that
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Old 14th July 2006, 03:24 PM   #9
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Quote:
Originally posted by ShinOBIWAN

I can get a better finish by hand sanding using a decent block but the problem is the amount of time it takes and especially when dealing with anything larger than a small standmount design. The sander gets around 80% of the quality and consistancy of the reflection results you get from block sanding but in around 25% of the time, for me the maths make sense and my arm thanks me for it
That was my point - save time and energy using a finishing sander, but take a few minutes with a block to remove random orbit swirls. That should get you up to the level you get by hand.
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Old 14th July 2006, 03:31 PM   #10
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Quote:
Originally posted by jackinnj
did you spray the black ? -- HVLP -- if so the orange peel might result from using the wrong air pressure or the wrong ratio of solvent to solids.

this was a big problem for US car manufacturers in the 1980's (as if they didn't have enough problems of their own design) -- the environmental regs in the US reduced the amount of VOCs and as a result considerable time was spent buffing out the problems.

The gun is setup correctly and you rarely thin most laquer. But what I tend to do is spray many coats of laquer(over 10) with absolutely no sanding between coats. This results in a fair amount of orange peel as you can see from the photo above. Again some folks will sand between every couple of coats but I see no advantage to that and only that it take a lot more time, I've done both with and without sanding and I get virtually identical finished results at the end of each. I should mention that you need more coats if you don't sand between.

I then do all the work to correct it in the finishing process and this is where it all comes together.

There's many ways to skin a cat and through experimenting this method I describe here is quick(er), easy and produces good results. All methods require a fair amount of hardwork if your wanting high gloss though and a true piano finish(perfect and uniform reflection) is an insane amount of work.
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