Discussion about gloss paint finish technique

[richie00boy]

That's a big improvement, nice one. I guess on speakers that size it's OK doing it by hand. Wouldn't fancy it on a big pair though!

Did you sand much or would you say it's the car polisher and cutting compound that's made the difference?

 

[ShinOBIWAN]

That's a big improvement, nice one. I guess on speakers that size it's OK doing it by hand. Wouldn't fancy it on a big pair though!

Did you sand much or would you say it's the car polisher and cutting compound that's made the difference?

I'd be interested to hear about this too. I tried what I think Vikash is describing with the paints I use but it didn't come up very good and had a smoothed out faint orange peel type reflection. I could only really get decent results using sanding and then rubbing compound, wax etc. Its likely that 2k stuff dries harder and more quickly making it tougher on the rubbing compound alone. However, it would appear the paint Vikash is using allows more freedom with finishing.

 

[Vikash]

I found that the cutting compound I had needs to be applied by a powered polisher to be effective. It's like the consistency of toothpaste. I tried it directly on the orange peel surface in the post 12 pic and it didn't do much even with the polisher.

I got the results in post 30 by flattening as best as I could with 1200 grit (wet) and then using the polisher and compound. Most of the work is defintely in the sanding.

I've been advised to go no less than 1500 grit and then move on to the cutting compound: http://www.paints4u.com/ProductDetails.aspx?productID=2789

I'm going to order a palm sander, spray another 5-8 base coats, flat with 1500 grit then polish with the above compound. Hopefully for the final time. Note that my last pic has no clear coat!

In case you've never tried it, I find a silicone car dyring thingy very useful for checking your wet sanding work perdioically: http://www.thepartsbin.com/sitemap/gmc~car_wash_supplies~parts.html

 

[ShinOBIWAN]

Ah I see now.

Pretty much the same thing I do; sand lightly and then compound with a powered polisher. After this I then simply apply the ultrafine cutting compound and acrylic sealant by hand using the finest quality applicator towels I could find.

If you want less work and a finer finish then use this paper:

http://www.paints4u.com/ProductDetails.aspx?productID=360

http://www.paints4u.com/ProductDetails.aspx?productID=6030

I think the finish is even finer if leave it to soak in water overnight.

 

[Cortez]

Hi Vikash !

Nice work, it looks really fine now !
The only difference between post #12 and #30 is that you
wet-sanded that orange peel surface with an 1200 grit paper
and then you polished it with a rubbing compound ?
Even without clearcoat it looks really shiny, just like a perfect mirror...
Otherwise could you later write a "conlusion" or "summary" post
about the steps, and collect your final experiences and advices ?

Thx and congratulations !

 

[Vikash]

Hi, yes difference between the two pics is just wet sanding with 1200 grit and then polish with cutting paste compound. It's still not perfect but now I understand how most of it works and it's just a matter of tweaking the compounds and grit values used.

I will write up all the details once I've finished, but I also recommend reading the posts beginning here: http://www.diyaudio.com/forums/showthread.php?postid=908705#post908705

 

[Vikash]

Some more questions for you Shin:

Did you get two nozzles with the spray gun, or is it just available in two? (1.5mm and 1.78mm)

Since we're using the same compressor and gun, would you mind reading the pressure setting on the compressor next time you're out, and also the exact spray width and flow settings on the gun (number of turns perhaps). This would be a big help as I'm not confident I've set things up well. It's a shame you're not located closer...

 

[ShinOBIWAN]

Hi Vikash

I got two nozzle sizes 1.5 and 1.78 with mine, along with a cleaning brush, reducer and a wrench. I only use the 1.78 for primers since they are high viscosity, for the rest I use the 1.5.

I adjust the fan depending upon what coat I'm applying and size of the work. For the primer I use a fairly concentrated fan size of around a 3inches, this is mainly to lay down thick coats. Be sure to hold the gun a little further away from the work(around a foot is good for me) or use quicker movements since its easy to get buildup and runs using these thick passes. If you mess up then it can be fixed later with sanding, try to get it good and even though since it does effect the uniformity of the final and can cause very slight distortions even after you sand away runs.

For the important coats be sure to hold the gun around 6 inches from the work and keep the coats as even as possible and use light dropcoats to ensure good uniformity - this is absolutely critical for metallics since they very easily highlight the spray pattern. I always use the largest spray pattern for clearcoats and metallics. It goes on finer and this is fairly important for these critical coats.

For the pressure settings it depends upon what I'm spraying but to set the pressure press and hold the trigger with an empty gun and then adjust the regulator until it reads whatever you need. Here's what I use; basecoat 1.6bar, primer 1.6 bar and clearcoat is 2 bar.

You'll notice that the pressure will have dropped after using it for a time and just before the compressor kicks back its around 0.3bar below what you originally set it at, so average it out and set it a little higher to compensate - Last thing you need is a big blob of paint shooting out the gun and onto the work because the pressure was insufficient to keep the spray thoroughly atomised.

Hope that helps.

 

[Vikash]

I've been using whichever nozzle is fitted as standard when you get the gun. I didn't notice another in the box, but when I read the website description again the other day it led to me to think I may have another one in there...

For the important coats be sure to hold the gun around 6 inches from the work

If I did it at six inches I'd probably blow the work piece away. I obviously need to play with my settings a bit more...

Last thing you need is a big blob of paint shooting out the gun and onto the work because the pressure was insufficient

Though my pressure setting appears to be higher, this is the exact problem I had. All the coats went on fine, until the last panel when I got some blobs of paint that ruined it. During sanding they come off and leave spots that requires touching up - which to me means respraying.

How do you touch up? I tried sorting it by dabbing some paint on with a brush which messed things up even more. Hence I'll be sanding it all down again, and putting lots of coats on.

All fun and games hey.

 

[ShinOBIWAN]

I've been using whichever nozzle is fitted as standard when you get the gun. I didn't notice another in the box, but when I read the website description again the other day it led to me to think I may have another one in there...

If I did it at six inches I'd probably blow the work piece away. I obviously need to play with my settings a bit more...

Though my pressure setting appears to be higher, this is the exact problem I had. All the coats went on fine, until the last panel when I got some blobs of paint that ruined it. During sanding they come off and leave spots that requires touching up - which to me means respraying.

How do you touch up? I tried sorting it by dabbing some paint on with a brush which messed things up even more. Hence I'll be sanding it all down again, and putting lots of coats on.

All fun and games hey.

That sounds like moisure or oil from the compressor. Runs of paint will be just be that and won't displace the paint, oil and moisture will though. A coalescent filter will eliminate that or you can bleed the tank before use and then fill the tank up, turn the compressor off and then empty it to shift the bad cr@p out of the tank that's gathered whilst its been idle.
When a compressor is new this also tends to happen, oil from the motor mixes with the air but once the motor gets worn- in this is rare. Also be sure not to move the compressor from one temperature extreme to another and then use it, for example - cold shed and then moved into direct sunlight when spraying. Also be sure that you've not run the compressor hard for a while otherwise your shooting hot air from the gun, again this is a problem with direct drive compressors. The best ones are the medical grade types, these have all the filters required to have air of breathable quality, expensive though.

If you need to touch up with a brush then you must ensure that the paint has fully hardened(1 month+ for 1k) otherwise the fresh paint you apply simply reactivates the existing paint and you just end up rubbing the coats away.
The best method by far is an air brush for small area touch up, I rubbed through a small spot of the laquer on the base of my speakers. All I did was clean the work with panel wipe and then sprayed the affected area using the air brush. It has superb control and virtually zero over spray. After this I carried on as normal and its invisible, just looks like its supposed to.

 

[Vikash]

That Makita sander has been a revelation. Making good progress with it now. How did I live without it

 

[ShinOBIWAN]

That Makita sander has been a revelation. Making good progress with it now. How did I live without it

You know Vik, those were exactly my thoughts when I first gave it a go.

It scares the hell out of you at first; sanding precious work with an electric palm sander of all things. But as you soon pick up a feeling of just how far to go before you stop and finish the little bits the sander missed by hand. The biggest thing for me is that it makes the job a whole lot quicker and gives a more uniform reflection.

Looking forward to seeing your latest paint revision

 

[Vikash]

The best method by far is an air brush for small area touch up, I rubbed through a small spot of the laquer on the base of my speakers. All I did was clean the work with panel wipe and then sprayed the affected area using the air brush. It has superb control and virtually zero over spray. After this I carried on as normal and its invisible, just looks like its supposed to.

Did you end up with the Badger 250 in the end? What's the verdict and are you using it with the Sealey compressor? What additional fittings are required?

 

[Vikash]

The airbrush is brilliant! I think I could have done the whole cabinet much better with it. And it's a pleasure to clean up afterwards compared to the spray gun!

I've decided that an airbrush is a neccessity when spray finishing and I'm very tempted to have a go on my car with it. Someone stop me quick...

 

[ShinOBIWAN]

The airbrush is brilliant! I think I could have done the whole cabinet much better with it. And it's a pleasure to clean up afterwards compared to the spray gun!

I've decided that an airbrush is a neccessity when spray finishing and I'm very tempted to have a go on my car with it. Someone stop me quick...

Did you go for the 250 in the end? I think that's what I bought, can't remember now, it was around £30 or something like that and the reducer was another £15.

I agree that it does lay the paint down very nicely compared to the compressor and gun but you've got to realise that its really a touch up or fine work tool and doesn't have the fan size nor the paint laying down capacity to do anything approaching the size of speaker, even a small bookshelf.

Its much better to lay down thick heavy coats with the gun and then sand and flat out. If you tried to lay down thick coats with the airbrush you'll quickly see that the results are comparable to the compressor and gun, only your spending an order of magnitudes worth of extra time doing so. What the airbrush does well is single fine quality coats and definitely not multiple coats whereby they're too thin to sand flat between coats or if you build up multiple coats to get the thickness without sanding inbetween then you've still got a finish that resembles the sort of quality you get from a compressor and gun.

 

[Vikash]

Yes it was the Badger 250. The reducer was about a fiver. It's just a threaded brass, errr, reducing nut right? (only fits directly to the compressor and not the air hose which is a bit restricting atm). It leaks quite a bit when plugged into the compressor but works fine. I think maybe it's supposed to do that from reading something related on the airbrush spec sheet.

Yeah I was really just referring to the overspray and control afforded from the airbrush. Even on the smaller touch ups I quickly found that I still have to apply many coats with the airbrush before attempting to sand down. Defintely couldn't do without it though. As well as the sander.

You've struck two so far. I might as well ask what polisher you're using too?

I can see light at the end of this miserable sanding tunnel finally. I'll have some pics up soon

 

[ShinOBIWAN]

Yes it was the Badger 250. The reducer was about a fiver. It's just a threaded brass, errr, reducing nut right? (only fits directly to the compressor and not the air hose which is a bit restricting atm). It leaks quite a bit when plugged into the compressor but works fine. I think maybe it's supposed to do that from reading something related on the airbrush spec sheet.

What a rip! I'm sure I paid £15 or something close to that for the reducer and it sounds the same thing as that your using.

The leaks are fixed using PTFE tape on the threads. The airbrush uses virtually zero air and you only need a small amount a pressure. A full tank of compressed air lasted me an entire spray session without a top up when doing some laquering on the alu disks used for feet.

You've struck two so far. I might as well ask what polisher you're using too?

I can see light at the end of this miserable sanding tunnel finally. I'll have some pics up soon

Polisher is one of these:

http://www.paints4u.com/ProductDetails.aspx?productID=6609

I've actually got two of these now, one is completely unused. My first one that I bought in the middle of last year had a crack in the casing on arrival, of course I was impatient and couldn't wait for the replacement so ordered another so as to be able to carry on with the finishing work I was doing at the time. Anyway the replace turned up and its been in the box ever since.

Yours for £27 including postage if your interestered?

BTW this will make your life so very very very much easier, buy it

 

[Vikash]

Yours for £27 including postage if your interestered?

BTW this will make your life so very very very much easier, buy it [/B]

Yeah go on then. You twisted my arm.

FYI: The reducer/adapter is on the site now: http://www.paints4u.com/ProductDetails.aspx?productID=783

[misc ramblings]
I tried some Halfords 1500 grit wet and dry and I have to say that all papers are not made equal! My usual 1200 grit gives a finer finish and lasts a lot longer than the Halfords range.

I've taken the finish to 1200 grit. The parts done with the sander are much better and the edges/touch ups done by hand are visibly not as reflective. I won't be taking it any further up the grits, just the compound and then a polish now because I'm in danger of not ever finishing it otherwise. Plus I've got the other speaker and sub in the queue awaiting the same finish.

Incidentally I remember a few posts ago you mentioned you go straight to 2000 grit on the laquer whereas other people have started with 600 grit and worked up. I've tried various combo's and I absolutely and reluctantly had to start at 600 grit (again Halfords) to have any chances of flatting back properly. I then jumped straight to 1200. Using 1200 straight away just tickles the finish and there's no chance of flatting back so 1500 or 2000 just wouldn't work unless the 3M stuff was that different. Obviously we're using different materials/techniques but thought it may be worth mentioning.

I also found the solution to my spraying problems that was reducing my scalp hair considerably. Embarassingly simple, the breather hole in the paint container is blocked and that's why I was getting such inconsistent results. I now spray without the lid on and I get consistent, even, thick spray. Grrr...
[/m.r.]

Its much better to lay down thick heavy coats with the gun and then sand and flat out. If you tried to lay down thick coats with the airbrush you'll quickly see that the results are comparable to the compressor and gun, only your spending an order of magnitudes worth of extra time doing so. What the airbrush does well is single fine quality coats and definitely not multiple coats whereby they're too thin to sand flat between coats or if you build up multiple coats to get the thickness without sanding inbetween then you've still got a finish that resembles the sort of quality you get from a compressor and gun.

Basecoats are more expensive than laquer so I may have shot myself in the foot by not going for the basecoat plus laquer route. I can see a good use for the airbrush on a small speaker - to apply a single even basecoat layer before getting lots of thick heavy coats of laquer on?

 

[Vikash]

How many sheets of the 3M 2000 grit would you say you went through per cabinet on the Perceieves?

The bloke at Paints4U had a good laugh when I told him I tried the Halfords stuff

 

[ShinOBIWAN]

Yeah go on then. You twisted my arm.

Good man! Email sent.

FYI: The reducer/adapter is on the site now: http://www.paints4u.com/ProductDetails.aspx?productID=783

I bought mine from a local model shop, never again though.

I tried some Halfords 1500 grit wet and dry and I have to say that all papers are not made equal! My usual 1200 grit gives a finer finish and lasts a lot longer than the Halfords range.

I've taken the finish to 1200 grit. The parts done with the sander are much better and the edges/touch ups done by hand are visibly not as reflective. I won't be taking it any further up the grits, just the compound and then a polish now because I'm in danger of not ever finishing it otherwise. Plus I've got the other speaker and sub in the queue awaiting the same finish.

Incidentally I remember a few posts ago you mentioned you go straight to 2000 grit on the laquer whereas other people have started with 600 grit and worked up. I've tried various combo's and I absolutely and reluctantly had to start at 600 grit (again Halfords) to have any chances of flatting back properly. I then jumped straight to 1200. Using 1200 straight away just tickles the finish and there's no chance of flatting back so 1500 or 2000 just wouldn't work unless the 3M stuff was that different. Obviously we're using different materials/techniques but thought it may be worth mentioning.

I see... I always go straight to 2000 grit as you've said and never had anything like that problem.

I suspect its more likely a combination of paper quality and more importantly, paint finishing requirements. Laquer is a very easy to work surface, the black basecoat below this is more like what you've just described, requiring coarse papers to do anything meaningful with it. I do realise that your not using the Rage basecoat like I am but I'm betting they're similar once they dry.

I also found the solution to my spraying problems that was reducing my scalp hair considerably. Embarassingly simple, the breather hole in the paint container is blocked and that's why I was getting such inconsistent results. I now spray without the lid on and I get consistent, even, thick spray. Grrr...
[/m.r.]

I hate cleaning the gun out. When I did the two tone bass cabinet I have to clean it out 3 times and its just neccessary evil. I mainly keep pouring some of that cheap (~£6 for 5ltrs) gunwash that p4u sells until the gun is clean. Just pour a small amount in the cup, shake the gun and then shoot the rubbish into a container, keep doing that until its relatively clean and then use a rag with some guncleaner to do inside the cup and around the nozzle.

I've had the breather blocked myself, mainly with the primer since its fairly thick. It does ruin the spray.

Basecoats are more expensive than laquer so I may have shot myself in the foot by not going for the basecoat plus laquer route. I can see a good use for the airbrush on a small speaker - to apply a single even basecoat layer before getting lots of thick heavy coats of laquer on?

Yes thats a good use for the airbrush. TBH though the basecoat is only 2 maybe 3 coats at the very most, as long as you've got good coverage its fine in my book. The sheer amount of laquer I use then makes sure the no problems arise through careful sanding.

A black basecoat with a thick laquer over the top hides many things including orange peel on the basecoat when its sanding flat. This is true of all solid colour basecoats.

When you deal with metallic and pearlescents then the quality of how they go down matters greatly as you see absolutely every imperfection - joints, surface irregularities in the wood, spray pattern and orange peel are easily seen with a bright metallic such as silver. So you have to put in more care and work when dealing with those but as for solid colours, you can be less so.