Applying Lacquer

lacquer straight over the paint.

mrcheerful

Best results by sanding the base coat flat with very fine wet or dry then applying the lacquer. Done carefully, it will need very little polishing.

When you use a metallic paint, the tiny metallic particles stand up in the paint, the light reflecting from the metal bits gives the interesting visual effect of metallic paint, the lacquer fills the gaps and gives a smooth surface over the top. If you sand or flat before lacquer you will get a very different effect to the original intent. Some of the metalflake effect paints are so sensitive that a light brush of the hand before lacquer can give a very noticeable mark.

mrcheerful

Except you don't flat metallic basecoats, you're only supposed to tack off the dust before applying lacquer on top.

Even lightly flatted, metallic basecoat will still require another mist of basecoat colour sprayed over the flatted area.

Flatting metallic basecoat can introduce minute scratches that you may not see until it's lacquered, lacquer will always exaggerate imperfections never hide them.

Steve,

In article , mrcheerful . writes

Thanks

In article , mrcheerful . writes

Thanks Again- excellent scientific advice

In article , Stephen Hull writes

Thanks Steve

If you use wet and dry paper, however fine, on metallic paint you'll bugger it quite comprehensively. If the finish isn't good enough straight out of the gun then the problem lies in the preparation or the paint and spraying technique. Sanding it won't cure anything. The only place for wet and dry in body repairs is on filler and sometimes on the primer coat before paint goes on if any imperfections are still visible.

-- Dave Baker - Puma Race Engines

and of course on solid colours ;)

Steve.

Strange. I've just done a minor repair on my BMW - Oxford green metallic - using Halfords mixed to order paint and got rather better results than a dealer repair done previously. Of course the overall finish on the car is crap anyway - like most modern water based paints. If you're really saying having a perfectly smooth base to add coats of paint to isn't the way to go anymore, fine.

No, you have the most perfect primer coat you can possibly get, but the metallic coats on top are left alone.

mrcheerful

If you get a run or other imperfection then I suppose so although so far I've never had to resort to sanding a top coat. Not that I've done a huge amount of spraying but 25 years ago I bought one of those little electric airless guns and provided you get the paint viscosity right it's always done a damn good job for me. Maybe a touch of orange peel every now and then but at least as good as the OE paint on my Focus which looks like it's been applied by Outspan.

-- Dave Baker - Puma Race Engines

I think I'm saying the opposite - and then leave the top coat well alone.

-- Dave Baker - Puma Race Engines

You shouldn't need to flat top coat (solid) or lacquer unless to remove minor imperfections although some paint finishes tend to leave a rough orange peel finish as standard, It's customary then to flat the whole car and then polish. This is only ever done on the final coat of colour or lacquer and is not practised by the average car manufactures who are not worried about producing orange peel finishes.

At Rolls Royce motors for example it was common practise to flat the whole vehicle simply to achieve the mirrored finish.

Steve.

So what causes the orange peel effect and how can it be avoided? I have recently learnt the hard way that you do not rub down metallic top coats...simply because I read so many conflicting statements on line...snake oil i say!

But through actual experience I have learnt. Now I am about to rub it all down and hide my earlier tests by painting the whole car i think. It was just patches here and there before, but looking at it, it wil be easier to do the whole lot.

Orange peel can be caused by: Paint material being too thick. Spraying too close to the surface or passing the gun over too slowly. Insufficient spray pressure to atomise the paint correctly. Incorrect spray gun nozzle size. All these factors relate to poor flow out.

To obtain the best results all these factors have to be just right. Spraying the material thin will achieve the best finish even on low pressure settings and applying several thin coats first then one final thicker coat is commonly practised, if each layer is applied thinly the paint has less chance to orange peel.

The pressure settings differ depending on what paint material you use and if you use a HVLP gun then this is a different animal altogether.

Steve.

Thanks for the reply, very handy.

I am about to give painting a go, as stated, but need to decide what gun to buy. I am not about to start doing lots of it so buying an expensive one seems a waste. I have heard about these HVLP guns...how do these differ to 'normal' guns? Should I try to get a HVLP gun?

Cheers in advance.

An HVLP stands for High Volume Low Pressure, these particular spray guns are expensive as is a Devilbiss JGA type gun both ideally suited for most paint materials.

I would hazard a guess (as it's been a while since I bought one) a Devilbiss or HVLP gun will now cost you about 200 ukp.

You have to work out the pros & cons as to whether you buy a cheap gun that might be up to the job or an expensive gun that definitely will given the correct setup.

HVLP spray guns use less paint, will reduced overspray considerably and work at much lower pressures.

I would suggest you hire a spray gun if you only intend to use it occasionally.

Steve.

OK thanks for that. What about a gravity fed gun? Whats the disadvantages of them?