Sanding between coats of paint or lacquer?

[Estoril-5]

So I've made up a small box using 12 and 18mm MDF I had lying about, I've just applied a single coat of MDF sealer.

Im now about to paint it in dulux Just Walnut (have some knocking about).

Question: done sand between coats of paint and if so what grade?

I'm also going to apply spray lacquer for some gloss.

Question: how many coats should I apply, how much time in between coats should I leave and should I sand in between coats?

Here's a pic of the box (before sealer).

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[RobinBHM]

Generally denibbing is done with something like 320grit, ideally with a foam backing.

Definitely after first coat as it will be rough, then very lightly on subsequent coats as required, but always check for nibs or roughness.

Drying time depends on the material. its always best to avoid over coating too early in case of solvent issues.

 

[Estoril-5]

Is denibbing between paint coats or lacquer coats or both?

I have 240 available to hand or is that too coarse?

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[ED65]

Denibbing is done as needed. Since you're unlikely to have a pristine, dust-free environment it's best to expect to have to do a bit of it.

If you do happen to not have any dust specs at all land in the drying finish (very much easier with lacquer than with paint because of the very fast drying time) then it's not at all necessary if you're applying the next coat without an extended gap.

240 paper may be a tad too aggressive for this but if you use a light touch you can get away with it. Remember you're not trying to sand the finish uniformly, just denib.

As an alternative do you have any brown paper bags? You can use the rough side of brown paper to denib most finishes, it's just abrasive enough. Failing that, is there a 'magic sponge' in the house?

 

[Estoril-5]

Cheers for that, I think I'll purchase some 320 as I'm sure it will come in useful.

I guess I'm also going to need very fine grades of wet and dry when it comes to polishing the lacquer.

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[ED65]

I guess I'm also going to need very fine grades of wet and dry when it comes to polishing the lacquer.

Yes you'll want to go up well above P600. I think most take it past P1200 but depending on what you;ll use to polish with it may not be worth sanding any finer than P1600.

 

[Estoril-5]

I'm just going to polish with a standard body shop cutting compound by hand or on a drill mop

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[Estoril-5]

Where is the best place to get wet and dry from guys?

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[ED65]

Buying in person I suppose a motor factors might be the best place, but you'll have to see what the prices are like where you are compared to B&Q or any of its competitors.

Obviously if you were to buy online you should better those sorts of prices, and possibly net a better class of paper too. But you never know what bargains may lurk nearby.

Bog standard stuff is available in Poundland but I don't know that it's good enough for this sort of thing.

 

[Austinisgreat]

Try to get 3M wet and dry paper. From 1500 up to 4000 grit it comes in small (half) sheets. Seems to be the best overall. Can't recall the last place I bought some from but a search of luthiers supplies online will probably turn something up, if your local car body finishing place doesn't keep it, as mentioned above.

HTH. Cheers

Andrew

 

[RossJarvis]

I can't remember which one (possibly Satinwood??) but one Dulux paint I was using in the last wok said NOT to sand between coats. It didn't say why. Probably best to check all instructions and data sheets just in case.

 

[Estoril-5]

Dulux satinwood is pain to apply, too draggy.

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[Estoril-5]

How long does lacquer need to cure before you can start cutting it back with wet and dry?

Here's the box with three coats of dulux Egyptian cotton.

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[RossJarvis]

Dulux satinwood is pain to apply, too draggy.

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A lot of, if not all recent water based paints are a complete pain, draggy, dry too fast and can't be layed off properly :x

 

[Jake]

How long does lacquer need to cure before you can start cutting it back with wet and dry?

Here's the box with three coats of dulux Egyptian cotton.

I had to google it because that looked like an emulsion not a lacquer, and so it is, although it is a tougher version (different adhesive content, perhaps a cross-linking one given it says it is washable).

Still, this is not a good starting point for a burnished gloss finish. I hope you prove me wrong, but I fear the answer to your question may be approximately: "Forever".

 

[Jake]

A lot of, if not all recent water based paints are a complete pain, draggy, dry too fast and can't be layed off properly :x

Generally they need a very different technique - you can't drag them around and lay off like with oil-based. On a flat surface, microfibre roller on and immediately lay off with one pass only. With a brush application aim to use as close to a single pass as possible. The good ones at least will flow out well on their own with little help. Going over and over it like is good practice with oil-based leads to a good impression of a monotone Van Gogh painting.

 

[Estoril-5]

How long does lacquer need to cure before you can start cutting it back with wet and dry?

Here's the box with three coats of dulux Egyptian cotton.

I had to google it because that looked like an emulsion not a lacquer, and so it is, although it is a tougher version (different adhesive content, perhaps a cross-linking one given it says it is washable).

Still, this is not a good starting point for a burnished gloss finish. I hope you prove me wrong, but I fear the answer to your question may be approximately: "Forever".

This is just the colour coat, I have Upol spray lacquer to go on top of this

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[Estoril-5]

Any idea on how long to let the lacquer dry before I can cut it back with wet and dry?

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[Estoril-5]

Well I've put three coats of Upol clear coat on with about 15 minutes in between and no sanding.

You can see a slight reflection in the finish, although picture was taken 30 seconds after 3rd coat was applied.

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[Estoril-5]

So after 12 coats of spray can lacquer and over a week to cure, I sanded from 600 grit all the way through to 2000 grit, and then mop and compound polish.

The results in my opinion are awesome for a diy job.

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