Smoother varnish

[Idrisdraig]

I'm using some Ronseal Daimond Hard Varnish on a box. I've used a sponge roller and a brush on different coats (and test pieces) an both leave significant texture. I've sanded which helps but the next coat is never perfect.

The best finish I've got so far is applying the varnish with a sponge and sanding with 360 grit. But this still leaves some light texture (looks like brush strokes) and doesn't get as smooth as I'd like.

Am I doing something wrong or do I need to use some wet'n'dry, and if so can I expect a perfectly smooth finish?

 

[misterhelpful]

You probably won't get a perfect finish with a brush and a foam roller often leaves tiny bubbles.

You could try a very short pile mini roller or Jenny brushes.

http://www.decoratingdirect.co.uk/Tools/Mini_Paint_Rollers/
http://www.flints.co.uk/acatalog/Jenny_Foam_Brushes_and_Rollers.html

 

[Idrisdraig]

As I understood it, rollers with pile were for adding texture - certainly the rollers for a textured paint finish seem to have a pile. Or have I got that wrong?
And isn't a Jenny brush just a piece of foam on a stick?

 

[misterhelpful]

The roller sleeves I linked you to are supposedly excellent for varnishing, although I can't say I've ever tried them myself.

Yes, a Jenny brush is basically a bit of foam on a stick, but they do smooth out the varnish without leaving brush marks and give a better finish than a foam roller. This is because they are used in long strokes rather than the back forth motion of the rollers.

It is generally the build up of layers, with sanding in between each coat, that will give you that glassy smooth finish I suspect you are after.

 

[HH1]

Have you seen the Ronseal "perfect finish" pads ?

Basically they are foam pads with a layer of tiny bristles, the foam pads being held by a plastic hand grip. The bristles are actually quite soft. I'm sorry but that's the best way i can think of describing them at the moment.
You get the pad "free" with a tub of Ronseal Perfect Finish varnish.
If you search google images, there will be some pictures shown, It's the rectangular tubs (as opposed to round tins), or go to the ronseal site.

I felt the pad gave a better finish than a brush, and went on quicker for larger semi-flat areas, but I'm not sure if it will live up to your needs, certainly worth a try though.

B&Q stock this type of varnish, not sure about the other big stores.
Don't know if the pads can be purchased separately.

 

[Idrisdraig]

I did look at the Ronseal pads, but having read about rollers and sponges they just lloked like a marketing gimick to my uneducated eye.

I shall have another look, and at the short pile rollers.

Having re-read the instructions on the tin I'm womdering whether ambient temp might be working against me. As I'm working in an unheated garage I'm wondering whether the varnish doesn't "flow" as well. Or whether I'm applying too bin a coat.
Any thoughts?

 

[HH1]

I used the pads to varnish several doors and preferred the pads to brushes. Felt they gave a better finish and application was quicker. Can be a bit awkward in the fiddly corners though. Didn't try the rollers as I had bought the "perfect finish" complete with the pads so decided to stick with the supplied applicators.

On the cold front, Doesn't most paints like a little heat in the air for them to flow better? Haven't used the diamond finish so can't really say one way or the other.
To heat up the paint a little why not stick the tin in some hot water (luke warm) for a while to see if it goes on any better? Don't want it too warm, bit of a "try it and see" what temperature works best type of thing.

The diamond varnish may not work to well with the pads, would it be worth trying out the "perfect finish" instead?

 

[Idrisdraig]

I've spoken to a proffessonal joiner who suggested thinning the varnish to help it flow.
The top coat is currently reasonable, but I'd like it perfect, and seeing as I have no choice but to work in a cold garage, this seems to make sense.
Unfortunately I forgot to ask him to suggest a ratio of varnish to white spirit. Any thoughts?

 

[misterhelpful]

I can't say I have used Ronseal Diamond Hard very often but seem to recall it is water-based. If so, then you do not use white spirit to thin it but water, and then only about 10%. If I am wrong about it being water-based, then thin with 10-20% white spirit at most, otherwise it will be too thin to cover the imperfections you already have.

Water based varnishes will never give the same finish as oil/solvent based ones, so this could be the source of your problem.

 

[foxhole]

You can rub down between coats with '000' wire wool for a smooth finish, flood painting method give a nice finish [ a very thick final coat which is allowed to flow with very little brushing].Though perfect finish is best achieved with a spray gun and an solvent based paint or varnish.

 

[Tuffnall]

The ratio of thinner to varnish should be 10 to 1 for a first coat. Subsequent coats should be unthinned. Apply with a very high quality brush. Do not wipe varnish off the brush on the side of the tin as this will introduce air bubbles into your finish. Tap the brush lightly on the side of the tin to remove excess. Brush against the grain first and lightly drag your brush WITH the grain to finish. Use a very fine grade wire wool between coats to remove minor blemishes and wipe with white spirit if using a solvent based varnish (water if its acrylic varnish) Be sure to remove all loose wire wool debris before applying another coat. 3 coats total should be enough. A final light rub with wire wool and polish with white spirit should give you the finish you are after. The only way to get a better finish than a brush is to use a sprayer which is expensive and overkill for most diy'ers.. Good luck

 

[sixeighth]

As a decorator I would second Tufnall's advice although I prefer to finish with an up stroke regardless of grain direction.

Ambient temperature and therefore moisture content in the garage may be a factor in not getting the finish you want. If it were possible to do the prep work in the garage and varnish in a warmer area you might get a better result.

When it comes to sanding between coats - the harder a varnish dries before sanding the better. I would usually use worn (well used) 240 or even 120 wet & dry sandpaper to sand between coats but keeping the paper dry.

You might find it easier to get a smoother, higher gloss, finish with oil rather than water based varnish.

Quality of applicator is key (decent brush with fine tips - usually a well worn brush - is my preference).

 

[matz]

think I'd be tempted to use a cellulose lacquer etc. Brushing on and flatting between coats if you put enough coats on will result in a perfectly smooth and faultless finish once burnished up. Polyurethanes in my experience are a pain to get a nice finish with unless you thin them, brush on and mop off and only use a couple of coats - the more you put on the worse it gets and thats oil based varnishes. As for water based - yuk

 

[Idrisdraig]

This has got me thinking about sanding technique:
Intuition tells me that, having varnished parallel to the grain, sanding across the grain will take off more of the "peaks". But there's something in my head that says this is the wrong way to do it.