To undercoat or not

5 Dec 2006
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United Kingdom

I'm going to repaint the skirting etc in the house which currently has a gloss finish on it.

If i sand it down to i need to undercoat or i can i just add another coat of gloss?


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Best paint is Satinwood. You can get it in One Coat.
Will depend on how clean the original gloss is. If it has aged too much and gone yellow, one coat of gloss might not be enough. Too much gloss on gloss can make it difficult to rub down in the future and can stop the gloss adhering to the previous coat. Every now and then its best to have an undercoat. Satinwood doesnt need any undercoat and is easier going on than gloss.
I second robbieUK

If you are repainting because of discolouration it will require more than one coat of gloss, perhaps 3 or more.

Undercoat has much better obliteration powers than any finish coat.

I recently did a job, forgot to pick up undercoat on day one and thought I would get away with 2 coats of eggshell. In the end 3 coats of eggshell were inferior to 1 uc and two coats of eggshell. I ended up applying 4 coats of eggshell, mea culpa.

You will also find that total time to cure for one u/c and 1 gloss is less than two (or more) gloss.
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I'm going to repaint the skirting etc in the house which currently has a gloss finish on it.

If i sand it down to i need to undercoat or i can i just add another coat of gloss?



If it's in good condition. Gently wash and light rub with 400 wet/dry and apply Crown Solo gloss.
Well I hope Crown Solo has improved over the past 15 years as I'd rate it the worst paint I've ever used.
Best paint i've ever used.

What's your problem with using it?
It was thick and gloopy and dried to a poor finish. Actually it was over 20 years ago when One Coat first came out. I'll give it another try if you reckon it's good stuff today.
Tell you what ....just try it my goes.

Let's take a door casing in good nick/ish, or anything you like really. As I said earlier, dampish sugaur/soap or soda crystals ;) light rub with 400 (I could get riskier but for now a light rub :) ) Do not scratch with coarse sandpaper.

Temp above 15c..Purdy or softish brush , take small amount out of the tin to work with at all times.

Forget all the liquid glossing you've done in the past...rubbing it out with a stumpy glosser, cos it runs like Usain Bolt.

This is self undercoating gloss which never shells off like the ord stuff.

Try it....adapt to it and you'll rarely go back to the liquid stuff.

You can achieve a staggeringly beautiful finish with it under the correct circumstances....window sills etc.

It works best, gloss on gloss.

Let me know. :eek:
I agree about the crown solo , without a doubt it is the best gloss I've used in 35 years of painting. I will never go back to the liquid glosses, this stuff covers so well with a high sheen and is very very white.
Paints such as Solo and Dulux Once are termed as thixotropic, these paints have been around for over 50 years. Tradesmen in those early days disliked them due to their poor perfomance regarding application, EG. Difficult to apply.

Solo has now become one of the finest thixotropics ever produced, yet not unlike other paint systems it does have it's limitations. Paints such as these rely on warmth and natural light, firstly for the ease of application and secondly to deter yellowing.

If you were to apply a liquid gloss within the Summer Months it would be far easier and produce better flow than if it was applied in Winter, so heat is therefore important. This is of far more importance regarding Solo for you are in esscence applying two paints in one.

This may or may not have any purpose on this thread,but here goes.I used to work in textile printing as a colourist,having to get *the* right colour for customers to print the fabric.Sometimes the intensity that the customer wanted wasnt achievable (max 6%),the heavier the colour the denser the actual colour became.As mentioned previous thixotropic was a occurance,to counteract,we first thinned the paste,then back thickened until a desired "flow" was achieved.The paste was always better for this process.I am talking on a huge scale,by where all was automated,we printed in excess of 500,000 meters per week.Again a very deep red bucket that was on the floor for a few days thickened by itself,but a quick remix,and slight thinning,brought back to standard.Hope i havent confused anybody!! :rolleyes:

No on the contary your post was far from confusing, you have in actual fact defined thixotropic coatings. So what are they, thixotropics when kept unstirred and in no way agitated will remain to be semi solid, if you were however to stir or shake the paint it would revert to a liquid. After use and stored again it will revert back to a semi solid.

Think of ketchup, for that to is thixotropic.

Toothpaste, ketchup, and paint are frequently mis-labeled as being thixotropic materials. In reality, these are often pseudoplastic or "shear thinning". The viscosity of these materials decrease under increasing shear rate, not increasing time.[dubious – discuss] When squeezed out of a tube, toothpaste flows easily but will set-up on the toothbrush. When shaken or squeezed out of a bottle, ketchup will thin and flow readily but will retain its shape on a burger or plate. When modern paints are applied the shear created by the brush or roller will allow them to thin and wet out the surface evenly. Once applied the paints regain their higher viscosity which avoids drips and runs.

The Dec,Phew,just glad it didnt confuse,was actually quite intresting when we had big chemist boffs in from major companys,trying to get a compromise,with this situation getting adequate flow against bleeding into other colours within the designs,happy days,sadly now defunct.

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