Yellowing Gloss

[GarethSullivan]

Hi

I've done some glossing recently and i noticed the other day that it's started to yellow. It was dulux trade gloss so i was surprised to see the yellowing take place.

Also, on the subject of yellowing. I've done some satin glossing in the bathroom, also using dulux but not trade and that has also yellowed.

How can i stop the yellowing in both instances????

Thanks for your help

 

[Robbie uk]

I'm presuming it was oil based gloss ? Even the best gloss will yellow, and they seem to yellow quicker than they used too. Probably the only way to stop it it to use water based gloss, this lasts much longer. I'm not a fan of water based products as many will know but might be an idea to give it a try !!

 

[joe-90]

If the surface you were painting was yellowed then it can often bleed through to the top. Did you undercoat first?

 

[GarethSullivan]

hi joe,

it was all done properly, undercoated then 2 good coats of gloss. it was done on MDF if that makes any difference

 

[opps]

Hi Gareth

As Robbie says- oil based paints yellow MUCH faster than they used to since 2010 VOC compliance.

They now yellow in weeks rather than months.

They aslo take longer to dry and the tramlines are heavier.

I still use them because I don't like waterbased finishes but i recommend that clients go for off whites.

There are some oil based paints that claim not to yellow but i have never used them and don't know what they are like to work with

eg

//www.diynot.com/forums/viewtopic.php?p=1725984#1725984

 

[GarethSullivan]

Hi Gareth

As Robbie says- oil based paints yellow MUCH faster than they used to since 2010 VOC compliance.

They now yellow in weeks rather than months.

They aslo take longer to dry and the tramlines are heavier.

I still use them because I don't like waterbased finishes but i recommend that clients go for off whites.

There are some oil based paints that claim not to yellow but i have never used them and don't know what they are like to work with

eg

//www.diynot.com/forums/viewtopic.php?p=1725984#1725984[/QUOTE]


WOW, thanks for the info!

The father in law has just painted some wood work in non yellowing glos and the finish is abit crap to say the least but i suppose its better than having yellow skirting boards etc.

I'll defintley b taking the tin og gloss back that i bought the other day!!

 

[opps]

The non-yellowing gloss might well be water based.

Part of the reason that I dislike waterbased finishes is that they are harder to layoff without brush marks, they are also less durable.

IMHO the 2010 VOC stuff has been ill concieved- I now use more solvent based paint additives and clients repaint more often because of the yellowing.

 

[joe-90]

If the yellowing is very heavy then even with 2010 paints I'd say you have other factors involved. I use them and don't have any major issues.

 

[opps]

On site today I had two tins of dulux trade white eggshell. One is over a year old and the other up to 5 months old.

The dried dribbles/runs on the outside of the new tin are far more yellow than the pre 2010 voc tin.

Rather bizarely, the dried paint on the inside of the tin is also more yellow, an area not subjected to much UV light.

 

[GarethSullivan]

the paint in the bathroom was done over eggshell which incidently went yellow in days. I didn't undercoat before going over the eggshell (i didn't think i'd need to). So i guess, from reading earlier posts, is the reason the satin went yellow but i've also painted a door using the same satin that i primed and undercoated first which has also gone the same.

 

[opps]

have been reading up on the subject and it seems that exposure to DIRECT sunlight will reverse the yellowing effect.

The fatty acids in the paint will yellow even in dark conditions, eg the tin that I referred to, or the inside of a cupboard.

It is the degree of direct sunlight that will determine not the yellowing but rather the bleaching of white oil based paints.

For years I had laboured under the misapprehension that uv light made the paint yellow. Now I see that I was wrong- thinking about it, exterior wood work rarely yellows much.

I can only guess that the plant based oils in the new 2010 paints are those with more linoleic/ olec acids or that the solvents previously reduced the yellowing.

Time to research the matter more me thinks...

BTW I have come across many reports of paint noticeably yellowing in 2 weeks since 2010

 

[opps]

the paint in the bathroom was done over eggshell which incidently went yellow in days. I didn't undercoat before going over the eggshell (i didn't think i'd need to). So i guess, from reading earlier posts, is the reason the satin went yellow but i've also painted a door using the same satin that i primed and undercoated first which has also gone the same.

Hi gareth

It is the case that eggshell doesn't need undercoat but one of the (less obvious) functions of undercoat is obliterate the previous coating.

In the past I have used eggshell over old yellowed gloss- I didn't have any UC with me. rather than using two eggshells I needed 4 to get rid of the yellowing

 

[GarethSullivan]

have been reading up on the subject and it seems that exposure to DIRECT sunlight will reverse the yellowing effect.

The fatty acids in the paint will yellow even in dark conditions, eg the tin that I referred to, or the inside of a cupboard.

It is the degree of direct sunlight that will determine not the yellowing but rather the bleaching of white oil based paints.

This would explain a few things actually.

The eggshell/satin has been done in an internal bathroom with no direct sunlight. The yellowing gloss is in a bedroom which gets the brightest sunlight first thing in the morning when we're in bed and the curtains are shut. The bedroom is still bright during the day though.

 

[opps]

This would explain a few things actually.

The eggshell/satin has been done in an internal bathroom with no direct sunlight. The yellowing gloss is in a bedroom which gets the brightest sunlight first thing in the morning when we're in bed and the curtains are shut. The bedroom is still bright during the day though.

I believe that the sunlight needs to be direct, ie not bounced off walls (as this will absorb much of the higher radiation) for optimum results

 

[GarethSullivan]

Thanks for all the help guys!