New gloss paint over old

[Rollerball]

I need to paint a few interior doors which have assorted chips in the old paint, the old gloss has been on the doors for a little over 20 years.

Not sure how to go about this, do I:

a) Sand the old gloss then paint on new gloss

b) As 'a' but put an undercoat on first?

c) Undercoat straight onto the old gloss (no sanding) then apply gloss?

d) Or is there a modern gloss paint that will adhere to old gloss paint?

 

[johnny2007]

Always give a rub with 120 paper before applying new paint.
Also, make sure to degrease the door before painting, especially around door handles.
Don't need undercoat.

 

[sparkwright]

Myself, I would sand, UNDERCOAT and gloss.

 

[michealangelo]

I need to paint a few interior doors which have assorted chips in the old paint, the old gloss has been on the doors for a little over 20 years.

Not sure how to go about this, do I:

a) Sand the old gloss then paint on new gloss

b) As 'a' but put an undercoat on first?

c) Undercoat straight onto the old gloss (no sanding) then apply gloss?

d) Or is there a modern gloss paint that will adhere to old gloss paint?

Always undercoat , always

I would use a combination of fine grade abrasive to flatten major nibs

and the rough side of the yellow and green sponges used for washing up , in a bit of fairy liquid and water

Between these methods you will have given the surface a key

Clean down with clean rag and clean water

If you dont want to sand you can apply Zinser Bin , Zinser 123 , Zinser Aqua , Crown PX1 etc all of which will give you a bond coat to paint on

After each option above , get an acrylic primer fast dry undercoat on like leyland , johnstones or .....an oil based undercoat ....but that's a longer drying time

Then top coat with gloss , satinwood , one coat , solo etc or one of the modern water or hybrid finishes like johnstones aqua , crown fast flow

It may be that you can get away with a quick rub down and a gloss or whatever straight on without an undercoat but I am an old school city and guilds decorator and we were always taught to use the paint system of ....

Seal knots and stains

Prime

Fill

Undercoat

Top coat

 

[michealangelo]

Always give a rub with 120 paper before applying new paint.
Also, make sure to degrease the door before painting, especially around door handles.
Don't need undercoat.

I agree about decreasing but undercoat , especially on 20 year old doors , is absolutely required

To give a base coat and also for likely colour yellowing

 

[michealangelo]

Myself, I would sand, UNDERCOAT and gloss.

Agree , one coat decorating wether it's emulsion , masonry , wood stain , gloss , satin , oil or water based , is not a proper approach

You might get away with it but somethings going to give

Even these once or solo paints are one coat ......but that doesn't mean no undercoat ....its , with a good brush and experience.....one coat gloss .....

 

[johnny2007]

Always undercoat , always

I would use a combination of fine grade abrasive to flatten major nibs

and the rough side of the yellow and green sponges used for washing up , in a bit of fairy liquid and water

Between these methods you will have given the surface a key

Clean down with clean rag and clean water

If you dont want to sand you can apply Zinser Bin , Zinser 123 , Zinser Aqua , Crown PX1 etc all of which will give you a bond coat to paint on

After each option above , get an acrylic primer fast dry undercoat on like leyland , johnstones or .....an oil based undercoat ....but that's a longer drying time

Then top coat with gloss , satinwood , one coat , solo etc or one of the modern water or hybrid finishes like johnstones aqua , crown fast flow

It may be that you can get away with a quick rub down and a gloss or whatever straight on without an undercoat but I am an old school city and guilds decorator and we were always taught to use the paint system of ....

Seal knots and stains

Prime

Fill

Undercoat

Top coat

Paint technology has advanced.
Have you tried removing any good modern paint stain from masonry or wood?
It's impossible.

I agree about decreasing but undercoat , especially on 20 year old doors , is absolutely required

To give a base coat and also for likely colour yellowing

It depends how bad they are.
My 25 years old door are still pristine, a few nibs but from a 2 foot distance they're perfect.
To repaint them a quick rub and 1 coat of paint should be absolutely fine.

 

[michealangelo]

Paint technology has advanced.
Have you tried removing any good modern paint stain from masonry or wood?
It's impossible.

It depends how bad they are.
My 25 years old door are still pristine, a few nibs but from a 2 foot distance they're perfect.
To repaint them a quick rub and 1 coat of paint should be absolutely fine.

I am not going to argue with you , I will repeat that using an undercoat provides a key , bond , evens out colour differences , reduces top coat from being sucked in to the surface and weakened and very importantly means a top coat is almost always going to look sharper , brighter and last longer

Best regards for all your decorating

 

[johnny2007]

I am not going to argue with you , I will repeat that using an undercoat provides a key , bond , evens out colour differences , reduces top coat from being sucked in to the surface and weakened and very importantly means a top coat is almost always going to look sharper , brighter and last longer

Best regards for all your decorating

We're talking about previously painted doors, or I misunderstood?

 

[michealangelo]

We're talking about previously painted doors, or I misunderstood?

Yes , a previously painted door , especially one of 20 years age regarding the surface , is definitely going to require an undercoat to ensure the top coat is going to perform well and be durable

If a surface has been previously primed then that's the first stage of the paint process dealt with

But not undercoating before using even a more modern , one coat paint is not something city and guilds / college trained decorators would be taught to do

It's simply not good practice

I am not doubting in some circumstances ....yours for example ...it can't succeed but I think a general suggestion that undercoat is not needed is not correct

 

[Rollerball]

Thanks everyone for the very helpful advice.

 

[johnny2007]

Yes , a previously painted door , especially one of 20 years age regarding the surface , is definitely going to require an undercoat to ensure the top coat is going to perform well and be durable

If a surface has been previously primed then that's the first stage of the paint process dealt with

But not undercoating before using even a more modern , one coat paint is not something city and guilds / college trained decorators would be taught to do

It's simply not good practice

I am not doubting in some circumstances ....yours for example ...it can't succeed but I think a general suggestion that undercoat is not needed is not correct

Possibly correct, although in my experience it's not.
What they teach is best practice that sometimes is not updated.
In carpentry for example, they still teach to drill a pilot hole and countersink when in fact, modern screws can go in without any preparation, unless you're working on the edge of hardwood.
Doesn't mean that screwing 2 pieces of wood together without pilot hole and countersink is incorrect.
On that note, i've always used primer, undercoat and 2 coats of paint on bare mdf, until I went to help on a job and my friend said to slap the paint straight on the mdf (sanded to get a key).
I told him it would peel in a few months.
2 years later, the paint is still perfect despite being in a single skin garage.
What can I say?
Modern paint seems to stick better than old one.

 

[michealangelo]

Possibly correct, although in my experience it's not.
What they teach is best practice that sometimes is not updated.
In carpentry for example, they still teach to drill a pilot hole and countersink when in fact, modern screws can go in without any preparation, unless you're working on the edge of hardwood.
Doesn't mean that screwing 2 pieces of wood together without pilot hole and countersink is incorrect.
On that note, i've always used primer, undercoat and 2 coats of paint on bare mdf, until I went to help on a job and my friend said to slap the paint straight on the mdf (sanded to get a key).
I told him it would peel in a few months.
2 years later, the paint is still perfect despite being in a single skin garage.
What can I say?
Modern paint seems to stick better than old one.

We all have examples of where paint failed or in your case succeeded

The general point that suggesting you can slap on one coat of " one coat gloss " over 20 year old surfaces is incorrect and backed up by time served and trained decorators and those that train and teach them and I don't know any reputable decorators who would do one coat work like that or suggest that way of working

That's my last comment in this thread

Regards

 

[johnny2007]

We all have examples of where paint failed or in your case succeeded

The general point that suggesting you can slap on one coat of " one coat gloss " over 20 year old surfaces is incorrect and backed up by time served and trained decorators and those that train and teach them and I don't know any reputable decorators who would do one coat work like that or suggest that way of working

That's my last comment in this thread

Regards

I never said to slap one coat gloss on 20 year old surface.
In fact, I don't use one coat paint.
Read my comments.

 

[michealangelo]

You said to someone asking about 20 year old doors to put on gloss or whatever top coat without an undercoat

That's your advice

Its shoddy advice wether it's one coat gloss , one coat satin , oil , water based , one of the latest wonder all in one paints .....

A year or so after a decoration you might consider putting on a solo , once , high gloss , satin paint ......but it's dodgy

In fact using a solo paint , as poor as they are is a better idea than using ordinary top gloss which is your latest answer ....at least once and solo paint is thick enough to give you a short term solution , high gloss is far thinner and without an undercoat .....your suggestion ....on older surfaces ., 20 years ...its far more likely to fail , grin , flake etc etc



That's what you suggested

There is no point in going down further rabbit holes on this matter

Regards