What is the difference between a primer and an undercoat?

Looking to paint doors, skirting, and facings - all are now striped.

Was looking at http://www.screwfix.com/app/sfd/cat/...93859&id=12383
and http://www.screwfix.com/app/sfd/cat/...93763&id=18002, with the
later much cheaper (I have 5 doors inc. facings and skirting in 5 rooms to
paint).

Plan it to finish with
https://www.screwfix.com/app/sfd/cat...94082&id=11842.

TIA.

"JoeJoe" wrote in
:

What is the difference between a primer and an undercoat?

I think that paint is hard to find these days

mike

In article ,
JoeJoe wrote:
What is the difference between a primer and an undercoat?

The primer is to give good adhesion to the material. Hence different ones
for wood and metal, etc. Undercoat at one time was always near the same
colour as the top coat but less expensive, so made the job slightly
cheaper than using two or more coats of top to get the depth of colour.
But things are a bit blurred these days. ;-)

--
*INDECISION is the key to FLEXIBILITY *

Dave Plowman London SW
To e-mail, change noise into sound.

mike ring wrote:

"JoeJoe" wrote in
:


What is the difference between a primer and an undercoat?


I think that paint is hard to find these days

mike

?

I can find lots of it. How much and what type do you want?

Dave

The primer is to give good adhesion to the material. Hence different ones
for wood and metal, etc. Undercoat at one time was always near the same
colour as the top coat but less expensive, so made the job slightly
cheaper than using two or more coats of top to get the depth of colour.
But things are a bit blurred these days. ;-)

What Dave said.

The need to achieve a good bond is still with us, but modern paints have
such good covering power they make undercoat almost superfluous.

Dave

"JoeJoe" wrote in message
...
What is the difference between a primer and an undercoat?

Traditional painting uses a three coat system: primer, to prepare an
unpainted surface to receive paint; undercoat, to build up the colour; and
top coat, to provide protection to the whole. Modern paints tend to be one
coat paints, which achieve colour build and protection in the same paint.

If you want the paint job to last, buy Dulux.

Colin Bignell

"David Lang" wrote in message
k...

The primer is to give good adhesion to the material. Hence
different ones
for wood and metal, etc. Undercoat at one time was always near the
same
colour as the top coat but less expensive, so made the job
slightly
cheaper than using two or more coats of top to get the depth of
colour.
But things are a bit blurred these days. ;-)

What Dave said.

The need to achieve a good bond is still with us, but modern paints
have
such good covering power they make undercoat almost superfluous.


Depends on what you are painting, some surfaces still require the use
of a primer and then undercoat.

"nightjar .uk.com" nightjar@insert my surname here wrote in
message ...

"JoeJoe" wrote in message
...
What is the difference between a primer and an undercoat?

Traditional painting uses a three coat system: primer, to prepare an
unpainted surface to receive paint; undercoat, to build up the
colour; and
top coat, to provide protection to the whole. Modern paints tend to
be one
coat paints, which achieve colour build and protection in the same
paint.


Err not IME, totally wrong about one coat paint, you still need to use
undercoat (if not primer) were the surface has not been painted before
or the paint has been removed, 'one coat' paint is for final top coat
/ *re-finishing*.

In article ws.net,
:::Jerry:::: wrote:
Traditional painting uses a three coat system: primer, to prepare an
unpainted surface to receive paint; undercoat, to build up the colour;
and top coat, to provide protection to the whole. Modern paints tend
to be one coat paints, which achieve colour build and protection in
the same paint.


Err not IME, totally wrong about one coat paint, you still need to use
undercoat (if not primer) were the surface has not been painted before
or the paint has been removed, 'one coat' paint is for final top coat
/ *re-finishing*.

Don't think anyone is disputing you still need a primer on a bare surface.
It's the undercoat which may be dispensable.

--
*Geeks shall inherit the earth *

Dave Plowman London SW
To e-mail, change noise into sound.

JoeJoe wrote:
What is the difference between a primer and an undercoat?
Looking to paint doors, skirting, and facings - all are now striped.

You're supposed to paint it on all over in one coat, not stripe it!

Primer is supposed to "stick" well to the timber (or whatever).

Undercoat covers and is very opaque.

Gloss is the final thin "shine".

I wouldn't buy cheap paint.

David Lang wrote:
The need to achieve a good bond is still with us, but modern paints have
such good covering power they make undercoat almost superfluous.

It's also a problem. Great thick coats of D-I-Y "one coat", "non-
drip" and similar can give rise to problems.

JoeJoe wrote:

What is the difference between a primer and an undercoat?

Primer is there to stick to the ioriginal surface and seal it and
possibly to create a smooth surface - i.e a good primer sticks well to
teh (wood) is thick and can be sanded to give a toally grain free finish.
The unedrcaot is there to basically provide MOST of tghe coulr - its teh
bit that reflects most of te light.

The top coat is there to provide the corect surface finsih and be the
main defense against damage - so it might be hard and glossy, but often
has less pigment in it than the undercoat.


Looking to paint doors, skirting, and facings - all are now striped.

Was looking at http://www.screwfix.com/app/sfd/cat/...93859&id=12383
and http://www.screwfix.com/app/sfd/cat/...93763&id=18002, with the
later much cheaper (I have 5 doors inc. facings and skirting in 5 rooms to
paint).

Plan it to finish with
https://www.screwfix.com/app/sfd/cat...94082&id=11842.

TIA.

In article , "The
Natural Philosopher" says...
JoeJoe wrote:

What is the difference between a primer and an undercoat?

Primer is there to stick to the ioriginal surface and seal it and
possibly to create a smooth surface - i.e a good primer sticks well to
teh (wood) is thick and can be sanded to give a toally grain free finish.
The unedrcaot is there to basically provide MOST of tghe coulr - its teh
bit that reflects most of te light.

Primer doesn't give much build, it's the undercoat that you sand for
a smooth finish.

Rob Morley wrote:
Primer doesn't give much build, it's the undercoat that you sand for
a smooth finish.

You shouldn't "sand" primer at all.

In article , "Chris Bacon"
says...
Rob Morley wrote:
Primer doesn't give much build, it's the undercoat that you sand for
a smooth finish.

You shouldn't "sand" primer at all.

I never said you should :-)

Really traditional paint is made of linseed oil and pigment. On bare
wood you first put on a coat of linseed oil then three coats of paint.
All the same stuff - no primer and undercoat. Buy Sweedish Allback
linseed paint from Holkham Paints (Their website has lots of good
information: http://www.holkham.co.uk/linseedpaints/why.html ) It's
expensive but the manufacturers say you won't need to add another coat
for 14 years. Which makes it very cheap. Plus it's genuinely
breathable so the wood can dry out. Modern paint cracks, lets water in
and traps it leading to rot and flaked paint.

"The most expensive paint is cheap paint"

Rob Morley wrote:
Chris Bacon says...
Rob Morley wrote:
Primer doesn't give much build, it's the undercoat that you sand for
a smooth finish.
You shouldn't "sand" primer at all.

I never said you should :-)

I didn't say that you said you should. Leave it there?

":::Jerry::::" wrote in message
eenews.net...

"nightjar .uk.com" nightjar@insert my surname here wrote in
message ...

"JoeJoe" wrote in message
...
What is the difference between a primer and an undercoat?

Traditional painting uses a three coat system: primer, to prepare an
unpainted surface to receive paint; undercoat, to build up the
colour; and
top coat, to provide protection to the whole. Modern paints tend to
be one
coat paints, which achieve colour build and protection in the same
paint.


Err not IME, totally wrong about one coat paint, you still need to use
undercoat (if not primer) were the surface has not been painted before
or the paint has been removed, 'one coat' paint is for final top coat
/ *re-finishing*.

The statement that one coat achieves colour build and protection in the same
paint means that it replaces both the undercoat and the top coat used in
traditional systems. Primer will still be required if the base material is
unpainted. You should not use undercoat as the base coat on an unpainted
surface and you shouldn't need it over primer if you are using a one coat
paint.

Colin Bignell

Biff wrote;
"The most expensive paint is cheap paint"

Ain't that the truth......

Dave

Rob Morley wrote:

In article , "The
Natural Philosopher" says...

JoeJoe wrote:


What is the difference between a primer and an undercoat?

Primer is there to stick to the ioriginal surface and seal it and
possibly to create a smooth surface - i.e a good primer sticks well to
teh (wood) is thick and can be sanded to give a toally grain free finish.
The unedrcaot is there to basically provide MOST of tghe coulr - its teh
bit that reflects most of te light.


Primer doesn't give much build, it's the undercoat that you sand for
a smooth finish.

Depends. I use filler primer a LOT on stuff that has to have an
immaculate finish. It is often the best place to fill grain.

Undercoat is only there for colour.

Chris Bacon wrote:

Rob Morley wrote:

Primer doesn't give much build, it's the undercoat that you sand for a
smooth finish.


You shouldn't "sand" primer at all.

Depends what primer and what you are doing.
Alot of promers raise the wood grain, and need sanding and a second
coat - especially cellulose.

When painting car bodies and fibreglass we uwse many primer coats to
cover up scratches and blemishes, all rubbed down.

I used three coats of acrlyic primer, rubbed down, on the bathroom T &
G. That came up immmaculate after another undercoat rubbed down, and two
top coats, the first one rubbed down.

Of course if you want a crap finish, none of that is necessary.

In article , "The Natural
Philosopher" says...
Rob Morley wrote:

In article , "The
Natural Philosopher" says...

JoeJoe wrote:


What is the difference between a primer and an undercoat?

Primer is there to stick to the ioriginal surface and seal it and
possibly to create a smooth surface - i.e a good primer sticks well to
teh (wood) is thick and can be sanded to give a toally grain free finish.
The unedrcaot is there to basically provide MOST of tghe coulr - its teh
bit that reflects most of te light.


Primer doesn't give much build, it's the undercoat that you sand for
a smooth finish.

Depends. I use filler primer a LOT on stuff that has to have an
immaculate finish. It is often the best place to fill grain.

Primer filler is a special case because it's designed to build, not
just to seal like ordinary primer.

The Natural Philosopher wrote:
.... snipped

Depends. I use filler primer a LOT on stuff that has to have an
immaculate finish. It is often the best place to fill grain.

Undercoat is only there for colour.

Filler primer sounds useful but I don't recall seeing it - is it a
specialist thing or have I just not recognised it in the sheds?

Dave

Dave wrote:
The Natural Philosopher wrote:
... snipped


Depends. I use filler primer a LOT on stuff that has to have an
immaculate finish. It is often the best place to fill grain.

Undercoat is only there for colour.


Filler primer sounds useful but I don't recall seeing it - is it a
specialist thing or have I just not recognised it in the sheds?

Dave

Dave wrote:

The Natural Philosopher wrote:
... snipped


Depends. I use filler primer a LOT on stuff that has to have an
immaculate finish. It is often the best place to fill grain.

Undercoat is only there for colour.


Filler primer sounds useful but I don't recall seeing it - is it a
specialist thing or have I just not recognised it in the sheds?

Dave
halfords. Car body stuff..
But acrylic primer fills well and can be rubbed down too.