Am repairing window frames and sills where they have gone rotten with
the above excellent product (having already given it a good coat of
the Ronseal Wood Hardener) and need some tips on how to work with this
filler. Is there any trick to making it spread more evenly and
smoothing the surface? The instructions say it can be carved shaped
with a modelling knife after 20 minutes, but I imagine that
presupposes that one has managed to add the exactly right amount of
catalyst for it not to go off quicker or slower, which I have
considerable difficulty getting right. Also, there is a piece of
window beading which has rotted and affected the wood underneath it.
When I replace the beading, I will need to build up the wood
underneath it with filler, but presume that the filler will stick to
the new beading, so that if I ever have to replace the glass the
beading will be firmly attached to the window frame and I will have a
devil of a job getting it off. Any tips on how to stop that
happening?

TIA

Keith

In article
,
Keefiedee wrote:
Am repairing window frames and sills where they have gone rotten with
the above excellent product (having already given it a good coat of
the Ronseal Wood Hardener) and need some tips on how to work with this
filler. Is there any trick to making it spread more evenly and
smoothing the surface? The instructions say it can be carved shaped
with a modelling knife after 20 minutes, but I imagine that
presupposes that one has managed to add the exactly right amount of
catalyst for it not to go off quicker or slower, which I have
considerable difficulty getting right. Also, there is a piece of
window beading which has rotted and affected the wood underneath it.
When I replace the beading, I will need to build up the wood
underneath it with filler, but presume that the filler will stick to
the new beading, so that if I ever have to replace the glass the
beading will be firmly attached to the window frame and I will have a
devil of a job getting it off. Any tips on how to stop that
happening?

It's basically very similar to car body filler which I tend to use for
this as it's cheaper - especially in larger amounts.
That can be shaped with a variety of tools when hard - files, sandpaper,
Sureform etc. As regards the beading if you make good the wood underneath
and let the filler harden then shape as needed before fitting the beading,
it won't stick to it. However, if you need to fill up to something you
don't want it to stick to use some PVC insulating tape.

These fillers ain't as long lasting as cutting out the rot and replacing
with new wood - about 5 years seems to be a good life.

--
*Marathon runners with bad footwear suffer the agony of defeat*

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

On Jun 4, 9:58*am, "Dave Plowman (News)" wrote:
In article
,
* *Keefiedee wrote:



Am repairing window frames and sills where they have gone rotten with
the above excellent product (having already given it a good coat of
the Ronseal Wood Hardener) and need some tips on how to work with this
filler. *Is there any trick to making it spread more evenly and
smoothing the surface? *The instructions say it can be carved shaped
with a modelling knife after 20 minutes, but I imagine that
presupposes that one has managed to add the exactly right amount of
catalyst for it not to go off quicker or slower, which I have
considerable difficulty getting right. *Also, there is a piece of
window beading which has rotted and affected the wood underneath it.
When I replace the *beading, I will need to build up the wood
underneath it with filler, but presume that the filler will stick to
the new beading, so that if I ever have to replace the glass the
beading will be firmly attached to the window frame and I will have a
devil of a job getting it off. *Any tips on how to stop that
happening?

It's basically very similar to car body filler which I tend to use for
this as it's cheaper - especially in larger amounts.
That can be shaped with a variety of tools when hard - files, sandpaper,
Sureform etc. *As regards the beading if you make good the wood underneath
and let the filler harden then shape as needed before fitting the beading,
it won't stick to it. However, if you need to fill up to something you
don't want it to stick to use some PVC insulating tape.

These fillers ain't as long lasting as cutting out the rot and replacing
with new wood - about 5 years seems to be a good life.

--
*Marathon runners with bad footwear suffer the agony of defeat*

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

I don't have the expertise to cut out the rot and replacing with new
wood myself. We have had a friendly joiner do that at the bottom of
door posts etc, but window frames would seem to me to be a lot more
fiddly, and therefore presumably a lot more expensive. I assume from
what you say that there is no way of shaping the filler before it sets
- I don't suppose something as simple as a wet finger would help!

What car body filler do you use?

When you say it only lasts 5 years, what actually happens? Does it
just disintegrate and fall out? I presume that at the very least it
can't rot, but then if we keep up with proper maintenance of the paint
the wood shouldn't rot anyway. We only bought the house 3 years ago,
and are discovering that this sort of maintenance was sadly neglected
for quite a while before then.

Keith

In article
,
Keefiedee wrote:
I don't have the expertise to cut out the rot and replacing with new
wood myself. We have had a friendly joiner do that at the bottom of
door posts etc, but window frames would seem to me to be a lot more
fiddly, and therefore presumably a lot more expensive. I assume from
what you say that there is no way of shaping the filler before it sets
- I don't suppose something as simple as a wet finger would help!

A plastic spreader will get it reasonably close - there should be one
supplied with the product. But it does sand very easily with a coarse
paper. Then use a finer one to get a better surface.

What car body filler do you use?

The one my local car paint supplier has on offer - there's not much
between them for this sort of use. But only worth doing if you need fairly
large quantities like say would fill a 5 litre tin. You could also check
Ebay, or a decent local car accessory shop, not Halfords.

When you say it only lasts 5 years, what actually happens? Does it
just disintegrate and fall out? I presume that at the very least it
can't rot, but then if we keep up with proper maintenance of the paint
the wood shouldn't rot anyway. We only bought the house 3 years ago,
and are discovering that this sort of maintenance was sadly neglected
for quite a while before then.

The snag is wood tends to expand and contract with the seasons whereas the
filler doesn't. So it will eventually come loose. But certainly should
last better than ordinary fillers - even those said to be suitable for
outside use.

--
*A closed mouth gathers no feet.*

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

On Thu, 3 Jun 2010 21:40:02 -0700 (PDT), Keefiedee
wrote:
Also, there is a piece of
window beading which has rotted and affected the wood underneath it.
When I replace the beading, I will need to build up the wood
underneath it with filler, but presume that the filler will stick to
the new beading, so that if I ever have to replace the glass the
beading will be firmly attached to the window frame and I will have a
devil of a job getting it off. Any tips on how to stop that
happening?


Remove the beading. Fill underneath. Wait at least 20 minutes for
the filler to set before fitting the new beading, and the beading will
not stick. Simples.

I suggest that you need to do a little more than just fill the areas
that have rotted. There is a very good product called Ronseal Wet Rot
Wood Hardener which does exactly what it says on the tin. g

http://www.ronseal.co.uk/products/wet-rot-hardener

Make sure that you remove as much of the rotten wood as possible -
preferably all - then use this product on all the wood surfaces that
you have exposed. It stops the rot and ensures that any filling you
do subsequently will not be threatened by any rot re-starting in the
surrounding wood.

I used this product quite a few years ago in a very similar situation
to yours, and the repair has worked perfectly, with no sign of any wet
rot returning.

It is very important to get out as much of the rotten wood as
possible, because the product's ability to penetrate and cure rotten
timber is inevitably limited to a small number of millimetres.

Dave Plowman (News) wrote:
In article
,
Keefiedee wrote:
I don't have the expertise to cut out the rot and replacing with new
wood myself. We have had a friendly joiner do that at the bottom of
door posts etc, but window frames would seem to me to be a lot more
fiddly, and therefore presumably a lot more expensive. I assume from
what you say that there is no way of shaping the filler before it sets
- I don't suppose something as simple as a wet finger would help!

A plastic spreader will get it reasonably close - there should be one
supplied with the product. But it does sand very easily with a coarse
paper. Then use a finer one to get a better surface.

What car body filler do you use?

The one my local car paint supplier has on offer - there's not much
between them for this sort of use. But only worth doing if you need fairly
large quantities like say would fill a 5 litre tin. You could also check
Ebay, or a decent local car accessory shop, not Halfords.

When you say it only lasts 5 years, what actually happens? Does it
just disintegrate and fall out? I presume that at the very least it
can't rot, but then if we keep up with proper maintenance of the paint
the wood shouldn't rot anyway. We only bought the house 3 years ago,
and are discovering that this sort of maintenance was sadly neglected
for quite a while before then.

The snag is wood tends to expand and contract with the seasons whereas the
filler doesn't. So it will eventually come loose. But certainly should
last better than ordinary fillers - even those said to be suitable for
outside use.

Dunno if you can still get it, but there used to be a resin stabiliser
that soaked into rotten wood and turned it into a completely impervious
composite.

Use THAT and THEN body filler..

Keefiedee wrote:
On Jun 4, 9:58 am, "Dave Plowman (News)" wrote:
In article
,
Keefiedee wrote:



Am repairing window frames and sills where they have gone rotten with
the above excellent product (having already given it a good coat of
the Ronseal Wood Hardener) and need some tips on how to work with this
filler. Is there any trick to making it spread more evenly and
smoothing the surface? The instructions say it can be carved shaped
with a modelling knife after 20 minutes, but I imagine that
presupposes that one has managed to add the exactly right amount of
catalyst for it not to go off quicker or slower, which I have
considerable difficulty getting right. Also, there is a piece of
window beading which has rotted and affected the wood underneath it.
When I replace the beading, I will need to build up the wood
underneath it with filler, but presume that the filler will stick to
the new beading, so that if I ever have to replace the glass the
beading will be firmly attached to the window frame and I will have a
devil of a job getting it off. Any tips on how to stop that
happening?
It's basically very similar to car body filler which I tend to use for
this as it's cheaper - especially in larger amounts.
That can be shaped with a variety of tools when hard - files, sandpaper,
Sureform etc. As regards the beading if you make good the wood underneath
and let the filler harden then shape as needed before fitting the beading,
it won't stick to it. However, if you need to fill up to something you
don't want it to stick to use some PVC insulating tape.

These fillers ain't as long lasting as cutting out the rot and replacing
with new wood - about 5 years seems to be a good life.

--
*Marathon runners with bad footwear suffer the agony of defeat*

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

I don't have the expertise to cut out the rot and replacing with new
wood myself. We have had a friendly joiner do that at the bottom of
door posts etc, but window frames would seem to me to be a lot more
fiddly, and therefore presumably a lot more expensive. I assume from
what you say that there is no way of shaping the filler before it sets
- I don't suppose something as simple as a wet finger would help!

What car body filler do you use?

When you say it only lasts 5 years, what actually happens? Does it
just disintegrate and fall out? I presume that at the very least it
can't rot, but then if we keep up with proper maintenance of the paint
the wood shouldn't rot anyway. We only bought the house 3 years ago,
and are discovering that this sort of maintenance was sadly neglected
for quite a while before then.

Keith

Sounds like it would pay you track down a local car finishing trade
outlet and invest in a 3.5 kg tin of the cheapest one they do. I was
paying about £12 (Bondaglass Easy Sand) until mine closed down. IIRC
Halfords are the cheapest for the 1 kg size.

I have body filled sliding sash windows that have lasted 25 years but
you need to be ruthless getting rid of the soft, pappy stuff, however
deep it goes, and the price of Ronseal doesn't exactly encourage that.

The catalyst is just that. Any amount will make it go off providing it
is well mixed (the usual bright red colour makes this easier). Shallower
filling goes off more slowly due to less heat being generated.

You have about 5 minutes where you can carve and sculpt quite easily
with a scraper, so only mix a golf ball or 2 size at a time if you have
any fiddly bits to do. No fingers and no water :-)

Anything smeared with washing up liquid will not stick to the filler,
and this makes it possible to get smooth, straight edges by using
formers. This might just be a scrap of hardboard pinned to the front of
a sill, or something more elaborate. Avoid the need to sand where possible.

Be organised. Have scraps of something to mix on, and ditch them each
time. A set of Poundshop paint scrapers is handy. One stays in the main
tub so you can dispense the resin without contamination from the
catalyst. One does the mixing, and a couple for applying the stuff. When
what's left on the mixing scraper is semi hard, use one to clean the
other. The residue is now dry enough not to stick to everything but can
easily be removed from metal tools.

Not as complicated as it sounds. Honest :-)

In article ,
The Natural Philosopher wrote:

Dunno if you can still get it, but there used to be a resin stabiliser
that soaked into rotten wood and turned it into a completely impervious
composite.

Use THAT and THEN body filler..


I think the OP already has:

"having already given it a good coat of the Ronseal Wood Hardener"

That's the stuff you are talking about IIRC

Darren

On Jun 4, 2:04*pm, dmc@puffin. (D.M.Chapman) wrote:
In article ,
The Natural Philosopher wrote:

Dunno if you can still get it, but there used to be a resin stabiliser
that soaked into rotten wood and turned it into *a completely impervious
composite.
Use THAT and THEN body filler..

I think the OP already has:

"having already given it a good coat of the Ronseal Wood Hardener"

That's the stuff you are talking about IIRC

Darren

Many thanks to all for all the useful comments, especially the ones
about washing up liquid, and PVC tape.

Keith

On Jun 4, 11:23 am, Bruce wrote:

I suggest that you need to do a little more than just fill the areas
that have rotted. There is a very good product called Ronseal Wet Rot
Wood Hardener which does exactly what it says on the tin. g

http://www.ronseal.co.uk/products/wet-rot-hardener


boing!:- reality to tony, please come in:-

OP(having already given it a good coat of
the Ronseal Wood Hardener)

¦{0}

Jim K

Dave Plowman (News) wrote:
In article
,
Keefiedee wrote:
I don't have the expertise to cut out the rot and replacing with new
wood myself. We have had a friendly joiner do that at the bottom of
door posts etc, but window frames would seem to me to be a lot more
fiddly, and therefore presumably a lot more expensive. I assume from
what you say that there is no way of shaping the filler before it
sets - I don't suppose something as simple as a wet finger would
help!

A plastic spreader will get it reasonably close - there should be one
supplied with the product. But it does sand very easily with a coarse
paper. Then use a finer one to get a better surface.

What car body filler do you use?

The one my local car paint supplier has on offer - there's not much
between them for this sort of use. But only worth doing if you need
fairly large quantities like say would fill a 5 litre tin. You could
also check Ebay, or a decent local car accessory shop, not Halfords.

When you say it only lasts 5 years, what actually happens? Does it
just disintegrate and fall out? I presume that at the very least it
can't rot, but then if we keep up with proper maintenance of the
paint the wood shouldn't rot anyway. We only bought the house 3
years ago, and are discovering that this sort of maintenance was
sadly neglected for quite a while before then.

The snag is wood tends to expand and contract with the seasons
whereas the filler doesn't. So it will eventually come loose. But
certainly should last better than ordinary fillers - even those said
to be suitable for outside use.

Maybe thats the difference between 2 part wood filler & car body filler?

The Medway Handyman wrote:
Dave Plowman (News) wrote:
In article
,
Keefiedee wrote:
I don't have the expertise to cut out the rot and replacing with new
wood myself. We have had a friendly joiner do that at the bottom of
door posts etc, but window frames would seem to me to be a lot more
fiddly, and therefore presumably a lot more expensive. I assume from
what you say that there is no way of shaping the filler before it
sets - I don't suppose something as simple as a wet finger would
help!
A plastic spreader will get it reasonably close - there should be one
supplied with the product. But it does sand very easily with a coarse
paper. Then use a finer one to get a better surface.

What car body filler do you use?
The one my local car paint supplier has on offer - there's not much
between them for this sort of use. But only worth doing if you need
fairly large quantities like say would fill a 5 litre tin. You could
also check Ebay, or a decent local car accessory shop, not Halfords.

When you say it only lasts 5 years, what actually happens? Does it
just disintegrate and fall out? I presume that at the very least it
can't rot, but then if we keep up with proper maintenance of the
paint the wood shouldn't rot anyway. We only bought the house 3
years ago, and are discovering that this sort of maintenance was
sadly neglected for quite a while before then.
The snag is wood tends to expand and contract with the seasons
whereas the filler doesn't. So it will eventually come loose. But
certainly should last better than ordinary fillers - even those said
to be suitable for outside use.

Maybe thats the difference between 2 part wood filler & car body filler?




I'm sure they're the same apart from the colour. At least I was told
that by some technical bod at Scott Bader a few years back.

Keefiedee wrote:

What car body filler do you use?

Depending on the size of the gap to be filled, and also whether the gap
is simply cosmetic or strucutral I'd use either the normal car body
filler which is polyester resin with an inert filler or for the bigger
gaps I would use "Bridging Compound" which is glass fibre strands in
polyester resin.

Briding compound is much stronger than filler and works about as well as
wood. An alternative is to buy liquid polyester resin and to mix in wood
as either surform shavings or sawdust. A paste of sawdust + resin is
better than most car fillers it has about the same density as wood and
when cured can be cut and shaped as Dave Plowman has suggested.

You mention difficulty getting the correct ratio of catalyst to resin.
That's not too hard, the rule is a lump of resin about the size of a
golf ball to catalyst about the size of a pea.

The Natural Philosopher wrote:

Dunno if you can still get it, but there used to be a resin stabiliser
that soaked into rotten wood and turned it into a completely impervious
composite.

The best solution for that use is slow-cure epoxy resin. It's used by
boat builders to saturate wood with resin when making wooden boats. It
has low viscosity so that it penetrates wood fibres and when correctly
mixed it doesn't go off for at least 24 hours giving it plenty of time
to soak in.

stuart noble wrote:

The catalyst is just that. Any amount will make it go off providing it
is well mixed (the usual bright red colour makes this easier). Shallower
filling goes off more slowly due to less heat being generated.

Not quite true for polyester. The "catalyst" is an organic peroxide that
gets used up as it promotes setting. Use too little and the filler will
never set properly. Use too much and it sets in seconds.

In message
(Steve Firth) wrote:

Keefiedee wrote:

What car body filler do you use?
[snip]

You mention difficulty getting the correct ratio of catalyst to
resin. That's not too hard, the rule is a lump of resin about the
size of a golf ball to catalyst about the size of a pea.

Absolutely spot on!

To add to this though, use a smaller than a pea amount of
hardener in this hot weather and slightly more in winter.

Stephen.


--
http://www.stephen.hull.btinternet.co.uk
Coach painting tips and techniques + Land Rover colour codes
"Whatever is rightly done, however humble, is noble". Henry Royce

js.b1 wrote:
Wood hardener stabilises the wood and acts as a fixer/primer for
filler.

As mentioned the problem with fillers is they do not expand/contract
at the same rate as wood.


What I've found with sills is there may be an initial shrinkage in the
wood as it dries out after being filled. It may be a couple of months
before this shows as a hairline crack around the filler but, if that gap
is filled, the problem doesn't re-occur.

Car body filler is probably flexible enough to cope with normal movement
in wood that is in reasonable condition but, in older houses, the wood
is often so porous that it quickly swells by absorbing water.

Steve Firth wrote:
stuart noble wrote:

The catalyst is just that. Any amount will make it go off providing it
is well mixed (the usual bright red colour makes this easier). Shallower
filling goes off more slowly due to less heat being generated.

Not quite true for polyester. The "catalyst" is an organic peroxide that
gets used up as it promotes setting. Use too little and the filler will
never set properly. Use too much and it sets in seconds.

I'm guessing the makers specify more catalyst than is actually
necessary, based on the assumption that it won't be properly mixed. On a
3.5 kg tin, I usually end up with a third of the catalyst unused (not by
design), and I've never had a mix not set fully. Main thing is, you
don't have to be *that* careful with the amounts

wrote:
In message
(Steve Firth) wrote:

Keefiedee wrote:

What car body filler do you use?
[snip]

You mention difficulty getting the correct ratio of catalyst to
resin. That's not too hard, the rule is a lump of resin about the
size of a golf ball to catalyst about the size of a pea.

Absolutely spot on!

To add to this though, use a smaller than a pea amount of
hardener in this hot weather and slightly more in winter.

Stephen.


This would appear to contradict Steve's assertion that the resin
requires the pea size to cure.

stuart noble wrote:

This would appear to contradict Steve's assertion that the resin
requires the pea size to cure.

Perhaps you can provide a reference to the post in which you think I
made such a comment?

On Jun 5, 8:50*am, stuart noble wrote:
js.b1 wrote:
Wood hardener stabilises the wood and acts as a fixer/primer for
filler.

As mentioned the problem with fillers is they do not expand/contract
at the same rate as wood.

What I've found with sills is there may be an initial shrinkage in the
wood as it dries out after being filled. It may be a couple of months
before this shows as a hairline crack around the filler but, if that gap
is filled, the problem doesn't re-occur.

That is exactly what I suspect.

Never let relatives "flash the pressure washer" at windows to clear
dirt sprayup, the pressure opens any gap between putty & glass right
to the wood creating a water pocket. Obviously such cracked putty
should be replaced, which is best done as a program of replacement
rather than "patch or fix when you find it" :-)

USA do offer flexible epoxy, www.conservepoxy.com/catalog.htm for
example although 1/2 gallon quantities are more suited to timber
buildings. I have met the old structural epoxy, it makes 50yr old
foundation concrete look like Chamberlain.

In message mNrOn.55589$em4.2632@hurricane
stuart noble wrote:

wrote:
In message
(Steve Firth) wrote:

Keefiedee wrote:

What car body filler do you use?
[snip]

You mention difficulty getting the correct ratio of catalyst to
resin. That's not too hard, the rule is a lump of resin about the
size of a golf ball to catalyst about the size of a pea.

Absolutely spot on!

To add to this though, use a smaller than a pea amount of
hardener in this hot weather and slightly more in winter.

Stephen.


This would appear to contradict Steve's assertion that the resin
requires the pea size to cure.

No it doesn't, in normal temperatures the pea size is correct, I
merely pointed out the amount required in differing temperatures
from either extreme.

Stephen.



--
http://www.stephen.hull.btinternet.co.uk
Coach painting tips and techniques + Land Rover colour codes
"Whatever is rightly done, however humble, is noble". Henry Royce

wrote:
In message mNrOn.55589$em4.2632@hurricane
stuart noble wrote:

wrote:
In message
(Steve Firth) wrote:

Keefiedee wrote:

What car body filler do you use?
[snip]

You mention difficulty getting the correct ratio of catalyst to
resin. That's not too hard, the rule is a lump of resin about the
size of a golf ball to catalyst about the size of a pea.
Absolutely spot on!

To add to this though, use a smaller than a pea amount of
hardener in this hot weather and slightly more in winter.

Stephen.


This would appear to contradict Steve's assertion that the resin
requires the pea size to cure.

No it doesn't, in normal temperatures the pea size is correct, I
merely pointed out the amount required in differing temperatures
from either extreme.

Stephen.




It will cure *eventually* with *any* amount of catalyst, providing this
is *evenly* distributed through the resin. That's my experience anyway,
and I have never had reason to doubt the strength of the cured resin.
Too much hardener, however, is known to weaken the end result.

stuart noble wrote:

It will cure *eventually* with *any* amount of catalyst, providing this
is *evenly* distributed through the resin. That's my experience anyway,
and I have never had reason to doubt the strength of the cured resin.
Too much hardener, however, is known to weaken the end result.

That's not my experience. I have mixed up test batches of filer with
varying amounts of catalyst. When the quantity of catalyst is below 30%
of the manufacturer's recommendation the filler never sets properly and
remains "cheesy" in consistency. It's best to stick to the recommended
ratios.

Steve Firth wrote:
stuart noble wrote:

It will cure *eventually* with *any* amount of catalyst, providing this
is *evenly* distributed through the resin. That's my experience anyway,
and I have never had reason to doubt the strength of the cured resin.
Too much hardener, however, is known to weaken the end result.

That's not my experience. I have mixed up test batches of filer with
varying amounts of catalyst. When the quantity of catalyst is below 30%
of the manufacturer's recommendation the filler never sets properly and
remains "cheesy" in consistency. It's best to stick to the recommended
ratios.

Below 30% is perhaps pushing it, if only because it becomes impossible
to ensure uniform dispersal. In the one I'm using at the moment the red
catalyst turns the grey resin brown so it's easy to tell whether you
have uniformity.
In practice there's no reason to skimp on the catalyst, but its useful
to know that there's an awful lot of leeway.

stuart noble wrote:
Steve Firth wrote:
stuart noble wrote:

It will cure *eventually* with *any* amount of catalyst, providing this
is *evenly* distributed through the resin. That's my experience anyway,
and I have never had reason to doubt the strength of the cured resin.
Too much hardener, however, is known to weaken the end result.

That's not my experience. I have mixed up test batches of filer with
varying amounts of catalyst. When the quantity of catalyst is below 30%
of the manufacturer's recommendation the filler never sets properly and
remains "cheesy" in consistency. It's best to stick to the recommended
ratios.

Below 30% is perhaps pushing it, if only because it becomes impossible
to ensure uniform dispersal. In the one I'm using at the moment the red
catalyst turns the grey resin brown so it's easy to tell whether you
have uniformity.
In practice there's no reason to skimp on the catalyst, but its useful
to know that there's an awful lot of leeway.

Be aware the same is NOT true of epoxy. Here there is no resin catalyst:
there are two components that must be mixed in the correct ratios, and
mixed thoroughly, or the resin will not set properly, ever.