Is there a ready mixed wood filler that is as good as the two part type?

[Foresty_Forest]

I've said at least twice: I want to fill the mitres with a non cracking filler. I already use the two part filler: dries too quickly for use on several frames at once. An alternative ready mixed filler would be better.

[vintage frames]

Have you tried decorator's caulk? It comes in white, but you could mix some paint into it to match whatever your frame colour is. Caulk is very flexible and intense, and the easiest way is to rub it over the mitre whilst wearing vinyl gloves.

[Justintime]

What glue are you using?
With barewood Oak the Brummer blue tin in Natural Oak is a really good match for all the Oak I get from Rose and Hollis. I use as little as possible and blend it into the wood. Like I said before, the Ronseal Natural is a really good match for Ash.
If you're using Tulip are you spreading the glue over the entire surface before pinning. You'll get a much better adhesion this way and should prevent the hairline crack. I was originally taught to just put a blob on the mitre, but this didn't prove sufficient.

[prospero]

I use the non-solvented 'No Nonsense' brand from Srewfix in cartridges. It's friendly to use. Dries very hard and will accept
water-based paint if required. It's also very cheap. On large frames that are going to be hand-finished, I pipe a bead of it
on the corner joint and work it in with a finger and damp sponge. Wipe off excess. It acts both as a glue and filler. Also useful
for 'grouting' the joins on stacked frames. You have to take off any excess with a damp cloth before it sets. It set quite quickly,
but it's not sticky as such. Gives a nice radius on the internal corner of a scoop.

Brummer Stopping is my go-to filler where you need to sand it flush.

For factory finished mouldings, Liberon filler waxes. You can keep them at the right consistency by adding a drop or two of Turps
now and then. This way, a pot will last years. You are never going to get the 'closed corner' look with factory mouldings. That's why
I almost never use them.

If you are regularly getting gaps bigger than hairline then recalibrating your machinery is maybe called for.

[Not your average framer]

I like hand finishing, because the mitre joints just disappear beneath the hand finishing. Normally there are no gaps before hand anyway, but sometimes there might be the odd little chip on the outside edge of a corner mitre. I use quite a reasonable amount of pine mouldings and sometimesa little bit of the grain creates a bit of tear out, when it is cut on a morso. I like to fill these chips with the water based version of "no more nails" and sand it down flush with my bench top belt sander. I also very slightly chamfer of the corner with a sand paper block, just to help the finishing to stick well at the outside of the corner.

I also like to brush "no more nails" into the joints between stacked mouldings. A wet brush helps to smooth things quite nicely, when hiding joints between stacked mouldings. Not all factory finished mouldings are all that easy to get perfect corner joints with and I don't really like some factory finished mouldings all that much. There are times when I mix my own custom coloured filler to match the colour of factory finished mouldings, ofter i do this with paste wax and a little bit of custom mixed oil colour to get exactly the right shade and then smooth it into any slight chip, or gaps with my finger. Since I am so used to doing so mang hand finished frames, I get more fussy about how good the corners look on factory finished mouldings.

To be honest, I don't regard many factory finished moulding as being particularly good value for money, but there are a few factory finished mouldings that I stock, purely because they fit the bill for some jobs that need to be done in a hurry. One of these is a very nicely priced antique coloured and traditionally shaped pine moulding. I like to give some factory finished moulding a name, because the right name can carry a useful message. This particular moulding gets called "traditional country pine". Customers like the name and it sells quite well.