Mountcutting and Dry Mounting Qs

[RobM]

Morning All,

Just in continuing some practice, I have a few questions relating to a poster I've been working on.

1. The mount I'm using has a coloured purple finish. When doing the bevel cut, a problem I've noticed with a few such mounts is that coloured layer tends to tear easily when pulling out the window, as if not thoroughly cut. See first photo. How do you get around this issue? Would you alter the over/undercut tolerances, change the blade depth in the cartridge, or otherwise?

2. Attempting a v groove: this seems hard to get right. As with 1, the cut is better on some sides than on others, leading to a clear defect, best shown by the 2nd and 3rd photos. How would you better improve this problem?

3. Lastly, as you can see in the final photo, the poster I'm mounting has been rolled up. What's the conventional approach to flattening this? I know framers who would just dry mount the poster onto a hard board, but others that say that sort of practice is strictly verboten.

Can anyone out there help please?

[prospero]

Most mountcutting problems are down to blunt blades. Blades are cheaper than mountboard.
Also the blade depth. It should just cut through.
Are you using a slip sheet?

What method are you using for V-grooves?

As for flattening things.... If the item is easily replaceable and of little intrinsic value then drymounting is
the way to go. Otherwise, sandwiching between two boards and leaving under weight for a while will help.
You can put it in a press without adhesive and give it a quick squeeze can do the trick - but beware as
things can go pear-shaped.

[NTG999]

As I asked previously; are you using S 012 blades? As Prospero mentioned the blade should only just cut through the mountboard and regarding the slip mat the cut should ideally be made in to a new uncut area of slip mat each time. I shuffle my slip mat across on each cut being especially careful of this if a fancy mountboard

[RobM]

Morning Prospero. Thanks for your feedback.

I response, I actually installed a new blade in the bevel cartridge following earlier advice from NTG999. I also replaced the slip mat upon realising I wasn't replacing it enough.

As for V-groove method, I essentially cut a window out as normal, and then place the cut window back into the mountcutter face-up. I then repeat the cuts to allow for the second side of the "V". Is there a way this could be amended for more success?

Cheers for the advice on flattening, too. Much appreciated, my friend.

Most mountcutting problems are down to blunt blades. Blades are cheaper than mountboard.
Also the blade depth. It should just cut through.
Are you using a slip sheet?

What method are you using for V-grooves?

As for flattening things.... If the item is easily replaceable and of little intrinsic value then drymounting is
the way to go. Otherwise, sandwiching between two boards and leaving under weight for a while will help.
You can put it in a press without adhesive and give it a quick squeeze can do the trick - but beware as
things can go pear-shaped.

[RobM]

Hi NTG999. Thanks for your help again.

In answer, yes, I did actually switch over the the blades to the S version, following your prior advice. So, really, this defect is happening with a brand new blade.

I am trying to vary the slip mat more, too, as you advise.

As I asked previously; are you using S 012 blades? As Prospero mentioned the blade should only just cut through the mountboard and regarding the slip mat the cut should ideally be made in to a new uncut area of slip mat each time. I shuffle my slip mat across on each cut being especially careful of this if a fancy mountboard

[prospero]

V-grooves....

That's the method I use. It does take a bit of practice. One point is that you should ensure the a dropout is replaced
in the same orientation - I always make a pencil mark on the back to cross where the cut will be. The blank mount will
not be perfectly square so a tiny bit off will not be apparent unless you are doing v-grooves.
When you do the slicing the the guide bar must be exactly parallel to the cutter bar. I check this with a drill (can be anything)
to use a a feeler gauge to make sure the two ends have an equal gap.
When slicing I place the cutter block back from the edge of the dropout and start the cut from there. So when it connects with
the dropout it is in the right track. You can get a slightly bent corner if you start right on the edge.
When all four edges are done run you finger lightly along the edges to take off any fluffy bits.

* The slicing-off width is critical. The bevel part should go about 2/3 of the thickness on std board.
Take your time and practice on scraps to get the machine calibrated just right.

When it comes to v-grooves accuracy is paramount. Any tiny deviation will shout.

[Gesso&Bole]

Is your table completely flat? Many mount cutters will follow the contours of the table, so the blade depth is varying as you cut.

Are you using a good quality mount board? Cheap boards are very inconsistent, and generally more difficult to get a good result.

[RobM]

Thanks for the thorough information, and some good points. I'm starting to see that V-grooves is something that cannot be perfected overnight.

Yes, I forgot to mention I make a "registration" mark - as the window never fits back so well unless its orientated correctly.

Good point re: the making the slice. I've tried doing similar to what you suggest and pulling the block as quickly as possible, and not just just starting from the beginning of the card.

Do you ever alter the V-groove stop setting on your machine?

V-grooves....

That's the method I use. It does take a bit of practice. One point is that you should ensure the a dropout is replaced
in the same orientation - I always make a pencil mark on the back to cross where the cut will be. The blank mount will
not be perfectly square so a tiny bit off will not be apparent unless you are doing v-grooves.
When you do the slicing the the guide bar must be exactly parallel to the cutter bar. I check this with a drill (can be anything)
to use a a feeler gauge to make sure the two ends have an equal gap.
When slicing I place the cutter block back from the edge of the dropout and start the cut from there. So when it connects with
the dropout it is in the right track. You can get a slightly bent corner if you start right on the edge.
When all four edges are done run you finger lightly along the edges to take off any fluffy bits.

* The slicing-off width is critical. The bevel part should go about 2/3 of the thickness on std board.
Take your time and practice on scraps to get the machine calibrated just right.

When it comes to v-grooves accuracy is paramount. Any tiny deviation will shout.

[pramsay13]

That looks like quite a large poster and therefore mount.
I would go much smaller and do it over and over again until it is perfect, changing the blade regularly and the slip mat every time. I never cut twice on the same piece of slip mat.
Start with the corners. If the mountboard is tearing there is an undercut so you need to adjust and correct it. If it's on all 4 corners it's probably blade depth, and there should be a mark on your machine to show you where to put the blade. If it's on just one or a few corners it's probably a stop issue.
To fix it start with a small piece of mountboard, maybe 300mm x 300mm. Check the piece is square. Cut the mount 60mm all the way round. After the first 2 cuts check if the cut is perfect, if not adjust the correct stop and cut the other 2 sides. Then cut 50mm all the way round checking as you go, then 40mm.
Once that's done sort the v-groove, again by practising on small pieces of mountboard. From your photo it looks as though the blade hasn't gone through enough but if you've sorted the overcuts / undercuts, then the v-grooves should be fine. If it's a struggle just talk people out of going for them. I probably do 1 v-groove a year if that as it's just not something people ask for and that's with me having a sample of one on my desk.

[prospero]

The v-groove setting is part of the calibration of the machine. It is largely trial-and-error but once set
should be left where it is. Very rarely will you want to vary the groove width.


What cutter are you using btw?

[RobM]

Thanks for the detailed feedback, Peter.

A fair point there: I should probably be practising V-grooves on smaller pieces. I have done a few smaller ones - and actually did as you suggested with cutting a larger piece into several pieces in 10mm increments - but got a bit a carried away with trying it on that large(ish) poster.

I do think it's useful being able to master V-grooves, though. I'm back at the studio at the weekend, I'm going to follow your advice with the settings a bit more closely. If I fail, I'll no doubt be back on here asking more questions!

Thanks again, Peter.

That looks like quite a large poster and therefore mount.
I would go much smaller and do it over and over again until it is perfect, changing the blade regularly and the slip mat every time. I never cut twice on the same piece of slip mat.
Start with the corners. If the mountboard is tearing there is an undercut so you need to adjust and correct it. If it's on all 4 corners it's probably blade depth, and there should be a mark on your machine to show you where to put the blade. If it's on just one or a few corners it's probably a stop issue.
To fix it start with a small piece of mountboard, maybe 300mm x 300mm. Check the piece is square. Cut the mount 60mm all the way round. After the first 2 cuts check if the cut is perfect, if not adjust the correct stop and cut the other 2 sides. Then cut 50mm all the way round checking as you go, then 40mm.
Once that's done sort the v-groove, again by practising on small pieces of mountboard. From your photo it looks as though the blade hasn't gone through enough but if you've sorted the overcuts / undercuts, then the v-grooves should be fine. If it's a struggle just talk people out of going for them. I probably do 1 v-groove a year if that as it's just not something people ask for and that's with me having a sample of one on my desk.

[RobM]

Admittedly, I like the idea of just leaving the V-groove stop and not touching it all.

I'm using a Ultimat Futura cutter.

The v-groove setting is part of the calibration of the machine. It is largely trial-and-error but once set
should be left where it is. Very rarely will you want to vary the groove width.


What cutter are you using btw?

[Justintime]

Just coming back to a question Gesso&Bolle asked. Is your table that the mountcutter is sitting on flat and without flex if you put pressure on it? There is a slight bit of flex in the mountcutter base in my experience. Have a look under the mountcutter, there should be a number of little rubber feet supporting it, check that none of these are missing. Sometimes it's the little details that can throw everything off. I resorted to an offcut of kitchen worktop to put my keencut on eventually, it solved my table issues.

[NTG999]

Lion sell the rubber feet; code 10543, I bought some and spread them evenly

[prospero]

Good point from Justintime. It's a good idea to get the bed flat and not move the machine
unless you have to.

[RobM]

I think it's flat...but you never know. Fair point, actually George - I'm finding is can be some of the details that can make all the difference. I'm going to check this in the morning.

Just coming back to a question Gesso&Bolle asked. Is your table that the mountcutter is sitting on flat and without flex if you put pressure on it? There is a slight bit of flex in the mountcutter base in my experience. Have a look under the mountcutter, there should be a number of little rubber feet supporting it, check that none of these are missing. Sometimes it's the little details that can throw everything off. I resorted to an offcut of kitchen worktop to put my keencut on eventually, it solved my table issues.

[RobM]

Thanks for all the feedback, All!
I'm be taking a look at some of the suggestions in the morning and will no doubt be back with further questions.