Guillotine damaging mouldings

[Perfection]

Hi everyone. Can your experience tell me what's going wrong with some moulding cuts? I have a Charnwood VMM guillotine (I'm told by them it's the same as a Morso but it's red - that's the only difference!)

The blades are sharpenned and honed and join together exactly at the apex - there's no gap. But with a lot of coated mouldings, I'm getting this damage - what you can see in the picture is the back of the moulding and the damage is at the bottom.

Any ideas??

Perf

[Gesso&Bole]

How many chops are you taking?

The final one should be just a shaving, and as gentle as possible

Or it could be poor quality moulding . . . . . .

Or try putting a pice of MDF or similar between the moulding and the fence, sometimes that can help (but remember to adjust measurements)

Or your machine might be out of alignment or the blades not quite as sharp as you thought

Hope that helps

[birdman]

The edges of the cut look a little raged in the photo as well as the nick in the back corner. If your blades are sharp then it would indicate the moulding finish is not that great and prone to damage.

Gesso has made some good points. If your blades are sharp, set properly and you're cutting it gently then I would forget ordering that moulding again.

[Not your average framer]

If your blades are sharp, then I would suspect that it is the black finish on the moulding.

A little gentle warming of the moulding before cutting it may be the solution.

It's very easy to do. Just cut the four lengths you require, but oversized and place them on your bench with an electric blanket under them, then fold part of the electric blanket over the moulding lengths.

Now switch on the electric blanket and go and make yourself a nice cup of tea. Enjoy your cup of tea and by then the moulding will have warmed up nicely, which will have considerably reduced the brittleness of black finish on the moulding.

Normally this results in a clean cut and no chipping of the finish. Trim both ends to arrive at the correct finished size and your ready to join them.

[Roboframer]

Mark (NYAF) posted that idea some time ago and I thought 'Yeah - right'

But heating some of these plastered/coated mouldings really works (emphasis on the word 'some' though) - however, not having an electric blanket I just mark the mitre and either zap it (just that area) with a heat gun, or simply hold it over my workshop heater.

I wonder if heating the blades would work too - instead of or as well as heating the moulding?

Have to say though that I don't need extra procedeures like this - some mouldings are simply guillotine-unfriendly and I don't want to get in to saws/sawdust/dust extraction - I don't have a problem with letting my moulding selection suit the equipment I have, plus there's always chop service if it comes to it - which, bar aluminium, would be once in 17 years for me.

[prospero]

I think maybe this is a combination of things. Many mouldings have the back edge radiused slightly at the bottom. This makes tiny unsupported gap. If the same moulding has a thick coating...... Well you can see what happens. Not all mouldings are Morso-friendly. That one would be much better suited to a saw.

The solution? (Apart from finding a better mouding....)

Sometimes a thin piece of plastercine temporarily jammed in the gap will stop it. Plastercine goes quite hard when it's cold. Basically anything that you can find that will mould itself into the corner and not damage the blades. Of course you then have the fecky job of scraping the stuff out to use other mouldings.

[Perfection]

Guys, that's a brilliant response, many thanks. Unfortunately, I've got 60metres of that moulding to frame some art that we've bought for the gallery. So, in addition to replacing the blades (I have a spare honed pair), double-checking all the machine's settings & level, I'm seriously off to slee pee zee or whatever it's called to get me a blanket.

I'll let you know how we get on.

Paul

[huntvambo]

I've had the same problem on one particular moulding in the past week and I remembered this suggestion by Bill Henry, fill the gap between the right and left fences on the Morso with a bead of Silicone Rubber Sealant to give the blades something to push against when the blades slice down. This was better but not a full solution.

I then followed the suggestion of heating the area about to be cut, I used a heat gun (carefully), and this gave a significant improvement. I found that if you go through to last couple of cuts and then heat the back of the moulding it seems to give a better heat distribution and hence cuts better.

So problem sorted for this frame but I think I'll take the chevron of the stand.

Thanks to all for the advice.

Paul
Framed in Alvechurch

[Nigel Nobody]

Some of the 'modern' compo is very, very, very brittle and is really unsuitable for the job. While framers continue to buy this rubbish, manufacturers will continue to use it because it's 'cheap' for them to use and 'cheap' is what a lot of framers want!

IMHO there are three alternatives available to us:
1. Spend an enormous amount of extra time finding ways to overcome the brittleness, then spend more time making every frame! Then you will have to charge more for those 'cheap' mouldings, which negates the lower price!
2. Buy a double mitre saw. I have one and it reduces the problem but doesn't eliminate it! This can also mean reducing the standard of your joints.
3. Send the moulding back and do the same every time you receive a similar product, then take those samples off your display!

PS. Using this type of moulding doesn't fit with anyone who is concerned with quality workmanship and by the look of your business name you are concerned!

[Not your average framer]

heating some of these plastered/coated mouldings really works (emphasis on the word 'some' though)

As John so rightly says, it works on some. In my experience it does not help very much with the thick grey coloured gesso used on mouldings imported from the far east. Poor quality mouldings are still poor quality, whether warm or cold.

I wonder if heating the blades would work too - instead of or as well as heating the moulding?

I doubt it. Heating the moulding introduces some added flexibility to the coated finish. Flexibility is associated with lack of brittleness, where as excessive hardness is associated with brittleness).

Sadly very few black coated mouldings seem to be free from this problem. To be honest, I only resort to the electric blanket trick in extreme cases and if the cut does not look to bad usually it will not get noticed.

Most narrow black cushion mouldings seem to exhibit this tendancy to some degree and are probably produced in warmer climates where the manufacturer has never encountered any problem due to all year round warm temperatures.

The electric blanket trick is also good for cutting and underpinning polymer mouldings in cold workshops during the winter months.

[Jamma]

I have found this problem over the past 6months with the enamel finish mouldings and there is no way around it just extra care on the cut but i am finding more and more mouldings are being geared out towards saws i.e 3 phase cassese ect: if you get it on chop service with arqadia you will find it comes perfect but i defo put it down to needing a saw to get a single clean cut

[Perfection]

Indeed - we saw quite a few saw-based mitring machines demonstrated at Spring Fair - mostly around the £7K to £9K mark and not a scratch on the moulding backs.


I hear it's a double rollover this weekend.

P

[mikeysaling]

you gotta have a lot of space and a lotta work to justify a saw! - i know one who came to grief locally with this 'investment' . It only takes one good contract job to close out!

[An Old Master]

Apart from the "There's a gap on the inside of my mitres" one, this is probably the most common question to my Agony column - it's a classic symptom of the top blades not passing far enough into the bottom dies or blades. Make sure you adjust the drawbar so that the blades go at least 5mm past the bottom dies at the end of the stroke.

[astraios]

We had the same problem with the same moulding (judgging by your photo) on the Morso guillotine. We did every trick in the book (i mean this forum ... new blades, sillicone, masking tape ... but we didn't achive the perfect cut.

We suceed to eliminate the bottom damage of the moulding with adjustments of height of blades. They should go down into the down blades (i dont know the right term) 4-7mm (our was going 1 cm which was too deep) But still perfect cut is imposible because this is a really bad qualitty moulding and when you finish with your stock i advise you to eliminate it from your offer.

When you look how this cheap mouldings complicate the cutting proces they dont look so cheap any more.

Our final solution was to buy a mittre saw ... we are gitting it next week ... but the cut on this types of mouldings is almost perfect.

[Perfection]

Thanks again everyone

I've put the new blades on and am getting nice smooth edges but still getting corner damage.

I will try heating it later - this moulding is for a couple pf particular stock prints that we think will sell well but we've withdrawn it from our customer boards for framing work. We've only just bought the guillotine, damned if we're going to spend (yet) another 7 grand on a saw!

Well, not yet anyway!

Onwards .. and thanks for all your help.

Paul

[GL@profile]

I think your blades have possibly been incorrectly sharpened.
They should be hollow ground (NOT FLAT GROUND -- which may be responsible for your problems).

Best wishes

[Nigel Nobody]

I prefer my blades to be hollow ground, but the issue here is the brittle modern 'compo'. Sharp blades will do a better job, but won't eliminate the brittleness of the product.
My advice is that if you don't have a saw, don' t sell stuff with the brittle compo. Although that's becoming a more difficult choice with the proliferation of mouldings made with this rubbish.

[Perfection]

Just wanted to let the forum know that Frinton Mouldings today agreed to take back all of the moulding I'd bought - all 60 metres of it. I've ordered a similar qauntity of a replacement moulding that shouldn't damage.

Two things influenced that - the power and strength of this forum and the fact that Frintons are a darned nice company and their main sales guy - Chris Draper - is a top man. Chris came out here, looked at the evidence, cut a few pieces himself on our VMM and didn't hesitate to agree to take it back.

This industry needs companies and people like them.

Thanks everyone

Paul

[swanlinnet]

Well done Paul ...Glad things worked out in the end. Will be keeping a look out for this type of moulding in future.