The Framers Forum

Hi,

I'm having a bit of trouble with Lion's Minerva mouldings in that they sometimes spring apart when I v-nail them.

I glue them together using Mitre Mate - this is normally brilliant, but recently it's sprung apart when adding the 10mm v nail - perhaps 10mm is too generous (the moulding depth is approx 15mm and the frames are big ones).

Has anyone else had any similar problems? I also bought some Bison Max glue but haven't tried that yet.

Thanks!

Hi Bagel Framer,

Are the joints widening at the top or at the bottom?

I've just thrown some of that moulding away having got fed up with trying to get good mitres. I even tried Lion's special Plastibond glue which, the tine says, takes 3 to 5 days to set.

With one frame I tried filling the gap with some brown Liberon polish but that just removed the surface of the moulding.

If I HAVE to use that moulding again I think I'll glue the frame and then let that dry for 3 or 4 days before pinning.

The ones I had problems with were M130-56 and M130-53.

Last week I made a frame with M108-13 and together with no problems.

The main thing to remember is not to pin anywhere near the outer edge, preferably not even in the outer half. I had more success with those mouldings with a hand pinner (logan lever type). I'd guess the gentle pressure brings better results.

Bagel Framer wrote:I'm having a bit of trouble with Lion's Minerva mouldings in that they sometimes spring apart when I v-nail them.

May I ask -what is a 'Minerva' moulding???

osgood wrote:May I ask -what is a 'Minerva' moulding???

Plastic, basically.

OIC.....otherwise known as 'synthetic'.

Mmmmmmm....this is my method. Try it if you wish to join these mouldings successfully.

On a hard flat surface, place a piece of silicone release paper.

Place the two parts of one joint together to ensure that they are the same height. If not, use the leaves out of a cheap set of feeler gauges, under the lowest side to raise it to the same height as the other side.

Sometimes I find it necessary to place a couple of thicknesses of matboard under both legs about 18 inches from the joint so that the top of the joint will be nice and tight.

Pick up one piece of moulding being careful not to dislodge the feeler gauge leaf if it is under that piece.

Dab small dots of 'superglue' all over the surface of the joining area.

Place this piece of moulding back on the silicone release paper and gently, but accurately push the two parts of the joint together and hold firmly together for about 12 seconds.

Repeat the gluing process until all four corners are joined. The final joint needs to have the superglue added a little differently. One part of the joint can easily be lifted above the other and the glue can be dotted on while it is above the other piece. Care needs to be taken with this joint.

When applying superglue, be careful not to add so much that it oozes out on the finished surface of the moulding as it will bugger up the finish. This is a great product to be frugal with!

Like concrete, the joints in synthetic moulding need some re-inforcement so now add some vee nails. Keep the vee nails away from the edges so that it doesn't split. Some synthetics are more prone to cracking than others.

As you learn which synthetic mouldings are good and which are crap, delete the crappy ones from your range!

I've been joining these mouldings this way since the early 90's and have always been successful. Occasionally have had to recut a piece, where I have clumsily dropped a spot of superglue on the finished surface.

We have chosen not to carry plastic mouldings, but we’ve been called upon to try to repair a few whose corners have broken apart. Like yourself, we have found that driving V-nails into them often disrupts the corners.

If the moulding to which you are referring is made from polystyrene, the most common standard glue/adhesive is cyanoacrylate (SuperGlue or something similar), although some framers on The Grumble have begun to use a product 707 which they claim is as strong as or stronger than SuperGlue. I haven’t tried it, and don’t know if it needs to be applied with a glue gun or not, but it may be worth looking at.

Ormond,

What is the advantage of joining these corners “freehand” rather than placing them into a vise? It would guess that if the corners were “pre-fit” before applying the glue (using a shim, if necessary), then only one rail removed and glued, it should slide back into the remaining clamped rail perfectly.

Bill Henry wrote:What is the advantage of joining these corners “freehand” rather than placing them into a vise? It would guess that if the corners were “pre-fit” before applying the glue (using a shim, if necessary), then only one rail removed and glued, it should slide back into the remaining clamped rail perfectly.

Bill,
I don't have a corner vise! I did once, but found it a pig of a thing so I sold it.

You could indeed use a vise, but I think it might take longer to set up and may not be worth the extra effort. That old 'KISS' principle comes to mind. Why complicate a process that is already simple and successful?

Many of the profiles of the synthetic mouldings I use could be very awkward to vise successfully. Hand clamping works very well on any profile!

Many framers like yourself do not use synthetic mouldings for varied reasons, but many, like me, do use them because they can be very profitable and can, in some circumstances allow us to provide a lower cost alternative to a customer who is looking for an inexpensive frame.

The finishes on these mouldings are much better than they were a few years ago and the appearance of many of them are not distinguishable from good finishes on wood mouldings.

Obviously it is a personal choice whether to use them or not, but I would encourage everyone to at least try them out then make a decision on whether to offer them permanently or not.

Ormond
I use exactly the technique that you described on these Minerva mouldings with a lot of success.

I only put one 'wedge' (v nail) into the middle of the moulding.

They are a good range and sell quite well.

Thanks all - M118-32 was the problem moulding and the splitting problems did seem to be because we were pinning to near the edge.

I tried two hardwood v nails in the centre part of the moulding and it worked a treat (I use Lion's drillstand and do all my pinning by hand - very slowly in Minerva's case).

One joint that opened out I have filled with Bison Max too.

Minerva are ok, but I wouldn't go out of my way to recommend them to customers.

Bagel Framer wrote:One joint that opened out I have filled with Bison Max too.

Minerva are ok, but I wouldn't go out of my way to recommend them to customers.

Your method of inserting vee nails is probably the main cause of your problems. If you don't have the right equipment, you probably should stay right away from these mouldings.

All:

I'm following this thread with interest - obviously. We'll be studying it and hopefully coming back with some helpful ideas.

Meanwhile, some quick points:

- is anyone getting similar problems with other brands, such as Emafyl and Polcore?

- polymer mouldings are only designed to be used by professional framers, with good levels of skill and good equipment. They are not really for hobby framers.

- they generally work better at room temperature.

- their closed cell core structure is not as flexible and absorbent as that of wood. Wood absorbs the thickness of the steel wedges more readily than does polymer. So, whereas with wood, wedges are typically placed 1/3 and 2/3 of the way across the line of the join. With polymer, they are better placed 1/4 and 1/2, reading from the inside. This minimses any slight opening of the join.

- polymer mouldings have a closed cell structure which does not absorb the water of water based glues, which is why normal PVA type glues don't work too well. When we make up samples, we find that cyanacrylate (?) adhesive works well, although the short open time means that we have to work quickly.

try the "gel" type superglue.
I found that the best to work with.
also try no glue

What do you recommend then Ormond Williams CPF?

Bagel,

In my post further up the page, in fact the seventh from the top, I listed the steps in my joining procedure and recommended "superglue", but did not think to mention that it is called 'cyanoacrylate'.
Someone also mentioned the gel type and I guess that would be good too, but it may not go off as quickly.
I have tried many types of this glue in many dispensers, but find that the ordinary stuff in an ordinary little tube that costs $2 for seven tubes works the best for me!

I hope that helps!

Hi Ormond,

I got some of the gel glue when I picked up the minerva mouldings from Lion, so I'll try the gel glue next time. My wife was so taken with the M118-32 that we're going to make some frames for the house so can try it all then.

I didn't make it clear, but in your earlier thread I thought you were referring to pinners - I appreciate that the drill stand that I use is a bit entry level but it always puts the wedges in fine, hence me staying with it.

I understand that I should probably upgrade to a better underpinner over time - whilst I don't have the budget or facilities for a air/pneumatic one, is there another one that anyone suggests?

Martin Harrold also says that minerva/plastic frames are for proffesional use only - presumably a top knotch pinner is meant in this case. If so, what speed should the v nail go in at and what v nails do you all use typically?

Thanks

Hi Bagel,

I've got a foot-operated pinner, the CS-88. I only use one synthetic moulding (Simons 68-01), but it seems to work well wth the CS-88.

Hi Moglet,

It's ironic you write about Cassesse machines as there's a CS88 on Ebay at the moment, plus Lion do the CS79 at £479.00.

The CS88's at £102.00 just now with the reserve not met.

I like the look and price of the CS79 - I suspect I'm asking an old question but do you know the key differences between the two other than the price (the CS88 is £820.00 from Lion).

Thanks,

Sean

Hi

Being a small one-woman business with not a lot of available space, I use the Kimberley underpinner - I've not used anything else so have no comparison, but the thing I like about it is there is nothing to go "wrong" with it - it's just a solid piece of kit! As I said, I've never had the opportunity to try anything else so maybe it's not as great as I think!?