Using Polcore mouldings / tricky?

Discuss Picture Framing topics.

PLEASE USE THE HELP SECTION
WHEN SEEKING OR OFFERING HELP!
Post Reply
Nicole
Posts: 81
Joined: Tue 30 Sep, 2014 9:01 pm
Location: Eastleigh
Organisation: We Frame It
Interests: Professional picture framer. Triathlete
www.weframeit.biz

Using Polcore mouldings / tricky?

Post by Nicole »

As a newbie and supporter of recycling I thought that Polcore was the way to go. However on using it I've not found it is not so easy. I find joining the mitres tricky with the underpinner, a spot of super glue in the wrong place and it doesn't wipe off the moulding surfaces and the plain finishes scratch and mark very easily. Would love to know anyone else's experiences and if there are any hints to make it easier otherwise I might remove them from my selection altogether.
To be creative we must lose our fear of being wrong.
User avatar
IFGL
Posts: 3087
Joined: Sun 06 May, 2012 5:27 pm
Location: Sheffield UK
Organisation: Inframe Gallery Ltd
Interests: Films ,music and art, my wife and kids are pretty cool too.
Location: Sheffield
Contact:

Re: Using Polcore mouldings / tricky?

Post by IFGL »

is plastic not made from oil?

there is a lot of pefc mouldings about
BaBaZa
Posts: 210
Joined: Tue 21 Jun, 2005 1:03 pm
Location: Nottingham
Organisation: http://www.mainlinemouldings.com
Interests: Pubs
Location: Nottingham
Contact:

Re: Using Polcore mouldings / tricky?

Post by BaBaZa »

When joining Polcore the wedges need to be positioned away from the back edge.

Superglue will not come off anything so you should only use a very small amount on one surface.

I can't see where you have purchased Polcore from us so I assume it was from one our distributors. If you would like to message me I can arrange a visit from our sales agent to help or I can phone and can talk you through it.

Ricky
Mainline Mouldings (Polcore)
Ricky @ Mainline Mouldings Ltd

Twitter #MainlinePolcore
Glimpse

Re: Using Polcore mouldings / tricky?

Post by Glimpse »

I've been using Polcore mouldings for a while, and I almost gave up at first! I've learnt a few tips through trial and error that might be of use.

In my experience, superglue-type adhesives are a waste of time - they're too thin so you get very little surface-to-surface contact, and the working time is so short it's usually gone off by the time you get the joint in the pinner.

After asking for advice on here, Titebond Polyurethane glue was suggested, and whilst not perfect, it does work quite well and has the advantage of being wipeable-offable with a damp cloth.

I've also found it best to use much smaller wedges than you would if it was a timber moulding, and of course, follow the advice of not putting wedges further than halfway towards the outside edge.

I find smaller frames give me more agro than larger ones, and I more often than not use band clamps. These from Screwfix are so cheap, it's good to have a few for this purpose. I glued a bit of brushed nylon loop fabric into the corners just to protect the moulding but at 5 quid a pop, they do the job splendidly.

I'd much rather spend all day gluing/pinning a good quality timber moulding, but I'm now getting consistently good results with Polcore. Hope this helps!

http://www.screwfix.com/p/adjustable-band-clamp/16857

Image
User avatar
prospero
Posts: 11492
Joined: Tue 05 Jun, 2007 4:16 pm
Location: Lincolnshire

Re: Using Polcore mouldings / tricky?

Post by prospero »

Why not just use PVA?

Poly moulding does vary. When it's made, an agent is added to the mix which gives off gas. This forms tiny cavities to create a sort of 'crunchie bar' effect which makes the plastic sligthly porus. So actually PVA will stick up to a point depending on the pore structure. To really stick it you would need polystyrene cement which has a strong solvent and virtually welds the joint together. But with this stuff any stray bits will strip the finish.
Watch Out. There's A Humphrey About
User avatar
prospero
Posts: 11492
Joined: Tue 05 Jun, 2007 4:16 pm
Location: Lincolnshire

Re: Using Polcore mouldings / tricky?

Post by prospero »

Why not just use PVA?

Poly moulding does vary. When it's made, an agent is added to the mix which gives off gas. This forms tiny cavities to create a sort of 'crunchie bar' effect which makes the plastic sligthly porus. So actually PVA will stick up to a point depending on the pore structure. To really stick it you would need polystyrene cement which has a strong solvent and virtually welds the joint together. But with this stuff any stray bits will strip the finish.
Watch Out. There's A Humphrey About
Glimpse

Re: Using Polcore mouldings / tricky?

Post by Glimpse »

I've experimented with ordinary PVA, but even after a couple of days, the glue can remain wet. That Titebond stuff is quite weird - it behaves more like an epoxy. It seems to expand to fill joints (which is why clamping gets better results) and you have to be careful not to overglue the joints as it has a tendency to bubble out whilst curing. Having said that, any excess scrapes off quite easily with a fingernail.
233ART
Posts: 111
Joined: Tue 28 Jun, 2011 1:32 pm
Location: BERKSHIRE
Organisation: ART233, GALLERY/FRAME SHOP
Interests: COLLECTING & RESTORING OLD TOYS...

Re: Using Polcore mouldings / tricky?

Post by 233ART »

I find PU MAX POLYURETHANE WOOD ADHESIVE, from Lion Mouldings excellent for polymer mouldings.Using a very small amount,as it expands, and keeping away from the edges.Clamp the frame up over night, then the next day underpin.Perfect...
pete...
233ART
Posts: 111
Joined: Tue 28 Jun, 2011 1:32 pm
Location: BERKSHIRE
Organisation: ART233, GALLERY/FRAME SHOP
Interests: COLLECTING & RESTORING OLD TOYS...

Re: Using Polcore mouldings / tricky?

Post by 233ART »

By the way.Acetone, avaliable from the chemist, is the solvent for PU MAX...
User avatar
JohnMcafee
Posts: 1145
Joined: Sun 10 Oct, 2010 9:58 am
Location: Belfast
Organisation: Scenes
Interests: Picture Framing
Putting the world to rights
Location: Belfast
Contact:

Re: Using Polcore mouldings / tricky?

Post by JohnMcafee »

Lighter fluid is pretty good too.
"A little learning is a dangerous thing"

(Also known as John, the current forum administrator)
Not your average framer
Posts: 11013
Joined: Sat 25 Mar, 2006 8:40 pm
Location: Devon, U.K.
Organisation: The Dartmoor Gallery
Interests: Lost causes, saving and restoring old things, learning something every day
Location: Glorious Devon

Re: Using Polcore mouldings / tricky?

Post by Not your average framer »

I stick polcore with Bison plastic glue. You still have to be careful not to use too much glue, because you can't get remove it from the surface of the moulding, but the glue produces a very strong mitre.

It is a solvent based glue and can slightly soften the core of the moulding, so the glue needs to set fully over night, which will also allow any softening of the moulding to become fully hardened again.
Mark Lacey

“Life is short. Art long. Opportunity is fleeting. Experience treacherous. Judgement difficult.”
― Geoffrey Chaucer
Nicole
Posts: 81
Joined: Tue 30 Sep, 2014 9:01 pm
Location: Eastleigh
Organisation: We Frame It
Interests: Professional picture framer. Triathlete
www.weframeit.biz

Re: Using Polcore mouldings / tricky?

Post by Nicole »

Thanks everyone for your comments I will take them all on board and keep practicing. I might well take up Ricky's offer too from Mainline Mouldings for a sales visit. Thanks Ricky.
To be creative we must lose our fear of being wrong.
grahamdown
Posts: 222
Joined: Thu 16 Jun, 2011 11:43 am
Location: Hollingbourne, Maidstone
Organisation: The Village Framer
Interests: Photography, Mountainbiking

Re: Using Polcore mouldings / tricky?

Post by grahamdown »

is it worth all the effort of clamping overnight etc. do yo actually save anything?
DCS
Posts: 149
Joined: Sun 11 Dec, 2011 12:48 pm
Location: Durham UK
Organisation: Durham City Studios
Interests: Photography and Framing
Location: Durham City
Contact:

Re: Using Polcore mouldings / tricky?

Post by DCS »

We use tons of Polcore moulding on all sorts of jobs from 5x7 pictures of kids to football shirts and manage to join it using the mainline super glue and prefer to use a 10mm wedge where on wood a 12mm wedge would be better. As has been said keeping the wedges well away from the outer edges is a must to avoid spreading but we now rarely have this problem.
On occasions you will find that the depths aren't always identical so if possible make your frame from the same length.
For my sins I own and operate
http://www.durhamcitystudios.com
ComeOnYouReds!
Posts: 67
Joined: Thu 01 Apr, 2010 8:09 pm
Location: Lincolnshire
Organisation: Our house
Interests: Trying to get it right first time.

Re: Using Polcore mouldings / tricky?

Post by ComeOnYouReds! »

I use a lot of the Polcore moulding and I too have problems joining them..... at times.
I can't glue them as I have to make up hundreds at a time, so from a price aspect it is not viable. I can only underpin them and hope !!!!
The main problem I get is that the bottom surface of the moulding is not always flat especially on the narrow ones I use and the pieces "roll" on the underpinner thus leaving an open gap on the visible top face of the frame.This of course is after having cut them on my Morso where I imagine they will "roll" a bit whilst cutting. Not an acceptable result no matter how cheap the frame is priced up at.
Unfortunately this varies between batches of the same moulding so a good tight frame today can be a loose looking load of rubbish in a few weeks time.
I imagine this is a manufacturing problem but how it comes about is beyond my remit.
233ART
Posts: 111
Joined: Tue 28 Jun, 2011 1:32 pm
Location: BERKSHIRE
Organisation: ART233, GALLERY/FRAME SHOP
Interests: COLLECTING & RESTORING OLD TOYS...

Re: Using Polcore mouldings / tricky?

Post by 233ART »

Surely this is because of the lack of adhesive...


"Unfortunately this varies between batches of the same moulding so a good tight frame today can be a loose looking load of rubbish in a few weeks time."
Post Reply