Underpinning and gesso

Get help and framing advice from the framing community
Post Reply
RobP
Posts: 17
Joined: Mon 04 Sep, 2017 2:49 pm
Location: North East England
Organisation: Garden House Picture Frames
Interests: Countrymatters

Underpinning and gesso

Post by RobP »

Hi
I have not been framing that long and have glued and fixed all frames up to now. However as things were going well I have bought an underpinner.

I gesso, bole and guild some frames. My underpinner advises against using glue and when I paint the bare wood direct this is fine, however I am concerned that if the frame is just underpinned then as the frame is moved there will be flex and the gesso and bole will crack over the joint.

Am I over thinking this problem or should I use a little glue to hold it all together?

Many thanks
Rob
Not your average framer
Posts: 11014
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: Underpinning and gesso

Post by Not your average framer »

I don't think you are over thinking the problem at all, in fact I do plenty of hand finished frames and I aways glue and underpin every frame. It seems very strange that the manufacturer of the underpinner would suggest otherwise. I can't see why they should suggest that - most strange!
Mark Lacey

“Life is short. Art long. Opportunity is fleeting. Experience treacherous. Judgement difficult.”
― Geoffrey Chaucer
vintage frames
Posts: 1349
Joined: Tue 12 Jun, 2012 6:05 pm
Location: West Wales
Organisation: https://www.dermotmcardle.co.uk/
Interests: Making picture frames
Contact:

Re: Underpinning and gesso

Post by vintage frames »

Hi Rob. I've made hundreds of gilded frames over the years and like you now, have been using an underpinner to join the corners. All very fine if you want it to happen very quickly. But then after I'd spent how many seconds joining the frame, I went on to spend several weeks gilding and finishing the frame. And seeing that an underpinned frame is still inherently weak at the mitres, it didn't seem such a lot of sense to keep using the underpinner. Carefully using a good PVA will of course strenghten the joint but you really can't beat a strapped frame with a few well placed framing pins through each mitre.
Another thing to look out for is wood shrinkage after gesso. If you havn't spread the glue evenly over the whole cut mitre, then the wood can shrink to show a visible crack in the dried gesso, even though the joint is secure.
So, pity about the underpinner but I'm sure you'll find it useful otherwise.
Affordable Gilding Course for Professional Framers-https://www.dermotmcardle.co.uk/
https://www.instagram.com/dermotmcardle/
Not your average framer
Posts: 11014
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: Underpinning and gesso

Post by Not your average framer »

I've not had any problems underpinning frames for hand finishing, but I don't use real gesso . I use quite a bit of Chalky emulsion mixed with an approximately equal amount of quite thick acrylic paint. I think that this has a bit of elasticity / flexibility, so perhaps it will not be quite so prone to cracking. I do deliberately use the chalky emulsion, mixed with some cooked up starch paste to produce a cracked gesso finish at timrs.

The results with the cracked gesso finish can be somewhat variable and probably depend upon the thickness of the coat, how fast the coat dries and other variabilities. If you blast it a lot with a hot air gun and over do it a bit, the surface can be made to blister and form the basis for other effects, including scraping the top of the blaster and adding a contrasting top coat followed by distressing the overall finish.

Pete Bingham made the blistered and disressed type finish look easy, but myself I have not found it at all easy. He also got a lot more consistancy than I ever did. Fortunately, I don't get customers wanting this sort of finish, so I guess that's just as well. The blister type finish is one that I prefer to do with candle wax, which I find more controlable.

Cheap birthday cake candle's are nice and easy! The wax comes off very easily, complete with any paint over the wax, with the careful use of a hot air gun. There is a bit of a knack to it, but it does not take much practice, before you've got the knack. I usually remove any wax residue with a rag and a little white spirit. I think that it look's great with a final warm grey wash to finish the effect.
Mark Lacey

“Life is short. Art long. Opportunity is fleeting. Experience treacherous. Judgement difficult.”
― Geoffrey Chaucer
RobP
Posts: 17
Joined: Mon 04 Sep, 2017 2:49 pm
Location: North East England
Organisation: Garden House Picture Frames
Interests: Countrymatters

Re: Underpinning and gesso

Post by RobP »

Thanks for your advice, that is really helpful.

I think the manufacturers guidance is so that you dont get glue in the v-nail slot. So if I am careful it might be ok. I certainly dont want to go to all the work of gesso and gilding only for there to be a crack on the join. I will have a bit of a play around but perhaps on gesso frames the old technique might be best.

Really useful about putting glue on evenly too, i had not thought of the shrinkage, I had thought of putting glue on the top half of the miter only but that may cause me more problems in the long run.

Really helpful advice, thanks for taking the time to reply.

I will see how I get on.
Rob
Not your average framer
Posts: 11014
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: Underpinning and gesso

Post by Not your average framer »

Dermot's advice sounds good to me, particularly on thinner mouldings, where the bent section of the underpinning wedge is cutting through across the grain of the wood within the moulding and creating a potential weakness in a location within the frame wher strength matters. I think that using traditional pins to cross pin the corners (as Dermot suggests), does not weaken the wood at the corner to anything like the same extent.
Mark Lacey

“Life is short. Art long. Opportunity is fleeting. Experience treacherous. Judgement difficult.”
― Geoffrey Chaucer
User avatar
prospero
Posts: 11492
Joined: Tue 05 Jun, 2007 4:16 pm
Location: Lincolnshire

Re: Underpinning and gesso

Post by prospero »

The main strength of a join is the glue. The v-nails should be thought of as internal clamps that hold the joint in place
and squeeze the faces together. After the glue is set they continue to provide a 'failsafe' fixing should the glue fail for any reason.
Many cheapo frames do use v-nails only. The join may feel secure but will gradually gape, especially if it's of any weight and
is hung. These are made to a price, not a quality and this is a half-arsed shortcut. :|

This time of year if you store your moulding is an unheated area it's a good idea to leave it in a place with 'living room'
conditions for a few days prior to joining. This is especially relevant to wide mouldings and those of softwood (pine).

Never let anyone tell you that you don't need glue if you underpin. :evil:
Watch Out. There's A Humphrey About
User avatar
Steve N
Posts: 2992
Joined: Sat 21 Jul, 2007 2:32 pm
Location: Somewhere Staple Hill Bristol
Organisation: Frontier Picture Frames ltd
Interests: Walking our retired Greyhound,art, falling asleep on sofa in front of the telly
Location: Now in Bristol
Contact:

Re: Underpinning and gesso

Post by Steve N »

I think you all got the wrong end of the stick, I think it means moulding with a gesso finish already applied to the length of moulding which you cut and join yourself, if you get glue on the surface,the moisture from the glue could have an effect of the surface of the gesso
https://www.wessexpictures.com/COMP012.html
Steve CEO GCF (020)
Believed in Time Travel since 2035

Proud to sell Ready Made Frames
http://www.frontierpictureframes.com
http://www.designerpicturemounts.com/
Not your average framer
Posts: 11014
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: Underpinning and gesso

Post by Not your average framer »

I would say that if you get glue of the surface of the moulding, that it may reduce the adhesion of the gesso to the moulding. Therefore it would be good to wipe of any glue that has got onto the surface of the moulding and sand the surface to ensure that the gesso can adhere to the bare wood of the moulding.

If the surface of the moulding has been sealed and therefore made waterproof by any residual PVA glue, then the gesso which contains a water based glue cannot penetrate the wood used to produce the moulding and properly adhere to the moulding. If the gesso does not have an adequate bond to the base moulding, it matters not if everything applied to the gesso is firmly bonded to the gesso, when the gesso does not have a solid bond to the moulding.
Mark Lacey

“Life is short. Art long. Opportunity is fleeting. Experience treacherous. Judgement difficult.”
― Geoffrey Chaucer
vintage frames
Posts: 1349
Joined: Tue 12 Jun, 2012 6:05 pm
Location: West Wales
Organisation: https://www.dermotmcardle.co.uk/
Interests: Making picture frames
Contact:

Re: Underpinning and gesso

Post by vintage frames »

As regards joining a frame to be further gessoed, it's essential to use a good PVA wood glue. Titebond 111 is your only man. You can be as messy as you like with it and if it does squish out over the mitre, that does not matter. Use a damp cloth to clear it away otherwise the glue will harden to little beads that are impossible to remove. I know you're now thinking that this is waterproof glue and will seal and prevent the gesso sticking. Well it doesn't. You'd need a fairly thick film of excess glue to have any affect on the gesso.
The main thing is to make sure the whole cut face is well glued. You'd be amazed at the force dried gesso can exert on the surface and contours of the wood.
For anyone who does gesso wood and has experienced the annoying crack that appears on the dried surface, the best remedy is to sand back the gesso as usual and then make some gesso putty and squish that into the exposed split. The crack should be pre-wetted first and to make gesso putty, drop some warm RSG into a small heap of whiting. Bind it together to make a small ball of putty, rolling it around in the whiting and ignore the mess until you have a lump you can usefully use. After that has dried you can finsh sanding and go on to polish the gesso.
Affordable Gilding Course for Professional Framers-https://www.dermotmcardle.co.uk/
https://www.instagram.com/dermotmcardle/
RobP
Posts: 17
Joined: Mon 04 Sep, 2017 2:49 pm
Location: North East England
Organisation: Garden House Picture Frames
Interests: Countrymatters

Re: Underpinning and gesso

Post by RobP »

Dear All
Thank you for all your advice and tips. I have alot more to think about now! But I will proceed with more knowledge and confidence.

I think I need to raid the off cuts box and try making a few chevrons first but will bash on and hopefully make a few good frames!!

Thanks
Rob
Post Reply