Fixings for Heavy MDF Art in Tray Frames

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123hackney
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Fixings for Heavy MDF Art in Tray Frames

Post by 123hackney »

Hi framers 
I am making a tray frame which is 180cm x 125cm.  It is for a 12mm thick painting on a panel of Mdf. It will have a 1cm shadow gap all around in a wooden tray frame.
I just wanted some advice about fixings to use for something this heavy. 
I make these regularly 1m x 1m. I use 7mm x 38mm batons which I adhere with Gripfill to the back just in from the edges of the painting to build it out. I then screw in from the back of the tray frame into the batons and through into the painting itself.
I then use strap hangers and I attach them in the same line as the earlier screws where I can screw through the tray frame, batons and into the mdf painting as I feel this is going to make it most secure. 
I was planning to do the same with this larger one but I don't feel it's enough for the weight of it? Especially since the fixings would be less than 1cm from the painting edge. 
Should I build a brace bar with the batons and attach the fixings just directly to the mdf painting itself (through the baton) and the frame is just purely decorative but not bearing any weight?
What fixings would be good for this?
Thank you for any help.
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Re: Fixings for Heavy MDF Art in Tray Frames

Post by Not your average framer »

Hi Kitty,

This is largely a judgement thing. Obviously you are the framer on the spot doing this, so it's largely your call. The fact that you are asking these questions is illustrating the fact that you have your own concerns about if you have done enough in this particular case, so it makes sense to take such actions as to adress your concerns. it is perfectly normal for framers to trust their instinct and address their concerns, it's what we all are doing when situations like this arise.

Many tray frames mouldings are made from Obeche and that is quite a large frame. Obeche is not necessarily particularly a wood known for it's structural uses when used for larger frames and in this case, this is another judgement thing! How strong and rigid is this frame? If it is able to be flexing to much it might be able to cause the mitred corner joints to fail, perhaps some sort of sub-frame to add some extra stiffness to the obeche frame may be an appropriate way of stiffening it up a bit.

Personally, I would not be wishing to screw in to the frame and the painting. I would like it to be obvious to anyone re-framing the painting at a later date, which screws are securing the painting into the frame and which screws are securing the sub-frame to the frame. I hope this all makes some sense and that you find this helpful. I expect that others will have useful and helpful things to sat about this as well.
Mark Lacey

“Life is short. Art long. Opportunity is fleeting. Experience treacherous. Judgement difficult.”
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Re: Fixings for Heavy MDF Art in Tray Frames

Post by 123hackney »

Thanks Mark.

Its definitely the heaviest thing I've framed to date so questioning my own judgement!

That is a very good point regarding the screws. I had previously been advised to not screw into the mdf as the screws wouldn't hold well and therefore was just securing the painting to the subframe with an adhesive (gripfill) and then screwing the frame to the subframe. I since have decided to use longer screws that will go all the way into the painting too. So really the screws are only securing the frame to subframe. The fact that they go all the way into the painting is just my paranoid secondary security device.... or the gripfil is, depending on how you look at it.

Do you have any advice for fixings that could be used for something as large as this? I estimate it will be about 25kg

Many thanks

Kitty 
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Re: Fixings for Heavy MDF Art in Tray Frames

Post by Not your average framer »

Hi Kitty,

25kg is quite a lot of weight to hang on normal wall hook, some walls are not structurally going to give enough support to adequately retain normal wall hooks with that kind of weight. If the walls are older, weaker plaster the fixings could give way under the load, or alternatively this may also be a problem if it a more modern building with plaster board walls. I am thinking about having wall hooks screwed into something more solid to be sure that this is going to be adequate. I would be reluctant to supply the painting back to them with anything like D rings, incase this could be taken as justification for stringing the picture and hanging it on a weak and flimsey hook. I'm thinking about supplying but not fixing some reasonably subantial mirror plates. There's no point in fixing the mirror plate to the frame as the customer needs to identify secure places of the wall suitable for fixing the mirror plates, before deciding where to position the mirror plate on the rear of the frame.

Fixing the batterns to the artwork with gripfill, is making me wonder about this. Gripfill is an impact adhesive and impact adhesive can be less cure when bearing weight in shear. Not only this, but is the gripfill the best thing to be using to carry that sort of weight when adhering to a material like MDF, the layers within a sheet of MDF don't seem to be particularly strongly bound together and I'm wondering if the area used to bonding to the batterns is large enough. Impact adhesives only bond to a surface, they do not penetrate below the surface, so is the width of the batterns going to provide enough area to create a sufficiently load bearing bond without the MDF delaminating under the load. I hope that you realise that determining how secure this is likely to be under load involves some measure of guesswork, Have you already glued the batterns on to the painting,or is there still a possibility to use wider batterns. I honestly don't know if I am over thinking this, or whether the width of the batterns you have already suggested are quite adequate, again this is a judgement thing and I honestly don't know the answer.

I think that you are going to think about this and see how solid this needs to be.
Mark.
Mark Lacey

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Re: Fixings for Heavy MDF Art in Tray Frames

Post by 123hackney »

Thanks Mark

I haven't glued them down yet no. But I have done this with all the smaller ones and they've held up fine.

I asked the advice a long time ago on the framers only page on facebook and it was about 50/50 whether people screwed into the mdf or glued the mdf. 2 people recommended gripfil. 

So I'm now doing both. Which maybe is a little mad. But I'd have thought if it's screwed in and glued in its pretty much foolproof?

I also think now I've started discussing it that it doesn't particularly matter too much about the gripfil strength if I am going to screw the fixings directly into the mdf? As the painting would be taking the load not the frame?

Hmmm

I didn't get into framing for the heavy duty / large scale carpentry side of things! I have just found myself here!  

Thanks for your time on this anyway Mark.
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Re: Fixings for Heavy MDF Art in Tray Frames

Post by prospero »

I've been thinking about this and I've just had an epiphany. :D

Use fairly hefty batons on the back, maybe 19x70mm PSE softwood. These would be glued only, with PVA and
clamped firmly while the glue sets. You would need to cushion the clamps where they bear on the paint surface.
This creates a large glue area that will not fail if you use plenty of glue and plenty of clamps.

(It would have been better if they were fixed before the paint was done. :roll: )

Here's the clever bit.... Screw a length of PSE (12mm think) along the back of the painting, overlapping the
top rail on the inside about 12mm. This would not encroach on the area where you the outer frame would go.
Then make another identical length that is fixed to the wall. This wall baton will need two little 'catchers' - mirror
plates with the one-hole end pointing up so the painting can be dropped on top. All the weight will be spread along
the wall baton and it will not move forward because the little plates will prevent that.
The outer frame will then play no part in supporting anything.

I've used this method on large mirrors and the like. Fixing the wall baton is easy. For a solid brick wall I use Hammer Fixings.
Simply pre-drill the holes (5-6) and carefully measure where it needs to go on the wall. Drill one of the middle holes and bang
in the first fixing, but not fully. This allows you to swivel it and get it dead level. Then drill another hole. Hammer Fixings are
easy because the holes are the same size and you can use a masonry bit the same size as the per-drilled hole in the baton and
poke it though the hole in situ.
For a cavity wall the principle is the same, but there would be a bit more fiddling about because you would be using expanding
fittings which would need to be set in dead register to the holes in the baton.

That probably all sounds like gobbledegook. I will clarify if need be... :lol:
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Re: Fixings for Heavy MDF Art in Tray Frames

Post by Not your average framer »

I've never heard of gripfill being used by framers before, so I don't know if it is the best choice, or not. I don't have any concerns about PVA glue, because every framer uses it without any issues. I suspect that the PVA would penetrate in to the MDF and add strength to the bonding between the layers within the MDF, but that's only a guess. As a matter of interest, does anyone use gripfill as an adhesive for sticking things like this and is this something that I would find satisfactory uses for in similar situations as items need to be framed, or should I leave well alone?
Mark Lacey

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Re: Fixings for Heavy MDF Art in Tray Frames

Post by 123hackney »

Hi Prospero, thanks for this.

Yes I pretty much understand your suggestion, thank you! but do you have a link to the mirror 'catches' you are referring to? I just can't picture this part.

Re the hefty size batons.. The problem I have is I only have a depth of 10mm maximum for the batons to fit in the tray frame profile we have gone with. (Which is already cut and prepped)
I wasn't able to find any wood easily that would be so wide.

I am overthinking all of this so much I have gone a little cuckoo. But part of me thinks that the surface area of the adhesive (currently 40mm) is not hugely important if I am going to be screwing into the mdf in multiple places anyway? I feel like the weight will be displaced around the piece well enough for it not to be a problem. But do say if you don't agree!

I am sure that I can source wood thats 10mm x say 70mm if I really need to...

As an alternative fixing solution - what do you think about just screwing heavy duty fixings into the area where the frame, subframe & mdf all meet? All the way through about 8mm into the painting? I was thinking this would be the strongest part. I felt that 23kg was v heavy but many people are now telling me 'ahhh just stick some heavy duty d rings on there' and there are many that carry this weight.

Thanks again.
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Re: Fixings for Heavy MDF Art in Tray Frames

Post by prospero »

23 kg is a lot of weight. The weak link would be the wall fixings. The more you have, the less strain on each one.
With a horizontal baton you can add as many as you like.

The little 'catchers' I mentioned can be anything that prevents forward movement of the frame baton from the wall baton.
I use little mirror plates because they are handy. It's a variation on the time honoured 'French Cleat' method used from mounting
cupboards to walls. The trad way is the cut 45º angles on the batons so they lock together, but that involves extra machining.

I'm all for keeping things simple.

Yes, the slightly tricky bit would be sourcing 10mm thick timber, but not impossible. DIY stores
often stock a range of 'stripwood'. If no joy there is bound to be a timber yard that could mill some up for you. :D
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Re: Fixings for Heavy MDF Art in Tray Frames

Post by prospero »

A picture paints a thousand words.....
french cleat.jpg
That's the traditional way. The top piece would go on the painting, bottom piece on the wall.
My way uses two square pieces. The catchers go on the lower piece - slightly overlapping the upper edge.
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Re: Fixings for Heavy MDF Art in Tray Frames

Post by Richard Photofusion »

I'd go for french cleats, with the painting PVA'd (Titebond original) and (stainless steel) screwed.

If depth is an issue, https://www.lionpic.co.uk/r/25506/Z-Bar-Cleat-Strips could be your answer.
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Re: Fixings for Heavy MDF Art in Tray Frames

Post by Not your average framer »

I rarely use french cleats, but they are my go to answer when all else fails. If I need french cleats, I always make my own, as it's so quick and easy with a band saw. My band saw works really well as long as it is not a long cut in a really hard wood and then the motor gets hot and the band saw gets really slow and eventually trips out. I tend to lose interest when I need to make long cuts in a really hard wood and use the table saw, or the slidind mitre saw instead. It's more meesing around setting thngs up, but bench top band saws have their limitations.
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Re: Fixings for Heavy MDF Art in Tray Frames

Post by Not your average framer »

Of course, the great thing about french cleats is if you have the necessary resources to make your own, they are only going to cost you the cost of the bits of wood. Also if the wood comes out of the waste bin, it's only a little bit of your time instead. Buying a band saw was one of the best things that I ever did. I'm guessing that I may have perhaps bought my first band saw, before I had the stroke. I'm now on my second band saw and it has made a tremendous difference to the things which I can still now be capable of since my stroke.

I would gladly recommend getting a decent band saw to anyone. It's the most used saw that I have and I have plenty of different types of saws. It's very controllable, produces a very clean cut surface and needs the minimum amount of cleaning up the cut for a perfect finish. It works amazingly well on Obeche and Pine, but you have to be nice to it and take things a bit slower when cutting through Oak. I've also got a bench top belt sander, which I use mostly with a fine abrasive belt and a quick touch of a cut made on the band saw and you've got a first rate professional finish. Job Done!
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Re: Fixings for Heavy MDF Art in Tray Frames

Post by 123hackney »

Ah ha. Gotcha. Yes I have been thinking about this sort of thing originally. I used to use these when installing headboards in another life. But as you say was unsure what to do about creating this angle.
The metal french cleats I had found before were all v pricey but I think maybe this is the answer for me at the moment. But I'll investigate your method a little further first Prospero.
Thanks so much. I really appreciate the level of detail you've all gone to.

p.s. I'm a way off from a band saw Mark. I mainly work from behind my sofa in the sitting room. One day.....
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Re: Fixings for Heavy MDF Art in Tray Frames

Post by Richard Photofusion »

Not hard to cut with a circular saw on a track - pick a sunny day and cut a batch outside. I've done them on a little battery powered ryobi saw on a couple of occasions, ripped down a left over half sheet of 18?mm mdf into future use pieces.
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Re: Fixings for Heavy MDF Art in Tray Frames

Post by 123hackney »

Thanks Richard. Yup I have a circular saw, will keep in mind. Found some 10mm x 68mm that will suffice, so all good.

So these cleats... I'm going to get 450mm ones and put them either side across the top of the frame and screw them in to the area where I can screw all the way in through the frame, subframe and into the mdf. This is quite a narrow space 20mm so there will be just about 10mm of MDF above the screws. I don't think this is an issue is it?

They say they take 3kg per screw hole. 9 on each side for 450mm. That will hold 54kg in total. (Piece is 23kg)

I'm going to fix some of these security locks at the bottom https://www.lionpic.co.uk/p/10369/3-T-S ... ames-1-bag

Any errors in my plan? (Other than throwing cash all over the place)
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