Maintaining Depth at Assembly

[RobM]

Hi All,

Another fundamental one I should already know, so be gentle...

For the first time today, I struggled a little with fitting the assembled layers into the depth of the moulding. No biggie - it just meant that the points had to be inserted at an angle and therefore protrude out at an angle. See these pics.

So, I guess the easy answer is to be more selective with my backing board. Do you folk keep thin backboard for this reason? Or even vary with backboard depths?

Overall, does this problem really matter all that much? Or is considered imperative the points aren't protruding out, for fear of wrath of the Guild?

[Justintime]

"the wrath of the Guild..." or a professional finish? Maybe they're the same.
I don't think this looks very professionally finished.
Alternative techniques are available. You could use round head staples to fix the backing, which will be fired at a angle through the backing board and be flush with it. This requires the expense of a compressor and a round head air staplegun.
You could also glue and nail some mitred bare wood spacer to the back of the frame which would give you an additional 5mm of depth,or cut down some bare wood moulding offcuts to the required depth.
I don't think it's a question of your backing board being too thick (it's produced to that thickness for a reason), it's a question of your moulding not being deep enough to accommodate your sandwich. The simple solution is to extend the depth of your moulding to accommodate the sandwich.

[Rainbow]

One solution would be to staple the backboard to the moulding instead of fitting it inside the rebate (obviously a bigger piece of backboard will need to be cut). The moulding has plenty of width to enable you to do that. Equally obvious but I'll say it anyway, is to make sure the depth of the staple is sufficient to bind it to the moulding but not so long as to protrude out through the face of the moulding. Then finish off with your choice of tape to cover the staples, I prefer gummed tape. Use tabs in the normal way to hold the rest of the sandwich within the rebate.

I would use more tabs than are shown in the image, particularly closer to the corner, but not too close. Otherwise you could find the corner lifting over time.

Has the wood split? If it has, it's possibly because the tabs are too close to the top edge but it's not clear from the photo whether that's the case.

[JFeig]

You have not identified what layers are in your frame package inside the frame. Is the bottom layer 2-3mm MDF?

The basics are that 5 pounds will not fit into a 3 pound tin can.

You have two alternatives, select a frame with a deeper rebate or add to the depth of the rebate.

To enlarge the depth you can glue on strips of additional raw moulding with a bevel facing outwards to camouflage its depth. Some paint this bevel with a dark paint to simulate a shadow. Here in the US we have a product called Rabbitspace. It is made by Frametek who makes spacers. https://frametek.com/rabbetspace/
I do not know if it is available in the UK.

[JKX]

Lion sells rabbetspace, it's quite expensive for what it is and it wouldn't be difficult to fashion something similar yourself.

There is a slightly better way of botching this, use flexi tabs or semi rigis tabs (semi rigids would need a pneumatic gun), bend them over the backing board with the handle of a pair of plieres or something, then put two or three layers of tape over them. If you tried to bend those rigid tabs you'd risk breaking the glass. You'd still get those pinched points though, there should be a bit of play.

Prevention is always better than cure though, just source mouldings with sufficient rebate depth, but I think the best cure suggested otherwise is to pin the undermount as per a backing and then fix a larger backing board to the back of the farme with staples, then seal.

[technoframer]

Fix the sandwich (excluding the back) into the frame with rigids. Insert flexis between each rigid. Insert the back.

[prospero]

This is a perennial problem for framers.

Sometimes you can shave a bit off the backboard with a small plane to create a slight bevel. I use
exclusively 2.5mm MDF. I find the standard 'green gun' points not very good in this situation. They
are a tad thick and won't bend. I prefer the Mulitipoints which grip better and can be bent down it
they stick up.

For more extreme cases I keep a stock of PAR stripwood (R&H) for extending the rebate. You can glue/screw it
to the back of the moulding but on thinner stuff glue and a few staples makes short work. There is also a beveled
slip that R&H do where you can have the bevel facing outward to gain 7mm. The extension will not be too visible.

But on really narrow mouldings with a shallow rebate basically you're stuffed.

[Rainbow]

Occasionally I've created a smidgeon of space within the rebate by using a barrier sheet instead of an undermount, in which case the art would have to be attached to the top mount. Every little helps, as they say

[RobM]

"the wrath of the Guild..." or a professional finish? Maybe they're the same.
I don't think this looks very professionally finished.
Alternative techniques are available. You could use round head staples to fix the backing, which will be fired at a angle through the backing board and be flush with it. This requires the expense of a compressor and a round head air staplegun.
You could also glue and nail some mitred bare wood spacer to the back of the frame which would give you an additional 5mm of depth,or cut down some bare wood moulding offcuts to the required depth.
I don't think it's a question of your backing board being too thick (it's produced to that thickness for a reason), it's a question of your moulding not being deep enough to accommodate your sandwich. The simple solution is to extend the depth of your moulding to accommodate the sandwich.

Hi Justin. I walked right into that one, didn't I? Sloppy use of prose.

I agree, it doesn't look very professional, and would be uncomfortable sending out to a client (the example in question is one of my own pieces, so I can afford to let it slide this time).

I do like the solution of building out slightly, using spacers, so this might be what I aim to do in future. The moulding in question is quite narrow, but not unusually so, so I imagine this is a regular problem for many framers.

Thanks Justin.

[RobM]

One solution would be to staple the backboard to the moulding instead of fitting it inside the rebate (obviously a bigger piece of backboard will need to be cut). The moulding has plenty of width to enable you to do that. Equally obvious but I'll say it anyway, is to make sure the depth of the staple is sufficient to bind it to the moulding but not so long as to protrude out through the face of the moulding. Then finish off with your choice of tape to cover the staples, I prefer gummed tape. Use tabs in the normal way to hold the rest of the sandwich within the rebate.

I would use more tabs than are shown in the image, particularly closer to the corner, but not too close. Otherwise you could find the corner lifting over time.

Has the wood split? If it has, it's possibly because the tabs are too close to the top edge but it's not clear from the photo whether that's the case.

Hi Rainbow. I must admit, I'm struggling to visualise the stapling solution you're suggesting. I'm going to pursue some videos tonight to better review this option.

Good point about the wood splitting: yes, the wood did split slightly on at least one of the points. Thankfully, not too badly, but that was one of the other red flags that signalled I need to better prepare for this issue in future.

[RobM]

You have not identified what layers are in your frame package inside the frame. Is the bottom layer 2-3mm MDF?

The basics are that 5 pounds will not fit into a 3 pound tin can.

You have two alternatives, select a frame with a deeper rebate or add to the depth of the rebate.

To enlarge the depth you can glue on strips of additional raw moulding with a bevel facing outwards to camouflage its depth. Some paint this bevel with a dark paint to simulate a shadow. Here in the US we have a product called Rabbitspace. It is made by Frametek who makes spacers. https://frametek.com/rabbetspace/
I do not know if it is available in the UK.

Hi Jerome. Okay, so I've got a the glass (2mm), double mount (each only 1.5mm), the print itself (paper thin, negligible), and then the card backboard (only 3mm). The frame depth is only about 9mm, however.

In hindsight, yes, of course I should have selected a deeper frame. This is the first time I've faced this issue, so it's really a newbie problem, and I guess I didn't pay much attention to the depth when ordering.

I ought to get used to building out the frames otherwise. Mind, I like that rabbetspace product you've highlighted.

[RobM]

John, Technoframer, prospero and Rainbow - some excellent points, as well - all of which I need to spend a little time with.

Thanks for all your help.

[Justintime]

@robM the spacer comes in 12mm and 18ishmm +. To save the hassle of the backing paper going over the spacer, I usually brush some stain over the back of the moulding and the side of the spacer and just tape over the face of the spacer. I've done this with deeper spacers I've made too and it does hide it visually from the side and it looks nicely finished.

[Justintime]

It's surprisingly quick too if you've got a headless pin gun.

[JKX]

I've got a the glass (2mm), double mount (each only 1.5mm), the print itself (paper thin, negligible), and then the card backboard (only 3mm).

Well you need more rebate space still then, as there is no undermount!

The undermount should be hinged along the longest side, to the aperture mount, to open like a book, the atwork should be attached to that undermount, not the aperture mount. I know this is for yourself so you can treat it however you like but the glass/mount/undermount/backing package is standard even at lower levels of framing.

[Rainbow]

Hi Rainbow. I must admit, I'm struggling to visualise the stapling solution you're suggesting.

Do these drawings help?

[JFeig]

Hi Jerome. Okay, so I've got a the glass (2mm), double mount (each only 1.5mm), the print itself (paper thin, negligible), and then the card backboard (only 3mm). The frame depth is only about 9mm, however.

So you do not have the art attached or backed with an appropriate "backing/mounting board" made from mount board. Does this mean that the art is just held in place by friction and being the same size as the window mats? The 3mm board should be only used to support all the other layers. You have to place an engineers cap on to assure that everything fits properly to allow for expansion and contraction.

You have not identified if this project is for short term use, IE disposable as in an advertising display, or ment to be kept for a year or many years.

[RobM]

Do these drawings help?


Screenshot 2025-01-27 at 17.09.12.png

Screenshot 2025-01-27 at 17.06.03.png

They're very helpful! Thanks for putting those together.

Okay, so this makes sense now...the backboard covers the entire footprint, not just the rebate, and finished with staples. I can see this as a good solution insofar as it limits building out the mouldings with extra bits.

[RobM]

Well you need more rebate space still then, as there is no undermount!

The undermount should be hinged along the longest side, to the aperture mount, to open like a book, the atwork should be attached to that undermount, not the aperture mount. I know this is for yourself so you can treat it however you like but the glass/mount/undermount/backing package is standard even at lower levels of framing.

Hang on...John, you've highlighted my novice-ness again. It seems I've been missing a crucial part of the process. I had attached the print to the aperture mount - no undercount. Oh dear. Back to the drawing board.

[RobM]

So you do not have the art attached or backed with an appropriate "backing/mounting board" made from mount board. Does this mean that the art is just held in place by friction and being the same size as the window mats? The 3mm board should be only used to support all the other layers. You have to place an engineers cap on to assure that everything fits properly to allow for expansion and contraction.

You have not identified if this project is for short term use, IE disposable as in an advertising display, or ment to be kept for a year or many years.

Hi Jerome. I fear I'm showing myself up here now.
In answer, I have the double mount...against which I have attached with tape the art print. Behind that is backboard. I hadn't realised that I should have a separate undermount strictly for attaching the art.

This is not a limited edition print or anything, and is something I will be hanging at home for myself. that said, I need to normalise working as if every project is for a client so I need to get these standards correct now.