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Print touching glass question

Hoffmann Dovetail Joining System

Jedimagic3

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Dec 5, 2020
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15
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Oxford uk
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Hello there guys,I have a few questions I hope you can help with.
I just got back some framed prints from a local framers,I sent them to have the glass changed to u.v. glass.
When i got them home and looked at them it seems the prints are flush with glass.
Every other print I have had framed in the past has always had a small air gap between the print and the glass.
I asked the framer about this today and he said it was fine for the print to be touching the glass as it was u.v. glass and the coating on the glass would prevent it sticking.
Is this correct?.Should I get him to redo the job and use spacers to create a small gap between the print and glass?.
They are valuable prints so need to have it done right.Hoping you guys can advise me on this as this seems the place to ask.

Regards
 

Manny Costa

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Jun 12, 2020
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toronto
Similar method to the kreg machine except i created a jig on my drill press which holds the strainer on a 45 ° angle. first I cut the lengths to size and mark out the positions and drill the holes prior to joining. I use a 1/8'' bit with a countersink attached.

This photo is from

I have been in the business of milling solid hardwood mouldings for nearly 40 years. I would NEVER consider trying to mill a 5/8 wide rabbet (rebate) in a 3/4 face profile.

All wood has stress/tension to one degree or another; if you take 5/8 out of a 3/4 wide profile it is going to bow out so bad that you will be hard pressed to make a 5x7 with decent miters. On a 3/4 profile we will not put more than a 5/16 rabbet, and to do that we massage our blanks/setup to remove as much material from the outside of the moulding to counteract the material removed from the rabbet.

We have a couple custom profiles that have a 3/8 rabbet on a 7/8 face, and we deliberately prepare the moulding blanks so they're warped in the opposite direction before going through the moulder. Additionally, we are constantly fine-tuning the amount of material removed at the first bottom head, which is the outside of a cap moulding such as this, to compensate for the amount of stress in the particular batch of lumber.

Making moulding is at least as much art as it is science. At least, if your goal is to produce the best quality at the highest level of efficiency. I have visited shops where it's "gang-rip, stuff it in the moulder and ship it out". That's about as far away from what we do as you can get.
The wood stainer is great for fixing any bowing actually! In fact when i create a wood strainer i cut them just slightly over sized and i plane then down so that the fit is 100% perfect. And when screwed in the moulding straightens out. i also cut a thin spline through the 1/4" lip with a 3/32" thin kerf flat top blade to ensure that the mitered corner will not separate.
You are right that 1/8" definitely pushing it. And if tje wood is wetted it will curl. I appied a hand finish on this to avoid that. I was also fortunate that the screws did not pop through!

For 3/8" moulding the back of the frame is 3/16" to 1/4" and this is even very risky.

You are right in many ways that this is risky and the reason why i use 3/4" is because this moulding in particular came from fotiou which is my supplier for framing materials and They offer raw ash in 3/4"
If i was to mill from absolute scratch then 1" moulding is a safer bet 100%
 

Manny Costa

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Messages
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Location
toronto
Manny, that seems to check all the boxes, and is very much akin to a platform mount in theory. My only concern is the proximity of the art to the frame, with 1" being the minimum recommended for preservation grade framing. That might be able to be resolved by lining the rabbet with metalized frame sealing tape.
I think you are right to work with smaller pieces. The expansion/contraction ratios are directly proportionate with size, and a large piece might not do as well with this kind of treatment.
Only time will tell. You might want to do a little experimenting with different weight art and print papers and expose them to some extreme-ish environmental conditions. For instance, put the paper in a freezer, remove it, measure it, expose it to a hot humid day (do you have those?), and remeasure the paper to see how much it has expanded.
I'm sure you will get some additional responses. Best of luck on your research.

Edit: I just noticed you are using foam board and Coroplast. Both are considered support boards, not preservation grade mounts boards. Why not eliminate the foam board and use 4-ply rag or alpha-cellulose board instead?
i would most likely avoid doing this on larger peices for sure. Sometimes you have to lay down the rules to artists and collectors and break their hearts. But also know our limits as framers..

I am convinced that this process will not destroy the artwork... The only other alternative really is to drymount. if this was a digital print then id highly recommed dry mounting on dibond for example to an artist and to sign the backing.
But for this particular project i was dealing with a darkroom print that was signed on the back.

I also took in your advise in regards to using 4ply instead. Great point and i think ill do this continuing on!

M

As for the expirimenting.l with tempuratures, I am curious to how much artwork will expand!
 

Manny Costa

Grumbler
Joined
Jun 12, 2020
Messages
30
Location
toronto
I have been in the business of milling solid hardwood mouldings for nearly 40 years. I would NEVER consider trying to mill a 5/8 wide rabbet (rebate) in a 3/4 face profile.

All wood has stress/tension to one degree or another; if you take 5/8 out of a 3/4 wide profile it is going to bow out so bad that you will be hard pressed to make a 5x7 with decent miters. On a 3/4 profile we will not put more than a 5/16 rabbet, and to do that we massage our blanks/setup to remove as much material from the outside of the moulding to counteract the material removed from the rabbet.

We have a couple custom profiles that have a 3/8 rabbet on a 7/8 face, and we deliberately prepare the moulding blanks so they're warped in the opposite direction before going through the moulder. Additionally, we are constantly fine-tuning the amount of material removed at the first bottom head, which is the outside of a cap moulding such as this, to compensate for the amount of stress in the particular batch of lumber.

Making moulding is at least as much art as it is science. At least, if your goal is to produce the best quality at the highest level of efficiency. I have visited shops where it's "gang-rip, stuff it in the moulder and ship it out". That's about as far away from what we do as you can get.
@Shayla @David Waldmann I just realized i made an error! The rebate was cut to 1/2" not 5/8" 😂 sorry about that!
 

David Waldmann

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Would you please share more details about your milling process with me, especially how you describe setting up the blanks?

My mainstay is an ~3"x 13/16" shadowbox, with a rabbet 5/16" deep. My substrate is African Mahogany with veneer pressed to the backside and lip and then another trim profile added to the cap, which is done so after milling the rabbet.

I had been milling the substrate with the gangrip and 5 head molder in the past but you know about how well that works plus the complications of setup; I mill only a few hundred LF at a time. I am now setting up blanks by jointer/planer/thickness sander and then removing the rabbet with the shaper. This keeps my proceess much more nimble than fussing with the moulder and I'm having very good results, but I'm still striving for the truest stock possible.
We find that, for a cap type moulding, removing as close to similar amounts of material as possible from each side of a straight blank is the most reliable way to end up with straight stock when complete. The other option, as I alluded to, is to create a warp in the opposite direction so that as the rabbet material is removed the the stock "warps" it actually ends up straight.

It's a bit hard to describe in writing. Feel free to give me a call if you like. Although please wait until next week as I am covering for a key employee this week and am busier than a one-armed paper hanger.

By the way, we do lots of very short runs (less than 100 LF) regularly and find that setup is rarely an issue. I would also be happy to discuss our methods and tooling that allows us to do that.

I don't recall where you're located, but you would be more than welcome to come take a tour of our shop if/when you're in the area.
 

David Waldmann

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@Shayla @David Waldmann I just realized i made an error! The rebate was cut to 1/2" not 5/8" 😂 sorry about that!
Well that's a whole lot better, but still way past my comfort zone. I would refuse to make a profile like that without a waiver that included not only liability for quality, but also disassociating our name with the product.
 
Hoffmann Dovetail Joining System

CHolt

CGF, Certified Grumble Framer
Joined
Nov 20, 2012
Messages
158
We find that, for a cap type moulding, removing as close to similar amounts of material as possible from each side of a straight blank is the most reliable way to end up with straight stock when complete. The other option, as I alluded to, is to create a warp in the opposite direction so that as the rabbet material is removed the the stock "warps" it actually ends up straight.

It's a bit hard to describe in writing. Feel free to give me a call if you like. Although please wait until next week as I am covering for a key employee this week and am busier than a one-armed paper hanger.

By the way, we do lots of very short runs (less than 100 LF) regularly and find that setup is rarely an issue. I would also be happy to discuss our methods and tooling that allows us to do that.

I don't recall where you're located, but you would be more than welcome to come take a tour of our shop if/when you're in the area.
I appreciate this.

SOP is to mill off evenly from both sides of the board and come up with the straightest blank possible but sometimes they just won't cooperate. I do already face any crowned side toward the knife but intentionally setting up the blanks to bow is interesting.
I'm finishing some pieces tomorrow and I will post or PM some pictures.
I'm overdue for an East Coast trip but the pandemic has everything off the hook for now.
Mahalo, Aloha
 
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