Necessary to affix 2 ply 100% cotton mount board to Coroplast back board?

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Kyle

Grumbler in Training
Joined
Jan 30, 2017
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Loc
Chicago
Hello,

Found the G incredibly helpful, and I was hoping to get feedback on a specific frame package containing Coroplast.

Frame package details:
-roughly 35x24 photograph cold mount to 2ply 100% cotton mount board
-metal frame
-OP3 P99 glazing
-Coroplast back board
-No mat

I'm concerned the 2 ply mount board will become wavy over time if I do not glue or somehow affix the mount board to the Coroplast back board. Do I need to glue or affix the 2 ply mount board to the Coroplast mount board?

I would greatly appreciate hearing about the experience others have on this topic! I hope everyone had a nice weekend.
 
Kyle said:
Hello,

Found the G incredibly helpful, and I was hoping to get feedback on a specific frame package containing Coroplast.

Frame package details:
-roughly 35x24 photograph cold mount to 2ply 100% cotton mount board
-metal frame
-OP3 P99 glazing
-Coroplast back board
-No mat

I'm concerned the 2 ply mount board will become wavy over time if I do not glue or somehow affix the mount board to the Coroplast back board. Do I need to glue or affix the 2 ply mount board to the Coroplast mount board?

I would greatly appreciate hearing about the experience others have on this topic! I hope everyone had a nice weekend.
Click to expand...

Welcome to the Grumble, Kyle.

I am wondering why you would mount to 2 ply rag.
We use Coroplast as a backing most of the time except for certain pieces that we feel require acid free Fome Core.

Why not mount to acid free Fome Core or 4 ply or 8 ply 100% cotton rag if you really need it?
That would help eliminate any waviness that the 2 ply would cause.
If you are cold mounting the photo, I think that if the backing is acid free Fome Core, you're good to go.
If this photo has some extreme value, then it should probably not be mounted at all.
I would also suggest a spacer between the Acrylic and the photo since there is no mat.
I'm not sure why you are not dry mounting but there might be some details that you haven't given.

I started framing in Chicago in 1969 and framed there until 1977, 4 blocks from Wrigley Field. I'm in Phoenix now.
Good luck and feel free to post more info if you need to.
 
Neilframer- thank you for your comment. I appreciate you taking the time to help me out.

I'll address the points you raised:

-I was hoping to save cost by using 2 ply instead of 4 or 8. It's worth mentioning that cost is a consideration for this frame package.
-Spacers are indeed going to be included in the frame package
-The cold mount is mostly for aesthetic reasons. I have seen many debates on the G and anywhere picture framing is talked about online regarding mounting... I have made a decision.
-My impression is Coroplast is superior to acid free foam core because of its rigidity and greater blessing from conservationists compared to foam core. I don't want to mount directly to Coroplast, though.

I hope this adds clarification on my OP. Ideally, the 2ply will not become wavey because of the Coroplast behind it. I want to know if I should use glue or something else to adhere the mount board to the back board. I will again mention an important detail- the photographic print is large (approx 35x24).

PS:
Go Cubs! Wrigleyville/area right next to the field is being totally transformed. Some big condos and a hotel going up right across the street. I would not mind being in AZ right now. The sun has not been out for the last 8 days here in Chicago.
 
Kyle said:
Neilframer- thank you for your comment. I appreciate you taking the time to help me out.
Click to expand...

I would not mount to Coroplast, I was just saying that we use it as backing on a lot of framing, but not for mounting.
The Coroplast has lines or ridges that would show thru on the piece being mounted.

We do a lot of dry mounting in a Heat Vacuum press using Kool Tack and also Mount Cor.
Mount Cor has a lower mounting temp, about 130 degrees versus Kool Tack at about 170 degrees.
24" x 35" is not really that large.
I just took in a piece today that is 46" x 70" and we have worked on pieces larger than that.

The only pieces that we cold mount are ones that are larger than our 40" x 60" press or pieces that might be affected by heat.
We use an outside company to cold mount.
They have the rollers and the size to handle it and we also do work for them so we help each other.

If you want super rigid then there is Gator board but honestly, If it was me I would just mount on Fome Core or Kool Tack and then you wouldn't even need the Coroplast.
Our shop is involved nationally with the PPFA in education, competition and certification.

The Frameshop/ warehouse where I worked was on Waveland and Halsted.
We also had a shop in Skokie.
I'm sure it's long gone.;)

Good luck with your project.
 
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I agree that mounting to 2-ply board is a bit of a hiding to nothing. If you are going to mount something,
use something with a bit more meat on it. :D Using 4-ply or thicker would be better. In fact, if you mounted
the 2-ply to another sheet of 4-ply you would have a good solid base.

As for sticking it to the backboard, Coroplast is polypropylene and tricky to stick anything to. And as my learned friend
above says, it is lumpy. Great as a backer, but a backer is a backer and ideally shouldn't be connected to the internal
contents of a frame.
 
I think it will be fine. Back in the 80's "Poster" Days it was common to mount to 2 ply board and back that to foam.
Just use 3/16 foam or Gator and attach with ATG and few small dots of glue.
 
Interesting comments. I just want to make sure I'm explaining myself in a clear manner. I don't want to have the Coroplast touch the artwork. 2 ply 100 cotton board is my mounting board. If my frame package is snug (tighter fit), can I avoid having to attach the mount board to the Coroplast? The print is a larger print. A big general concern I have is the 2 ply bending over time. Will it bend forward if it is not attached to the Coroplast?

All this talk about Gator board has me thinking... should I use Gator instead of Coroplast? Is art/2ply/Gator better than art/2ply/Coroplast? My selection criteria for frame package components includes cost (material cost and labor cost when putting together frame package), archival level, and ability to contribute to the best presentation of the artwork (i.e. no bending).

Thanks for the comments. Looking forward to hearing more comments and making a decision.
 
I think you're over thinking this.
If you're using spacers, the 2-ply/with art will probable want to bow and and "fall" into the space created by the spacers.
I've been framing for over 25 years, never found a need for Coroplast. It's a sign making material.
The fact that you and customer are OK with mounting the photo, indicated it replaceable or not of high value.
You can test it without adhering the backing.
But, I would just glue/tape backing.
 
2 ply rag expands and contracts a great deal with changes in humidity. Probably the worst choice for mounting. I would mount to "Acid free" 3/16 foam board, use a spacer, tape seal from the glazing around to the backing to prevent rapid changes in humidity. Your costs will probably be about the same.
 
What are you using to cold mount it? If it is has a plastic carrier then that's what you are mounting to, not the rag board.
 
Greg- well noted about 2 ply not being sufficient. Thank you for commenting.

IFGL- Planning to use a vacuum press. Currently looking into different models and not sure if it has a plastic carrier.

At this point, I'm sticking with Coroplast. I will list the reasons why because I want to help others that may view this thread in the future. 1. Conservators agree polypropylene/Coroplast is a good choice of material for a backing board (two exceptional sources: https://www.loc.gov/preservation/care/mat.html and http://www.wilhelm-research.com/pdf/HW_Book_11_of_20_HiRes_v1c.pdf. Quick doc search shows where authors mention the material). 2. Properties are great for picture frame backing. It's strong, performs well under temperature/humidity changes, and it's rigid.

I'm also going to use 4 ply. I feel uncomfortable using 2 ply. I don't have evidence to back up that 2 ply won't work, but my intuition tells me it's not the right choice.

I will post the results of not affixing the 4ply to the Coroplast in due time. I welcome more comments from anyone having cold mounted a large (35x24) inkjet pigment print to 4 ply and using similar frame package components (i.e. Coroplast as backing board, Nielsen metal frame, spacers, OP3 P99 glazing). Did you affix your 4 ply to the Coroplast backing board? Is this necessary?
 
If I remember correctly, the ISO deemed "Acid-Free" foam board fine to use for long time storage boxes for art including both photo prints and film as it passed the PAT tests. (Photographic Activity Test) And... since you are mounting the art - it is no longer "Archival" meaning that it is not removable from the substrate without damage. Attaching the 4 ply rag to any other substrate will most likely result in bowing as rag board (any thickness) expands and contracts a tremendous amount with changes in humidity. Coroplast does not. The Library of Congress, the Canadian Conservation Institute, and the FACTS standards agree that both rag and bleached wood pulp boards are equally acceptable for conservation framing. In rudimentary test I have made, the wood pulp boards expanded about 1/3 as much as rag boards.
 
Kyle said:
...If my frame package is snug (tighter fit), can I avoid having to attach the mount board to the Coroplast?...
Click to expand...
A snug fit would only create problems. Everything in a frame must be able to expand and contact freely; otherwise, the parts will warp, cockle, buckle, etc.

All this talk about Gator board has me thinking... should I use Gator instead of Coroplast?
Click to expand...
No, Gatorfoam is chemically unstable and could cause reactions inside the frame. Coroplast (aka polyflute, aka fluted polypropylene) is chemically stable in normal environments, which is why it is good to use in preservation framing.
 
The term "cold mount" does not describe the adhesive, and I did not find any mention of it in the posts above. Did I miss that detail? If you are planning to use a pressure-sensitive adhesive, then understand that it would be permanent and irreversible. Water-based pastes used for cold mounting are reversible, but the moisture can be problematic in mounting photographs.

In any case, using 100% cotton (PPFA Class I, FATG "Museum") board for a photograph seems like overkill, since the cotton-fiber board probably would not provide any better protection than a virgin alpha cellulose PPFA Class II, FATG "Conservation") board.

If preservation framing is required, whether this is a traditional-process photograph or a modern inkjet (giclee) print, and if it is in good condition, then I would first consider using a non-adhesive mounting technique, such as a platform mount or edge supports; second choice would be hinging; third choice (or maybe first choice if the photo is wrinkled) would be dry mounting to a pre-adhesive board, such as Kool Tack, which is thermoplastic (reversible with reapplication of heat), and it activates at only 160 degrees F.

If you are reluctant to use foam board, Kool Tack "Competition Plate" is aluminum composite material (ACM, such as DiBond, Alucobond, etc.) with the low-temperature adhesive pre-applied. If you do not have convenient cutting tools for that sort of aluminum/plastic/aluminum composite board, the company will cut it to size for you.
 
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