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Author Topic: Too much coating?  (Read 2664 times)
rgvsdigitalpimp
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« on: December 10, 2012, 10:42:16 PM »
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Hey all quick question.  I just recently switched canvas paper to LexJet Sunset Reserve Bright Matte Canvas and also got some Sunset Satin Coating.  Since I've only using BC's Lyve and Timeless I wasn't sure how many coats to put since this finish is a little thicker when dried than the Timeless.  I have coated a couple pictures with no problem at all.  I just finished stretching a 16x20 that seems to feel as if I coated it too much.  Almost feels like cardboard hard and difficult to fold when doing corners.  I also noticed that with every fold I made, it was cracking as if not enough is on there.  Is it possible to overcoat and cause cracking?  I always believed it was undercoating that caused this.  If it's undercoated, why does it feel as if I sprayed 10 layers of coating on it? 
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bill t.
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« Reply #1 on: December 10, 2012, 11:06:56 PM »
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For a data point, try stretching an uncoated piece of scrap canvas.  Then try a piece with two coats, etc.  It seems like a PITA to do tests like that, but in the end you can be truly confident about the durability of your product, without doing unnecessary work on a routine basis.

When I tried the Sunset coatings I felt they didn't have anything even close to the almost magical leveling qualities of Glamour II.

Since I only mount canvas, my sole criteria for "enough coating" is to go one coat past the point where I don't get any color at all on a clean cotton glove when I rub it hard against the dried surface of a medium density print placed on a hard surface.  A wrapper would have to include a cracking test.  When I was doing wraps, my impression was that I had the least cracking and abrassion problems with thin coats wrapped in the time frame of 24 to 48 hours after coating, when the coatings had set up pretty well but were not completely hardened.
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rgvsdigitalpimp
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« Reply #2 on: December 10, 2012, 11:21:40 PM »
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Thanks for the quick response, Bill. I actually coated up and down then sideways with heavy coats about 2 or 3 times.  So it was pretty coated. 
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Colorwave
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« Reply #3 on: December 11, 2012, 12:11:45 AM »
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Odd.  I made the switch from BC to Lexjet about six months ago, and am using a rather heavy application their coating, applied via HVLP sprayer.  I don't find it to be cardboard-like, although it is a little thicker than the BC canvas.  Curiously, I have absolutely no cracking issues whatsoever, and find that there is much better ink adhesion and overall durability with the Lexjet Sunset Reserve/Sunset Coating combo.  Perhaps it is an ink difference?  I use HP Vivera ink.  Did you let the canvas dry well before coating?
« Last Edit: December 11, 2012, 12:14:21 AM by Colorwave » Logged

rgvsdigitalpimp
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« Reply #4 on: December 11, 2012, 07:44:23 AM »
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Color, the weird thing is that I've already stretched a couple of prints with this combo and have had great results.  All of a sudden it seems like these couple prints I just tried have all started cracking on me.  Only thing I can think of that changed was the weather.  It dropped to about 45 degrees F. And since my spray room is in my garage, a bunch of cold air was blowing into the garage and into my spray room.  Would this cause any change to the prints?
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Colorwave
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« Reply #5 on: December 11, 2012, 11:21:45 AM »
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Since I'm in Hawaii, I'm not a good person to ask about cold weather spraying. That could be the issue, but past experience with other acrylics in California in cold weather mainly affected drying time.  If the raw material was in your garage the whole time and it got below freezing at any point, though, then that almost certainly is the problem. Most waterborne products suggest application when over 50 degrees, so if the liquid didn't get too cold, emperical testing in a warmer environment will tell you a lot. At the very least, I'd wait to stretch until it is warmer.
« Last Edit: December 11, 2012, 01:24:35 PM by Colorwave » Logged

John Nollendorfs
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« Reply #6 on: December 11, 2012, 01:21:51 PM »
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If your spraying environment is cold, bring the prints into a warmer environment to cure. Sounds like you are applying the coating too heavily.
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rgvsdigitalpimp
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« Reply #7 on: December 11, 2012, 01:24:25 PM »
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John I got off the phone with LexJet this morning and they confirmed that I was overcoating.  They recomment two coats with about an hour or two in between the coats.  And that should be all I need.  I was just used to spraying so much of the Timeless coating.  So I was trying to coat it over and over
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Colorwave
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« Reply #8 on: December 11, 2012, 01:30:03 PM »
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I spray significantly more Lexjet coating than I did Timeless when I was still using their coatings.  I find it very flexible and extremely durable.  I really think that temperature is more an issue than coating thickness.  Acrylics soften in warmer temperatures, so I suspect that it was probably not well cured and too brittle when you tried to stretch.  Granted, a thinner coating would be better cured faster in cold weather, but to say that it is the coating thickness itself that is the problem is a bit of a red herring, IMO.
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philbaum
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« Reply #9 on: December 25, 2012, 03:25:29 AM »
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After reading about it in a post on this forum, I've been trying Miniwax Polyurethane over Epson pigment.  On one canvas, i had taken too long to finish spreading it, so had to give it a second, then a third coat to get rid of a holiday area, sort of.  I noticed the thread texture of the canvas filling in and it was difficult to stretch and fold it around corners - as you suspected for too many layers.  However i did not have any cracking of it.  I've still been using polyurethane as a coating, but only 1 coat.  very self leveling and UV resistant.  9 years ago i put polyurethane on my outside hardwood door, exposed to sunlight and rain.  No checking or UV damage in that time.  I use a foam brush to spread it. 
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rgvsdigitalpimp
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« Reply #10 on: January 05, 2013, 12:35:57 AM »
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Oh what a day.  Had couple big prints to have ready for the weekend for some wedding expo going on.  Well ended up I was overcoating with Lexjet on Lyve canvas.  Canvas was feeling real hard to manage and would crack at every fold test I made.  This was with 3 semi heavy passes (left-right, up-down, then diagonal).  So re-printed and did was lexjet tech said . . only one heavy pass is all thats needed.  Did that.  Waited for picture to dry and sure enough cracking on every fold test.  And not minor cracking BAD cracking.  So I saw I had some timeless left over from last batch.  Sprayed that on like usual.  And guess what?  No cracking.  Ugh.  With all these headaches and stress coming from BC's products (bubbles with too much coating, cotton seeds on the canvas in all areas of the canvas) I think I'm done with BC.  Sorry just venting

Edit: Well after letting the Timeless fully dry I went back out and did a fold test . . cracking.  Clients need these prints tomorrow.  Wow what a weekend. 
« Last Edit: January 05, 2013, 01:20:30 AM by rgvsdigitalpimp » Logged
KenBabcock
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« Reply #11 on: January 05, 2013, 11:24:04 AM »
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To get the prints out the door for your client tomorrow I would suggest spraying some water on the back of the canvas where you're folding and using a hair dryer on low to subtly warm up the canvas.  This should make it softer and more pliable to prevent the cracking.

Another option is to grab a can of Krylon Preserve It from a craft store and spray the canvas with this as a topcoat.  I've used gloss and I guarantee it won't crack when folded.  It is super glossy though, but you have the option of spraying a final topcoat on AFTER stretching with the Krylon applied to finish the canvas with the desired glossiness.

Both methods will work and I have used both in the past when in a serious time crunch.  Wouldn't recommend it as part of your workflow (mainly cause it's a PITA), but they will work to get your canvases out the door in time for your client's needs.
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rgvsdigitalpimp
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« Reply #12 on: January 05, 2013, 01:22:37 PM »
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Thanks for the tips, Ken.  Gonna try the water and blow dryer method right now.  Sure enough as I'm spraying this large 30x40 (3rd time I print it because of cracking) I notice 3 dark black canvas cotton seeds right on the part of the image thats the sky and clouds.  I'm out of canvas.  No more to reprint with.  Oh brother . . . I'm so done with BC
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KenBabcock
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« Reply #13 on: January 05, 2013, 01:37:14 PM »
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Give the canvas a few minutes to absorb the water before folding.  And when you do fold the corners take it slow.  I find a fast pinch will sometimes cause it to crack.

That really sucks about the cotton seeds.  Always happen right when you're out of canvas and in the lightest area of the print.  Never fails.

Good luck!
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rgvsdigitalpimp
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« Reply #14 on: January 05, 2013, 02:56:13 PM »
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KEN!  You are a LIFE saver!  Thank you so much!  Wow the water and hair dryer trick softened the canvas so much it was almost fluid like.  I handled the corners gently and not ONE crack!  Whew . . what a close one.  Ken so here's my question.  It has been a little cold here in south Texas (45 degrees F) and I work in my garage which faces south.  So I do get a lot of cold air coming into the garage when I've been recently working with these past couple prints.  I did a lot of prints with same canvas and same coating during Christmas time (weather was about 80 degrees) and the only difference is that it's cold now.  It seems to stiffen up my canvas when I'm working in the cold environment.  Although last night I brought in a print to leave in the house to see what the difference was and of course it was easier to work with but still cracked on fold test.  Would the cold have anything to do with my crack corners?
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KenBabcock
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« Reply #15 on: January 05, 2013, 04:25:27 PM »
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Great to hear you can deliver your canvases on time as promised!

The cold definitely affects your coating and corner cracking problem.  I'm in Canada and all winter long I have that problem with the cold unless I use Epson Exhibition Gloss canvas, which folds and stretches like a dream but costs quite a bit here ($159 + 13% tax for a small 24" roll).  Right now where I am it's -15C or about 5F for you and it's not even really cold here yet, so you can imagine the problems here in Canada when it's cold LOL.

I've also found the adhesive inkjet receptive coating on canvas can vary from batch-to-batch with the same manufacturer.  I've used canvas that stretched and folded beautifully.  Ran out of canvas so switched rolls with one already here from the same manufacturer, although a different batch number, and it was horrid.  Very stiff and it was like folding cement.  Of course it cracked like crazy, the stiff batch that is.  I've suffered that from a couple of different manufacturers and the only element that changed was the batch number off the canvas.  Some of these guys have to get it together and start producing the receptive coating in a more controlled manner.  Had the same problem with rubber when I molded it many years ago.  The supplier would change the formula ever so slightly and we would produce nothing but scrap because the rubber was so dry.  But definitely the cold temperatures will affect your canvas.  I can give you a list of canvases that are more pliable and softer to work with if you'd like, but some of them cost more than the Lyve you were using, at least here in Canada it does.

Anyway, so glad to hear the water and hair dryer trick worked for you!
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rgvsdigitalpimp
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« Reply #16 on: January 08, 2013, 10:36:49 PM »
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Well cold front passed us by and now it's back to being humid and in the upper 70's lower 80's.  Wow what a world of a difference.  Same exact spraying and stretching method as before in the cold and this time everything felt like butter.  Super easy to work with.  Not to self:  No more stretching prints in low temperatures again. 
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bill t.
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« Reply #17 on: January 08, 2013, 11:41:56 PM »
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Have been having excellent results spraying GlamII in a space with 1.5 of 4 walls exposed to the outside, with ambient air temps below 40F/4C.

All it takes is a kerosene heater.  It can warm the space up to 55F/13C in about 3 minutes and keep it there.  It's the equivalent of about 15 of those 1500 watt electric room heaters.  It's a little like working in a closed garage with the car engine running, but hey, I'll do anything for my art/money.  Using a face mask with an organic filter is highly recommended.  And it's very loud, much louder than the HVLP turbine.  When the weather warms up I plan to convert it to a pulse jet engine for my bicycle.
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rgvsdigitalpimp
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« Reply #18 on: January 09, 2013, 06:46:33 PM »
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Just got my roll of Sunset Select Matte Canvas by LexJet.  Wow I'm in love.  No cotton seeds.  Folds and moves around coated like there's no coating on there.  So smooth and easy to play with.  I think I'm in love Smiley
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peterln
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« Reply #19 on: January 09, 2013, 06:50:33 PM »
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the cold definitely has an affect on cracking for me with epson exhibition canvas matte up here in canada. i have to keep the heat on at the studio 24/7 to avoid it
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