Luminous Landscape Forum
Raw & Post Processing, Printing => Printing: Printers, Papers and Inks => Topic started by: iCanvas on December 03, 2014, 09:47:45 am
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This may have been talked about before but doesn't come up on a search. I am using Epson exhibition satin canvas and a generic clear coating. I use a Wagner control spay max for spraying the coating. Sometimes, but not all times, when the coating dries there are bumps left on the canvas. I generally put three coatings on a canvas print. The bumps are sometimes slightly there with two coatings. Can't figure this out. Can anyone help with this?
Gar
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Are you being sure that the canvas is spotlessly clean before spraying? I assume so, just asking. Also, use of a "generic" coating may play a role. Brand name coatings, such as those from Breathing Color, are more expensive, but perhaps they are worth it!
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Any chance you can show a picture of the bumps? Are they solid? or air pockets? If solid bumps in coating, I would consider a different coating, if they are air pockets, you need to try backing away from the canvas, and or less coating hitting the canvas. More than likely if it's a Wagner, it's the latter. You can control the spray with the screw down near the trigger. Remember you also want a perfect fan when you spray.
If you take a matte canvas from the printer to coating, with no drying time for the print, you will also see outgassing. This creates a much finer set of bumps, that may actually end up as pin holes in the coating. I always allow my matte canvas 1 day to hang free before I coat.
Paul
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Try spraying whatever you are using on some flat surface like a foam core board and see if it leaves bumps. Could be the Wagner isn't atomizing well enough too, or getting condensation in the process causing the bumps.
I get very good results with Premier Imaging Products "Print Shield" (lacquer based) which seems like water out of the bottle and flows out nicely. Using a Sata Mini-Jet gun along with the condensation filters out of the compressor.
SG
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@peteralt: Yes, I am sure the canvas is clean before I spray. I have a fine haired brush that I use before coating. Thanks for your reply.
@Paul2660: The bumps are solid. Perhaps I'm using too much coating per spray. I'll try a lighter coating. Thanks for that tip.
@Someguy: I don't want to use lacquer based coatings. The clean up time and smell is not conducive for me. The water based coatings are what I want to use. Thanks for your input.
Gar
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a bump here and there or a bumpy texture (like a textured wall)? if the later, you need to adjust how you spray if the former you need to adjust what you spray.
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@Someguy: I don't want to use lacquer based coatings. The clean up time and smell is not conducive for me. The water based coatings are what I want to use. Thanks for your input.
Gar
I've been using Premier Art Eco Print Shield for 7 years, although I roll it on instead of spraying. No room for a proper spray booth. Aside from the fact that it does tend to settle in the container it's a cinch to use. A good hard shaking will get it back into solution. Lots of bubbles but that's not an issue when rolling, might be for spraying, not sure. Now to the main reason for this reply. Eco Print Shield is NOT a lacquer based product. It is indeed an aqueous based coating, so you have to be careful to never let it freeze. No nasty smell and very easy to clean up. About a year ago I had a new container in which the coating was cracking at the edges of the canvas when stretched. I called Premier Art and they advised the local distributor to replace that container with a new one. No problem! They assumed that although the product is well labeled against freezing it had probably been shipped in the winter and did actually freeze in transit. I've been in touch with service department at Premier Art a few times and found them to be very helpful. Hope this helps.
Gary
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Thanks Gary for the advice.
You cannot roll any type of coating on Epson Exhibition canvas. The ink will smear. The canvas has to be sprayed and the first coat must be light. The Epson Exhibition matte and Satin can be sprayed. The Epson Exhibition gloss cannot be sprayed or rolled, because the ink will smear. I have already been through that. I particularly like the 23mil canvas because it stretches so nicely and it doesn't leave stretch marks toward the edge of the stretcher bar. If there are other 23mil canvas out there that one can roll on the coating, I would like to know about that.
Gar
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Thanks Gary for the advice.
You cannot roll any type of coating on Epson Exhibition canvas. The ink will smear. The canvas has to be sprayed and the first coat must be light. The Epson Exhibition matte and Satin can be sprayed. The Epson Exhibition gloss cannot be sprayed or rolled, because the ink will smear. I have already been through that. I particularly like the 23mil canvas because it stretches so nicely and it doesn't leave stretch marks toward the edge of the stretcher bar. If there are other 23mil canvas out there that one can roll on the coating, I would like to know about that.
Gar
I've only used the Epson canvas very sparingly, but since I don't spray I cannot sell the product. I would never let an uncoated(protected) canvas leave my premises, since I have every reason to believe that it would be returning soon for a redo. I use Breathing Color Chromata White(OBA Free), 19mil, matte finish. Been using that product for at least 5 years with no issues at all. I have tried the BC Lyve, but I find that if there's an abundance of black it can smear slightly as well, but I may give it another try at some point. And quite frankly, after printing the same image on both, I couldn't see any advantage with Lyve. I'm sure others might disagree and perhaps my "testing" method was not as fastidious as it should have been. However, ChromWhite works for me and I'm not about to make any unnecessary waves at this point. I send my customers to a local framing company for the stretching and the owner says she has no problems at all with that canvas. I use 3 coats of the Eco Print Shield. The first two are the Satan finish and the last one is the preference of the customer. I also offer Gloss as well as a 50/50 mix of Gloss and Satan. The latter is the most popular. As I mentioned I have had only one issue with the Print Shield coating and it was replaced immediately. I'm including the Breating Color URL for the Cromata White below if you'd like to take a peek.
http://www.breathingcolor.com/action/bc_shop/93/
Gary
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do you see the bumps right after coating or do they appear during the drying process? maybe you need to adjust your sprayer if you see them after coating. or check the air/ventilation quality if they appear during the drying process.
do yourself a favor and try a sample pint of the breathing color timeless. I switched half a year ago from eccoshield :)
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You are not talking air bubbles are you?
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The first two are the Satan finish and the last one is the preference of the customer. I also offer Gloss as well as a 50/50 mix of Gloss and Satan. The latter is the most popular.
Gary
Yes, the devil is in the details. :D
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OP, please attach a photo of your "bumps." It could be any of a dozen things. Google "orange peel." Does it look like that? - Jim
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First off, if your coating anyway don't buy the Satin or Gloss Exhibition Canvas which is more expensive !!
Use Exhibition Matte and roll on the Eco Print Shield gloss in three coats. It is a pleasure to use! The first coat (light) seals the ink and keeps subsequent coats from smearing, Second coat heavier to protect and then a final also heavier coat. If you need a satin finish do the last coat in Satin EPS.
I can roll any size canvas as fast as spraying, without any expensive equipment, and clean up is less than 5 minutes to wash out the roller! I have been using the same foam roller for over a year (despite the fact that they are cheap as dirt). I keep the roller moist in a baggie between uses), which helps to get the first application absorbed onto the roller easier ;-)
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@davidh202: that sounds great David! So you never get bubbles or bumps when you roll the Eco print shield on Epson exhibition canvas Matte? I would much rather roll the coating on than spray it. Much less cleaning time and overspray waste. Thanks, Gar
@Dan Berg: no Dan I'm not talking about bubbles. When the spray coating is put on it appears smooth. But when it dries, especially after the second coat, the bumps start to appear. The canvases dry in our storefront, and while driying, I don't turn on the AC or the heat. So there's no dust flying in the air. Gar
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Yes, the devil is in the details. :D
Hi Jim,
I haven't been able to get back to the forum for a few days and as I was perusing I noticed your quip. At first I wasn't sure what you were referring to, but it soon jumped out and grabbed me by the "!¡!¶¡™∞§¢"s --- OUCH!!! Had a good chuckle, polished my horns, stomped my hooves and set about the task of issuing a "thank you" for pointing out the obvious. I was going to say that I don't know what got into me when I was writing that one, but actually I suppose perhaps I do know. Been watching too many SNL reruns I guess(the devil made me do it). My original name on the forum was "Lucifer II" until I decided that might not be the best approach to all of the great people residing here. So I guess now I've been outed. Glad I was able to at least offer up some fodder for a guffaw or two.
SEE YOU LATER JIM!!!
Luc.....WOOPS---Gary
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First off, if your coating anyway don't buy the Satin or Gloss Exhibition Canvas which is more expensive !!
Use Exhibition Matte and roll on the Eco Print Shield gloss in three coats. It is a pleasure to use! The first coat (light) seals the ink and keeps subsequent coats from smearing, Second coat heavier to protect and then a final also heavier coat. If you need a satin finish do the last coat in Satin EPS.
I can roll any size canvas as fast as spraying, without any expensive equipment, and clean up is less than 5 minutes to wash out the roller! I have been using the same foam roller for over a year (despite the fact that they are cheap as dirt). I keep the roller moist in a baggie between uses), which helps to get the first application absorbed onto the roller easier ;-)
I was just about to offer one more piece of advice if you are thinking of rolling EPS, as I have done for many years. Just read David's reply and he has mentioned it as well. Although I choose not to let the roller set in a bag damp(possibility of mold occuring), I definitely do wet it down and then get almost all of the water out of it before applying the first coat. In my experience, and David's as well obviously, starting a first coat on matte canvas with a dry roller will use considerably more coating than necessary. A damp roller will absorb more of the coating and apply it in a more even fashion for the first coat. I've found that it makes no difference for the additional coats, but it can't hurt either. As far as bubbles are concerned you will have an abundance of them when you roll EPS. First of all, you MUST shake the coating vigorously before applying, since to does tend to separate(fall out of solution) while sitting in the container. The agitation alone will cause a copious amount of bubbles(foam) to accumulate on top of and within the coating. Secondly, the foam roller is filled with air, which also tends to add to the bubble "issue". When you finish applying your first coating with EPS you will likely be tempted to re-roll it repeatedly until all of the bubbles have disappeared. Not only is that not necessary, it can also eventually draw back some of the coating into the roller. The best thing to do at this point is to not give in to temptation. "OH OH, I feel another Jimism coming along after that last statement". But seriously, just ignore the bubbles. They will magically disappear once the coating has completely dried. Of course you will likely notice a bit of streaking after the first coat, which is normal and also to be ignored. The second coat will even things out completely. Not to worry! This probably sounds like an add campaign for Premier Art EPS, so let me state that I have NO affiliation to the company other than the fact that I find their product to be easy to use, clean up and best of all, it does a fine job of protecting the canvas to which you have dedicated your time and efforts. Hope this has been useful.
ROLLIN' ROLLIN' ROLLIN' It's the only way to go!
Gary
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I've been following this thread and am a bit disappointed to still not see pictures of the issue. It could be too many things, all very different, and hence a picture would go a long way to helping the diagnosis for the OP and anyone else reading this thread at a later date.
I coat canvas with the Wagnar gun and have zero problems. For reference, I use Timeless, a mix of gloss and matte, and spray right after printing, no need to outgas. (using Canon printer hence Canon inks). The only issue would be if using 100% pure gloss and spraying too close which might leave different levels of shine on the canvas if not applied uniformly. But since I'm going more with a matte look (80% matte, 20% gloss mix), it simply doesn't matter and I don't have to be careful. So I'm curious to read about all these problems since I find it so easy.
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Hi Jim,
I haven't been able to get back to the forum for a few days and as I was perusing I noticed your quip. At first I wasn't sure what you were referring to, but it soon jumped out and grabbed me by the "!¡!¶¡™∞§¢"s --- OUCH!!! Had a good chuckle, polished my horns, stomped my hooves and set about the task of issuing a "thank you" for pointing out the obvious. I was going to say that I don't know what got into me when I was writing that one, but actually I suppose perhaps I do know. Been watching too many SNL reruns I guess(the devil made me do it). My original name on the forum was "Lucifer II" until I decided that might not be the best approach to all of the great people residing here. So I guess now I've been outed. Glad I was able to at least offer up some fodder for a guffaw or two.
SEE YOU LATER JIM!!!
Luc.....WOOPS---Gary
Sorry, Gary, [in my best Geraldine {Flip Wilson}] "The Devil made me do it!" - Jim
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I've been following this thread and am a bit disappointed to still not see pictures of the issue. It could be too many things, all very different, and hence a picture would go a long way to helping the diagnosis for the OP and anyone else reading this thread at a later date.
OP, please attach a photo of your "bumps." It could be any of a dozen things. Google "orange peel." Does it look like that? - Jim
I, too, asked for the very same thing. - Jim
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Ok, here is a pic of the bumps. Any advice will be helpful.
Thanks,
Gar
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From that shot, they look like air bubbles, that did not pop.
If the canvas is coated right after printing, the outgassing can cause air bubbles, but they tend to be much smaller.
These would be possibly from a too heavy coating applied up too close to the canvas. I would try thinning your mix and or spray, (add more thinner coats).
Paul
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I've never seen this before. I read your original post and see you are using Satin canvas. These tend to already have a bit more of a bumpy texture I would say and are usually quite stiff. I think these canvases also are sealed more which prevents out-gassing from behind the canvas. In my opinion, if you're using a matte canvas, if any gasses do need to vent, they can always do so from the back. I've never had a problem with out-gassing, perhaps Canon inks don't suffer from this as much.
The suspect might therefore be the coating, but its still interesting how in some part you don't get this and yet you do in other areas.
Sorry I can't help but thanks for the pic. Any chance you could provide a higher resolution and sharper image? The reason I ask is because I assume an out-gassing bump would look a little bit like a volcano in that it would have a center depression, whereas if these bumps are random and closed, it might be possible to see if its just gunk buildup.
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@landscapes: The bumps do not look like volcanos. The coating looks smooth when I apply it, but as it dried the bumps appeared.
I did an experiment this morning and my problem maybe that I am spraying too far away from the canvas. I think I need to be about 6" away from the canvas. There were no bumps when I did this. Hopefully that's the case. Thanks for everyone's input. I'll update this thread when I try my next coating.
Gar
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those don't look like air bubbles they look like lumps or thicker possibly dried particles in the coating. When the overall coating is still wet it is thick and the lumps are hidden. As the coating dries it shrinks ( its carrier base evaporates), and the lumps do not so they stand out!!
are you straining the coating in a fine enough mesh before you load it in the spray gun, or possible moisture contamination in the air line ?
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Coatings are essentially an acrylic (plastic) suspended in a carrier which dries rapidly when the coating is sprayed or rolled.
Always strain or filter your coatings prior to pouring the coating into the spray gun cup. Use a 120 mesh disposable filter. These filters can be purchased at any auto body supply store or at Harbor Freight in their paint department. (in store only, not available on the web) When rolling, I always filter the coating out of the gallon jug into a smaller cup. I then pour the from that cup onto the canvas. For best results, put on multiple thin coats.
The bumps on the canvas are most likely partially dissolved chunks of acrylic that have begun to solidify. As you use more and more coating from a gallon jug the air volume over the top of the coating increases and causes a skim coat to form on the coating if has been sitting around a while.
Filtering the coating will also eliminate the dried crap that may flake off around the cap when you are pouring out of the bottle. Shake or agitate the coating every once in a while and then let the air bubbles settle before you try to coat with it. Another trick is to purchase an additional gallon of coating and pour some of the new coating into the old jug. Then pour them back and forth from bottle to gallon bottle. This mixing of old and new coating (provided they are the same brand and gloss level) will pretty much keep your coating stock fresh.
However, always filter the coating - new or old.