Full Version: Doming - testing the waters.
From: Terry-Morris [#41]
5 Apr 2005
To: Rodney Gold (RODNEY_GOLD) [#39] 5 Apr 2005
Rodney,
It is true, UV doming is best suited for smaller runs. If you are doing thousands of items then 2 part mixes are the way to go. But if you are doing small amounts like a hundred, dozens or even a single item then UV has some advantages, once you learn to dispense properly you literally have zero waste of material, zero clean up and it's convenient. For many people this is enough reason to pay a little extra for the UV resins.
I am curious and would like to find out more about your resins that are done in an hour or two, I tried about 6 brands myself and none set up in less than 24 hours which always gave time for every piece of dust or gnat to land in mine. I am also curious how well it degausses, The 2 part mixes I tried did not work well in my 60% humidity, many of the items I domed were ruined due to bubbles that were not there when I domed them, the bubbles developed during the 24 cure.
Thanks!!
From: Ken D. (KDEVORY) [#42]
5 Apr 2005
To: Terry-Morris [#37] 5 Apr 2005
Terry,
Glad to see you on the forum. I hope its not a one time thing, and you stick around. Its amazing the variety of applications people are doing, and the variation of scale. For doming I'm doing single pieces. I love the convenience of UV epoxy. Others are dealing with large scale production where pennies add up. (materials vs labor.)
Last night I printed 2 photos one on the special paper, the other on my standard office paper. Today I domed them along with a blank sample of the photo paper. You were correct, it is the ink.
The plain photo paper worked perfectly. The office paper was interesting. It soaked in the epoxy and cured hard. except for the solid black hair. Same problem there. - It worked where the paper was able to fully absorb the ink and have absorbency left for the epoxy.
The photo on the photo paper - same as my first try. It won't be practical for me to wait a week; I'll need to explore methods to expedite drying. - You mentioned heat. I'll have to explore my options.
From: Harvey only (HARVEY-ONLY) [#43]
5 Apr 2005
To: Ken D. (KDEVORY) [#42] 5 Apr 2005
If you have a heat press running at 400*, close it for ten seconds, then open it and lay the paper, face up, on the bottom platen. Use a rag or something to prevent burned fingers and stroke it for about ten seconds. leave it there for maybe half a minute and it is well dried. The only time this might not work is if there is oil in the ink.
This is a process I use in sublimation.
If you have an old warming tray it might work, timing will be different.
From: Ken D. (KDEVORY) [#44]
5 Apr 2005
To: Harvey only (HARVEY-ONLY) [#43] 5 Apr 2005
Another reason to consider a heat press...
Does anyone know if the HP Officejet 7140 has oil in the ink?
If there is oil will it take longer, or heat won't work?
From: Rodney Gold (RODNEY_GOLD) [#45]
5 Apr 2005
To: Terry-Morris [#41] 5 Apr 2005
Terry we use a dopag dosomat dispenser with a variable stroke mix ratio and a mixing block and disposable mixing nozzles (tho we clean them with ethelen chloride and re use them). The resins are from National Urethane Industries in Johannesburg South Africa and work out at about $15 per kg mixed. (I dont have the website atm) They can modify the resins for you in respect of shore hardness values , pot life etc.
If we want a 1/2 hour cure , we elevate drying temps to 40 degrees C. We use pretty noahs arc drying racks , bookshelves with lights screwed under them that heats the shelf below and a nice heavy duty clear builders plastic curtain in front (a cardboard box with a globe would do to for small runs)
Degassing isnt a problem as we pull a vacuum in the feed canisters , but even if we dont , its still ok due to the fact that the stuff gets mixed in the mixing nozzle and the only time it sees air is at the tip of the nozzle as its being dispensed. (the cart guns have this advantage too). Moisture is always the problem , we dome in a climate controlled (read aircon) environment and de humidify. Once the stuff has gelled , then it shouldnt bubble or foam. But suffice it to say , foaming is always due to moisture absorbtion prior to gelling (a problem with long pot life stuff is that it takes a long time to gel , and you need long pot lifes if you hand mix)
Key to using 2 part quick cure urethanes is good mixing , precise ratios and a dry warm environment when curing.
Regards
From: Harvey only (HARVEY-ONLY) [#46]
5 Apr 2005
To: Ken D. (KDEVORY) [#44] 5 Apr 2005
"Does anyone know if the HP Officejet 7140 has oil in the ink?"
No idea if any still use it, the ribbon printers used oil soluble ink.
"If there is oil will it take longer, or heat won't work?"
If it is a very light oil it might evaporate also. Testing is the only to be sure of a specific combination.
From: Terry-Morris [#47]
5 Apr 2005
To: Rodney Gold (RODNEY_GOLD) [#45] 6 Apr 2005
Thanks for the info, It sounds like you have a good setup for mass production. I think I'll stick with UV for now as I don't do thousands, in fact my average domed order is 100 or less pieces, this does allow me to get a premium $$ for it though since large house don't want the work.
And I work from an office built onto my home so don't really have the space or money for the equipment. I like the idea of using book shelves with lights and plastic, I will have to remember that for future use.
From: Terry-Morris [#48]
5 Apr 2005
To: Ken D. (KDEVORY) [#47] 5 Apr 2005
Ken,
I just had an idea, if you have a heat roller type laminator you could try to use it to dry out the print. I would sandwich the print between two pieces of plain paper after it had air dried for 30-60 minutes then run it through the laminator once or even twice, I would think that would force it dry. Of course it might also destroy the print but it would be worth a test.
Just an idea!!
From: Ken D. (KDEVORY) [#49]
5 Apr 2005
To: Terry-Morris [#48] 5 Apr 2005
Interesting idea, unfortunately I don't have a laminator. But it got me to thinking about the iron I've used for waxing my skis, wonder where it is. It looks like there've been plenty of ideas for heat sources, now I need to do some of my own experimenting.
Where can I get the MSDS for the epoxy. I'm hoping getting it on my skin isn't much of an issue. :-)
From: Harvey only (HARVEY-ONLY) [#50]
5 Apr 2005
To: Ken D. (KDEVORY) [#49] 6 Apr 2005
Good idea. A dry iron set just below the boiling point should remove virtually all of the moisture in the ink and paper also. Just be sure that the coating on the paper can take the heat and you are set. It should take less than 20 seconds for each section, then a partial minute to cool and expel the moisture.
We used to bake stacks of 2,000 record labels at 150* overnight to expel all moisture. 200* and one thickness of paper should take those few seconds.
Good luck, and let us know.
From: Terry-Morris [#51]
5 Apr 2005
To: Ken D. (KDEVORY) [#49] 6 Apr 2005
You can get the MSDS sheet here http://www.epoxies.com/msds/60-7155uvresin.pdf It is listed as "Mild skin sensitizer and mild eye irritant".
Some people are sensitive to it and should wear latex gloves. Myself I have had no reaction to it after handling it for 4+ years now. By the way you can use rubbing alcohol to clean it up.
From: Ken D. (KDEVORY) [#52]
6 Apr 2005
To: JayBeeOz [#24] 7 Apr 2005
John,
I believe you have UVA and UVC reversed. After reading your posts I decided to try and get an 'A' bulb. Found out blacklights are UVA, and sterilization lights are UVC.
Don't know if the UVC will help with the epoxy sold by Ultradome and Coast Graphic Supply. They're formulated specifically for a blacklight, with a cure frequency of 365nm. (Their supplier has other broad-spectrum high intensity formulas too. I suspect you're using a broad spectrum formulation given the information in your various posts.)
From: JayBeeOz [#53]
7 Apr 2005
To: Ken D. (KDEVORY) [#52] 7 Apr 2005
Ken
You are right, my apologies, in my original post where I described the lamps, I did get the A & C back to front. UVA is the normal Blacklight, UVC is the dangerous one. In one of my other posts where I described the commercial unit, I did get the bulbs the right way around.... Oh well...At least I know that my cabinet is germ free!!:-)
I'm not sure about the curing frequency of the Epoxy that I use, only that UVC alone will not cure it completely. It will only skin the surface of the epoxy (It does this within a minute or two). Before I fitted timers to the cabinet, I forgot about a batch of badges that stayed under the UVC Lamps for about 6 hours. It may have made the skin a micron thicker, but the epoxy still remained liquid under the skin. I think the advantages to using the UVC are a clearer looking Dome, quick skinning stops dust and bugs from settling on the surface, and from what I have read, seems to remove the tacky feeling of the soft epoxy, plus the fast curing times.
I will stress though, to anyone thinking about experimenting with the UVC lamps, they may look innocent enough but they ARE dangerous, even short exposure to them can burn your skin or the retinas of your eyes. PLEASE be careful.
John
From: Ken D. (KDEVORY) [#54]
7 Apr 2005
To: JayBeeOz [#53] 7 Apr 2005
I did my first piece with the flexible epoxy yesterday. I forgot about it after the timer went off. I think it was under the light for 40 min. It doesn't feel tacky to the touch. It was 2" from 2 15W blacklights. I'm wondering if the tackiness requires more time/power to cure. Since I'm doing single pieces under a very small box dust and bugs are not an issue. Now if I had to scale up production...
A quick film would allow me to make a higher dome. My box gets a little warm and the epoxy flows off if too high.
From: Harvey only (HARVEY-ONLY) [#55]
7 Apr 2005
To: Ken D. (KDEVORY) [#54] 7 Apr 2005
Best way to keep the heat down if it affects the product is to put a small whisper fan over a hole over a lamp socket blowing out. Lay the product on a small furnace filter so air and not dust will be drawn into the box.
From: Ken D. (KDEVORY) [#56]
7 Apr 2005
To: Harvey only (HARVEY-ONLY) [#55] 7 Apr 2005
From: JayBeeOz [#57]
8 Apr 2005
To: Ken D. (KDEVORY) [#54] 8 Apr 2005
Ken
Its easy to forget about those little badges just laying there getting a tan...It happened to me frequently. I ended up getting a couple of Timers for a small toaster oven from the oven manufacturers spare part division. Tthey are Mechanical/Electrical timers usually with a 30 - 60 minute range. Spin them around to how many minutes you want to cure for and they 'tick' away and turn off the lamps for you. (They have to be hard wired into the lights circuit)
My cabinet has two seperate areas, the top contains 4x 15W Blacklights and the bottom 4x 15 UVC tubes. (these are stamped GE/Hitachi). The two sections are light tight, so not a lot of airflow. I do however have the Ballasts that drive the tubes, and the Flourecent Starters in a seperate section that is isolated from the curing chambers and have vent holes for cooling.
The badges get only just warm but not warm enough to cause the epoxy to flow off the edge. If you increased the distance another inch and a 1/4, (I think that works out to around the 80mm mark, this may help with the heat side of things. I have found that if I have too much epoxy on the surface I tend to get "Mattress" corners on the badges after curing under the UVC Lamps. Little ripples that start at each corner and and run in towards the middle. My domes are normally around 2 - 3mm high in the very centre of the badge.
John
From: Ken D. (KDEVORY) [#58]
8 Apr 2005
To: JayBeeOz [#57] 8 Apr 2005
Yesterday I added a 0.5" hole over each bulbs base, and put 1/8" raisers under the box. It made a big difference.
I also expanded the keyring hole to 0.2". When the hole is too small the surface tension pulls the epoxy over it. (and therefore into it.)
==
For those following this thread the HP Premium Plus Glossy Photo Paper won't work. I had previously posted that the paper will and the ink won't. The paper won't. (I didn't check my test sample well enough the other day.) I have some other papers I plan on trying.
From: Barbara (RGILE) [#59]
8 Apr 2005
To: Ken D. (KDEVORY) [#6] 8 Apr 2005
Ken,
As a former nail technician, I used UV light to make acrylic gel fingernails. I had a UV Lamp that was big enough inside for a whole hand to cure. Perhaps that would work and be relatively cheaper than making one. You could slip small item into it, but not larger ones.
Just a thought. You never know what might work for someone.
Barbara
RGile Engravers
From: Ken D. (KDEVORY) [#60]
8 Apr 2005
To: Barbara (RGILE) [#59] 12 Apr 2005
My box is working well for me. Do you have any idea what the nail curer cost, or where to get them. Others may be interested, who don't want to wire up their own box.
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