Hi there, I am setting up a home screen printing studio and am currently trying to find the proper amount of time to burn my screen for.
I started with a 200 watt incandescent and had some success, but it took an hour and 15 min to burn the screen. I was hoping to speed things up so I got a 500 watt halogen which I set up 24" above my screen. With the new bulb I tried a 20min exposure then a 10 min exposure which was still too long. I eventually tried 3 min which wasn't long enough.
In the end 6 min with the 500 watt halogen yielded an acceptable result, but here is my main concern: After having gone through this series of tests I was unable to reclaim my screens. I wasn't even able to reclaim the 3 min exposure after I put it aside for about 30min. It's worth noting that I had no problem reclaiming the screens which were exposed under the 200 watt incandescent.
I'm using speedball chemicals to reclaim the screens, I use a shower head to wash them out and clean/reclaim as I don't have a pressure washer. Does anyone know what might be going on here?
Speedball reclaimers are absolute shit, you need a pressure washer for that and even then I'm kind of skeptical. What emulsion are you using? Not all reclaimers work on all emulsions, and Speedball emulsion isn't going to be the best/most reliable in terms of exposure and reclaiming.
Also, reclaiming in the shower is going to be tricky - I used to do it at my old place which had better water pressure, but the emulsion needed to be really fresh (month old at most and refrigerated) otherwise it was out to the car wash. That was with Ulano TZ, and I couldn't reclaim 925WR in the shower at all. I just go to the car wash now.
Last edited by cecilyrhys; 01-30-2014 at 09:50 PM.
Reason: Late night thought rearranging
Some possible issues if you are having difficulties reclaiming screens:
--Ink dried on the screen. (be sure to wash your screens well after printing. If using water based ink, use regular dish soap and water)
--Dried emulsion remover on screen. (If it drys on the screen, you are hooped.)
--Coated screens too old. (Long-ago coated screens are more difficult to reclaim.)
--Emulsion remover too old. (It has a shelf life. I used to use the Speedball remover and it usually worked okay. However, if it is old it loses its potency. Best to mix your own. Buy a powered product from your local screen printing supply company. We have hard water here in Calgary and I mix mine up with distilled water--I think it works better. Mix enough for the next month or so.)
--Emulsion too thick. (How are you coating? One scoop coat on each side? What's your mesh count?)
Spray pressure: I used to use a regular sink sprayer. Now I wash out in a commercial restaurant sink with a restaurant sink sprayer. It works well for me. I have a pressure washer but it gathers dust mostly.
I have read that under-exposed emulsion can cause wash out problems. That has not been my experience, however.
Hank stamper, thanks for that list I've run through it and I feel confident that I can eliminate all of those possibilities, here are my answers in the order you posted them.
-not an ink problem, some of them we didn't even print with before trying to reclaim.
-emulsion remover didn't have time to dry.
-just coated screens the day before.
-emulsion remover is brand new
-I suspected emulsion might be too thick so I put it on as thin as possible, I don't have a scoop coater so I used the squeegee I go once on each side and then I take a clean squeegee through again to remove any thicker spots.
-as for over and under exposure I feel like I went to both extremes and everything in between and none of them came clean.
Cecilyrhys you may be right regarding the speedball products. I actually also realized one other thing that changed is that the times I didn't have issues reclaiming I was using a reclaimer that came in a kit along with the speedball emulsion. Now I am using emulsion and remover that are sold in separately in bigger quantities (still speedball), could it be that they have a different remover or emulsion in the "non-kit" version of the product? Or maybe I guess the product is not reliable and sometimes it works sometimes it doesn't...
Check the labels, they might not align. The emulsion remover I use only works with certain Ulano emulsions, I know. But yeah, might be worth it to pick up some other thing (TZ + Ulano #4 Reclaimer is what I use, 925WR works with #4 too). I used Speedball waaaaay back when I was first starting and it wasn't reliable, I switched pretty quickly.