I've been using the Dr J for a while now. I use them all the time for our one hits on darks. The squeegee as a flood bar fills the stencil better and you can see a difference in ink deposit between a metal flood bar and squeegee. The other day when I was asking what would be the best substrate to print on to test ink deposit thickness was to measrure those differences between different flood bars, squeegees and also mesh counts. Hopefully I'll get a chance to test and measure soon.
A couple of questions....
Do you think putting a normal squeegee in place off my flood bar would give me any advantages? Or would it be a poor trial to see if the Dr J's would be worth it?
If someone was to take a 16" Dr J or Smilin Jack and trim either a half inch or an inch off both sides, do you think it would alter the performance being that it would change the profile of the smile cut?
Do you think the advantage to a squeegee base/Dr J flood bar is only worth it for white and high opacity inks? Or do you think you would get a noticeable benefit even using them on wow and general purpose inks?
You can use a normal blade to try it out. I see what Jon and Blue are saying but running a typical floodbar over the top of an image and not doing a hard flood simply does not "prime" or load the stencil with enough ink. The purpose of flooding hard is to prime the pump so to speak and they are right in that there will be dot gain on certain types of printing, that's why we wouldn't use the Dr J on a sim process job or something that doesn't need a thicker ink deposit.
Another reason we fill the stencil by using a hard flood is it reduces the amount of print pressure we need to shear the ink, by a good margin, say 20% on average.
It will alter the performance but probably not noticeably especially if using it as a fill blade. I wouldn't use the Dr J or any squeegee to fill with on any top colors or general printing on light garments because it will affect the WOW aspect by probably depositing too much ink. But, say you are not getting enough ink down and you can see the shirt through the print with one stroke, most people will double stroke, well, you could fill the stencil better however you choose and get a better ink deposit and still stay with one stroke. If that job is a multi color with the need to print WOW then you'll have to be careful and use WOW inks and meter the ink deposit accordingly to keep the buildup to a minimum.
My question is why do you need to flood that much ink? Using a squeegee is going to have dot gain galore if you are using it to make contact with the screen.
You could possibly over fill the stencil and have dot gain galore but we haven't run across this problem. The only time we are using the Dr J to fill with is when I'm shooting for a one hit white or other color on darks. For that purpose, a heavy/hard fill is sometimes the missing 5-10% ink deposit that we are needing. I can't say for sure just how much more ink gets deposited using a Dr J over a regular fill blade but I've got prints of both through the same screen and settings and you can tell by eye there is a difference. If I can ever stop working 15 hour days trying to do shipping/receiving and still run the screen printing department I will do some experimenting and measure the results.