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Minibrush
08-07-2001, 11:50 AM
I have a problem which involves the liquid acrylic paints that most people use for crafts. I design and paint my own frames for my miniature oil and watercolors and I usually use liquid acrylics for painting the frames.

Last week I painted 2 frames with a faux marble finish. I used blending gel to stretch and soften the lines and squigglies (I've done this many times before with no problems). This time, the last layer of color will not dry. I live in Colorado, very dry, normally, and lately our humidity has been up. But not as high as other parts of the USA. I now have the frames in my food dehydrator, trying to help, but 24 hours later, the frames are still sticky.

Any suggestions would be very appreciated.

Thank you,

Minibrush

cuttlefish
08-07-2001, 05:48 PM
This sounds like the result of using too much retarder. If your blending medium works by extending drying time, it probably contains propylene glycol or something similar. With artist grade paint, it is recommended that you use no more than 15% retarder per volume of undiluted paint. Using more will result in a weak paint film that is prone to delamination and may not properly dry ever.

The problem with craft grade paints is that you never really know what you're getting. They often have weak binders, sub-optimal pigment loads (rarely identified), and appear pre-diluted with water. I've seen many full bottles that have sat on the shelves long enough for the pigments to settle out of suspension, making the bottle look half-full. If the paint you use has insufficient acrylic polymer, it could easily be overwhelmed by slight miscalculations when you add retarder.

LDianeJohnson
08-07-2001, 10:18 PM
...and depending on some brands, clay and filler is used and very little pigment. Sometimes, even if dry, the paint will come off as if powder, scratch or mar very easily.

If you have to, wipe off as much as you can with a damp cloth then using higher grade acrylics repaint. I hate to even ask you to wipe off, but if it does not dry it may be your solution. If it dries enough to the touch, then try to recoat (gently) using acrylic varnish (either matte, satin or gloss) which will take up the slack and dry with a nice finish for your frame.

Diane

Einion
08-08-2001, 12:51 AM
Just a note about the amount of retarder that you can safely add. You will likely see two different figures most often in print: no more than 15% or no more than 2-5%, by volume. As there is more than one type of retarder it would be a good rule of thumb to stick to any manufacturer's own suggestions but my own experience would tend to suggest one be conservative, regardless of the recommendations.

I have used two types, one liquid and the other a gel. The gel specifically states "not more than 1/6th [~16%] for Umbers and Siennas; not more than 1/3rd [33%!] for other colours, in humid conditions less should be used." In my use of this product I think these proportions are about right but very much the upper limits.

My main complaint with retarders is they tend to change the character of the dried paint film, making it unpleasant to overcoat (I paint very thinly) so I try to avoid them as much as possible. Even used in small quantities, at a guess I would say as little as 10%, the liquid type would leave the paint film slick, glossy and feeling damp. If you like to paint thickly gels are definitely the one to go with as they won't alter the consistency of the paint much, if at all, and I think they yield better results anyway.

Einion

Minibrush
08-08-2001, 10:56 AM
Thank you for all of the helpful information. One frame did finally dry in the dehydrator, but the other just seems to get stickier. I guess I will have to wipe off and start over on that one. It would not be the first time I've had to re-do a finish, so I won't be too heart broken. Thankfully the one that did dry is the one I need first for a show in Wash. DC.

It's strange as I've used this technique and materials before on my frames, but I guess I may have gone too thick with the blending gel. Sometimes in this climate, I've had the paint dry on the brush before I even touch it to the frame. So I think I overcompensated for the blowing fans of summer.

I sure appreciate all of the information. I've learned so much from your replies. The next time I do marbeling on a frame, I think it will work much better. What a wonderful place Wet Canvas is. Everyone is so helpful, thank you again, and again.

Minibrush