Testing 30+ year old size

[joe cieslowski]

This thread got lost so I'll post my test process and hope that Kent Smith can jump in with the great info/history that he added in the original.

This is a can of size I found from more than 30 years ago. It's quite full because after I used it a couple of times, I couldn't get the cap off so I switched to another brand.



Here's the back label (hmmmm, you can actually read it without a magnifying glass)



To solve the cap "problem", I put a sheet metal screw into the top. I do this with all my paints. To remove the size, I tip the can and remove the screw, squeeze out the amount I need and return the screw before tipping it back up. By doing it this way, the air that gets in has to go thru the paint, picking up vehicle as it does and a skin will not form.



To do the test I applied the size in about a 3"x3" square. For a control sample, I did the same with a much fresher Rolco size next to it.



Because, normally, I only apply a very thin film of size for the mostly small signs that I do, I applied a heavier coating (not real heavy tho) on each sample, dividing them in half. ( this heavier coating is probably closer to what most folks use in surface gilding and is what I would use on a bigger job) I think you can see the difference in color on the Yellow Kurtz sample.

THE TEST:

First, I was concerned about mixing all the size so I shook it for quite a long time and then set it upside down for a while and then shook it again.

Room temp was 68 degrees with 28% humidity.

I was concerned about how well the Kurtz would dry so I made another sample with just the Kurtz and set it under a quartz heater which raised the surface temp to 94 degrees (I hoped that would speed up the drying test)

After 12 hrs, both the Rolco and Kurtz were still too wet. The sample under the heater was dried hard (I tried to apply a gild but it was spotty at best)

At 18 hrs, both the Kurtz and Rolco took a decent gild although the heavier size side, was a bit dull.

At 21 hrs, both samples took a very good gild and at 24hrs, the thinner samples had a spotty gild.

In all the tests, I used patent leaf pressed on with a finger.

Conclusion......I have a pint of usable size.

When this side of the site was down yesterday, I found this by Rick Glawson on the original site. (An excellent read)

http://www.theletterheads.com/glawson/goldsize.html

I hope Kent can fill in the history of this brand and any insite/info that is helpfull.

Joe

[Kent Smith]

You tax my memory about what I said before but Kurz is the company who purchased Hasting gold leaf company. They now primarily make stamping foils, not leaf. Their size was still being made by Kemp who private labeled for just about everyone else. This long oil size, in both yellow and clear, had a predictable open time and strong tack lasting upwards to 3 weeks. Shelf life of the oil itself is indefinate but the lead dryer typically will have settled to the bottom along with the chrome yellow pigment. Unlike alkyd enamels, the dryer can be remixed into the size but typically it will need to be scraped up from the bottom and since it is clear it is hard to know when it is done. While shaking or agitation will remix some of the dryer, for more reliable results, I would reccomend scraping the bottom which probably means transferring this amount to a new container. As you have included in this new post, it is critical to do some step testing to be certain of the dry to tack and cure times. This is the procedure one should always do with size that is a few years old. Also, yellow size tends to set up faster than the clears.

Thinking about accelerating with heat, I have found in the past that too much heat tends to just dry the top film surface of the oil, causing a skin to form that the gold will not adhere to well. That is why I reccommend using a fan without heat to help size set up as well as cure. Air movement helps the solvets to disipate and forced oxygen exchange acts as the second component in curing.