[Harpmaker]

What about the HE558? Any uses for it... or are BlackJack & AAA clearly superior if obtainable?

Blackjack and AAA-F are superior in that they don't change color, but if you can repaint your screen every year or so HE558 would work for you. However; if your friend can return the HE558 I would recommend doing so.

Of the 3 aluminum paints, HE558 has the largest aluminum particles, AAA-F the smallest and Blackjack is about half way between them.

For the new buyer, AAA-F is most definitely recommended over Blackjack and HE558, but if you have the others on hand...

 

[Harpmaker]

Bill is the Black Jack expert here. When this subject first came up I believe he said he has had a number of test batches of latex paint/BJA in storage for over a year with no signs of trouble.

Tiddler was kind enough to send me some BJA, and he used old clear plastic Behr *** (white pearl paint) bottles to ship it to me. Those bottles DID react negatively after a number of months (one had never been opened by me) and were destroyed when the BJA turned into a solid mass in what was clearly an exothermic reaction; and while pressure was obviously present the container never burst or exploded. The chemical reaction that caused this was also not hot enough to leave any burns or marks on a sheet of wooden paneling the container was setting on when it occurred. This was straight BJA and not a mix with latex paint. Bill has had no problems with BJA in it's original container or with mixes using latex paints stored in plastic containers.

This is the first I have heard about a latex/BJA mix degrading over time. Has this happened to you?

 

[Harpmaker]

Yes. I had a couple quart cans of BJA Black Widow pre-mixed and it happened in both of them. One of them was a lined metal can for latex paints, and the other was a non-lined metal can used for automotive paints. The reaction occurred in both of them.

The solvent base used in BJA is apparently NASTY stuff.

Very interesting! Just to be clear, the reaction occurred in the cans right?
Did the reaction just ruin the paint or did the lids blow off the cans?
About how long from putting the mix in the cans did it take for the reaction to take place?
What latex paints were used?
What was the ratio of latex paint to BJA?

I never got around to experimenting with the BJA I had, but I have several sample test cards of mixes using BJA sent to me from Tiddler that seem to be stable in the thin film of a painted screen. My point is that anyone that may have used a BJA mix to make a screen doesn't have to worry about their screen blowing up.

It seems BJA is wicked stuff indeed! BTW, any photos of the aftermath?

 

[Harpmaker]

No matter what the problem is with Black Jack Aluminum, there is a problem. While it seems that it can be used to make a fresh screen mix, any unused mix should be dumped rather than stored. Also, BJA by itself should only be stored in it's original container.

I asked what paint David mixed BJA into since Bill never had a problem. I'm not sure what paints he tested with.

While BJA isn't explosive or anything like that, I see no reason to use it since AAA-F is available via mail-order if not from a local store.

My containers of BJA were one pint plastic jars with screw-on lids. I had opened one and done a small sample, but the other bottle was unopened by me. Both bottles "went bad" at the same time when I wasn't in my shop. The bottles showed signs of temperatures high enough to soften the plastic and as the liquid BJA turned into a solid it expanded which caused the softened bottle to distend and finally a small hole was formed and a small mount of liquid did run out of this hole. Again, these were bottles of 100% BJA so I would think this would be the maximum reaction to be expected.

The moral of the story is to use AAA-F.

Thanks for the report David! :T