sticky bronze coat

[harry]

Hi, is there a solution to correct a situation when the surface of a sculpture that was painted over with bronze powder mixed in resin and hardener, but wont cure and remains sticky? The idea was to cover a patch of clay that was applied to cover an uneven surface. thanks

[oddist]

To help narrow the problem down could you answer the following please?

Was this a "home-brew" finish (bronze and resin) or commercial product?

If a commercial fnish, what is the name?

What kind of clay was used for the repair?

[Landseer]

Sounds to me like either one of two things- inhibition of the cure from something in the clay, or part A was not mixed in the right proportion to part B, both situations will cause stickyness and no cure. The solution is likely to be as usual with this sort of thing- total removal of the uncured glop back to the bare substrate and starting over.

[ahirschman]

Two more posible problems come to mind. Temperature too low will sometimes inhibit proper cure, or incorrect humidity. But, Landseer's suggestions would probably occurr 99% of the time before these other two.

Ari.

[harry]

The bronze powder I used did'nt have a brand name, but I bought it from a company in West Palm Beach Fla. it was mixed with fibre glass resin, the clay was called terrecotta which has a red color. I have used both product before the same way, but I did'nt encounter this problem, I have also scraped it off, and rapplied it, and have the same sticky problem, so I guess it does have something to do with the atmospheric conditions. thanks for your kind assistance.

[Landseer]

There's a possibility the product itself is defective, I find it hard to believe temperature or humidity would cause this unless you are working in a room in the South Pole at -40ºF or in the Iraq desert at 140º or the steamy Amazon jungles- as long as your room temperature is normal 65-75 and the humidity is not the same as a steam sauna all paints, resins and other products should work normally.

Try a TEST by applying this on something else such as a piece of clean sheet metal and a scrap of dry lumber or plywood in the same vicinity as before, and if it STILL has this problem and you are working in a normal room temperature and humidity say around 35-50% then the product is defective or your mixing of the ingredients is either percentage wise off or not being mixed thoroughly and completely, or your mixing stick etc is contaminating it.

Some of these things need a specific ratio and some are critical that you use a gram scale for accuracy, read the label and instructions completely again to ensure for example that you are not mixing it at 50/50% instead of 90/10% or 10% hardener when it calls for 1%- easy to do!

[sculptor]

for my resin castings, I've discovered little difference in the resin-'cepting color and smell-a resin is a resin is a resin...............
however, the mekp(methylethylketoneperoxide(sp?)) being the more volatile of the 2 components seems to vary widely in it's ability to set the resin
whenever i use a new batch of catalyst, i test it in a smaller batch---usually, there isn't a problem but sometimes, i've had to double the proportion of mekp or triple, or just dispose of the batch, and get some new product

also, some bronze powders are coated to make them more comfortable in resin, and some are designed to be used in various clear paints
this is a problem a smaller % of the time.

recomendation
make a small batch without the powder and see if it sets

assuming it didn't set
make another batch doubling the catalyst

assuming it didn't set
try using a new batch of catalyst

basic scientific method bro
break the problem down into it's component parts and test them individually

you could always do all the above at the same time
-instant gratification

if at first you don't succeed
blame it on your supplier and get a refund

best of luck to you

rod
sculptor (http://home.mindspring.com/~mandali/index.html)

[harry]

Thanks once again guys for your sensible words of wisdom, I will give it another try and post the results.

[anton]

hi all a litte thourt , resin and water (mostre) i know my spelling suck's but i am a dislexsik so bear with me , the laer of resin that come into contact with the clay was it dry or stil moste if it was the second anser that could be the cores for the resin not setting , i did a resin cast of a hand with algenate and being water basted the resin top laer did not set, real sticky.if it was number one it could be that the harder to resin mix was not coreced. it soud be +- 3% of wieth of resin eg 100g resin 3g hardner.
try and try again , one will get it rigth soner or later.
anton

[ahirschman]

I just remembered something, which is that some resins will not cure properly when exposed to air. I looked up some info from a company that I have previously used for my resins and this is what one of their products states:

"Polyester Laminating Resin Waxed for Top or Finish Coats
#83 is a waxed resin for laminating thin fiberglass skins on plywood, or for general purpose fiberglass repairs. The wax in the resin will prevent surface tackiness even when applied in thin coats. Sand off the wax layer before painting or secondary bonding"

The trick here is that the wax is added to form a barrier between the resin and air.

Could this have been the problem?

Ari.

[icon]

You probably used non waxed polyester resin which will not cure completely when exposed to air. Try reaplying it and covering it with PVA (polyvynil alcohol) or spraying a sealer coat of clear acrylic over it. That should make it cure. If not, just get some waxed resin.

[Santosh Yes]

Tiranti's brochure "Wax Additive is 2% wax in styrene solution. When added to resin at 2% ... virtually eliminates surface tackiness caused by air inhibition". would love to know if this can be used with bronze powder.