Problem with Hycote primer

[droogie77]

just got a can of grey for a piece I have just started working on. Gave it a test run on some bits today and I dont like it. It would not stick to any brass etch, just pools up and drips off. I also found it to be very runny and seems like it could kill detail on a model. I am not sure if I want to risk using it on the forge world model I am about to start working on. Did I get a bad can ? I gave the can a good shaking and it has been stored inside so it was not cold.

 

[droogie77]

Ignore that last post guys. I ran the can under some hot water for a bit and it seems to be working a lot better now. As far as the brass etch goes, I gave a piece of it a coat with some chaos black paint first and then sprayed it after it had dried.

 

[Tercha]

Don\'t hold aerosols under running water especially hot, I have seen the result of an almost empty can exploding, it split the ceramic sink in two , needless to say the guy holding it wasn\'t in too good a shape either.

 

[Einion]

Always a good idea to warm cans up before using them (in addition to shaking for a good minute or more) as it reduces the viscosity of the paint and raises the pressure in the can, which equates with finer atomisation.

Regarding water temp, I\'ve had a can\'s recessed bottom pop outward from using water that was too hot in the past - very loud and very scary! - so I recommend nothing more than hand-hot. Leave the can to soak for a couple of minutes until it\'s evenly warmed.

Originally posted by droogie77
As far as the brass etch goes, I gave a piece of it a coat with some chaos black paint first and then sprayed it after it had dried.

Primer on top of paint won\'t give you any better bond than the paint had originally. If you\'re having difficulty getting primer to stick directly to the brass try either degreasing it first with alcohol or acetone or scuffing the surface with fine abrasive paper, Scotchbrite or steel wool.

Einion

 

[Ritual]

Originally posted by Einion
...scuffing the surface with fine abrasive paper, Scotchbrite or steel wool.

That was what I was going to suggest.

 

[airhead]

Originally posted by Ritual

Originally posted by Einion
...scuffing the surface with fine abrasive paper, Scotchbrite or steel wool.

That was what I was going to suggest.

Beat me to it.

It sounds like the can may not have been shaken enough. All solvent and no pigment to bead up and be runny.

Once the rattle breaks loose, then another 60 seconds; up/down, pendulum (rotate wrist) and spin the rattler on the bottom.

 

[droogie77]

Thanks for the tips guys. The brass etch cant be sanded because it is already in place on the base I am working on, some of it is bent and destroyed making it almost impossible to sand. I will give the brass a wash with some alcohol to de-grease it and see how that goes. I will post some pics when the base is primed.

 

[Tercha]

Look at this before you put a can in \"warm \" water
http://www.chemaxx.com/aerosol2.htm20exploding&f=false

 

[Einion]

First off I think we\'d all agree that caution is of course advisable. That\'s why I specifically recommend hand-hot water only since I know from experience that the metal of the can itself can distort if the water is hotter than this and there\'s no way I want to see firsthand what\'ll happen if it goes one stage further!

As far as the link goes, first thing that should be noticed:

Hot water bath testing demonstrated than an exemplar with some rust along the bottom double seam exploded at a temperature and pressure that was below government (DOT) specifications.

And, importantly, the page doesn\'t say what temp the water reached when it exploded - it\'s possible it was around 80°C, which is above the temperature most people drink coffee...

So yeah, caution is advisable. But let\'s compare apples to apples.

Einion

 

[airhead]

I get a broken link. But I normally leave my spray cans in the garage where temps can reach 120 F (50 C). I\'ve not had one explode yet.

Water (as Enion said) should not be too hot to put your hand in. If it is too hot to hold onto, don\'t use it. Simple.

Aerosol cans are under pretty good pressure to start with. Increasing the temperature causes the internal pressure to rise. Go beyond design and safety factor pressure and it will catastrophically fail - read that as explode.

As a kid I put enough aerosol cans in the incenerator barrel just to see how high they\'d go. If you missed one and it ended up in the middle of the burn barrel, it could bulge the 55 gallon drum or cause lots of burning trash to fly out of the drum. Either case usually resulted in me being in trouble.

 

[Einion]

Originally posted by airhead
I get a broken link.

Have to delete the 20exploding&f=false portion.

Einion

 

[Tercha]

\"...the fate of the youngster spraying canned \"snow\" on his christmas tree. when the can died down, he warmed the can in hot water to \'jack up\' the propellant. When he took it out, shook it - and lost an eye and half of his lower jaw to flying shrapnel from the exploding container\".
If the can dosnt work properly take it back and get it replaced or just buy a new one!
thats my last word on this subject

 

[Einion]