Riddle me this...

U

underdog

Been spraying the epoxy for several weeks, and I'm trying to figure out why when air is reintroduced into fresh epoxy within about a minute or less after laying it down it separates? I've sprayed several parts, test panels, masking paper and on every test panel when air is reintroduced to the fresh epoxy by blowing on it or using compressed air it seems to separate

Example I can spay a coke can with multiple passes NOT letting the paint stop flowing, let it set for a few minutes and the epoxy is fine.

I can perform the same test and the remove my mask and lighty blow on it and BOOM it separates. And no I'm not spitting on. I tried that too. Didn't separate.

I have attached a picture of three trigger pulls

From left to right.

1st blew on it within 2 seconds
2nd blew on it about 30 seconds
3rd didn't blow on it at all. NO separation. WHY?? Screenshot_2014-06-26-20-20-54.jpg
 
i know exactly what you mean. what is probably happening is your flashing off fast solvents in the epoxy which almost makes like huge solvent pop. it just the way the solvents are flashing is all. it doesnt hurt anything unless the epoxy needs to look good. whats funny is if you add flattener to the epoxy it sprays beautiful with none of that going on.
 
I'm just anal. I want everything to look perfect. I thought I had a contamination issue. I over think everything


Flattener huh. ?

What about reducer? Haven't had to reduce it yet.
 
Reducer helps because you can spray each coat thinner. You dont really want to hammer on thick coats of epoxy. 3 med coats is better than 2 heavy.
 
I'm on my phone sorry if I repeat myself.

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The epoxy, It just seems very sensitive.

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I spray everything like I'm spraying base clear/ so when I have problems with step one. I want to fix it before it becomes a real problem..
 
Nope there is nothing wrong with it. Always spray with a basecoat gun not a primer gun and dont double coat and spray it heavy. The epoxy just doesnt have fillers in it so yes its a little more sensitive than others to spray. Most others will have talc and clay for build. Makes it easier to spray but not as good really
 
Thanks for your response. I thought I was the only one that noticed.
 
probably not officially but you can flatten out just about anything. i also add fumed silica to the epoxy on a rare occasion to make it build up on these certain plastic parts i do. works great and you can hammer it on like its polyprimer with no weird textures or anything like that. the flattener i assume does roughly the same thing. flattener is usually talc so when thats added it just changes how the stuff goes down.
 
I would never have thought to put flattener in the epoxy, at i'm not sure I would want to now.. lol
 
haha. i forget, awhile back i needed some good coats on something and if you put that on heavier then it gets a bit glossy. it was a final finish so i put some flattener in it and was amazed at how it sprayed. i have done it quite a few times since. you can add fillers to almost any kind of resin especially epoxy. there is solvent in epoxy primer so you dont want to overload it but it certainly will bind a fair amount. epoxy is a strong plastic resin when its cured. i have used many epoxies over the years from floor epoxy, casting resin, laminating resin and of course primer. you can mix all kinds of stuff into it. saw dust, silica, aluminum powder, micro balloons. believe it or not i use saw dust in west system epoxy all the time.
 
Guess it makes sense as long as you don't go crazy, it would probably compromise the strength of the product a bit but epoxy is pretty tough. I am pretty jazzed about the SPI Hot Rod Black for flattened stuff, though, not sure where a flatter epoxy would be useful.

You use SPI flattener? What percentage?
 
yes spi flattener. as for amt, i have no idea. its been awhile so i really forget. it didnt need a whole lot. if i had to guess maybe 10-15%. normally for flat i always use the spi hrb. in the case of the epoxy i dont think i bothered to measure the flattener because it didnt really matter. just wanted it flatter.
 
Jim C;37439 said:
i also add fumed silica to the epoxy on a rare occasion to make it build up on these certain plastic parts i do.
Click to expand...

Ah Ha!!! Busted I say. Is that your secret to smoothing your 3D printed parts?
 
haha you got me!! actually no i was just kidding. i use the epoxy like that for these poly pieces on one of the sportbikes i paint all the time. they have this leathery texture to them. gotta fill it and sand smooth. regular 2k just doesnt flex like the epoxy does on plastic parts. the epoxy doesnt shrink either.
 
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