This is probably a question in the old archives but…can I put an epoxy gloss coat over a polyester hotcoat? If yes, are there any advanatges to doing it this way? To what grade should I sand the hotcoat?
Like the above said, it will work perfectly! No special sanding needed. A2tall has made a mistake, the mechanical bonding issue is with poly on epoxy (not with epoxy on poly).
the advantages of using epoxy gloss:
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Epoxy is more expensive
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More and harder sanding work
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Yellowing
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Precise mixing on scales
Or were these the disadvantages? The only real advantage for glosscoat I can think of is: * No penetrating smell
(Don’t get me wrong, I’m an epoxy guy! but this makes no sense to me)
Resinhead, I've seen you post this view before. Curious as to why? If the Poly is simply put over an epoxy board to achieve a high gloss, what's the problem?
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Cause it won't work and make you really mad...and when you get mad you do mean things, and when you do mean things to Po Po shows up.
you will only be getting a mechanical bond this way, you want to rough it up the rougher the grit (80-100 grit) the better the mechanical bond will be… more grooves or teeth. their is really no benefit by doing this. Why do you want to?
Epoxy won't shine out like poly gloss, or if it does you will blow out your rotor cuff trying to get it shiney. Just do it with a poly gloss.
And yes, epoxy over poly works, not poly over epoxy.
Resinhead, I’ve seen you post this view before. Curious as to why? If the Poly is simply put over an epoxy board to achieve a high gloss, what’s the problem?
I just wonder why you want to use a Epoxy over poly? Thats like dipping a egg in epoxy? Why
You want a high shine gloss then use gloss resin.
Epoxy will bond to everything but poly doesn’t really make a good bond to anything but its self.
I know they make a self leveling epoxy but its made for like molding and coating resin tables. Its thick as shit on a cold day.
I see no logic in useing epoxy resin as a gloss coat ! Epoxy is simply not a good product for gloss finishes . So I to am wondering why you want to do this.? But if I were to do so I would sand the hotcoat with 100 grit and be asking myself what the F am I doeing this for !!
I’m guessing the goal is to make it lighter? But no gloss coat will be lighter than an epoxy gloss coat every time : )
total bullshit’’ the same tired old chestnut geting trotted out again?
the reason there is a prblm is lack of knowledge. or lack of will for obvious reason
**oh and i have no idea? why you would even want to put epoxy over poly but we can all be a bit weird.
**
now go pluck a duck
cheers huie
Are you baiting?
You must be writing this from a Meth Lab!
There is no reason to do what you have stated if the intent is to acheive a gloss coat. Instead use Reichold gloss resin and forget about it. Having said that; It is a known fact that in lamination and subsequent filler coats that Epoxy bonds extremely well to Polyester. In marine application the first lam is often Poly with subsequent layers of Epoxy over the Poly. Adhesion problems are usually the reverse; Poly applied over Epoxy without proper surface prep.
Thanks for the comments and putting me in my place!! The reason I was or am considering a gloss coat with epoxy over the polyester is that when I did the hotcoat with polyester resin it went off with dollar sized holes! I don’t think these were air bubbles, it seemed as though the hotcoat layer contracted when it was going off and left these bullet hole dents all over the surface! I mixed the resin and catalyst correctly but I added a small blob of colour pigment which said was suitable for polyester or epoxy. The resin is a locally made, cheap resin from a builder’s yard and is thick to spread so I warmed it up first in a hot water bath. What did I do wrong? What causes these large holes in the hotcoat?
If the resin is to blame perhaps applying epoxy may help fill the dents and work better.
You mention holes? Did it make the foam dent like a golfball, or are we talking about fisheyes. Fish eyes are where the resin pulls away from the surface..ie, like when you try to paint over a crayon.
I've never seen resin make golfball indents in foam, so I'm assuming it's fisheyes. if its a fisheye issue then you had some form of contamination either on the board surface, or in the resin. usually it's a issue with the board surface. Things like oil, body lotion on your hands, something being sprayed in the area of the board..ie bug spray, oil, weedkiller etc.
How long did you let the board lay around before you hotcoated? Did anybody touch the board before it was hotcoated? were there kids anywhere around the board, and how many kids?
Pictures would help us tell exactly whats going on.
You mention holes? Did it make the foam dent like a golfball, or are we talking about fisheyes. Fish eyes are where the resin pulls away from the surface..ie, like when you try to paint over a crayon.
I've never seen resin make golfball indents in foam, so I'm assuming it's fisheyes. if its a fisheye issue then you had some form of contamination either on the board surface, or in the resin. usually it's a issue with the board surface. Things like oil, body lotion on your hands, something being sprayed in the area of the board..ie bug spray, oil, weedkiller etc.
How long did you let the board lay around before you hotcoated? Did anybody touch the board before it was hotcoated? were there kids anywhere around the board, and how many kids?
Pictures would help us tell exactly whats going on.
This is what fish eyes look like.
or like this
What did you use to mix the resin in? You said the resin was cheap, maybe it was contaminated in transit, in whatever container it came in, etc.
You have it exactly, it looks like the pictures above. So it is fish eyes. Can fingerprints cause the contamination? The resin was new and in a sealed tin and I poured it into a new, plastic measuring jug. I did wipe the board with a cloth and water before.
Should you always wear latex gloves when handling the board after laminating? Do you think that a final layer of epoxy will help fill the fisheye dents? Is epoxy better at self levelling? What would you clean the hot coat with before the gloss coat to make sure there is no surface contaimination?
Thanks for your help.
definetly contamination
you hit it with water!!!!!????
fricken why?
best way to glass is to lam it and hot coat in the same day
but if you must wait,,,blow off the dust then a lite acetone wipe is all you need to do before the hot coat with poly resin
let the acetone vent off before applying hot coat
when you gloss ,,,
sand the hot coat ,, blow it off ,, wipe with lite acetone,, drag a tape (litely) a few times to pick up any leftover dust
get the gloss on thin and WALK AWAY
you must have temps over 72 deg to get a bitchen gloss