I feel your pain, but you can do it with epoxy. What you are calling ‘blush’ is actually what I call ‘froth’. Tiny bubbles that make the resin turn milky, usually from over-working it with whatever tool you have (squeegee, brush, roller). Am I right? It looks HORRIBLE over dark colors, and wood.
Blush is usually the term for the soapy-like film that forms on top of the epoxy if it cures in cold or high humidity, and it just washes off with water and a green scrubbie, or light sanding. If this is your problem, then ignore the following:
The main froth problem is the viscosity. Thicker liquids will trap bubbles easier than thinner ones (think syrup vs water, put each in a different small bottle, shake, and watch what happens to the bubbles). There are several approaches to deal with this when using epoxy. One is heat, the other is thinning with a solvent (like Add F or Denatured Alcohol.
With the heat, you have a shorter time to make things happen. OK for a hot/gloss coat, but not when laminating. Also, I find that the recommended AddF by itself is not enough for me to get almost bubble-free hot/gloss coats (the only way to get them truly bubble-free is to apply vacuum to the mix to ‘boil’ the bubbles out before brushing, then only the brushing adds bubbles). Here’s my latest formula which works very well between 75 and 85 degrees:
Hotcoat:
measure 1.5 oz of resin per foot of board (you may be able to use less, but I like having leeway)
measure your hardener
measure 1cc of Add F per oz of resin
measure 0.5cc of Denatured Alcohol per oz of resin
Heat the resin 1-2 sec per oz in the microwave
Add hardener to warm resin, stir until it clears
Add Add F and DNA, stir until well mixed (about a minute)
Strain through paint strainer into another container
Get that stuff on the board, only cross-stroke once and walk/tip out and WALK AWAY. Every brush stroke more will just add more froth, because the warm resin begins to ‘gel’ quickly.
Example: 10 foot board:
15 oz resin
7.5 oz hardener
15 cc Add F
7.5 cc DNA
microwave 15-30 sec
For gloss:
Same as hotcoat, but with 1cc DNA per oz of resin, to make it thinner and flow better
For the example above, instead of 7.5cc DNA, you would add 15cc (the reason for this is the gloss need not be as thick as the hotcoat, and you want it to level better as well, to make wetsand and polish easier).
At 85 degrees, you need to work fast. It sets up fast enough that if you take your time brushing, you can see the brush strokes on the last side you walked out, while the first side levels well.
Once you get it right, you will know. It will flow out great, and best of all, sanding is cake. I now know why sanders can sometimes not hold hotcoaters in high regard…
I know that the thinning amounts are high, and reduce the epoxy’s physicals (strength), but the hotcoat and gloss coats do not contribute nearly as much strength as the lam does, and I only use the recommended Add F (1cc per oz of hardener) in the lam to keep the physicals strong where it is needed most.
If you are like me, though, the lams (especially laps over dark airbrush jobs on the foam) are frothy too. There are two ways to combat this: Do all artwork on top of the sanded hotcoat (can’t see the froth easily on top of a white surface), or modify your lam technique. Since heating is the only acceptable way to thin the lam (too much solvent makes the epoxy weaker), the easiest way to have thin resin and the have the time needed for a good lam (for my amateur/garage hack status) is to use a slower hardener, and wet your laps separately from the flats (do not squeegee the flats and use the frothy mess to wet your laps). The other way is to use 2 warmed resin batches, one that you spread over the flats, and while it is soaking in, another that you carefully brush onto the laps (tip from MrJ), then you squeegee out the excess. There are people (surferdave is one that comes to mind) that use rollers with good results.
To tell you the truth, I have never used poly, but the smell from boat fiberglass repair places in town (no surf shops in Lubbock) makes me never want to use it in my garage, which is only one door (with a cat door in it) and 20 feet from where I sleep.
If you have any questions about all the stuff above, let me know.
JSS
