After I have sanded down my epoxy filler coat(240grade). I clean the board with alcohol then spray a clear 2 pack on but I always have to sand this back (400grade)and in some spots sand down to the epoxy so I always end up doing a second respray with clear, which fills in the dips and gets sanded.
Ideally I would like to do just one spray and a light sanding. Which means doing a perfect spray.
So I’m after any tips or advice on spraying clear 2 pack, If I spray a white 2 pack no problems just a light sand and it looks sweet. But that kills the look of balsa.
After the clear has dried and I have sanded it there are lots of shiny low spots like small craters 1 to 3mm in diameter that really stand out against the sanded area, I’m using a Asturi gravity feed spray gun with a 1.9mm nozzle and the clear is industrial strength UV acrylic base with an epoxy type hardener.
I’ve also been wanting to give the stuff a try. The stuff that Bert uses is called U-Pol. It come in two forms: a spray paint can and the stuff that you mix yourself and put in a sprayer. Greg also sells a water based product that cleanlines says he really liked.
there are a few great one pot polyureathane paints .that can be brushed on or put on with a rag… they are self leveling so you dont have to sand the second coat.
i intend to try something like this on my latest board… i found the two packs(when repairing boats) really smelly
I’ll second the “speed spray” that Greg Loehr sells, its tough and covers well. It is a flat matt finish when done,not glossy…easy to spray. Keeps my boards lighter with no gloss coat after the hot coat…I like it…have fun…
2 pack is a paint in one container and a hardner in another and you mix the two which gives a super strong finish, most 2 packs have isocyanites in them but the one I have got my hands on is iso free, they are used usually in the auto trade or as industrial coatings. I really want to learn how to spray the stuff rather than just roll or paint it on. I think there are so many variables in spraying that it’s just going to be tial and error process and a lot of paint use.
Bote-cote have a “non-toxic” waterbased polyurethane paint/sealer line called Aqua-cote. Haven’t tried it, but it looks good, a little expensive though. Check:
Do you have an in-line filter on the air supply side of your compressor? Water or oil contamination can cause a “fisheye” depression in the finished surface.
Hi Pin, I have tied the bote cote stuff last year it was terrible didn’t bond well to the board it peeled of in big sheets like thin vinyl rang em up and they weren’t very helpfull or interested, love their resin though.
Yes I do have an inline filter between the tank and the line out, I was thinking that maybe I need a second one up near the gun as then any moisture in the line would have time to cool and condense into bigger drops to get caught in the second trap.
Thanks Bluejuice. I was thinking about odering some Aqua-cote today, glad I didn’t. Maybe adhesion problems are why they reccommend you use the fairing epoxy under the Aqua-cote.
Pinhead I did some test samples after my disaster with the stuff using various different primers and undercoats and on to straight epoxy and I still wasn’t very happy with the bond. A week later the stuff I had peeled of the board still wasn’t hard and dense/brittle it was soft and flexible.
Hi Guys, I’ll go off on the UPOL stuff again. It’s 2 bags in a compressed can, its expensive, its easy to use, it drys rock hard & scratch resistant, and it polishes out like gloss resin. It’s super toxic, and it’s hard to find. I got a local automotive place that always keeps a few can around for me. You can buy it in a 2 part set up, but you have to watch your mix and pot life. If it kicks off when your spraying it, your spray gun is toast. Yeah soaking in Acetone will clean it up, but it kills all your O-rings. The spray can is soooo easy to use.
I use a 2 pac acrylic car laqueur on my balsa boards, also have the separation problem, but mine is due to small pinholes from laminate that leave depressions in the sanded hotcoat. The best finish I have found is to brush the first coat as you would a gloss resin coat, making sure all pinholes are filled. Sand back almost to epoxy, then spray final coat, this can be polished if necessary. I much prefer using the water based speed cote, much better for you and the environment, but sometimes you just need that deep gloss!! I am also not happy about using a polyester gloss coat on epoxy, doesn’t make much sense to put all that resin on a lightweight board.
Hi Mark, I was discussing this issue with a friend who make sailboards he too thinks it’s more likely pin holes in the resin rather than oil or h2o in the line going on the board, When I do solid white on sailboards I put a primer on 1st with a roller which works into any pin holes. Looks like I’ll have to do the same with the clear 2 pack. Thanks for your input.