|Nov 20, 2014, 10:59 AM|
United States, TX, Tyler
Joined Sep 2009
Nelson Hobby Paint - Water Based & Fuel Proof!
Nelson Hobby Paint Review-
Paint available here: http://www.nelsonhobby.com/hobby_paint.php
This review is from the viewpoint of a long time SPORT modeler and builder dedicated to flying smaller glow powered aircraft. I am not into helicopters, scale, turbines, front row finishes or formal competitions. Just a sport modeler looking for a long lasting, nice looking, glow fuel proof paint that is easy to use and doesn’t take longer to apply than it did to build the plane in the first place. Plus if I can find something that is safer for me to use, safer for the environment and easier to clean up, so much the better. Why not a water based hobby paint?
I considered latex paints but after much research have decided that although latex paint is cheap, it comes with two big problems. First off it’s not GLOW fuel proof, so as a dedicated glow modeler, I would have to top coat with something that IS glow fuel proof. Second, although latex dries to the touch in a short period of time, it remains soft until fully cured which can take up to a month. To me this means that it would be best to wait 30 days before top coating with a fuel proof clear. Too long to wait to save a few bucks on paint!
Previously I have used primarily nitrate and butyrate dope finishes with an occasional foray into epoxy finishes like Klass Kote and the now defunct Hobby Poxy. I like these solvent based finishes but the harshness of the chemicals, thinner, and fumes started me looking for something better, plus I don't like wearing a mask and glasses when painting. Since my shop is small, painting with dope and epoxy usually means dragging everything outside if I want to spray or ventilating the workshop if I want to brush.
I don’t like iron on finishes because after having tried just about everything on the market, I have not had any luck in applying them so that they don’t wrinkle or sag after a year or two. After I finish a plane, I’m done with it! I don’t want to spend the next 10 years ironing down wrinkles!
What to use?
Enter Nelson Hobby Paint.
What is it?
Nelson Hobby Paint is a water based paint manufactured by System 3 which supplies paint to the marine industry and is distributed to modelers by Nelson Hobby at Nelsonhobby.com. A large variety of colors are available many of which will match the colors of popular covering films. Military colors, clear and white primer are also available. Because everything is water based no special thinner is required. Tap water is the thinner, so paint thinning and clean up is simple and cheap. Plus it is safe for the environment and much safer for humans so don't drink it and you should be OK. You should probably still use a mask when spraying but you shouldn't need a very expensive one as the paint is much safer than traditional hobby finishes.
At first glance the paint may seem expensive but when you consider that no thinner is required it compares favorably with other finishing products. I have found that about 6 to 8 oz (1/2 pint) of paint will be plenty to base coat the average .40 to .60 size plane if the plane is properly prepared and the paint properly thinned and applied with a foam brush. A 1/2 pint or 8 oz is about $13.00.
How do you use it?
Nelson Hobby Paint is a 2 part paint that utilizes a paint base which is mixed with a very small amount of a cross linker to increase it’s chemical resistance and then thinned a bit with water and applied to your model. The recommended ratio is 4 parts paint to 1 part water. The cross linker is added at the rate of 7 drops per oz of paint base. Without the cross linker the paint is supposed to be fuel proof up to about 15% nitro and with the cross linker it is supposed to be fuel proof up to about 40% nitro. I believe that the recommended ratio applies to application with spray equipment.
NOTE: Although the directions don’t suggest a mixing ratio specifically for brushing, after much experimentation, I discovered that for my uses something between 8 to 1 and 10 to 1 works best for brushing with a foam brush. If you have a problem with runs use less water, if brush marks don’t flow out use a little more water. My procedure is to start with 10 to 1initial mixture and add a little more water as necessary. So do your own testing and find what works for you.
After this test was completed I was informed by John Desilets owner of Nelson Hobby that he has applied the paint straight from the bottle without thinning at all, just moisten the brush and go.
What makes it stick?
Besides being water based, the other interesting thing about this paint is how it grips the underlying surface. According to Nelson, their paint relies on mechanical adhesion, which means the base surface should NOT be perfectly smooth but instead lightly sanded before applying the paint. This is both good news and bad news.
Most paints including dope adhere by the top coat partially dissolving the coat underneath and thus forming a chemical bond. This is why different types or even brands of paint are often incompatible and cause problems. No worries with Nelson Paint as it is water based and won’t attack anything underneath, which means that it can probably go over almost anything as long as the surface is sanded first to rough it up a bit.
NOTE: John Desilets the owner of Nelson Hobby suggests that if you wait at least 20 minutes but not more than 24 hours between coats then sanding is not necessary. After 24 hours you must sand to insure adequate adhesion. For the record I conducted my own test to determine if I could apply trim without prior sanding of the base. I discovered that the paint stuck very well without sanding, at least for the trim.
I initially understood the directions to mean that re-coat must be accomplished within a very short period, 20 minutes or so, otherwise sanding after an overnight cure would be necessary before every re-coat. This caused some additional work on my test subjects as described herein.
Let’s give it a try!
I have to state right now that I have many character flaws, 2 of which have a bearing on this review! The first is that I can’t seem to ever find the perfect finish so am condemned to wander the modeling wilderness in search for the “Holy Grail” of finishes. The second is that I am not as patient as I should be, which means that I don’t typically prepare multiple test blocks all prepped for paint so that I can test different paints on scraps of wood instead of my models. I prefer to go “ALL IN” and apply the new finish to a new plane and let the chips fall where they may.
Applying Nelson Paint!
The Flea Fli
I scratch built a .19 size pattern plane called the Flea Fli with a foam wing NOT sheeted with balsa but instead just covered with tissue to save weight. The remainder of the plane is balsa and was also covered with orange tissue applied with nitrate dope which is the standard prep applied to smaller planes in my shop. So I have a nicely built orange tissue covered plane all ready to go. The fact that I have an unprotected foam wing covered by only tissue and white glue makes it a perfect test of a water based paint.
I mixed up some Nelson Paint per their directions (4 parts paint to 1 part water), orange of course, and proceeded to paint my orange base color utilizing a foam brush as suggested by the directions supplied by Nelson. The first thing I noticed is the LACK of any obnoxious smell! Awesome! The second thing was that the paint was pretty thin, did not cover very well and tended to run if applied even a little too thick. Plus it dries much slower than the solvent based finishes I was accustomed to using, causing runs anywhere the surface is vertical. If you are VERY diligent on applying an extremely thin coat the runs can be minimized. The lack of coverage wasn’t a huge problem as the base was orange tissue, however it still required over 6 thin coats to get a good finish. Even with 6 coats I can see wood grain through the paint and the tissue.
I hate sanding!! Nevertheless I suffered through sanding between each coat but in the end the finish was very nice with a satin almost glossy finish. So far so good! (I have been advised by Nelson Hobby that sanding between coats is NOT necessary if re-coated within 24 hours)
Now for the blue trim!
I had just purchased some special masking tape from the auto body paint shop that I also wanted to try. It was sold as being low tack and capable of unusually sharp lines for masking. I masked the plane off with a simple design, just a stripe or two as this plane was the first prototype and I intended to build a few more and maybe even make a few kits for my friends.
This time I got out the airbrush, mixed up some paint per Nelson’s directions (4 to 1) and fired up the compressor. When I sprayed the paint it started to run the instant it hit the surface, I don’t mean a little drip I mean run! Everywhere. Almost like airbrushing water onto a vertical piece of glass. Worse, the paint pooled against the masking tape. I mixed up a little more paint and cut the thinner (water) way back which meant more pressure to the brush to get it to flow. Results were a bit better with fewer runs but still not what I was looking for. I tried less pressure, more pressure, faster travel, slower travel, gun further away and closer in. I tried fogging a very light coat waiting a few minutes and then going back over it with a little heavier coat. I just couldn’t find the magic combination! Despite all of this I did manage in spots, to get a decent layer of paint down without runs and with acceptable coverage. It is possible but certainly not easy to do. Thin it enough to flow from the gun and it runs as soon as it hits the model, less thinner and it wouldn’t flow from the gun unless I turned the pressure WAY up. It CAN be sprayed but it isn’t as easy as dope. Perhaps my airbrush is poorly suited to spraying with this paint. A bad night in my shop.
It was here that I learned something about paint that I had never really considered.
When you spray dope or most any solvent based paint from a gun, the solvent largely evaporates BEFORE the paint gets to the surface. In other words the paint that leave the nozzle of the gun is much thinner than the paint that actually reaches the surface because the solvent evaporates in flight so that the paint that hits the plane is thicker and resists running. With a water based paint this doesn’t happen, the paint that leaves the gun is the same as the paint that hits the surface. So that if you normally thin your paint to a milk like consistency for spraying you will need to be really good at spraying water on to glass to get a nice finish. Perhaps if I had some other type of gun capable of shooting much thicker paint I would have had a different experience by using much less water. In any case spraying this paint so as to achieve a nice finish was well beyond my modest abilities and equipment.
So how resistant to chemicals can a water based paint be?
NOTE: The following problem is related to my choice of masking tape and is no reflection on Nelson Paint!
I waited about 20 minutes or so for the trim to sort of dry so that I wouldn’t make a bigger mess smearing blue paint onto other parts of my airplane as I removed the masking tape and paper. I felt certain that the blue paint would wipe right off with a bit of soap and water, sort of like latex house paint. Secure in this knowledge, I removed the low tack tape and discovered problem number two. The low tack tape STICKS! In fact it sticks so well that in spots, it was pulling up my orange tissue base on the fuselage all the way down to raw balsa. Did I mention that it was a bad night in my shop?
Miraculously the tissue stuck to the foam wing without problems and I was able to pull the low tack tape up without damage.
Problem number three; The blue paint creeped underneath the masking tape, EVERYWHERE! More salty language!!!
No problem I thought. The water based Nelson paint is not cured yet, a little soap and water and maybe just a bit of alcohol and the blue paint will be all gone!
I scrubbed and scrubbed with a paper towel with the following results:
Soap and water - No affect
Denatured alcohol - No affect
I discovered that if I REALLY scrubbed hard with the denatured alcohol I could flatten up the finish a bit but could not get it off, even after drying for only a short period.
I decided I had enough for one night. Time to consume adult beverages and think on this a bit.
NOTE from Nelson Hobby: I contacted John Desilets at Nelson Hobby to describe my problem. He suggested that after masking I should apply a little bit of the base color paint along the edge of the masking tape to seal it and to make sure that any run under the tape was the same color as the base. I have yet to try his technique because I’m lazy and found a much better tape! More on that in a minute.
The next day I surveyed the disaster. Through no fault of the paint, I had a scratch built plane that I could have flown the next weekend if I had quit with the orange and not used that blasted tape! Better yet I could have trimmed it with blue trim Monokote. Instead I now had a horrible looking mess of an orange plane with large swaths of bare balsa and blue trim with ugly paint creep everywhere. I decided that the foam wing was the weakest link. If I could fix the wing then I would keep the plane, otherwise the Flea Fli goes in the trash! I figured fixing the fuselage would be easy enough, take dope thinner and sandpaper to it and start over. Therefore, if I was to save the Flea Fli from the trash can, I had to get the blue up from the wing.
I already tried alcohol without success, what to do now? I decided on the Nuclear option. I would attack the unsheeted foam wing, covered only with tissue, stuck down with white glue, and painted with 5 or 6 coats of Nelson orange paint. My weapon? A rag drenched with Sig dope thinner. Either the blue paint was coming off or I was going to throw the gooey melted foam orange and blue wing mess in the trash. I scrubbed and scrubbed with the rag and did manage to take off a tiny amount of blue paint but not a lick of orange and the foam survived the ordeal intact.
For all intents and purposes:
Dope Thinner - No affect
I guess Nelson Paint is glow fuel proof and probably everything else proof as well!
It took me a couple of weeks to emotionally recover from my masking tape/paint removal disaster, patch the bare spots on the fuselage, refinish with orange tissue and nitrate dope and top coat with orange Nelson Paint. But soon I was back to where I started with an orange fuselage ready for trim and an ugly foam wing leaning against the wall. By the way the nitrate dope applied without problems OVER the existing Nelson paint. So much for the fuselage, the wing I’ll get to in a minute.
A Better Masking Tape.
I’ve had my eye on some green masking tape I had seen in Lowe’s called Frog tape (frogtape.com). A little online research indicated that it was good stuff so I decided to buy a roll and mask the plane once more. I also decided to apply the blue trim with a foam brush and forget all about the airbrush. I mixed up some blue with a little less water than Nelson suggested. The result was excellent, the blue paint covered much better than the orange and in fact I was able to get away with applying only one coat of trim on most of the plane. No brush marks, looks like it was sprayed. Finally Success!
Furthermore the Frog tape is the best tape I have ever used by far! Nice crisp lines, low tack and NO CREEP.
I decided to try something different on the wing. I found some trim Monokote about the same color as the Nelson blue paint and applied it over the ugly stripe on the wing and then sealed the edges with a little Nelson clear paint. Perfect!!
I think the true beauty of this paint besides being water based, is it’s ability to resist aggressive paints, chemicals and especially glow fuel. Plus I believe it can be applied over most other finishes as long as they are sanded a bit first. I think Nelson clear would be awesome as a glow fuel proofer over decals or latex house paint although I have not yet tested that particular application. It seems to adhere very well to underlying surfaces. I wish it was a little easier to apply with an airbrush and although the dark colors seem to cover well the lighter colors may not, orange sure didn’t.
NOTE from Nelson Hobby: Lighter colors like orange, white and yellow will require a white primer or base for best results. White primer is available from Nelson Hobby.
Nelson Paint Pros & Cons
Some colors match Monokote!
Military colors available
Can sometimes be applied over other paints
Other paints can sometimes be applied over Nelson
No offensive smell
Easy clean up
Cheap thinner - water
Good coverage with dark colors - I tested Blue
Apply with foam brush - looks sprayed if thinned properly
Resistant to glow fuel and most chemicals
Cures much faster than latex - doesn’t stay soft for days afterwards
Sands nice after 24 hrs
Poor coverage with lighter colors - White primer base is essential!
Slower drying than solvent based paints
Difficult to spray - at least with my airbrush
Runs easily when mixed as directed
Must sand base surface before first coat and if not re-coated within 24 hours
Final Note: I tried Nelson Paint on another plane! A .40 size balsa plane covered with silkspan on the fuselage and Polyspan on the wings then sealed with nitrate dope. The plane was NOT properly prepared with white primer base, I had previously primed it with automotive gray primer before purchasing Nelson paint. I sanded most of the gray off before applying Nelson paint. This time I tried WHITE! After about 6 coats brushed on with a foam brush I have a nice white glossy finish without any hint of the gray primer underneath. I have very light brush marks but not very noticeable.
To paint my .40 size plane which is a bit larger than average, and NOT properly prepared, I ended up using just under 8 oz of white paint to apply about 6 coats with a foam brush thinned as specified above. I think that a 1/2 pint of white, yellow or orange paint would be plenty for the average .40 to .60 size model especially if properly prepared with white primer. Darker colors would require fewer coats and less paint.
All things considered I like the paint and have decided to use it exclusively for all of my future models. It is WAY more fuel proof than I need, much safer to use, no smell and easy to clean up. I’m pretty sure that I will be applying it with a foam brush from here on out, I only used one foam brush for each plane! Clean up with soap and water is great. Although the cost might seem a bit high at first glance, the fact that no special thinner need be purchased, and less than 8 oz of paint is required for a large 40 size plane makes it comparable in cost to Monokote.
I encourage modelers to give this paint a try. A little patience will be required to learn the different techniques required in it’s application, but I’m sure the benefits will be well worth the effort. Best of all John Desilets of Nelson Hobby is friendly, responsive, helpful and knowledgeable. I understand he is also a professional Yacht painter and a fellow modeler and thus well qualified to offer useful advice if you get in a bind.
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|Nov 20, 2014, 12:43 PM|
United States, WA, Lyle
Joined Jun 2005
Eugene I think that was a pretty fair review of the product. I do quite a bit more painting than most folks so the feel I have for the product is very comfortable.
If you order Nelson Hobby Paint by all means read tips and tricks on my paint page.
I like to discuss projects with builders.
My biggest issue is and always has been the paint wont stay on, it comes off with the masking tape. As Eugene has stated if you prep the surface with 220 grit the paint flat out will not come off. Very tough stuff, it is a marine finish and that in itself speaks volumes about the durability of the product.
Thanks for the comment and Happy Landings. John, Nelson Hobby
|Nov 23, 2014, 10:30 PM|
United States, TX, Tyler
Joined Sep 2009
Update #1 to Nelson Paint Review
I've been working on my .40 size Balsa USA Mars finished with Nelson Hobby Paint white so far.
I masked some trim stripes with Frog Tape after letting the white dry for a couple of days. Then I sanded the areas to be trimmed lightly as suggested by Nelson.
This time I tried John's tip about applying a bit of the base color with a small brush along the masked line to prevent paint from creeping under the tape. Bear in mind that I DID NOT have previous problems with paint creep when using Frog Tape. But I thought I would give it a try anyway. Can't be too careful!
It took about 5 coats of Nelson orange thinned at about 8 to 1 and applied with a foam brush to cover. I applied each coat at 90 degrees to the underlying coat to try to reduce paint streaks which are pretty obvious with the first few coats. I waited about 30 minutes between coats.
I waited about 2 hours then pulled up the masking tape. The base coat stuck down firmly without pulling up with the masking tape. John's tip about sealing the masking tape edge worked great! Nice sharp lines.
It all came out very nice in my opinion! Super easy to get a nice finish without a spray gun and all the masking and sealing.
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|Nov 23, 2014, 10:51 PM|
United States, TX, Tyler
Joined Sep 2009
One other note:
I've been developing a technique to better apply the paint with a foam brush. The biggest problem with a foam brush is that it holds too much paint making it difficult to apply in thin coats. Here are two tips: First the paint seems tho thicken slightly about 30 minutes after mixing so you might want to wait a bit before applying the first coat. Be sure the container is capped while you wait. Second I dip the brush into the paint and then gently press the brush down onto the surface in 3 or 4 spots on the area to be painted to squeeze out a bit of paint and distribute it over the area. Then I brush over the spots to evenly distribute the paint. As this paint dries slower than solvent based paint, you can go over a recently brushed area again to even out the coat.
|Nov 24, 2014, 10:57 PM|
United States, TX, Tyler
Joined Sep 2009
I haven't tried alcohol as a thinner for spraying. Perhaps John will pipe in and offer some advice. I think my problems with spraying are more related to my equipment and inexperience with this particular product. System 3 recommends HVLP equipment, they also say that typical pressure systems can be used. This paint is very different in application than traditional hobby paints.
However the foam brush is so easy, much less masking and mess and the finish almost as nice as spraying. Plus clean up is super easy, just wash the foam brush in the sink.
Why bother with the spray equipment?
|Nov 25, 2014, 09:08 AM|
United States, TX, Tyler
Joined Sep 2009
The System 3 application guide provides much useful information that when added to the info from Nelson Hobby, gives a very complete guide to successful application. Sadly, I only now discovered the availability of the guide.
Link to System 3 application guide: http://www.systemthree.com/reslibrar...Literature.pdf
|Nov 25, 2014, 09:23 AM|
United States, TX, Tyler
Joined Sep 2009
Highlights from the System 3 application guide listed in my previous post:
Paint cured without crosslinker may be recoated up to two weeks without sanding. However, a crosslinked film, because it is much tougher, must be sanded if recoating takes place more than one day after the previous coat was applied. Some sanding can be avoided, at the sacrifice of some durability, by mixing crosslinker into only the last coat. The crosslinker reacts with the polyurethane resin in the paint, but also reacts slowly with water. Crosslinked paint not used within 20-24 hours will lose the added durability. A readdition of crosslinker can be done, however, without any loss of properties.
Temperature: Use when the ambient temperature is between 55 85°F. Humidity: Higher humidity will allow the paint to stay wet longer. This will allow easier maintenance of a wet edge, and better paint flow-out before drying.
The amount of thinning will depend upon the environmental conditions and method of application. The recommended range is up to about 30%. The optimum amount of thinning will depend on the temperature and humidity.
It is more difficult to get good results in hot dry weather as the paint can dry in the air before contacting the surface when spraying, or before leveling out when brushing or rolling.
Subsequent coats may be applied as soon as the previous film has set and is not marred by a light touch. This is about 30 minutes at 80oF and 50 percent relative humidity. The previous coat may be masked in about an hour. Recoating of crosslinked coats should take place within eight hours of the subsequent coat while non-crosslinked coats have a non- sand recoat time of about two weeks. If more time than this elapses you should sand the previous coat to remove the gloss. Apply a minimum of three coats, four if sanding and buffing.
A crosslinked coat will be 90% cured in about four to seven days. However, polyurethanes do not develop 100% of their properties for two weeks.
Cleanup: Both the primer and topcoat should be cleaned up with water immediately after use.
Masking tape should be removed as soon after applying the final coat as the paint won’t run, but before the paint has dried. Cover any adjacent areas to protect from overspray.
While these products present no serious safety hazards, some precautions should be observed during use. Try to keep the material off your skin. Cured paint is difficult to remove without strong chemicals. The paint crosslinker and primer activator are skin sensitizers. They can cause a severe allergic reaction from prolonged and repeated contact. Except for the Activator all the products mix with water so you should immediately wash them off if skin contact occurs. Remove any Activator by washing in soap and warm water.
It is not necessary to wear a respirator when applying these products by roller or brush.
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