Enamel Paint

[jon_norstog]

I am continuing to experiment with Rustoleum. I painted this fork with the mix described above. It was 60 degrees when I sparayed which made it easier to apply too much paint. I applied some red paint, then put a band of 3M vinyl tape around the fork, then applied the black. Seemed to work well. Here is a picture of my gun and supplies and the fork.Attachment 105000Attachment 105001

Russ Kanz

That particular spray gun - actually it's a big airbrush - is pretty decent. I have a Sata MiniJet, but I find myself using the cheap gun a lot, I just mixed up about 1/4 teaspoon of black urethane this morning for a paint repair and used one of those. I have used that gun to shoot a whole frame, color and clear.

I haven't used Rust-oleum on a frame, but I have used it for other things. I have used automotive enamel. It is a lot cheaper than the 2-part stuff, plus if you have leftover paint you can dump it back in the can.

jn

"Thursday"

[jclay]

Supplies are on deck, orange is the goal. I'll try using acetone as the thinner since I have a gallon on hand. If that flashes too quickly I'll try something else.

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[jclay]

Test tube, clean metal primer with a tad of mineral spirits to thin; the primer can didn't list acetone as a thinner and if it works then that's one less chemical I have to keep around. The color cans say MS or acetone so maybe go with acetone there for a quicker flash? Russ, any advice as to time between catalyzed color coats?

I'm guessing that I'm in for a day or two dry time on the primer since I didn't use purpose formulated reducer and its 50ish degrees hereabouts.

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[Rkanz]

I think the reducer speeds the dry time. Paint thinner works but will not dry as fast, and the final paint will be softer. Acetone should flash faster than paint thinner. My primer dries overnight when thinned with reducer. Temps in the 50's may slow that down. I just spray light coats until I get the coverage/film thickness I want. On a frame I just keep going around until i get a nice wet looking coat. The clear goes on thick and shrinks a fair amount as it cures.

I just used red and yellow to mix an orange that is really close to the vintage Merckx orange. I started with a 50-50 mix and added more yellow to get the color. I put a small sample on white paper and hit it with the heat gun for a quick dry. Then adjusted and repeated.

[jclay]

Two color coats today.

I mixed roughly 50/50 sunrise red and sunburst yellow, changed the ratio a little in an attempt to get orange but ended up with salmon. Rustoleum sunrise red is a pretty dark, blood red, not a bright red. I'll have to experiment further to see if I can get something close to a Molteni orange out of it. Which red and yellow did you use? I'll try mixing droplets to figure out if I can get the Molteni orange.

I had a mental lapse and used mineral spirits for thinning instead of acetone. With such small quantities and ¼ teaspoon measuring spoons I could only eyeball estimate; maybe 30% thinner. I added catalyst at as close to 1:16 as I could. The first coat went on smoothly and leveled well. I gently heated it with a heat gun to speed the flash. About 20 minutes later I applied the second coat. It didn't look thicker in the gun but it certainly didn't spray well. It's as though it wouldn't flow and produced a matte finish. Through brute force (via very slow gun sweeping) and the intrinsic leveling qualities of the paint I managed to beat the matte finish out and get a reasonably slick second coat on. That's curing now. I'll leave it alone until it seems reasonably cured and then apply the clear.

It'll be interesting to see how the MS thinned approach works but I'm going to pick up a can of either the Majic or Rusto reducer and do some tests with that.

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[Rkanz]

Add more yellow and you will get the orange you want. It takes more yellow than you think is right. I don't wait that long between coats. The catalyst will make the paint gel - turns to cottage cheese. Reducer makes a big difference. It looks like you have really good gloss.

Russ Kanz

[jclay]

The on-line color tools had me going in the other direction but I see what you mean. I'll shoot some at larger scale, at shorter recoat intervals, to better see where it goes, color wise.

The gloss is good in spite of the problems I had. This morning I had to dig a fingernail in very hard in order to get a scratch. It seems pretty tough. I think I'll shoot some clear on the current test piece later today to see what happens.

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[jclay]

Shot one coat of un-thinned clear over yesterday's work. I think it's a little more glossy than before but it isn't a night and day difference. Increased toughness and UV protection will be nice though, if that's what it provides.

I put ¼ teaspoon of yellow into a cup and added one drop of red at a time, off the end of a toothpick (small drop), mixed and smeared onto white cardboard. You can see the evolution. It's orange-ish but too flesh toned until it tends towards salmon. My red isn't a bright, primary red; something else is going on in it. At least that's all that comes to my mind. I don't see how I can get to a real orange with it. It's not a bad red by itself though, much like my CX bike.

I'll swing by a Kuboto dealer and see if their signature orange rings the bell. If so then it's back to TSC for a quart of Kuboto orange. Unless I just punt to red straight out of the can.

But this is looking like success in terms of using inexpensive alkyd oil paint. It's simpler, less expensive, seems tough enough so far and comes out glossy.

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[jclay]

Rustoleum Farm & Implement Kuboto Orange

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Kuboto Orange with varying amounts (small) of yellow added. The large smear on the right is stock, no yellow added, and isn't very true to the actual color. The dab on the tube above is much closer to what the color actually looks like, at least on my monitor. It's a pretty intense orange.

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Not exactly a Molteni orange but I like it; and best stock but tinted with a little yellow is nice too. It's definitely far more orange than it appears on the cardboard.

[jclay]

After 24 hours in a 50 degree shop the clear can still be dented by a fingernail. I'm wondering if the activator can be used to speed things. I haven't been able to find much tech info. I suppose I'll give it a try.

[Rkanz]

It dries slowly. Put is somewhere warmer, it will harden. You are at or below the recommended temperature.

[jclay]

Attic when the sun's out.

[Andrew R Stewart]

Finally something I can add:) When I had my last Doug Fattic paint job we (and I did a lot of the prep/grunt work) used my car sitting in his open yard as the baking oven. With careful bracing no paint touched interior and a few hours later the 100+ degree interior made a world of difference.

My limited experiences with paint of many types is that they are very temp sensitive. Even just 10-20 degrees change can be a big deal. Andy

[Bewheels]

I can not add anything regarding the paint type and/or drying that hasn't been added - but once upon a time and I did a lot of work in the color correction space (digital and physical).
One trick to mixing is to determine a weaker 'base' color that and add very small amounts of the dominate color into the weaker color at a time.

For example:
If you are trying to get any type of grey...
If you start with black and add white to it, it will take a lot of white to make the color shift.
However, if you start with white, it take very little black to make the color shift.

If you are trying to get orange...
If you start with red and add yellow to it, it will likely require a large amount of yellow to shift the red into the orange range.
However, if you start with yellow, it will likely take very little red to shift the yellow to orange.

If you have a pint container of yellow, you can add a very small amount of red then mix. See where you are. Add an even smaller amount of red and mix. See where you are. There is a tipping point of adding the stronger color so each time you add more into the overall mixture, it takes exponentially less for the color shifts to happen.

The chemistry of the paint will play a role. Using artist oil paints, there are certain known combinations regarding what color will be the dominate color within a mix. While this general translates to other types of paints, it can vary and dyes are another story all together.

This may all be a very known thing within this group and I perhaps just stated a very obvious thing... but I used to witness a lot of wasted materials.

[jclay]

^^ Helpful information Brian. Thanks.

Andrew...nice job with the car as a paint baking oven! The attic above my shop is an excellent baking oven for most of the year. It's kind of embarrassing that it took me about a half dozen paint jobs to realize it.

It's been largely overcast and cool for the last week but some sunshine is on its way. I expect my test paint curing will accelerate soon.

[Andrew R Stewart]

I have used a variety of warming methods over the years. If the paint is somewhat dry (but still impressionable) the handling to get the frame above your local pizza shop's oven for an over night stay goes a lot easier:) as also placing the frame above the house furnace. Attics in the summers, cars in sunny warmth, kitchen ovens with a "tent" of sheets over a chair, hair dryers and more.

The curing rate of most paint is not linier WRT the temp levels. So if the painted frame is, say, 75* it might take days/weeks to fully harden. At 125* it might take a few hours and at 175* it might take under an hour. I would caution of not going too hot. I have seen decals gain "zits" when heated to 300*+. I suspect the out gassing of the paint under the decal was too fast for the gas's ability to escape through the decal.

I have toyed with building a curing oven/box. It would be a simple wooden construction with some baffling to deflect the direct blast of hot air coming from an industrial heat gun and an exit port placed just so.

What makes this all easier is to have some frame holding/support tools. I've brazed onto Bb cups and a der mounting bolt lengths of rod which can act as handles to carry and feet to place the frame flat or hang with. Doug Fattic used wooden shafts which can fit in the head tube and stick out past the HT as hand holds and such. Andy

[jclay]

I have used a variety of warming methods over the years. If the paint is somewhat dry (but still impressionable) the handling to get the frame above your local pizza shop's oven for an over night stay goes a lot easier:) as also placing the frame above the house furnace. Attics in the summers, cars in sunny warmth, kitchen ovens with a "tent" of sheets over a chair, hair dryers and more.

The curing rate of most paint is not linier WRT the temp levels. So if the painted frame is, say, 75* it might take days/weeks to fully harden. At 125* it might take a few hours and at 175* it might take under an hour. I would caution of not going too hot. I have seen decals gain "zits" when heated to 300*+. I suspect the out gassing of the paint under the decal was too fast for the gas's ability to escape through the decal.

I have toyed with building a curing oven/box. It would be a simple wooden construction with some baffling to deflect the direct blast of hot air coming from an industrial heat gun and an exit port placed just so.

What makes this all easier is to have some frame holding/support tools. I've brazed onto Bb cups and a der mounting bolt lengths of rod which can act as handles to carry and feet to place the frame flat or hang with. Doug Fattic used wooden shafts which can fit in the head tube and stick out past the HT as hand holds and such. Andy

Until using the attic above my shop dawned on me I was planning on building a shallow wooden box with a steel lid, all painted flat black. A few accoutrements inside the box to hold the frame and set it in the yard with the largest surface area facing the sun and there you go. Possibly a few small vent holes, some on the bottom, some on top. But in my case the attic is perfect. Plenty hot for 8 months of the year and even in winter it's hot enough, just not every day or even every week, but often enough.

The rule of thumb that I remember from somewhere is a doubling of chemical reaction rates for every 10F increase in temp. I'd imagine there are plenty of exceptions but for the purposes of painting bicycle frames it makes the point. Heck of a lot faster at 125F than at 80.

I think we're going to get some sun today so I'll see how the clear cure is going.

[jclay]

The weather hasn't been conducive to painting and won't be for at least the next week and a half. In the meantime I'm going to apply some model airplane decals to the test piece and shoot it with clear to see what happens. I don't know anything about decals. The test piece isn't fully cured but has been slowly getting harder and tougher in spite of the cold and wet weather.

[jclay]

The weather cooperated this afternoon. I shot the primer. It went on well.

As an aside, I did a lot more hand prep and leaned very little on the abrasive blaster than with all previous frames. That was rewarding.

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[jclay]

My latest attempt at Molteni Orange.

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