hey yall. i have a model that has to be done in exactly three weeks and two days for a Scale Auto forum CBP. the only thing left to do is throwin putty and paint. since im using a Testor’s enamel spray can, i have to wait for the paint to cure before i can do any work on it. enamels usually take a week or so to cure, and i have to spray paint three different times. like i said, i only have three weeks to finish, you do the math. so i need some suggestions on what i can do to help my paint cure quicker. ive heard of usinga food dehydrator, but i dont have one and the only one i can find is my grandmas. i know i would have to "modify it to fit a model and i dont want to destroy her dehydrator, dsince she uses it pretty regularly. im not sure my current technique cuts down on time any.i have a desk lamp that gets pretty hot, pretty quick. i bent a new “low-rise” spray stand that holds the model further away from the lamp. i turn the lamp on and turn it so taht its facing directly onto the model. will this help speed up the curing time? thanks for all your help and sorry for the long-winded post, im in a typing mood tonight. later.
Jon
[#wstupid]
I don’t know if this will work but try using the dehydrator in a plastic storage container with a lid , you can get some big one for the local hardware store.
Seal it off where the cable comes out .
the storage box turns into a large dehydrator…all been well…
Cheers mike[:p]
A week sounds like an awful long time for enamel to dry to me. 24 - 48 hours is normally sufficient time for it to fully cure unless it’s some kind of unusual paint. I have even painted on top of enamel after leaving it to dry for only a few hours (as in 3 or 4) but I was in a real hurry.
The best way to decrease drying time is forced warm air (not real hot, you don’t want to warp the plastic, just warm). You can use a box big enough to cover the model. Cut a hole in each end and cover them with coffee filters. Cut another hole the bottom the same size as an incandescent light of some sort (the kinds on flexible arms work well). Put the box over the model, blow air from a fan in one end of the box and the coffee filters will keep dust and dirt out. Put an incandescent lamp close to the hole that is now in the top and let it heat the air inside.
Have you ever heard the expression “baked on enamel”? Well thats exactly what I have done for a few models. I have an oven that shows the temp on a digital display so I can heat it up to around 100-120F. I put the model in for around 10mins at a time with the door cracked to let moisture out. What can I say, it works for me [:p]
However, I also agree with Musiccity. If you shoot the paint in thin coats, it shouldn’t take more than 3 days to cure.
I am no expert on gloss finishes guys but I understand that it does indeed take a long time for enamels to cure completely so that they can be sanded and buffed out to a glass shine.
I have a modeling tape that some of you may have from the Modeling Workbench series that is called, “Model Finishes & Painting Techniques” with Chuck Davenport.
On this tape he says that after painting the gloss finish you should let the model sit for 10 days. That may be overkill but I see his point of making sure it is completely cured from top to bottom before doing the rubbing out.
Mike
Mike is correct. Paint will harden first on the surface. It forms a crust with the paint under the surface still tackey. It takes time for the lower surfaces to cure because they are not exposed to air, which speeds up drying.
The trick is to paint in layers. Just paint enough to cover the subject (sometimes called misting). Let that dry, usually several hours. Then put on a second coat. Keep applying light coats, allowing each to dry before adding another coat.
All heat does is speed up the drying of the top surface. Handeling the model after may cause damage to the surface as the lower levels are not hard or cured. Sanding will cause more damage. It is best to wait for the paint to completely cure.
Good post Bernie and very true. [;)]
Mike
but once i put a thin red coat of red humbrol on a model and it took 6-8 weeks to dry 3/4 of the way
Ryan,
There were other problems involved to cause that.
Was the temperature too cold? If it is under 60 degrees or so it can take paint a long time to set up.
Mike
Amazing, I never would have thought it would take that long.
True, but once the top surface is dry capillary action will pull the solvents from the lower layers up to the surface so that they can evaporate. I have some rattle-can paint downstairs that reads something to the effect of, “Dries to the touch in 15 minutes, fully cured in 24 hours. Forced air drying decreases curing time.”
any acrylic car paints that I have used will fully cure in 24 hours.
If I were you I would ditch the enamel and go for the car paint.
Prime then dust on light coats and sand with those really fine nail boards that
you find at pharmacies.
Then gloss coat and polish with a tiny amount of metal polish paste (Peek or Weenol)
It will look like the real thing .
For a car model, you really want the paint to be fully cured before you polish. I’ve found that there are a few choices in this situation:
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You can build/use a drying booth as mentioned. I don’t have one, but I have put the model under a ‘light’ with a light fan blowing air across it. Seemed to work OK with the Humbol enamel I was using (my experience is that Humbrol enamels are about the slowest to dry/cure that I’ve used.)
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Change paint (although it sounds like you’ve already done some painting). Using a lacquer paint will decrease drying time significantly. Some rattle can paints are enamel, and some are lacquer. Pay attention to the label, or do a 'net search on the brand name and you’ll likely be able to find out exactly what kind of paint it is.
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Let the paint dry on it’s own. If you’ve got 3 weeks, that should be good. Do as much pre-assembly as you can. The only thing I think you’d really need to wait for ‘cure’ time is the car body. Assemble as much else as you can, then finish it off when the paint is cure.
Good luck, and hopefully we’ll see some pics over here too!!
Murray
Mike: It was in a 20ish degree weather, untouched, a really thin coat, red, humbrol. little moisture since it was in a sealed room, but still enough for comfert if you just walked in
Although that still sounds like a long time, Humbrol enamels do seem to take quite a while to completely cure (at least that’s what I’ve observed). On the other hand, I think they’re one of the smoothest, nicest paints I’ve ever worked with (except for those pain-in-the-@ss little tins…)
BTW, I’ve also found that the longest cure times are on black or silver paints. I have no idea whether or the the color makes any difference, but these two are ‘extended-dry-session’ paints for me (especially if I’m going to polish). Perhaps red is in that category too?? (although 8 weeks is still way outside of anything I’ve every seen. My max was about 3 weeks with a too-thick coat of Testors Silver…)
Murray
That depends on the chemistry of the paint Scott.
The rattle can paints are not normally sanded and buffed to a high gloss either and that is why they say it cures completely in 24 hours. Actually I doubt it is cured completely but for what most people use those paint cans for it is cured enough to handle. [;)]
Mike
No wonder it didn’t dry! [:0][:0]
There is no way paint is going to dry in those temperatures.
Mike