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I bought an Ivation 6 tray food dehydrator.  I put some parts in with 1K urethane clear and also parts with clear lacquer for 10 hours at 113 degrees.  Nothing cured.  Some of the parts were painted a few weeks ago and the clear was still not fully cured.  The dehydrator did nothing.  I thought it was going to make a difference.  I'm just going to return it.

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On 1/14/2022 at 11:18 AM, crowe-t said:

I bought an Ivation 6 tray food dehydrator.  I put some parts in with 1K urethane clear and also parts with clear lacquer for 10 hours at 113 degrees.  Nothing cured.  Some of the parts were painted a few weeks ago and the clear was still not fully cured.  The dehydrator did nothing.  I thought it was going to make a difference.  I'm just going to return it.

Nothing? Well, it  kept your painted items at 113 degrees F for 10 hours.  So it did its "thing".  Why the paint did not cure? I have no idea?  How long does that paint take for you to cure at room temperature?  None of the paints I use in my hobbies require elevated temperature for drying/curing, but elevated temperature does speed the curing/drying. 

Does the paint/clear you use specify that it needs oven curing?  If not, then the paint is designed to cure at room temperature. If it does not dry/cure at room temperature then maybe there is a problem with the paint?

Edited by peteski
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1 hour ago, peteski said:

Nothing? Well, the kept your painted items at 1003 degrees F for 10 hours.  So it did its "thing".  Why the paint did not cure? I have no idea?  How long does that paint take for you to cure at room temperature?  None of the paints I use in my hobbies require elevated temperature for drying/curing, but elevated temperature does speed the curing/drying. 

Does the paint/clear you use specify that it needs oven curing?  If not, then the paint is designed to cure at room temperature. If it does not dry/cure at room temperature then maybe there is a problem with the paint?

The clear lacquer is Gunze Mr Super Clear.  I've been using it for a few years.  I usually wait 1 - 3 months to polish it since lacquer continually reduces down over time.  The urethane is from KBS Coatings and one from Duplicolor.  I had sprayed the Dulpicolor 1K urethane on a body about 6 months ago and it's rock hard.  I sprayed the Duplicolor on another part a few weeks ago and was hoping the dehydrator would cure it faster.  I'm most surprised that the lacquer is still a bit soft after the 10 hours in the dehydrator.

Edited by crowe-t
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34 minutes ago, Mad Slammer said:

How can you lower the temperature on a fixed temp dehydrator? Thanks

Leave the door open -or- unwire a heating element (if there are more than one)-or- Plug it into a timer that will turn it on and off on a regular basis.

Myself I would wire in a thermostat that has the appropriate temperature range.

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6 hours ago, crowe-t said:

The clear lacquer is Gunze Mr Super Clear.  I've been using it for a few years.  I usually wait 1 - 3 months to polish it since lacquer continually reduces down over time.  The urethane is from KBS Coatings and one from Duplicolor.  I had sprayed the Dulpicolor 1K urethane on a body about 6 months ago and it's rock hard.  I sprayed the Duplicolor on another part a few weeks ago and was hoping the dehydrator would cure it faster.  I'm most surprised that the lacquer is still a bit soft after the 10 hours in the dehydrator.

If it really takes 1-3, and the other one 6 months to harden (!?), then I'm not really surprised that 10 hours in the dehydrator did not harden it either. I have been known to leave painted items in my dehydrator (around 120 deg. F) for few days.

I have no experience with that clears you're using. Maybe someone else who uses it will chime in with their experience.

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16 hours ago, Bills72sj said:

Leave the door open -or- unwire a heating element (if there are more than one)-or- Plug it into a timer that will turn it on and off on a regular basis.

Myself I would wire in a thermostat that has the appropriate temperature range.

I checked the filaments… they’re connected in series as far as I can tell… I have a timer switch wired to the power cord, how do I search for a thermostat switch?

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13 hours ago, peteski said:

If it really takes 1-3, and the other one 6 months to harden (!?), then I'm not really surprised that 10 hours in the dehydrator did not harden it either. I have been known to leave painted items in my dehydrator (around 120 deg. F) for few days.

I have no experience with that clears you're using. Maybe someone else who uses it will chime in with their experience.

Lacquer actually never fully cures.  After about 1 - 3 months it's more stable and hardens.  The 1K acrylic urethane takes more time but when it fully hardens it's like a rock.

I'll run the dehydrator again and see what happens. 

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  • 4 weeks later...
  • 2 weeks later...
On 1/14/2022 at 6:44 PM, crowe-t said:

The clear lacquer is Gunze Mr Super Clear.  I've been using it for a few years.  I usually wait 1 - 3 months to polish it since lacquer continually reduces down over time.  The urethane is from KBS Coatings and one from Duplicolor.  I had sprayed the Dulpicolor 1K urethane on a body about 6 months ago and it's rock hard.  I sprayed the Duplicolor on another part a few weeks ago and was hoping the dehydrator would cure it faster.  I'm most surprised that the lacquer is still a bit soft after the 10 hours in the dehydrator.

It's not the dehydrator that's the issue.  I remember using some off the wall 2K clear called "No Name" and few hours in the dehydrator and than rest with no heat cause i had too leave.  Next day i went too the hobby room the 2K was hard as a rock.  2K clear mixed properly with reducer if needed and hardner it will dry like  it's suppose too.  Waiting that long before polishing is crazy lol you really need to use better products i think, but if you enjoy waiting that long than enjoy.

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  • 2 weeks later...

If I'm not mistaken, 1K Urethanes cure from the humidity in the air.  The environment inside of a dehydrator would retard, rather than advance the curing rate of a coating that requires humidity to kick.  Dehydrators would be great  - for evaporative solvent type of coatings.  But not all coatings work by an evaporative solvent type of transfer method.

I'm at a loss to explain the problem with the lacquer clear however.  Unless.. it's a Nitrocellulose type of clear, like they use on wood instruments. (Which I doubt) NC clears are notorious for taking weeks to cure due to the material skinning over and trapping in the solvents.  Also NC clears 'cure' best at a relative humidity around 50%, so again the dehydrator is working against the material....  IF it is a NC clear. 

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The 1K urethane clear I'm using cures by evaporation and not from the humidity in the air.  It's not a moisture cure urethane.  I checked with the manufacturer.

I am finding that it is curing over time.  It's possibly the cold weather slowing down the cure time regardless of being in the dehydrator.

Edited by crowe-t
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11 hours ago, crowe-t said:

  It's possibly the cold weather slowing down the cure time regardless of being in the dehydrator.

If the temperature inside the dehydrator is let's say 100 deg. F, how would the cold weather (outdoors, or even in the room where the dehydrator is) affect the curing time?  100 degrees is 100 degrees, even if it is 16 degrees outside. Also, cold weather (like during winters in the Northeast USA) automatically means low humidity.  When that dry air is warmed up in the dehydrator it becomes even dryer, and that also speeds up the evaporation even more.

Yes, some 1-part polyurethane adhesives (like Gorilla glue) need moisture to produce the cure reaction, 2-part polyurethane paints or adhesives consist of resin and hardener/catalyst, so no external catalyst is needed for those to harden. Heat also speeds up the reaction.

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My Dehydrator came in today.  This Dehydrator can be found on Amazon, eBay, etc for $129.00.  I got mine at Lowe's just because I get the Military discount and I had a coupon so I picked this one up for $65.00.  This is a really nice unit.  You can set the temp to a number of pre-programmed heat setting and it has a timer.  I chose this Dehydrator because of the size.  I can get 3 car bodies on one rack and other parts on the other rack. 

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Edited by Zippi
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There is ALOT of info in this thread to have to go through.

Looking for the straight to the point answer to the following:

95-105 Degrees seems to be the perfect temp. Generally- How many hours do I need to leave a lacquer painted body inside the dehydrator at that temp until the paint is cured?

Do I have to put my fresh painted pieces on stands or can I put it directly onto the base of the dehydrator while drying?

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1 hour ago, kymdlr said:

There is ALOT of info in this thread to have to go through.

Looking for the straight to the point answer to the following:

95-105 Degrees seems to be the perfect temp. Generally- How many hours do I need to leave a lacquer painted body inside the dehydrator at that temp until the paint is cured?

Do I have to put my fresh painted pieces on stands or can I put it directly onto the base of the dehydrator while drying?

104 degrees is what I set my Dehydrator on.  I'm using Tamiya acrylic paint and it drys pretty quick.  8 hrs is fine.  24 hrs for lacquer and enamel and it should be dry.  I lay some of my parts right on the rack.  These answers to your questions is what works for me.  I'm sure others may have different results.

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3 hours ago, kymdlr said:

There is ALOT of info in this thread to have to go through.

Looking for the straight to the point answer to the following:

95-105 Degrees seems to be the perfect temp. Generally- How many hours do I need to leave a lacquer painted body inside the dehydrator at that temp until the paint is cured?

Do I have to put my fresh painted pieces on stands or can I put it directly onto the base of the dehydrator while drying?

Lacquer doesn't cure like enamel does, but it "flashes" where enamel cures created a hard shell.  If you use a tamiya stand to hold the body and use dehydrator either use tape to hold the stand to the inside body or be sure the springs aren't tight against the body because I've seen, and heard of bodies expanding because of that.  I use a small pvc pipe with tak to hold my bodies for painting and putting inside dehydrator.  I do 115 degree's and I've never had any issues with plastic melting etc as styrene has a higher melting point, and takes lacquer less than 30 mins to be ready for whatever.  I can sand primer within 30 mins, but a hour doesn't hurt & 2K clear cures in about 4 hours @ 115-120 degrees. If the paint is try to the touch you can put it on the base if you want, and i use auto motive paints for my car bodies, and there ready for clear coat within 30 mins.  I'm not sure about enamel, but that depends on what brand you use, but you could always test on a spoon for drying times.  Tamiya, scalefinishes, zero paint, etc 115-120 degrees 30 mins and there ready for clear coat, actually could be less i just always go 30 mins.  You can go longer, but you wont need a half or full day of drying even at 110 degree's.

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40 minutes ago, Dpate said:

Lacquer doesn't cure like enamel does, but it "flashes" where enamel cures created a hard shell.  If you use a tamiya stand to hold the body and use dehydrator either use tape to hold the stand to the inside body or be sure the springs aren't tight against the body because I've seen, and heard of bodies expanding because of that.  I use a small pvc pipe with tak to hold my bodies for painting and putting inside dehydrator.  I do 115 degree's and I've never had any issues with plastic melting etc as styrene has a higher melting point, and takes lacquer less than 30 mins to be ready for whatever.  I can sand primer within 30 mins, but a hour doesn't hurt & 2K clear cures in about 4 hours @ 115-120 degrees. If the paint is try to the touch you can put it on the base if you want, and i use auto motive paints for my car bodies, and there ready for clear coat within 30 mins.  I'm not sure about enamel, but that depends on what brand you use, but you could always test on a spoon for drying times.  Tamiya, scalefinishes, zero paint, etc 115-120 degrees 30 mins and there ready for clear coat, actually could be less i just always go 30 mins.  You can go longer, but you wont need a half or full day of drying even at 110 degree's.

Thank you for this. After clear coat do you put it in the dehydrator again to speed up the drying process on it? So all I need is roughly 30 minutes for lacquers, not 10+ hours or overnight like I’ve read in other post?

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3 hours ago, kymdlr said:

Thank you for this. After clear coat do you put it in the dehydrator again to speed up the drying process on it? So all I need is roughly 30 minutes for lacquers, not 10+ hours or overnight like I’ve read in other post?

Yeah i always put it back into the dehydrator after clear to keep it free of dust etc.  If I'm not going to do anything after clear coating that day - i just leave it till next day no heat, and it'll be ready. 30 mins at the temps i use, but if it's gloss lacquer i would probably go bout 1 or 2 hours.  Automotive lacquer paints already dry super fast so 30 mins or less @ 115 degrees it'll be ready for clear.  30 mins to an hour for all the lacquers i use tamiya, zero paints, scalefinishes, gravity colors, alclad, few others.  I say to a hour because most of the time after it's done drying i still leave the parts in as I'm working on something else, but there's nothing wrong letting it bake longer if you want, but you don't have to wait 8 hours or 24 hours that's for sure.  I've had 2K clear cured in 4 hours @ 120 degree's, and sand, and work on polish same day.  So there's no way lacquer etc needs to take hours n hours n hours to dry with a dehydrator @ 115-120 degrees, and the melting point of the plastic we deal with is like over 200+F.  I'm not knocking anyone else though if it sounds that way? I'm just stating what works for me, and you can always do some tests by spraying some junk parts or spoons , and put them in the dehydrator, and try different times/temps for different paints etc.

The dehydrator zippi showed is a good one that alot of folks have even though mines different.  All these food dehydrators in the $100+ range are all the same when it comes to how the heat is done inside the chamber.  Allows heat to do full 360 inside the chamber allowing the heat to fully surround whatever is in evenly drying unlike the ones from micro mark where the heat rises from bottom to top where the top is the hottest point.  

Edited by Dpate
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  • 2 weeks later...
On 1/15/2022 at 12:07 AM, peteski said:

If it really takes 1-3, and the other one 6 months to harden (!?), then I'm not really surprised that 10 hours in the dehydrator did not harden it either. 

I’m not buying it.

I’m not familiar with these clears either, but if they’re taking that long to cure, there’s no question that I’d be looking for a different clear.

As far as how long it takes lacquer to “cure”, I can’t tell you any of the science behind it, but I can tell you that the clear lacquer that I use, (Duplicolor) dries enough to be handled within a couple of hours, and is fully ready for cutting and polishing within a few days, to one week.

I can attest to this fact because I do it on every build.

I don’t own a dehydrator, and at this point, at least for me, I really have no reason to buy one.

 

 

 

Steve

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Likely old news, but for the new buyers of dehydrators, do an actual temp check of your new machine.

Perhaps the fan placement will decide on the heat produced?

Some pics of my unit and stated temp vs actual temp. Am in UK so Celcius is being used.

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Edited by D.Pack
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