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Lacquer drying box for cold climates?


acpken

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Hello all,

I live in the northern US, and it's wintertime here.

I have a bunch of bodies and necks here that all need to be finished, I don't want to heat my whole shop for the whole winter just to dry lacquer, and the wife says I can't 'nitro paint' in the house.

I'm thinking about making some kind of box with a heater and thermostat inside it that I can run 24/7 and put finished parts in to dry.

Have any of you made something like this, how did you do it, and how did it work?

Thank you,

ken

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PO wife almost worse... ;) She calls all paint 'nitro paint'.

I'm thinking about switching to waterbased lacquers, but I still have to get the stuff to dry before it freezes.

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Maybe just build the box and use a small wattage light bulb? They use 100watt bulbs in a fox bender for acoustic guitar side bending and trust me you can burn a side up in just a few minutes if not careful. So i would think depending on the size of the box a 25 to 40 watt bulb would be more than plenty to keep a constant temp that would be reasonable. Still you must make it so that it would not catch on fire though. :)

If need be you could set up the light using a solid state relay and a PID temp controller with a thermocouple. This would then monitor the temp and turn the light on and off at predescribed temp +/- a few degrees.

mk

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I dont know if a light bulb is a good idea. If you go to a properly set up body shop the lights in the booth and mixing room will be on the out side behind glass or ar sealed. The idea being a spark could ignight fumes. But they do heat the booths some how im not sure what kind of elemnts they use or how its set up

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I dont know if a light bulb is a good idea. If you go to a properly set up body shop the lights in the booth and mixing room will be on the out side behind glass or ar sealed. The idea being a spark could ignight fumes. But they do heat the booths some how im not sure what kind of elemnts they use or how its set up

yep then maybe a very low watt cartridge heat element? but it will need to be contained to keep anything from touching it so it does not cause a fire as well. The light bulb would work if contained also. The box would still need intake and exhaust vents no matter what type of heat is supplied. The thing is you don't want it to over 90* I would think? Anything over that and you may have other problems.

edited to add: My thought was for after the finish is sprayed, and using the box to dry.I beleive that was what the OP stated he needed it for.

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The real issue is guitar parts have to be over 55 degrees Fahrenheit as well as the paint.

Normally what I do is build a booth from 1x2 and plastic sheeting, put a small fan in one end to exhaust the fumes. Put the parts in it and run a small oil-filled electric space heater (read no open flame) until the temperature is up around 60 degrees. Sometimes that is 4 - 6 hours. The small oil heater will remain hot after it is shutdown and allow the parts to cool slowly (preventing checking).

I put the paint in the house (still in the can) the night before or until I am ready to use it. That way it is above 55F when I am ready to use it. Carry the paint out to the shop, mix, remove the heater from the booth, shoot with exhaust fan on, wait 30, shoot, wait 30 shoot. Put the heater (turned off) back in the booth. Repeat the next day and the next until you have 9 - 12 coats.

I usually mix the lacquer a little hotter (more thinner) to help fight runs. This of course leads to longer gass off times so you have to be patient. After a day or three out in the shop it usually has gassed off enough to move the guitar inside the house to a spare bathroom with the vent fan going. Luckily I live in NC and I just leave them in the garage cold.

Scuffing the clear with 600 grit after about 2 days should speed the gas off and let you buff it sooner.

Don't bother with water based lacquers. They go bad in sub freezing environments. It is a pain in the arse to get them shipped without freezing. The 2 times I tried a few years ago I had to reorder twice.

If you decide to try the water born nitros the procedure is the same just never leave the clear outside as it will freeze. It is still just as smelly and bad to breath the particles (not fumes so much) so don't think you are bringing the guitar inside any sooner.

Cheers!

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The real issue is guitar parts have to be over 55 degrees Fahrenheit as well as the paint.

Normally what I do is build a booth from 1x2 and plastic sheeting, put a small fan in one end to exhaust the fumes. Put the parts in it and run a small oil-filled electric space heater (read no open flame) until the temperature is up around 60 degrees. Sometimes that is 4 - 6 hours. The small oil heater will remain hot after it is shutdown and allow the parts to cool slowly (preventing checking).

I put the paint in the house (still in the can) the night before or until I am ready to use it. That way it is above 55F when I am ready to use it. Carry the paint out to the shop, mix, remove the heater from the booth, shoot with exhaust fan on, wait 30, shoot, wait 30 shoot. Put the heater (turned off) back in the booth. Repeat the next day and the next until you have 9 - 12 coats.

I usually mix the lacquer a little hotter (more thinner) to help fight runs. This of course leads to longer gass off times so you have to be patient. After a day or three out in the shop it usually has gassed off enough to move the guitar inside the house to a spare bathroom with the vent fan going. Luckily I live in NC and I just leave them in the garage cold.

Scuffing the clear with 600 grit after about 2 days should speed the gas off and let you buff it sooner.

Don't bother with water based lacquers. They go bad in sub freezing environments. It is a pain in the arse to get them shipped without freezing. The 2 times I tried a few years ago I had to reorder twice.

If you decide to try the water born nitros the procedure is the same just never leave the clear outside as it will freeze. It is still just as smelly and bad to breath the particles (not fumes so much) so don't think you are bringing the guitar inside any sooner.

Thank you for the good ideas! I spent most of last night trying to figure this one out. I just want the box to keep the bodies warm in while they dry.

Luckily for me, I can get lacquers locally.

Maybe just build the box and use a small wattage light bulb? They use 100watt bulbs in a fox bender for acoustic guitar side bending and trust me you can burn a side up in just a few minutes if not careful. So i would think depending on the size of the box a 25 to 40 watt bulb would be more than plenty to keep a constant temp that would be reasonable. Still you must make it so that it would not catch on fire though. :)

If need be you could set up the light using a solid state relay and a PID temp controller with a thermocouple. This would then monitor the temp and turn the light on and off at predescribed temp +/- a few degrees.

I wonder... would a ceramic heater work as a heat source? I have one here that is about 6" square and uses a computer box type cooling fan as a fan. I can short out the thermostat and use a controller and thermocouple to control it.

ken

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I just thought of this another thing they use on body shops arethe inferred heat lamps (think fast food) it would take some experimenting but after you spray you could set the guitar between lamps and just let it cook all night. Just make sure they arnt too close and over heat.

Btw if your bulbs burn out and your too cheap to buy some and you ever go to "pinks all out" in shreveport la and you and your buddies all stay in the same hotel you can get them to rob the heat lamps out if there bathrooms.

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Maybe just build the box and use a small wattage light bulb? They use 100watt bulbs in a fox bender for acoustic guitar side bending and trust me you can burn a side up in just a few minutes if not careful. So i would think depending on the size of the box a 25 to 40 watt bulb would be more than plenty to keep a constant temp that would be reasonable. Still you must make it so that it would not catch on fire though. :)

If need be you could set up the light using a solid state relay and a PID temp controller with a thermocouple. This would then monitor the temp and turn the light on and off at predescribed temp +/- a few degrees.

I wonder... would a ceramic heater work as a heat source? I have one here that is about 6" square and uses a computer box type cooling fan as a fan. I can short out the thermostat and use a controller and thermocouple to control it.

ken

Yes that would work as well. you would by pass the switch and thermostat and use the PID and SSR to control it. Similar to a small electric grill or smoker. The important part would be that the element be situated to not start the cube or anything else on fire. The thermocouple would need to be somewhere in the middle of the box or lower so that the temp would not be to high on stuff below the thermocouple level. YOU would have hot spots to some degree but if you keep it at say 70* to 90* most likely not a problem if the design is well thought out for safety.

Setting up the PID is the crucial part so you have very little variance in temp It's not difficult but the instructions for the PID can be very vague and is in CHINGLISH. I spent many hours testing the PID and a heat element, so I do have an understanding of it now. :)

http://www.amazon.com/IMAGE%C2%AE-SSR-25DA-Auto-tuning-Temperature-Controller/dp/B0087O6S2A/ref=pd_sim_sbs_hi_2

http://www.amazon.com/Amico-Thermocouple-Temperature-Control-Sensor/dp/B00843IKWK/ref=pd_sim_hi_1

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Maybe we are missing the point here.

Lacquer is evaporative finish. It dries by the solvent evaporating. Use the right thinner for the temperature you are spraying in and it just works. Temperature affects lacquers drying times but not as much as you may think. In my experience the difference in drying time between 55 - 75 degrees is not noticeable. Building a box to dry it in once sprayed is not necessary. Once the coat flashes off (about 30 minutes) I have never been able to tell a real difference in curing time except in the summer when the garage gets to about 110F during the day.

I was trying to explain that it is good to get the ambient temperature of the booth and the wood above 55F just because it makes for better flow out and it is easier to spray than in 40 degrees where you need a faster evaporating thinner. I use the heater to slowly lower the temperature of the finish and the wood to prevent checking and cracks.

What you should worry about is humidity. It will trap under the finish and cause a blush. It is reversible though as there are blush removes.

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Sorry about the wait. Wife wanted to 'DECORATE THE HOUSE... NOW' and I just finished last night. :)

Here it was less than 20F in the daytime all week, so I've been thinking about this a lot. Later in the winter, it will get to -20F at night.

Normally what I do is build a booth from 1x2 and plastic sheeting, put a small fan in one end to exhaust the fumes. Put the parts in it and run a small oil-filled electric space heater (read no open flame) until the temperature is up around 60 degrees. Sometimes that is 4 - 6 hours. The small oil heater will remain hot after it is shutdown and allow the parts to cool slowly (preventing checking).

Lacquer is evaporative finish. It dries by the solvent evaporating. Use the right thinner for the temperature you are spraying in and it just works. Temperature affects lacquers drying times but not as much as you may think. In my experience the difference in drying time between 55 - 75 degrees is not noticeable. Building a box to dry it in once sprayed is not necessary. Once the coat flashes off (about 30 minutes) I have never been able to tell a real difference in curing time except in the summer when the garage gets to about 110F during the day.

I was trying to explain that it is good to get the ambient temperature of the booth and the wood above 55F just because it makes for better flow out and it is easier to spray than in 40 degrees where you need a faster evaporating thinner. I use the heater to slowly lower the temperature of the finish and the wood to prevent checking and cracks.

So, you say that the lacquer coat is relatively safer in the cold once it flashes off? I have a larger oil heater here that looks like an old school water radiator, so this is doable. I will try to spray @60F, and wait till the paint flashes off before I turn off the heat.

I wonder... since a HVLP sprayer with a turbine supplies relatively warm air when it sprays, would this be a good idea or would this add moisture to the spray? Would I be better off just using a compressor and high pressure spray gun for this?

I never sprayed in the cold before, and I have 'visions' of my lacquer coats doing really weird things as they dry... if they dried at all.

Thank you,

ken

Edited by acpken
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Your HVLP setup should work. I use an HVLP gun with a regular compressor with a dryer and filter inline and about 40psi. I have a regulator of the gun and go between 22 and 25 psi at the gun.

Moisture is bad.

I am not sure about the -20F. That is friggin cold. That is where the oil heater would come in handy to keep the space above freezing. I know my finishes survived 20 F over the Turkey day holidays. I was very careful to raise the temp slowly in the shop then bring them in the house when they were closer to 60F.

I think you have enough knowledge now you just have to experiment. Let us know how it works out.

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I built a hot box for a friend that makes violins so he could put finishes on in winter even in his old dingy shop way up in the hills.

I used plywood for the bulk of it, with insulation board (sheet rock / Rockwool board) on the outside. An infrared heat lamp at one end & a few small holes drilled into the opposite wall (10 holes about 6mm diameter)

I used a habistat thermostat unit from one of my old snake vivarium's to control the heat. It monitors the temp & turns on or off the lamp as it is needed. I also sprayed the entire inside with high temp silicon paint to prevent any problems with scorching lamps right next to well dried out timbers.

Works very well, but traps fumes like a demon. he uses it for a day or two, then transfers the instrument into the main house.

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