Environmental effects upon finishes

[Frederick]

Hi all,

I have been working in the workshop for the last couple of days on a couple of pen and platter projects. Obviously the temperature in there is falling fast and given the amount of rain falling, humidity is climbing.

I have been having trouble trying to obtain a reasonable finish using Acrylic and Melamine; the results being very poor. I didn't experience this during the Summer and post Summer which lead me to believe that temperature, humidity etc could be the cause. I have read numerous articles on the subject but none really answer the question. Instructions printed on the liquid acrylic bottle say that it should not be used below 15 degrees centigrade but there is no information on the spray can version. Melamine produces a slightly better finish but not great and again, no information is printed on the containers etc.

I was wondering if anyone else has any comments or information reference this. I have tried using hair dryers etc but alas no improvement there. I would love to heat the workshop but that would just be too expensive to do, although i do have an heater oil on very low.

Cheers
Frederick

 

[alpha1]

Can't say that I have had any problems with finishes but then my small workshop has a fan heater if anything its to warm I quite often have to turn the heating off because it's overpowering.

 

[Penpal]

Sympathies Frederick trying times mate. other problem here 32 C today,with todays plethora of de humidifiers about you could create another situation or look elsewhere for that elusive perfect finish ,but from me there is no such thing it will always remain subjective to everyone. Good luck with this one mate.

Peter.

 

[wm460]

No problem warming things up here at 43°C.

 

[PetrolP]

This sounds like a problem of temperature and humidity.
Cool temps do not help lacquers, which are relying on the evaporation of a solvent, be it water or cellulose based.
Water solvents take longer.
There is a problem of adding more coats before the first coat has dried.The surface may well 'orange peel'

All these lacquers rely on evaporation and flow out, for a good even surface.
That is the lacquer surface flows together to form a uniform film, cold will inhibit this.

When it's cold ,obviously the surface takes longer to tack off, and can be susceptible to the absorption of water vapour, which can cause blooming ( a milky appearance)
You need to add heat!

A lacquer surface will take about 10/14 days to reach a fully cured state!!
Until it's cured the surface will always be vulnerable.

A fan will be quick but move dust around, an oil heater is probably better, of finish inside the house!!

Does this help?

Peter

 

[PetrolP]

Another thing to do would be to apply a couple of coats of your chosen lacquer in the workshop, then take them in the house overnight.

The cut back, or denib with 000 wire wool (gently) then wax and hand buff with a duster.
This will give a smooth finish.

Peter

 

[Phil Dart]

I'm not sure that humidity will be particularly excessive at the moment. I know its wet and horrible outside but that doesn't necessarily translate to inside. I have a hygrometer in my workshop, which is reading about 60%, but I don't regard that as especially high. Normal humidity in a house is around 50 to 55%. It's usually a bigger problem in a hot summer, when it can get to maybe 75 or 80%.

The temperature is maybe an issue though. Perhaps another solution, apart from Peter's suggestion to take the finished work inside to cure, is to keep the bottles inside. They'll be at room temperature before you begin, and will probably cure OK outside. I tend to turn the heating off in my workshop at about 16 degrees anyway as it becomes too warm to work.

 

[wm460]

A mate down south who lives in the hills, uses a heat gun for a few seconds on pen blanks while the lathe is rotating to cure CA.
Might work on lacquer?

 

[Bill Mooney]

I stand my lacquer tin in hot water for 10 mins or so before using, this makes the lacquer more fluid & quicker drying. I also use a hairdryer on low on the piece to help the lacquer dry after spraying. You can put a jump over you pride to be sprayed for a bit of local heating applied to your piece.