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Finishing in the winter without a conditioned shop

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Blog entry by jamsomito posted 02-22-2019 07:31 PM 303 reads 0 times favorited 3 comments Add to Favorites Watch

Finishing is always a struggle for me without a conditioned shop. I’m just a hobbyist with a shop the size of a nook in the back of my garage. Even when conditions are favorable for finishing out there, the environment can still swing drastically between night, day, rain, or shine. I can usually put up with that with strategic finish application schedules, but in the winter it just flat out won’t work in the bitter cold. Here’s what I do in those cases.

At first, for a really small project, I just finished on a piece of cardboard in my office. I’d try to do it right before bed or right before I left for work so the fumes, however little of them there are, can dissipate before I went to bed / got home. It worked fine, but it occurred to me later that it’s all just going into the return air duct and pumped throughout the house. While it is said the solution to pollution is dilution, I still didn’t like this and quit after the first try at it. I wouldn’t have done this with a large project either way.

What I’ve been doing for the last several years is taking over our guest bathroom. I can’t do it when we have guests for obvious reasons, but most of the time it’s vacant. I just throw out a piece of scrap cardboard on the vanity and it’s good for small projects, or bring down a couple sawhorses and some scrap wood for bigger things. I find that by running the exhaust fan, it’s enough negative pressure to keep all fumes inside the restroom and eventually exhausted out while the door is closed. Works really well – can’t smell it upstairs or even right outside the door. I’ve used a BUNCH of mineral spirits, minwax wipe-on poly, general finishes arm-r-seal, water based poly, boiled linseed oil, and minwax oil-based stain, the latter being the worst offender fumes wise, all with good separation from the rest of the house. I probably wouldn’t use lacquer in here because it’s so nasty, but if the negative pressure is enough to keep all of these other products’ fumes in here, I suppose it wouldn’t be bad either.

Just a quick note that while I’m finishing, I shut the heat vent from my furnace. There is no return duct to spread the fumes to the rest of the house (the exhaust fan sucks it outside), but the supply air volume I think in this particular room is greater than the exhaust fan is able to suck out, and so it creates a positive pressure situation which then can push any fumes in the room out to the adjacent room. So, keep the supply air to the room shut off, turn on the fan, and let it pull it’s make-up air from the space under the door when it’s closed.

There is one catch though. Now you’ve got minimal ventilation, and finishing in a pretty confined space. I wouldn’t recommend doing this without an organic vapor respirator. I use the 3M 6500 and just change out my P100 particle filters for the organic vapor cartridges here: https://www.amazon.com/gp/product/B000XBKLLE/ref=oh_aui_search_asin_title?ie=UTF8&psc=1 When I’m done, I disconnect the vapor cartridges and put them in a zip-loc freezer bag to preserve them until I need them next. I tried it once without the mask thinking my finishing session would be quick, but in a space like this it adds up quick and I wouldn’t recommend it. A respirator is a must.

One other problem I ran into is the temperature. This bathroom is in our basement, and with the exhaust fan on, even with the heat vent open (which is on the ceiling and doesn’t do much around the level the finishing is happening anyway), the room stays at around 58-59 degrees. Just a tad too cold for most finishes to work their best. So I went and bought this little guy for $10 from our local department store:

A rule of thumb for space heater sizing is 10 watts per square foot. I had a hard time finding anything less than about 1000 – 1500 watts in the store, and most were about $60-100. Too much. Then I found this little 250W dealie. Turns out it’s a little champ! My bathroom is only about 40-50 sf max, so this guy is technically about half the size it needs to be according to that rule of thumb. AND, I’m exhausting all the conditioned air, so it’s constantly needing to heat the “make-up” air it’s pulling in from the relief space under the bathroom door. But, despite all this, it manages to hold the room at about 64 degrees, so a nice little 6 degree bump or so, which is just enough to put the temps back into the recommended range for finishing. This particular unit is just on/off with a little fan in it, so it’s not going to shut off at a given temp, but when it can’t keep up, it’s perfect. For $10, it’s well worth it, and fits my needs exactly. I did find that I need to keep it on the same side of the room and located slightly below my finishing surface – turns out the toilet seat is a perfect location for it, haha. Just don’t point it directly at your workpiece or any wet finishes, and I probably wouldn’t want it set to directly intake any flammable fumes, but I’m comfortable with how I have it set up in these photos.

One final challenge I have is what to do with all of my soaked rags, applicators, and cleaning rags. This is always a problem for me as I manage to make about 2345907623 of them on every project. In the winter, it’s a worse problem. I’m not comfortable enough leaving them in my little finishing room (bathroom) given their history of starting fires, especially considering I would need to leave it flat on a piece of cardboard, a.k.a. something flammable. I do leave my sealed cans of finish in there, but the rags pose too much of a hazard. So I’ll take any excess mixed stain, soak it up with some scrap wood as if I was finishing it, and lay the scraps and rags out on my cold garage floor to offgas and cure. I leave the garage door cracked with a box fan blowing out, and if no snow is forecasted I’ll even open my side window. It’s safe; however, do realize it’s still between -10 to 30 degrees out there for me and curing times will be much longer. I find that mineral spirits rags dry off in a day, wipe-on poly rags tend to harden in a couple days, the oil-based stain takes about 4-5 days, and BLO… just find somewhere it won’t be in the way until spring. This should definitely be considered when you’re picking a finish for your project if you happen to be applying in the winter time. Brushed-on water-based poly has no rags :).

So there you have it. It really sucks, but I’m not going to let it get in the way of my down-time hobby, and this is how I’ve come to deal with the many problems of finishing in the winter. If you have any other tips, I’m all ears, but I hope this helps someone in the same boat.



3 comments so far

View EarlS's profile

EarlS

2530 posts in 2644 days


#1 posted 02-22-2019 07:51 PM

When I had limited garage space, we parked outside when a project needed to be finished and the space heaters were plugged in and running full time to hold 65 or so in the garage. I always tried to time the finishing work so I could spray on Friday night, let it dry overnight, sand Saturday morning, spray and let it dry all day. Sunday morning would be a repeat of Saturday if a 3rd coat was needed. The project was dry enough at the end of the day Sunday that it could go inside and finish curing. They key was getting the garage up to 65 or warmer so the finish (poly) would dry.

-- Earl "I'm a pessamist - generally that increases the chance that things will turn out better than expected"

View jamsomito's profile

jamsomito

427 posts in 722 days


#2 posted 02-22-2019 07:58 PM


When I had limited garage space, we parked outside when a project needed to be finished and the space heaters were plugged in and running full time to hold 65 or so in the garage. I always tried to time the finishing work so I could spray on Friday night, let it dry overnight, sand Saturday morning, spray and let it dry all day. Sunday morning would be a repeat of Saturday if a 3rd coat was needed. The project was dry enough at the end of the day Sunday that it could go inside and finish curing. They key was getting the garage up to 65 or warmer so the finish (poly) would dry.

- EarlS

Yeah, that’s a great option, and probably the only way to do larger projects. For me, a 1500W heater wouldn’t budge my garage temps much more than a few degrees when I tried it; it’s uninsulated and gets pretty cold here. If I was going to do that it would need to be a big install – a couple mini-splits or a big forced air heater or something.

So you think it worked well without any ventilation at all?

View EarlS's profile

EarlS

2530 posts in 2644 days


#3 posted 02-22-2019 08:47 PM

I just turned on the heaters and covered everything with plastic or painters tarps and sprayed. The smaller projects were easier because the heaters could be grouped closer to the project. There was more sanding due to dust nubs but it worked OK.

-- Earl "I'm a pessamist - generally that increases the chance that things will turn out better than expected"

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