What's the lowest outside temperature to spray filler primer?

The Rocketry Forum

Help Support The Rocketry Forum:

Ulexis

Well-Known Member
TRF Supporter
Joined
Sep 26, 2019
Messages
87
Reaction score
110
Location
West Central MN
I'm curious to see how low a temperature someone has sprayed a filler/primer? As it is quit cold all winter in Minnesota, I was wondering if I could get away with doing this in 20-30 degree temps. Afterall it gets mostly sanded off, so it doesn't need to turn out perfectly. I guess I could just try it, but I thought I would ask here first. Thanks.
 

burkefj

Well-Known Member
TRF Supporter
Joined
Jan 27, 2009
Messages
3,063
Reaction score
366
I've had okay results spraying in the forties typically I'll have my bathroom heater lamp and fans going and I'll soak the paint in medium hot water to warm it, I'll run out and spray a coat and immediately bring it in and put it in the bathroom and close the door to let it dry
 

blackjack2564

Crazy Jim's Gone Banana's
TRF Supporter
Joined
Jan 18, 2009
Messages
8,940
Reaction score
1,078
Location
Savannah Ga
same here. heat both rocket and paint. quick dash outside and back. it had just snowed so below 32.
don't try finish coats, it may blush/cloud.
 

mpitfield

Moderator
Staff member
TRF Lifetime Supporter
Global Mod
Joined
Jul 7, 2013
Messages
4,817
Reaction score
421
Location
Toronto, Ontario
Whatever it says on the can. For best results stick within the parameters on the label.
 

David Schwantz

Well-Known Member
Joined
Jul 23, 2018
Messages
1,418
Reaction score
522
Location
MN
I also live in MN. Spray year round. But I am lucky enough to have an inside paint booth. But before, I would spray in a non heated garage, just bring in to dry. Did this even with colors.
 

Pariah Zero

Gravity’s Plaything
TRF Supporter
Joined
Dec 15, 2019
Messages
101
Reaction score
82
Location
Salt Lake Valley
  1. If using a spray paint can, warm up the can and its contents. Warming up the primer/paint makes the stuff spray much better - finer aerosol, flows better, etc.
    1. If using a spray paint can, you can use a bath of hot water to heat up the spray can.
    2. Give it time to “soak” and come up to temp. You’ll probably need to change the water a few times.
    3. Don’t use temperatures higher than 105 °F. Spray cans aren’t made to be abused by temps higher than a garage in summer.
  2. Extend dry times. A lot.
    1. After the initial solvent flash-off “outside” (40-60 min), I bring it to a more heated room (50-60 °F), at which point I expect to wait at least a week before the paint will be dry enough to sand.
    2. Primer that hasn’t dried long enough will clog sandpaper fast.
      1. It’s really frustrating.
      2. Better to wait until there’s no discernible smell before sanding. (At any temperature) At that point, sandable primers don’t really clog sandpaper.
 

Bill S

Well-Known Member
Joined
Aug 6, 2019
Messages
386
Reaction score
120
I was introduced to a brand of spray paint that works in cold weather: Montana spray paints. They are a little more expensive than regular spray paints, but they claim to work in cold weather, down to zero degrees:

Quote: "Montana BLACK is possibly the best performing spray can in extreme weather conditions. It has been proven to perform perfectly in cold temperatures. Please note that a drop in can pressure can begin to occur when the temperature reaches 0° and below. For best performance it is important to keep your cans warm for as long as possible."

I'll report back when mine have arrived and I get a chance to play around with them.
 

Marc_G

Well-Known Member
Joined
Jun 6, 2010
Messages
6,378
Reaction score
516
Location
Indianapolis Metro Area
I've used both Rusto Auto Filler primer and the Bulls Eye 123 white primer outside in crisp cold weather in the 10-15F range with excellent results. Ambient humidity is so low I actually prefer to shoot when it is cold rather than warm/humid. The pro tips for doing cold shooting are to warm the can up to at least regular room temp by a water soak (or, keep the can inside for a few hours prior to shooting), and spray lighter coats than you are used to because the solvent won't flash off as quickly; less evaporates in the air on the way between the spray nozzle and the surface, as well as slower evaporation after the primer is on the surface.

Both of these primer dry fine in a cold garage (20-30 F) as long as you give an extended time for them to dry; I typically let them sit overnight before attempting any overcoating or sanding.
 

Ulexis

Well-Known Member
TRF Supporter
Joined
Sep 26, 2019
Messages
87
Reaction score
110
Location
West Central MN
Thank's so much for the input. I went ahead and sprayed some primer outside at 16°F. And it came out perfectly. I'm not so sure I'd try a color coat, but this gets me so much closer for when the winter ends.
 

Attachments

Bill S

Well-Known Member
Joined
Aug 6, 2019
Messages
386
Reaction score
120
I was introduced to a brand of spray paint that works in cold weather: Montana spray paints. They are a little more expensive than regular spray paints, but they claim to work in cold weather, down to zero degrees:

Quote: "Montana BLACK is possibly the best performing spray can in extreme weather conditions. It has been proven to perform perfectly in cold temperatures. Please note that a drop in can pressure can begin to occur when the temperature reaches 0° and below. For best performance it is important to keep your cans warm for as long as possible."

I'll report back when mine have arrived and I get a chance to play around with them.
I can safely say that the Montana paints are NOT suitable for rockets. While they were usable in cold temperatures, they went on thick (but didn't run much), but left a textured surface and even after a week plus, I can still feel some tackiness in the surface. Apparently they are optimized for graffiti useage on rough surfaces, and aren't good for smooth surfaced rockets. Back to the drawing board...
 

rocketman328

Active Member
Joined
Dec 2, 2019
Messages
35
Reaction score
17
Location
South Bend, IN
Cold in northern Indiana also, I sprayed grey primer the other day in low 30's with wind chill at least 10 degrees lower. The paint can was in a 70 degree room prior as well as the airframe, I took it out and sprayed it, about 5 min later I took it into the 70 degree room. Came out fine.
 
Top