Cold garage

[banderson]

Hello everybody - first post.

Purchased a PRS standard last week. Waiting on it now - should be here middle of March. I willl be putting it in a garage and mainly using it for wood signs to start with. My garage is not heated. Will it be an issue if I am using a torpedo heater now and then until spring? Not sure if machine will flex or move causing issues?

[billp]

Bret,
Depending on what you mean by "now and then" the biggest issue might be that You and the heater will be competing for the SAME air.....
I recently bought one of those "Amish style" electric heaters with a remote control for my garage, and now I can 'pre-heat' the garage for a few hours before I go out there to work on my boat project. Factoring in current electricity pricing in my area it costs me abut .75 cents to do this.
I used to have the "salamander" style of heater I believe you are speaking about and it would quickly use most of the oxygen in the room. Cracking open a door/window is self defeating in this case because you then allow more cold air to enter.
Unless you are going from a meat locker level of cold, to tropical I don't think you will see a significant change in your machine.

[Rob Gunn]

Bret, I am in SW Michigan and have my PRT96 in a mostly un-heated shop. I do heat it on weekends when I have more time to spend but during the week it is cold. I can say that I have never had any machine issue due to the shop being cold. As a matter of fact, the guy I bought my ShopBot from had it set up in a unheated garage and I asked him the same question before I bought it and he told me he never had any issue. I may be wrong but I have always felt that moisture and humidity are a much bigger issue. As we all know, wood will swell with moisture. All we can do is re-surface the table as needed.

[dana_swift]

My shop varies from about 40 degrees to roughly 90 when the outside temperature is from -10 to about 110 (the typical extremes here in Tulsa.) So my bot experiences a 50 degree temperature range.

The materials the machine is made from is mostly aluminum whose temperature expansion coefficient is 12.3E-6. So:

0.0000123 * WorkingGantryWidth * TemperatureChange = TotalWidthChange_inInches

Same formula applies in the GantryLength which will be another number.

I have the advantage of a BT-32 which is a very small machine so the total variation is proportionally smaller. But accuracy per inch, is the effectively the same for all the current (non-desktop) shopbots, as they are made from the same aluminum extrusions.

The worst dimension error for my gantry (34") is:
.0000123 * 34 * 25 = 0.010"

That is because I set everything up at nominal temperatures, so my calculation is based on being 25 degrees away from my setup-temperature.

However: this does not mean you cannot cut to 0.001 or 0.002 at any temperature. At most you would need to adjust your settings to correct for the situation. I dont bother. A hundredth of an inch is good enough over 34 inches for me.

Remember that your materials are usually reacting to the environment more than your bot will. Even though the thermal expansion coefficients of wood is much less than aluminum, the effects of humidity are substantial.

Plastics like HighDensityPolyEthelyene have a TEC of around 60.0E-6. Much worse than aluminum.

Hope that gives you some guidance as to what to expect.

My suggestion- get your bot. Set it up, and expect to be amazed!

This engineer is stepping away from the lectern-

D

[banderson]

Wonderful input guys. Thank you very much!!!!!

[chiloquinruss]

If my shop has been unheated for some period of time I turn the Bot on and run my table surfacing routine without a bit in it just to exercise and warm up the motors and the of course the spindle. Don't know that it is necessary just something I do. My temps range from a cold of 25 to 30 to a high of 90 so not to bad. For me personally if I can't see my breath then shop is OK to work in! :) Russ

[cowboy1296]

My response is just an echo of what has already been posted. I am in the moutains of Colorado. My garage is insulated and never gets below 47 with the door closed. When I work I turn on the heater for about an hour which takes the chil out. I use to work with the door open and remember once the temp hitting 25. It seemed to work just fine. naturally i have no humidity.

[myxpykalix]

This was my concern when i got my bot 6 years ago, and i thought "should i insulate or wrap the control box"? but the answer was No...
I have a rocket type heater that i fire up in an uninsulated shop and in 5 minutes i'm working in a tshirt when there is snow outside. The metal of the bot is still as cold as a "witches t*t" but it warms up after a while but expansion/contraction isn't something you need to be concerned with.

[MogulTx]

My biggest concern was that my previous bot controller was not liking the heat this past summer. I insulated the wall behind where I hung the new one... but I just wear a jacket and work gloves when it is cold- and a light shirt when it is hot- and don't pay attention to the temperature! Thus far, my new Alpha has been accurate, accurate, accurate.

[rcnewcomb]

Depending on the humidity in your area you may have to pay attention to condensation when the shop is cold.

But I've started the Bot at well below zero temperatures and the Bot was fine. The operator, however, began complaining after a bit and would wander back up to the house from time to time in order to get warm again.

[stump]

I have no trouble running the bot in an unheated garage in Minnesota. I do have a problem with the computer however. When it's below freezing I have to put a heater on it or else the hard drive won't boot. I suspect that it is more of a failing hard drive issue than anything else.

I used to use a "torpedo" heater to heat up the garage a little bit, but the fumes were worse than the cold, so now I just try to keep moving.

[CNYDWW]

A little off subject however...I love my shop heater. I tend to keep the shop at about 60 deg even when i'm doing physical work due to medical issues. I'm not in the shop everyday and heat is off at night or when i'm not in it.

http://www.northerntool.com/shop/tools/product_200316365_200316365

For the price, you can't beat it. I heat 1000 Sqft with 10ft ceilings. At aprox 20 deg. I can heat the shop for about 22hrs on a 20lb grill tank. Keep in mind the shop is well insulated with 4" blown in insulation in the walls and about 8" on the ceiling.

[myxpykalix]

"The operator, however, began complaining after a bit and would wander back up to the house from time to time in order to get warm again."

Unlike the bot who isn't as prone to temperature variations, the operators tend to not work so well in very cold or hot weather. I know for me I would much rather work in the winter cold because i can fire up the heater and be in a tshirt in 5 minutes whereas I have no AC and not an efficient way to get the heat out of the shop in the summer.:eek: