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Incandescent light bulb heating for drying paint at low temps...

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  • #16
    Go to the tractor/farm supply store and grab some nice cheap brooder bulbs- they'll heat the surface quickly and evenly and they are not hot enough or have any sparking contacts to worry about burning anything. I use them in my sort-of-heated workshop on epoxy glue-ups in the dead of winter (sub zero outside).

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    • #17
      Remember ALL electric heaters are 100% efficient. So a 100 watt light bulb produces 345 BTU of heat per hour, same as any other electrical device. Putting a light bulb or heater of any kind at the bottom under the hollow casting will do a fine job, as it will create a chimney effect of warm air rising up through the casting. Warm it up, turn the bulb off, turn it back on until the paint drys. Get back to work.

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      • #18
        What a bunch of good practical suggestions, thanks all! Wish I thought of the big cardboard box idea, would have been alot easier/cheaper... oh well.

        Testing: I'll see how long it takes to bring the casting up to temp this week, didn't think of that... V8 - why didn't I think of that moment.

        Looks like it'll be an all day affair when it comes to actually painting so I'll have to wait for the weekend. I'll re-read the specs on the paint but think I have to wait a couple hours between coats but not more than 4 or you have to wait 7 days for the next coat. Planning on a couple coats primer followed by a couple brushed on coats.

        Before all that though... what I discovered today: bondo? or something like it?... I applied a good thick coat of Citristrip early morning last Saturday, Sunday I scraped the vast majority of the original paint(s) down to primer. Turns out it has 1 coat rust-red primer, 1 coat gray, 1 top coat of some cracking, putrid green (why would anyone ever choose that color, but then again, maybe someone will say that about this latest paint). Good riddance. Anyway, after cleaning that best I could I applied one more Citristrip coat last night then high pressured washed it off today. Towel dried best I could, rolled back into the cave where it's sat with a fan blowing on it for a couple hours now.

        It was after the pressure wash that I discovered the black bondo stuff. New to me... so, I didn't know they did that. Wherever there is a void or bit of un-fairness, there the bondo could be found. I can't imagine buying enough tubes of JB-Weld even if it would fill the voids with something good and hard. So, what to use here? Bondo? Some other relatively hard resin?

        Thanks again for all the great ideas/input...

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        • #19
          "Bondo" or other car body filler works fine. Sets really quickly - multiple application / sanding in a few hors. JB weld would have to cure for a day before sanding. For small voids use one other metalglaze like products.

          Check for adhesion to the existing stuff though. I has a BP that has a black filler (some type of spray putty), and it had absorbed oil though surface cracks. I washed and degreased many times. Seem ok at first but "bondo" body filler just fell off with any pressure. I has to strip it back to the bare metal.
          Last edited by lakeside53; 11-10-2014, 09:40 PM.

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          • #20
            Thanks lakeside53, maybe some JB for the deeper voids then, I'm in no rush here. Wonder if primer stuck well on your BP, could you Bondo/Evercoat over the primer?

            Quick test looking good so far... popped a 100w bulb inside the casting a couple hours ago. Outside temp atm is 53°, the bottom of the column just measured 61°. Figured I'd just leave it on overnight to get it good and dry, will check the temp again in the morning.

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            • #21
              High build primer filler, mustard coloured stuff, thin with ordinary thinner, mind I've used gun wash many times as it's cheap, you can build up quite a thickness with it.
              Mark

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              • #22
                Originally posted by caveBob View Post
                Thanks lakeside53, maybe some JB for the deeper voids then, I'm in no rush here. Wonder if primer stuck well on your BP, could you Bondo/Evercoat over the primer?

                .
                You can apply Bondo in thick coats (you need to be quick with large masses - it sets up fast). There's no advantage in using an epoxy for purely cosmetic uses. Yes, if the primer and spray putty was in good shape, I could have used Bondo over it.
                Last edited by lakeside53; 11-11-2014, 02:14 AM.

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                • #23
                  Originally posted by caveBob View Post
                  Quick test looking good so far... popped a 100w bulb inside the casting a couple hours ago. Outside temp atm is 53°, the bottom of the column just measured 61°. Figured I'd just leave it on overnight to get it good and dry, will check the temp again in the morning.
                  Any chance for an update on the test results observed
                  with a 100W bulb positioned inside the casting overnight?

                  .

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                  • #24
                    Originally posted by EddyCurr View Post
                    Any chance for an update on the test results observed
                    with a 100W bulb positioned inside the casting overnight?
                    Hi Eddy, I think it's going to work pretty well thanks to all the ideas gleaned on this thread... I left the 100W bulb inside of the main base casting for a couple days then check the outside temp of the casting in the morning when it was about 30° outside temp. The casting was 53°, so about a 23° increase, not bad.

                    Since I told myself it was time for a new work light anyways, I ordered this from Amazon:

                    Designers Edge L113 Industrial Impact-Resistant Untippable-Spring Mounted Portable Halogen Work Light, Green, 500-Watt


                    ...it's pretty well made, fits inside the casting, and handy to have the light at whatever angle you want, and definitely warmer than a 100W bulb. This will work just peachy for bringing the base casting up to and holding paint temp.

                    Also, my old space heater was... getting... old, so, following lakeside53's advice... got a real nice little (about the size of a shoebox that only draws 1200W on high and 800W on low). Actually, what the Kill A Watt meter told me: Low: 6.67A, 770W - High: 9.90A, 1100W.

                    Crane #EE-6490 1200-Watt Crane Ceramic PTC Heater


                    I was concerned about how flammable the cardboard would be but this search result has me feeling a little better about it:

                    ignition point for cardboard is 427 degrees Celsius, or 800.6 degrees Fahrenheit
                    http://www.answerbag.com/q_view/2293781
                    ...hope it's accurate. Still plan on planting the heater between a couple cinder blocks though.

                    Reason I didn't want to use just any old heater... I have a 10A limit with something else I found to help with this, a thermocouple. Heard of them before but didn't know what they were or were for...:

                    IMAGE® All-purpose Temperature Controller STC-1000 With 2M Cable Cooling/Heating


                    I picked up a couple of them and have them mounted in small Radio Shack project boxes atm, just need to finish wiring them up. Going to use one on the halogen work light and the other one driving the heater & circulating fans. There's lots of tutes out there of folks using them for all kinds of stuff, i.e. heated aquariums, home brewers, meat smokers. Here's one I bookmarked:

                    DIY STC-1000 2-Stage Temperature Controller Wiring Diagram with Indicator Lights
                    Time to go autonomous. Growing tired of swamp cooling for fermentation “temperature control” I’ve decided it’s time to invest in the widely popular 2-stage STC-1000 “e…


                    This all might be old news to you and probably others here, but it's new to me... I've got high hopes.

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                    • #25
                      Very interesting, thanks for a thorough write-up.

                      First I've heard of the STC-1000 2-stage Temperature Controller.

                      .

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