BBQ paint and high temperatures

I have been busy this morning upgrading my firmware to give me temperature and gearmotor control for the Tommelise Mk 1 extruder from my PC rather than having it hardwired into the firmware.

While I was testing it I noticed that the insulated nichrome 80 heating coil had separated from the extruder barrel partly on two of the eight or so loops. I decided to apply more BBQ paint and tack it down again rather than wait for it to really come loose. As a result, however, I won't be able to test for the rest of the day since I have to allow for an hours drying between the six coats.

Another thing I noticed as well. As I've mentioned before the silicone boils off the insulation early on leaving the glass fibre sheathing. When you put a new BBQ paint job on the barrel the paint boils off of this insulation after a while leaving the insulation white on the barrel.

What I noticed was that the insulation had been rubbed off in two small places. I am betting that this occurred when I packed the Mk 1 for the trip down to ETech in San Diego or when somebody I allowed to handle the Mk 1 rubbed the barrel a little too hard with their finger. Mind, I'm not grumpy. The Mk 1 took very little damage at San Diego. I was fully prepared to have to make major repairs on it after the conference. That's certainly been my experience with other sorts of hardware that I've taken to conferences and passed around. 3D printing groupies apparently have gentle hands compared to most. :-)

I figure I've got roughly 30-34 hours of operation on the Mk 1 since the last paint job I had to do.

For you polycapralactone people, keep in mind that I'm running the Mk 1 at 190-205 degrees Celsius for HDPE. If you are running CAPA you're running at about half of that.

Quoting RepRap Forum Mailer :

> down again rather than wait for it to really come loose. As a
> result, however, I won't be able to test for the rest of the day
> since I have to allow for an hours drying between the six coats.

I get that down to minutes by just playing a hair dryer over it between
each coat.

Best wishes

Adrian

Dr Adrian Bowyer
[staff.bath.ac.uk]
[reprap.org]
_______________________________________________
Developers mailing list
Developers@reprap.org
[reprap.org]

_______________________________________________
Developers mailing list
Developers@reprap.org
[reprap.org]

You've already sold me on it Zach. I just didn't want to go down to the hardware store today and I also needed a good excuse to take the afternoon off.



----- Original Message ----

From: Zach Hoeken

To: Adrian Bowyer

Cc: developers@reprap.org

Sent: Saturday, April 7, 2007 2:35:45 PM

Subject: Re: BBQ paint and high temperatures



seriously you guys, take a look at jbweld. a few ounces should be no more than $5 at your hardware store. its rated for high temp stuff and is STRONG epoxy. even if you just smeared it over the coils, it would work wonders by both protecting and insulating.



btw, its rated to 600 deg F, which is 315C and plenty of room. People use this stuff to repair frickin engine blocks!



~Zach



On 4/7/07, Adrian Bowyer wrote:Quoting RepRap Forum Mailer < [email protected]>:



> down again rather than wait for it to really come loose. As a

> result, however, I won't be able to test for the rest of the day

> since I have to allow for an hours drying between the six coats.



I get that down to minutes by just playing a hair dryer over it between

each coat.



Best wishes



Adrian



Dr Adrian Bowyer

[staff.bath.ac.uk]

[reprap.org]

_______________________________________________

Developers mailing list

Developers@reprap.org

[reprap.org]





_______________________________________________

Developers mailing list

Developers@reprap.org

[reprap.org]














____________________________________________________________________________________
Don't pick lemons.
See all the new 2007 cars at Yahoo! Autos.
[autos.yahoo.com]
_______________________________________________
Developers mailing list
Developers@reprap.org
[reprap.org]

Quoting Forrest Higgs :

> You've already sold me on it Zach. I just didn't want to go down to
> the hardware store today and I also needed a good excuse to take the
> afternoon off.

Me too. Next time I'm in the shop (which should be Tuesday).

Best wishes

Adrian

Dr Adrian Bowyer
[staff.bath.ac.uk]
[reprap.org]
_______________________________________________
Developers mailing list
Developers@reprap.org
[reprap.org]