Scott and Warren and the Maytag man (ask Warren)

This topic has 32 replies, 9 voices, and was last updated 14 years, 4 months ago by Warren B. Musselman.

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May 10, 2011 at 6:53 am #54300
Warren B. Musselman
Moderator
Chris, as always you are right – or at least righter than I am in the explanation. It is related to the combination of airframe diameter, fin root chord length and semi-span. I still haven’t found the email with the specific math, but did drop another line to Henry and he popped that off in about 10 minutes following my email.

W
May 10, 2011 at 11:09 am #54301
SCOTT EVANS
JUST 1

I ordered 1 pint of that Cotronics high temp epoxy. 600 deg f. $90.00
Definitely be scraping every last drop off the bench with this stuff.
1 gallon was a deal at $320.00
I wanted to try it first, before I bit that though.
I would have to give it its own room in my house to keep it safe!
I was thinking about it for my top coat.
Might not peal at mach 2. 8)
Bad thing is it needs to be cured in an oven.
Any body have an oven 6 feet long? 😕
That is a serious question.
one thing leads to another. 😉
May 10, 2011 at 1:24 pm #54302
Jeffrey Joe Hinton
Moderator
Old school ovens for curing rockets were refrigerator boxes lined with aluminum foil and a few 100 watt light bulbs suspended inside. Properly sealed, you’d be amazed at the heat produced. Otherwise, Art had access to two large autoclaves but I think he’s given notice of un-employmental-ability to Scion.
May 10, 2011 at 2:35 pm #54303
Adrian
Participant
JUST 1

I ordered 1 pint of that Cotronics high temp epoxy. 600 deg f. $90.00
Definitely be scraping every last drop off the bench with this stuff.
1 gallon was a deal at $320.00
I wanted to try it first, before I bit that though.
I would have to give it its own room in my house to keep it safe!
I was thinking about it for my top coat.
Might not peal at mach 2. 8)
Bad thing is it needs to be cured in an oven.
Any body have an oven 6 feet long? 😕
That is a serious question.
one thing leads to another. 😉

It may be too late now, but I’d recommend the room temperature curing version that is good to 500F. I got the 600 F one that doesn’t cure at room temperature (actually it does, but it take a couple of months) and it’s a major PITA because all your mixing cups, tools, work area, etc. is goopy for months, or at least mine were. 😳 I was used to just popping the cured epoxy out of my mixing cup after a couple of days. Plus, you will need to run your vacuum bag into the oven. Oven curing is easier if it’s just a post-cure.

For an oven, you can have a space heater blow into a cardboard box and get it up to 150 or so. If you just leave bare carbon in the sun and out of the wind it can get to 180. I’ve used my kitchen oven for a post-cure to 250, but of course that wasn’t for a 6′ rocket. I’ve been thinking of getting the foil-backed foam from Home Depot and making a real oven, but I haven’t needed to do that yet.
May 10, 2011 at 3:54 pm #54304
Doug Gerrard
Participant
Bad thing is it needs to be cured in an oven.
Any body have an oven 6 feet long?

I do but it does requires assembly. It is regulated to 210F and has internal fans for forced air heating. The heated chamber is about 2’x2’x7′ and it is capable of having the parts in a vacuum bag while curing.

Doug
May 10, 2011 at 6:49 pm #54305
SCOTT EVANS
Bad thing is it needs to be cured in an oven.
Any body have an oven 6 feet long?

I do but it does requires assembly. It is regulated to 210F and has internal fans for forced air heating. The heated chamber is about 2’x2’x7′ and it is capable of having the parts in a vacuum bag while curing.

Doug

Ok, I will be right down 😉
May 13, 2011 at 12:03 pm #54306
SCOTT EVANS
Old school ovens for curing rockets were refrigerator boxes lined with aluminum foil and a few 100 watt light bulbs suspended inside. Properly sealed, you’d be amazed at the heat produced. Otherwise, Art had access to two large autoclaves but I think he’s given notice of un-employmental-ability to Scion.

Can I use your frig? My wife said no.. 😕
May 13, 2011 at 12:20 pm #54307
SCOTT EVANS
I’ve been thinking of getting the foil-backed foam from Home Depot and making a real oven, but I haven’t needed to do that yet.

Well I guess I will be building one this weekend. Foil backed iso.
I have a 20000 btu heater for my garage, not sure how I would regulate it though. Its fan could circulate the air. It might actually end up more like a hot wind tunnel. Not sure how hot it could actually get either.
I have a couple of inferred lamp set ups, but then I think I would need to circulate the air with a fan some how. Could one live at 250 d
How do I get myself into this. 😉
I should have got the 500 degree stuff.

Maybe a combination with the lamps on a themostat.
May 13, 2011 at 1:17 pm #54308
BEAR
Three thoughts here. None of them may be practical for your purposes, but they are just ideas that may germanate into somehting else. At the helicopter shop where I was employed, a friend of mine who ran the composite shop was alwasy building large pieces. While the pieces were in the vacuum bags, he would have incandescent infrared heat lamps turned on and focused on the parts, sometimes for days, especially if it was a part of an engine cowling. I will try to talk with him this weekend and see what he might suggest if that might be of benefit to you. The second thought is that when I ran a restaurant/cafeteria we had some big convection ovens that on an inside diagonal were about 6 feet across and could easily get to 500 degrees. Do you know anybody who could help you here or know of a group guys who could go in together and purchase a used one one or find a restaurant goin out of business selling all their equipment or even an auction. Then you might lease it out to others doing similar? Third thought; When I was a river guide, I would sometimes bake bread and cakes out on the side of the river. I needed to make an oven that could get to 350 to 400 degrees, that was extremely portable and light, and could perform other duties as well. I took a large cardboard box, turned it on it’s side so that the opening was not at the top but on the side, wrapped the whole thing in heavy duty aluminum foil, inside and out, and then I would place glowing charcoal briquets on the top and bottom, inside and out for cooking my foods. Sometimes just on the outside so the smoke did not affect the taste. Remember, I am on the side of a river and have to make do. The idea hear is that you could go to someplace like Shipper’s Supply in Fort Collins or Katzke Paper in Denver or anyplace else that sells double layer 4′ X 8′ sheets of cardboard and fabricate your own box. Cover it in foil and add heat lamps or some other heat source and you could possible have your six foot or seven foot oven for a rather inexpensive cost, then brake it down and fold it up for storage until the next time. In my past, I have made thousands of cardboard boxes of all different sizes for shipping components to Boeing and so I know it can be done with a little engineering.
May 13, 2011 at 1:24 pm #54309
BEAR
Forgive my spelling errors. I proofed my comments three times and after I posted it I got so damn mad at all the errors I made of desire to remove it all together. Probably the biggest error was posting these stupid ideas. They are still possible and feasible, but whether or not they are capable of standing on their own is another story.
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