The ACP carbon  .02 carbon tissue is what I use to use. However I have found 00 or 000 silkspan to finish lighter and is stronger for the weight. I am sure I will get some flack but that's what I found and I am doing. To each his own.

Hi Howard

With all of the CF mats or tissue, you need to work fast, and do not keep brushing over it, It works best if you brush it 1 time, once the dope melts the sizing the strands of CF are loose and stick, pile, and generally misbehave.

Randy

Maybe do a practice piece or two?

It's too bad you can't vacuum-bag dope.

If one covers a flat stab with mat and dope, then puts it between two pieces of glass with some Teflon film betwixt stab and glass, how long would it take for the solvent to find its way out?

Perhaps in time for the 2020 world's, but I wouldn't bet on it.

Yes, it is. I tried bagging some wet balsa, and it stayed wet a long time.  I'd guess dope would do the same.

You know, Howard, I think you just weren't thinking the process through.

You dry something out -- whether it's CF veil or a hunk of wood -- by keeping the vapor pressure of the solvent* you're trying to extract lower in the atmosphere than it is in the "dried" product.  The problem with vacuum bagging is that the atmosphere inside the bag becomes saturated with the solvent.  So you just need to pull a vacuum down lower than that critical vapor pressure!

(Of course, this may cause some slight mechanical stresses on the part that you're vacuum bagging.  Presumably you could alleviate these by putting your bagged item inside of a vacuum chamber.  Then you can control the absolute pressure in the bag independently of the pressure differential between the bag and its atmosphere, and dry out wet wood as you vacuum bag it!)

* water, the various constituents of lacquer thinner, etc.

Yes, it is. I tried bagging some wet balsa, and it stayed wet a long time.  I'd guess dope would do the same.

Carbon mat works fine with epoxy in female molds.  If one covers a flat stab with mat and dope, then puts it between two pieces of glass with some Teflon film betwixt stab and glass, how long would it take for the solvent to find its way out?  Maybe Z Poxy would be a better matrix.

Howard  the  Zpoxy is a better way to do that, but dope it first, dope the stab with the dope fairly thick, brush out and sand with 4-600 when dry, just enough to knock off the raised grain, then put on a coat of Zpoxy, it will take a tiny amount of the epoxy to go over the dope sealed stab, I do this with foam wings and it takes only 1/2 ounce as compared to the 2 ounces it takes of unsealed wood.
Once the 1 coat of Zpoxy dries, you can then put dope over the ZPoxy to seal of and fill the CF Mat.

Work well as I use that technique  for all of my wings stabs and sometimes flaps.

I also have the good stuff here, in both .5 and .3 weights

Randy

You dry something out -- whether it's CF veil or a hunk of wood -- by keeping the vapor pressure of the solvent* you're trying to extract lower in the atmosphere than it is in the "dried" product.  The problem with vacuum bagging is that the atmosphere inside the bag becomes saturated with the solvent.  So you just need to pull a vacuum down lower than that critical vapor pressure!

That's what I figured, but I kept the pump on the bag at 25 in. Hg, and the wood stayed wet.

That's what I figured, but I kept the pump on the bag at 25 in. Hg, and the wood stayed wet.

The vapor pressure of water at 23 degrees C is 22mm or so -- you needed to pull several more inches of vacuum to get it to boil out.

If you were in your basement, it may have been less than 23 degrees.  The relationship between water's vapor pressure and temperature is roughly exponential; it doubles every 12 degrees C or so at room temperature.

If you'd have baked it at just 150 degrees it may have boiled out -- water's vapor pressure at that temperature is about 150mm of mercury (absolute, of course, not 150mm of vacuum pulled).

Vapor pressures came from here, although you could look up the equation if you didn't mind distracting yourself from having a plane in Poland this year:

http://www.watervaporpressure.com/

Or, if you want to do the math:

http://en.wikipedia.org/wiki/Antoine_equation

It would be extra cool if I could remember what it is and where I got it from.

 Ok Howard, I figured out where mine came from. It's a place called ACP Composites, and it's the .2oz Carbon Veil. 

 http://www.acpsales.com/Carbon-Fiber-Tissue.html

 My routine: After the first couple of clear 50/50 coats and some light sanding on the bare wood per normal prep I'll then add another heavy/wet coat of 50/50 clear. While that clear is still wet I'll lay my pre-cut piece of veil on and lightly pat it down into the clear, using the clear as the adhesive. You do want to be careful not to slide it around too much because the more you do, the more it will begin to resemble your dreaded cat hair scenario. Don't worry if you do mush it around a bit though, it will still work just fine, it just may not look quite as pretty. If necessary during the wet application I'll maybe brush in a little more clear here and there to help sock it down, but gently with the interest of keeping things pretty, and then let it all dry. After the dope cures I'll then sand it down just enough to knock any high spots off and bury it in 50/50 clear once more. After that dries and is sanded it's just clear/sand/clear as usual...

 Hope this helps! 

Happy to hear you solved the problem, Howard. I was going to suggest getting some black tissue and using that.
Mr. Kimball used to use black tissue to simulate CF on most his models, and it seemed to work fine. This doesn't rhyme, but I don't give a chit.  Steve

I recovered it with the Brodak stuff, which worked fine.  I used the advice above.  Uncle Jimby told me that ACP has (or had) two different kinds.  The uglier of the two is the good stuff.  One calls ACP and asks for the stuff that the stunt guys get.  Thanks, folks.

  Right, the "bad" kind is what led to all those pinholes on the airplane I wrecked in 2005.

     Brett

I'll add one more suggestion. I was channeling Windy earlier and I remembered his advice to not put dope on your brush if you don't want the cloth to stick to the brush. I think these are wise words and putting the mat over the dope surface and brushing on thinner may be a better technique. I have a little more mat to apply to my plane so i'll let you know how it goes.

Hi,
I know I am late to the party, but I have started to use Eze Kote (one part laminating resin that cleans up with water) and carbon tissue from Deluxe Materials.

1) One coat of Eze kote
2) 30 minutes later sand it with 400 wet and dry
3) Another coat of Eze Kote (this might not be necessary, but it helps hold the tissue in place)
4) lay on the pre-cut cardon tissue
5) Another layer of Eze Coat. Sand when dry (30-60) minutes and done.

It worked very well for me the first time I tried.

http://www.deluxematerials.com/aeroezecote.html

http://www.deluxematerials.com/newitems.html

Jonathan