Ye Olde Rocket Forum

Go Back   Ye Olde Rocket Forum > Work Bench > Building Techniques
User Name
Password
Auctions Register FAQ Members List Calendar Today's Posts Search Mark Forums Read


Reply
 
Thread Tools Search this Thread Display Modes
  #31  
Old 05-27-2011, 11:17 PM
Mark II's Avatar
Mark II Mark II is offline
Forest Sprite
 
Join Date: Dec 2006
Location: Back Up in the Woods
Posts: 3,657
Default

I actually prefer to use water-based sealers on balsa nose cones rather than dope. On balsa fins, it's the other way around; dope is the better product for them. I have specific reasons for this. I prefer to do as little sanding as possible on the actual surface of nose cones. The reason for that is because I buy cones that conform to specific shapes, and I have had too many regrettable experiences that involved sanding just a little too much in spots, causing the nose cones to be misshapen. When you use either dope or CWF you are sanding down to the actual wood, and I just prefer to not do that. Using water-based sealers like Delta C. or Pine-Pro there is much less of a risk of over-sanding, especially with the method that I use. I don't begin sanding water-based sealers until after the second or third application, at which point there is a good protective layer over the actual wood. The wood is well-sealed in preparation for the next step: wet sanding. The nice thing about using WBSs is that you can wet-sand them; in fact, I almost never dry sand them. Wet-sanding produces far and away the smoothest, most flawless surface finishes, and does so with surprisingly little effort. I have never misshapen a cone during wet-sanding, and I doubt that it is even possible to do so without a great deal of deliberate effort. I also prefer to use this type of sealer on balsa transitions for similar reasons.

With fins, I have different needs and priorities. I am almost always sealing and sanding flat fins, so inadvertently misshaping them by over-sanding is not an issue. I don't like to put any product that contains much water onto bare fins due to the risk of warping them. A combination of dope-based fillers and sealers is the perfect solution; it provides all of the positives and avoids all of the negatives. Dope is particularly effective on flat surfaces, or at least it is very easy to use on them, which makes it much less of a hassle to put in the work that is necessary to get mirror-smooth surfaces. Dope seems to have the incidental benefit of making the surface slightly harder, too.

So in the course of building many of my rockets I end up using both types of sealer. Each type has unique qualities that make it particularly useful for certain tasks.
__________________
Mark S. Kulka NAR #86134 L1,_ASTRE #471_Adirondack Mountains, NY
Opinions Unfettered by Logic • Advice Unsullied by Erudition • Rocketry Without Pity
+09281962-TAK-08272007+
SAM # 0011
Reply With Quote
  #32  
Old 05-28-2011, 09:23 AM
Bill's Avatar
Bill Bill is offline
I do not like Facebook
 
Join Date: Sep 2008
Location: North Tejas
Posts: 3,087
Default

Quote:
Originally Posted by Mark II
I actually prefer to use water-based sealers on balsa nose cones rather than dope. On balsa fins, it's the other way around; dope is the better product for them. I have specific reasons for this. I prefer to do as little sanding as possible on the actual surface of nose cones. The reason for that is because I buy cones that conform to specific shapes, and I have had too many regrettable experiences that involved sanding just a little too much in spots, causing the nose cones to be misshapen. When you use either dope or CWF you are sanding down to the actual wood, and I just prefer to not do that. Using water-based sealers like Delta C. or Pine-Pro there is much less of a risk of over-sanding, especially with the method that I use. I don't begin sanding water-based sealers until after the second or third application, at which point there is a good protective layer over the actual wood. The wood is well-sealed in preparation for the next step: wet sanding. The nice thing about using WBSs is that you can wet-sand them; in fact, I almost never dry sand them. Wet-sanding produces far and away the smoothest, most flawless surface finishes, and does so with surprisingly little effort. I have never misshapen a cone during wet-sanding, and I doubt that it is even possible to do so without a great deal of deliberate effort. I also prefer to use this type of sealer on balsa transitions for similar reasons.



Good idea. I will have to try that.


Bill
__________________
It is well past time to Drill, Baby, Drill!

If your June, July, August and September was like this, you might just hate summer too...

Please unload your question before you ask it unless you have a concealed harry permit.

: countdown begin cr dup . 1- ?dup 0= until cr ." Launch!" cr ;

Give a man a rocket and he will fly for a day; teach him to build and he will spend the rest of his days sanding...
Reply With Quote
  #33  
Old 05-28-2011, 12:02 PM
LeeR's Avatar
LeeR LeeR is offline
Retired with Way Too Many Kits
 
Join Date: Jun 2007
Location: Colorado
Posts: 3,222
Default

Quote:
Originally Posted by MKP
Uh, maybe we like to keep our brain cells intact? I've tried Aero Gloss I wasn't really that impressed. Plus its a b*tch to clean up.


If you use the right solvent, Aero-Gloss, SIG, and other sanding sealers are super-easy to clean up. I keep lacquer thinner in a small bottle, and dunk my brush a couple times, then wipe with a paper towel. The small bottle gets periodically topped from the gallon can. And I've used the same brushes for years. I keep the sanding sealer, solvent bottle, and several size brushes in a small tote for finishing, so everythign is dedicated just to finishing. The brushes and solvents never get used for anything else, such as touch-up painting.

I dislike water-based sealers for balsa, for the same reasons I refuse to use water-based finishes when I do woodworking. The wood can easily swell, and the finish is just plain inferior. Safer? You bet. But I ventilate my shop, or use these products outdoors.

I'll concede that if I had started finishing years ago with water-based products, I might have learned the required techniques to get great results. But I've been doing woodworking for 40+ years, and I figure why mess with proven (for me) techniques.
__________________
Lee Reep
NAR 55948

Projects: Semroc Saturn 1B, Ken Foss Designs Mini Satellite Interceptor
In the Paint Shop: Nothing! Too cold!
Launch-Ready: Farside-X, Maxi Honest John, Super Scamp
Reply With Quote
  #34  
Old 05-28-2011, 05:57 PM
luke strawwalker's Avatar
luke strawwalker luke strawwalker is offline
BAR
 
Join Date: Dec 2007
Location: Needville and Shiner, TX
Posts: 6,134
Default

Quote:
Originally Posted by ghrocketman
Hey Now !!!
I use wood glue too for construction; but only to attach fins on rockets that will not sustain an average thrust level above that of a D21/D24.
I never use wood glue for fillets any longer though. 30-min epoxy makes PERFECT single-application fillets.
For anything that the "normal" engine choice will be of the E18 impulse level or above, I use epoxy to both attach and fillet fins.
Does epoxy weigh more than wood glue ? Yeah, but the amount is miniscule on a typical MPR.
To each their own I guess....for MPR it's kinda like asking which is better-Coca-Cola or Pepsi- largely personal preference.
For sealing fins, the lower dust of dope-based sealers/fillers far outweighs the sanding mess of water-based CWF and others in that same group.


Glad to hear it...

BUT, Titebond Moulding and Trim Glue make the fastest and easiest fillets that come out perfect with little effort and NO sanding (if you put them on right) and of course it's water-based so NO glove/allergy issues and no fumes...

Stuff is plenty strong as well for most LPR/MPR builds...

Later! OL JR
__________________
The X-87B Cruise Basselope-- THE Ultimate Weapon in the arsenal of Homeland Security and only $52 million per round!
Reply With Quote
  #35  
Old 05-28-2011, 06:02 PM
luke strawwalker's Avatar
luke strawwalker luke strawwalker is offline
BAR
 
Join Date: Dec 2007
Location: Needville and Shiner, TX
Posts: 6,134
Default

Quote:
Originally Posted by gpoehlein
Gotta agree with the dust factor between dope sealer and CWF. But the Delta Ceramcoat Sealer does not generate a lot of dust - as I said earlier, it just clogs up the sandpaper really fast. Believe me, I've used quite a lot of Aerogloss in my time - used to build a lot of stick and paper model planes and using dope is pretty much a given there. If you remember the old Sig Sinbad, you'll know there was a LOT of surface area to dope on that sucker! I think I put four or five coats on it (I was painting it white, and white dope never did cover well with less than three coats!) But I get sinus headaches a lot easier these days than I did back then (we are talking 30-40 years here), so I choose carefully when I use dope.

Actually, although you gotta have a lot of ventilation to do this too, I also like coating balsa with CA - talk about a really tough and smooth finish, and it usually only takes one coat to do the job. The finished product is about as smooth and tough as plastic. Again, you gotta be REAL careful about the fumes with CA too - even more than with dope.


Yep, like the water-thin CA on balsa parts-- I do all my balsa nosecones/transitions with that treatment... but your right-- you DO have to be really careful with the fumes coming off that stuff!! DON'T EVEN THINK about doing it INDOORS-- (not unless you have a paint booth with a GOOD ventilator system!) Even doing it outdoors, do it with the wind to your SIDE-- you don't want the wind in your face (obviously) because it will blow the fumes right at you-- BUT you don't want the wind at your BACK either because the wind can 'curl around you' and whiff the fumes right up into your face anyway...

Learned that the hard way...

We used to use that stuff in the Police Academy to develop fingerprints-- put whatever you want to lift a fingerprint off of in a ziplock baggie and then toss a cotton ball drenched with water-thin CA into the bag and seal it up-- the fumes will bond with the oils in the fingerprint and turn them into a reddish/purply/brown crusty "image" that can be easily lifted with tape for fingerprint ID'ing...

Later! OL JR
__________________
The X-87B Cruise Basselope-- THE Ultimate Weapon in the arsenal of Homeland Security and only $52 million per round!
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump



All times are GMT -5. The time now is 06:36 AM.


Powered by: vBulletin Version 3.0.7
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Ye Olde Rocket Shoppe © 1998-2024