Author Topic: Butyrate vs Nitrate (Read 5309 times)

Leester · « **on:** February 11, 2006, 08:14:15 PM »

In the past I have exclusively used Butyrate dope on my planes. Is there any advantage to using Nitrate for the clear coats before covering? I realize Nitate is low shrink and not fuelproof.

RC Storick · « **Reply #1 on:** February 11, 2006, 08:19:44 PM »

Supposedly its lighter? Maybe someone else knows. I have always used butyrate.

Bill Little · « **Reply #2 on:** February 11, 2006, 08:30:52 PM »

I have used Nitrate (tinted, non-tautening) for everything up to the color coats for a long time. Now I have been using auto primer/filler for the filler.
Nitrate sticks tissue, CF veil, Silkspan, etc., so much easier than butyrate.
I eve did a stunt ship about three years ago and filled it with nothing but clear nitrate, sanded very well. No grain, etc., has shown up yet. That was a really light finish, but took forever!
Sig Super coat to shrink open bays (ONLY) and Lite Coat afterwards to fill the paper. Then on to filler/color/clear.

It can get messy if you try to put nitrate over any other dope.
Bill <><

Leester · « **Reply #3 on:** February 11, 2006, 09:24:57 PM »

Bill: So you just use the nitrate up to putting the covering on wood surfaces then use the butyrate for open bays and the final coats to fill before sanding Correct? I am using Brodak because of the color selection of there color dope.

Oregon_Flyer · « **Reply #4 on:** February 12, 2006, 08:08:52 AM »

Hi Bill
Don't mean to hijack this thread but have a question regarding the filler. I did some test panels to see about compatibility and the product I tested was from Evercoat
called Dura Build. It's an acrylic and the label states wood as one of it's accepted uses. It sands real well and as near as I can determine is lighter than butyrate dope with a traditional filler. Problem that I am encountering is that I think this process is causing grain separation that requires correction. What process and product are you using? Reducer?

Thanks

Marv

Bill Little · « **Reply #5 on:** February 12, 2006, 05:04:39 PM »

Leester and Marv,

To clarify, I use the Nitrate up to and including the attachment of any covering. I have found the nitrate attaches covering better than butyrate, in my experience.

I use Supercoat only on the open bays after the covering is attached. That is the only "shrinking" dope that I use, and only on the open bays after the covering is applied.

Since I use the Supercoat then I have to keep on using butyrate over those areas.
To go back to nitrate over the Supercoat will cause a mess. I have never had a problem using any other "type" butyrate over the nitratre.

As to fillers, I use several, mainly depending on what I have in the shop, and how much of a hurry I'm in! hahahaha

I use talc in dope, zinc sterate in dope, or automotive primer/fillers.

The auto stuff is the quickest. I use Dupont "Fill'n'Sand" through the paint gun, or Duplicolor Primer/Filler in the spray can. I have had no problem using any color coat system over either of these; dope, acrylic lacquer or basecoat/clearcoat.

Randy Powell · « **Reply #6 on:** February 12, 2006, 11:21:40 PM »

>> Brodak does offer clear Nitrate and Nitrate thinner. <<

But that would require me to use Brodak dope.

I use both Nitrate and Butyrate, but I buy either Certified or Randolph's by the gallon from either Spencer Aircraft or Aircraft Spruce.

Jerry Bohn · « **Reply #7 on:** February 17, 2006, 10:28:59 AM »

I read long ago that nitrate has more solid stuff (forgot technical name) in it, making it a bit better for filling balsa grain with less coats.

Jim Thomerson · « **Reply #8 on:** February 18, 2006, 09:07:31 AM »

I've been using a nitrate of unknown origin, with Sig thinner and finding that Sig Litecoat or Supercoat do not go over it well. They tend to rope up like Aerogloss does over nitrate. Some of the colors go on OK, some don't. I've found the same to be true with an airport nitrate. Have to go out to the shop to check the brand, and it's raining.

Randy Powell · « **Reply #9 on:** February 18, 2006, 12:47:44 PM »

Jim,

I don't have the problem, but then, I use all the same brand and all the same thinner. Lately it's been Certified nitrate, butyrate and thinner. It all seems fine together.

Dave Cook · « **Reply #10 on:** March 02, 2006, 04:55:51 AM »

I use nitrate starting with 2 to 3 coats over bare balsa - then I put on silkspan with nitrate and fill the silkspan with 7 to 10 coats of thinned out nitrate (sand between coats). I then switch to butyrate, putting on at least 2 coats of clear butyrate before any color.

Try to stick to all the same brand. Stay away from old paint as VOC requirements in the last few years have changed formulars to a point of incompatability. Most of the paint comes from Randolf.

This gives a light and strong finish that will last if you use a plasticiser.

old fart · « **Reply #11 on:** March 02, 2006, 12:15:01 PM »

SOMEONEONCE TOLD ME THE LIGHTCOTE WILL YELLOW IN TIME OVER WHITE I HAVE NOT FOUND THIS TO BE TRUE HOWEVER.

Bill Little · « **Reply #12 on:** March 03, 2006, 06:23:57 AM »

Quote from: old fart on March 02, 2006, 12:15:01 PM

SOMEONEONCE TOLD ME THE LIGHTCOTE WILL YELLOW IN TIME OVER WHITE I HAVE NOT FOUND THIS TO BE TRUE HOWEVER.

Hi Ron,

I have not seen the yellowing effect either. Not with Lite Coat or most of the other clear dopes I have used in the past 40 plus years.

Enamels have a bad tendency to yellow, but lacquer based products (including Dope) seem to resist it much better. There was a time when I noticed it with one of the "stages" Aero Gloss was going through,

the original Steve Smith · « **Reply #13 on:** March 03, 2006, 09:59:48 PM »

Plasticizer? What's that? Is it a separate product or some secret ingredient? This old newbie wants to know.

RC Storick · « **Reply #14 on:** March 03, 2006, 10:02:20 PM »

1 drop Castor oil per OZ of dope used.

Steve Helmick · « **Reply #15 on:** March 11, 2006, 09:35:21 PM »

I used castor oil for years as a plasticizer, but Lee Hines sorted me out on several issues. The castor reduces the stickyness of whatever type of dope you're using, and Butyrate already is #2 on that. Important on undercambered FF wings, less so on stunt models, but then there are those polywog Chiefs.

I bought some "Flex-All" from Dave Brown Products, but haven't used it yet. It is claimed to be suitable for most types of paint. I'd think it would be the same stuff available at Auto Paint Stores, repackaged in smaller bottles. I think I got it at the LRCHS. A search at Tower didn't turn it up there.

Steve

SQ8s · « **Reply #16 on:** March 12, 2006, 12:34:08 AM »

Flex-all From Dave Brown. Read instruction on the back.

STEVE.... Find out the Part # on that Item is. Would be nice to get some.

Marv.....Using Different compatibilities of paint can cause a monthly thing.

Randy..... WHAT A GREAT PRODUCT!!! I use that brand with BRODAK and NO problems.

Bill....DO what Bill Says, can't go wrong!! opps got carried away.

peabody · « **Reply #17 on:** March 12, 2006, 12:38:53 PM »

Here's what I have learned from observing others and my poor building skills...

If your basic structure is smooth as a baby's behind and snaded to 400 or so....smooth!!!...then using nitrate will yield satisfactory results....BUT, if you use nitrate and sand through your "silver" coat, even a little bit, then the nightmare will begin.
Guys like Bob Hunt and Bill Little are great builders and have success with nitrate, although I seriously doubt that they save any weight at all....

Most will find that using regular dope works just fine....just use the correct thinner....

Bill Little · « **Reply #18 on:** March 12, 2006, 03:45:53 PM »

Quote from: peabody on March 12, 2006, 12:38:53 PM

Here's what I have learned from observing others and my poor building skills...

If your basic structure is smooth as a baby's behind and snaded to 400 or so....smooth!!!...then using nitrate will yield satisfactory results....BUT, if you use nitrate and sand through your "silver" coat, even a little bit, then the nightmare will begin.
Guys like Bob Hunt and Bill Little are great builders and have success with nitrate, although I seriously doubt that they save any weight at all....

Most will find that using regular dope works just fine....just use the correct thinner....

I don't know that I would consider myself in that class, Rich, but THANKS!
As to weight..... It might not be significant, but the notrate does "stick" tissue and everything else better IMHO.

Of course, the "Finish Master", Mr. Urtnowski hisself, uses just butyrate. His results can't be argued with! He has definitely proven that great finishes can be done with only butyrate dope.

I just got staerted with nitrate and like it. My last Classic ship has NO FILLER. It is just filled with non-tautening nitrate on everything but the open bays where I used Supercoat after I attached the paper. It is the lightest finish I have ever put on a plane. I believe Jimmy Borelli or Mike Rogers did the same thing once. (??)

Steve Helmick · « **Reply #19 on:** March 12, 2006, 04:31:25 PM »

Scotch wrote: "Flex-all From Dave Brown. Read instruction on the back.

STEVE.... Find out the Part # on that Item is. Would be nice to get some."

FLEX 5100 is the stock number, apparently, at Dave Brown Products. The bottle is maybe 4 oz, flat/oval plastic, shaped about like a pint whiskey bottle, for $3.95. Maybe more, by now.

http://www.dbproducts.com/
On the label, it says to use on Acrylic Lacquers, Acrylic Primers, and Butyrate Dope. Nitrate Dope isn't mentioned, but it may well work. Instructions say to use one to two tablespoons per unthinned pint. I gave it the "whiff test"...inconclusive. No idea what is, but it smells a little strange, and no "recreational use" seems likely. FYI. $:-\$ Steve

SQ8s · « **Reply #20 on:** March 13, 2006, 06:56:07 PM »

SNIP>>>>I'd think it would be the same stuff available at Auto Paint Stores, repackaged in smaller bottle.

Gee Syeve I know about DAVE BROWN. I'm asking about auto parts stores, as you posted.

Bill Little · « **Reply #21 on:** April 26, 2006, 06:48:30 PM »

Dupont (and all the other auto paint companies) make Flexative additives, or flex agents (depending on who is behind the counter). It is not cheap, but it is probably the exact same thing as what Dave Brown sells only in quart bottles. And it is much cheaper by volume. I have had the DB Flex All, and the Dupont additive. No difference in my experience. No "reactions" with the Dupont in any dope or acrylic lacquer.

Also, acrylic automotive thinner (I generally use Dupont 3608 S) will work in Sig with no problem. An advantage is that the Acrylic Lacquer thinners (not "$6 a gallon" Lacquer Thinner) are sold in "temperature" ranges, spot repair and "blending" ranges. This is a TREMENDOUS help in our area where it get SO HOT and humid.