Sig butyrate dope score

akjgardner wrote:Stopped by my local hobby shop today on the way home. picked up several pints of colored butyrate dope and some sanding sealer for $ 2.00 a pint. guess i'm gunna have to get a air brush now. Any sugestions on a decent one ? Thanks

Yes, Stay away from the cheap Harbor Freight and Amazon nightmares. Pay a little more and get a name brand. A good dedicated air compressor is nice but you can get by with canned air.

Bob

There are some really informative threads on airbrushing over at Stunthanger.

Phil

I disagree with Bob BUT his advice is very good depending on what you desire an Air Brush for:

For very fine detail and artistic work; He is absolutely correct, and you should look at the Pashe VL series or Iwata. Theses are some of the best. Hobby Lobby caries both brands and most of the new needles and other bits.

I do not recommend the dedicated air brush compressors as way over priced...ANY good compressor can be used. The important thing is a good pressure regulator and filter.

I have a Harbor Freight (HF) 3 gallon small pancake $39 compressor that is a bit noisier than the dedicated purpose built air brush compressors sold for $119~$249- but for $39 does the exact same job of supplying a constant, stable pressure, source of air

Back to HF, and what I suspect most of us generally use air SPRAYERS for: general application of paint or dope on large areas reducing the tedious task of brushing it on.

The very low cost HF small and medium automotive detail guns are real good value and work just fine for spraying sanding sealer and initial Nitrate or Butyrate dope coats and save a LOT of time

I always note that Nitrate Dope is never put OVER (on TOP of) any other coating it must be First down IF used.

I also highly recommend the Preval sprayers as one shot disposables, and the great thing is the included 6oz jar has a lid your mixed dope can last in for a while

Lowes and other places carry them but I am out in the sticks so I mail order them from this place: a six pack with shipping is $38, so around $6.50 per unit

http://www.ryderfleetproducts.com/preval-sprayer-pve267/sprayer-paint-complete-unit-p-tol-pve267

I got the HLobby one at 25.00 I think but the regulator is the trick and plenty of air with mine,,, hope you got thinner you will need to thin around 50/50 to get it to spray and I have found to mix enough paint /thinner to do the job first time or you will be lucky to get the color the same (or I am doing something wrong) ?? There fun and drys fast . Eric

Thanks for all the help guys.

I use a Badger Touch Up gun. Set the pressure to gun at 30lbs and you're good to go. Get some cardboard and for experimenting with the needles. Mix your dope to ~50% with thinners. Use real dope thinner. Experiment if you want to use anything else to thin it. Red doesn't go over silver well Yellow is best over white base coat. I use silver or white as base coats most of the time.

Probably good clean dry air is as important as the spray tool that you use. A friend gave me this high tech compressor used in places where clean air is a must, but in real life I use it very little.



Instead I have sloffed down to using Top Flights "Lustrekote" spray "paints" (dope in a can) which is adequate in my opinion for any finish that doesn't involve a judge looking over your shoulder.



I used it on my Bipe and Cyclone, great for overall use but air brushing on trim, not so good.

Damn what a set up there Bob , you could paint for NASA with that thing . The spray cans let you do a good job on that plane I like the air brush but it is a lot to set it up but when done sure looks good in my eyes . Eric

can I use denatured alcohol to cut Butyrate dope? thanks

No denatured alcohol will not work

you really need to use same brand thinner for good results....

There are exceptions, and DuPont 3608s is one of them, usually found at a auto paint supply place

Some folks swear auto parts store acetone based Lacquer thinners work ok....but you need to know what is in the can, 100% acetone is way too (HOT) Fast a thinner

I always use the butyrate thinners for Nitrate and Butyrate dopes but I use low quality Lacquer thinner, acetone, MEK, or Xylene for brush and spray equipment cleaning

Unfortunately I am bound to buy my thinner on line so I get the Sig stuff in quarts to bypass the hazmat fees

Each of the Dope distributors has some variation of the formulas but most of their dope is repackaged Randolph Dope-- at least I know Sig and Brodak is.
A reading of the MSDS (materiel safety data sheet) shows each of their thinners is a slightly different combination of ingredients

This is perhaps one of the oldest and most often asked questions on every model building forum I have ever been on

fredvon4 wrote:

Each of the Dope distributors has some variation of the formulas but most of their dope is repackaged Randolph Dope-- at least I know Sig and Brodak is.

I did not know that.
Brodak was clearing out some of their Randolph a month or two ago and so I bought some colors for a decent price.
I bought up some Indian silk and ante'ed up by buying a gallon of Sig clear + gallon thinner. Approx $100 delivered, I think. Enough for a good long while.
There's a few small projects I am working on to get back in the dope game. And, the temps are rising up here in the US Northeast, can start painting outside soon, I hope.

Post pics as you move along, will be interesting to see progress.

I wouldn't call it repackaged. Yes, Brodak dope is made by Randolph but it's not  the same formulation. In addition, Brodak has changed some of the formulation and a lot of this was based on Windy's input. They also have totally different qualities in terms of spraying and brushing. If your looking for a good sport finish, use Sig. In my experience with Brodak dope, I will say that the material in the 4 oz bottles is considerably less viscous than the 8 oz. cans. I had a lot more success using the bottles for brushing trim colors vs the cans which I typically use for spraying.  Sig  thinner is different and slower having more open time to allow brush strokes to melt back into it. From my experience Sig Lite Coat has the best fuel resistance. NO DOPE IS FUEL proof. Brodak dope will wash away with 10% fuel with regular contact. The same will happen with Sig especially if 35% nitro is used as the higher nitro is like thinner. Make certain you have plenty of clear over your colors coats for added protection. Sig Lite Coat is compatible with Brodak dope. John had a fire a few years back and the clear was unavailable for quite some time. Coming straight from him was to use Sig Lite Coat for the final. Brodak clear will yellow and it already looks yellow in the can. This gets worse with UV exposure. Sig Lite Coat is the clearest of ALL dope clear coats. John within the past few years came out with Crystal Clear which he used for his NATS winning Shoestring. John stated that this was on the same level and durability as the Sig Lite Coat but it costs quite a few dollars more than the standard BP 1085 clear that he offers.

            I have friends who own full size aircraft which were fabric covered and they have had access to excess material which was Randolph dope. From what I've witnessed, Randolph dope had a lot more shrinkage compared to Sig essentially constricting the model to the point of crushing it and breaking ribs. This was also models that were covered in silk. I can't say for certain if it was one or the other but it looks pretty bad nonetheless.