Author Topic: DuPont Thinner? (Read 5573 times)

Alex Givan · « **on:** July 27, 2010, 03:12:48 PM »

I use Brodak dope and have run out of thinner. I have been told that DuPont makes a thinner that works very well but I can't recall the part number or formula number that works best. Any help would be appreciated.

- Alex

Leester · « **Reply #1 on:** July 27, 2010, 03:24:00 PM »

Your Mileage may vary but 3608s is what has been used. Of course mixing thinners on a job is not recommended (disclaimer).

john e. holliday · « **Reply #2 on:** July 28, 2010, 08:55:51 AM »

Get some K2R or corn starch to soak up some of the oil. If itis not that oily, Balsa Rite works great before putting on dope or any finish.

Balsa Butcher · « **Reply #3 on:** July 28, 2010, 10:11:52 AM »

Just make sure it is not V3608S. That won't work. The "old school" 3608S may be hard to find in some areas of the country. This formula works OK with both Sig and Brodak but in my experience (just shot some w/Sig Miami Blue) dries faster so has a tendency to shot "dry" as opposed to the real deal Sig thinner. I only use it as a last resort or to clean spray guns. For the most part, it is best to stick to the same brands of thinners and dope IMHO.

Ward Van Duzer · « **Reply #4 on:** July 28, 2010, 11:25:53 AM »

3602S is a slow dry formula.

w.

Balsa Butcher · « **Reply #5 on:** July 28, 2010, 12:19:47 PM »

Thanks Ward, that's good to know. My comment was based on very recent experience - I may have to adjust my air pressure or amount of thinner I add to the dope. I still find it easier to shoot "wet" using Sig thinner than with 3608S. If 3608S is slow dry, maybe Sig is a "slower-dry" formula than 3608S? At least it seems that way to me.

Allan Perret · « **Reply #6 on:** July 28, 2010, 05:34:42 PM »

I have found another lacquer thinner that appears to work OK with Sig and Brodak dopes. So far I have only used it for clears, nitrate and butyrate.
I intend to use it for the colors and final clearcoat soon. The brand is Finish Pro, a product line I found in a local auto body supply.
They have a website http://www.finish-pro.com/Products_Frameset.html
They have 4 different lacquer thinners. General Purpose, Primer Grade, Premium Med, and Premium Slow. I been using the Premium Slow, $24/gallon.

Bill Little · « **Reply #7 on:** August 03, 2010, 01:34:32 PM »

Quote from: Pete Cunha on July 28, 2010, 12:19:47 PM

Thanks Ward, that's good to know. My comment was based on very recent experience - I may have to adjust my air pressure or amount of thinner I add to the dope. I still find it easier to shoot "wet" using Sig thinner than with 3608S. If 3608S is slow dry, maybe Sig is a "slower-dry" formula than 3608S? At least it seems that way to me.

Hi Pete,

Ward said 3602S is a slow dry formula.

There are several grades of Dupont 360_S thinner, just like all automotive lacquer thinners. Just the *V* prefix is no good for dope. Been using Dupont 3608S in all my paints for over 20 years now. Even auto urethane clear coats. Since I am not doing a $20,000 real car paint job like my friend used to do, I have never seen any problem using the 3608S. No crazing, globbing, lack of adhesion, etc...

Mongo

Lester Nicholson · « **Reply #8 on:** August 06, 2010, 12:55:19 PM »

Y'all don't jump on me to hard, but I have using acetone to thin dope for 45 years w/out any problems, but then I've never sought a front line finish. Nick

Balsa Butcher · « **Reply #9 on:** August 06, 2010, 05:55:21 PM »

3608s vs 3602S, thanks for pointing that out Bill. I owe Ward and apology, it was good information, must have had the wrong reading glasses on.

I too have used 3608S successfully in the past, this last time though it was spraying real dry but there may be other factors involved.

Steve Fitton · « **Reply #10 on:** September 28, 2010, 01:27:38 PM »

Ready to try 3608S here. Used sig thinner on my all sig dope finish on the new plane, and it acted awfully hot. Thinned 50/50, the final clear when shot caused the polar grey blocking coat to bleed through the white, making the plane look moldy in places. Also had blistering pop up where I went extra heavy with the clear, like over trim colours and lettering. The one good thing with the all sig is that the finish is mechanically bulletproof-I could probably mask with duct tape and not have any lifts or pulls.

Alternately, I may do the finish with Sig up to final clear, then shoot DuPont 480S clear to finish it off.

RandySmith · « **Reply #11 on:** September 28, 2010, 03:31:27 PM »

Quote from: Steve Fitton on September 28, 2010, 01:27:38 PM

Ready to try 3608S here. Used sig thinner on my all sig dope finish on the new plane, and it acted awfully hot. Thinned 50/50, the final clear when shot caused the polar grey blocking coat to bleed through the white, making the plane look moldy in places. Also had blistering pop up where I went extra heavy with the clear, like over trim colours and lettering. The one good thing with the all sig is that the finish is mechanically bulletproof-I could probably mask with duct tape and not have any lifts or pulls.

Alternately, I may do the finish with Sig up to final clear, then shoot DuPont 480S clear to finish it off.

If you do that let it*** DRY *** for a month before shooting final clear

Randy

Allan Perret · « **Reply #12 on:** September 28, 2010, 07:51:01 PM »

Today I used the Finish Pro lacquer thinner that I spoke of earlier in this thread with Brodak white dope, worked great. I also used some Randolph retarder with it. I had planned to spray Randolph white dope, but when I opened a new quart can, it was bad and could not use it. Reported it to Randolph and they are sending replacement.

Bill Little · « **Reply #13 on:** October 02, 2010, 11:55:35 AM »

Quote from: RandySmith on September 28, 2010, 03:31:27 PM

If you do that let it*** DRY *** for a month before shooting final clear

Randy

Hi Randy

Is the Dupont 480S a urethane? If so, I know you have to let the dope gas off or it may not adhere well.

I do not remember the Dupont clear acrylic lacquer number.

Bill

Steve Fitton · « **Reply #14 on:** October 02, 2010, 12:03:36 PM »

Quote from: Bill Little on October 02, 2010, 11:55:35 AM

Hi Randy

Is the Dupont 480S a urethane? If so, I know you have to let the dope gas off or it may not adhere well.

I do not remember the Dupont clear acrylic lacquer number.

Bill

Hey Mr Big Bear! 480S is the old 380S Lacquer, its just sold now as 480S and comes pre thinned. Derek used it on his Concours winning Evolution and it was very shiny, and he said it sprayed very well. My Sig clear is buffing out very shiny, but it was hard to get enough on because as soon as you got a good wet coat on it would start to blister...

Bill Little · « **Reply #15 on:** October 02, 2010, 12:11:29 PM »

Quote from: Steve Fitton on October 02, 2010, 12:03:36 PM

Hey Mr Big Bear! 480S is the old 380S Lacquer, its just sold now as 480S and comes pre thinned. Derek used it on his Concours winning Evolution and it was very shiny, and he said it sprayed very well. My Sig clear is buffing out very shiny, but it was hard to get enough on because as soon as you got a good wet coat on it would start to blister...

Hi Steve,

I never worried about the old Dupont lacquer and having the dope to gas off since the lacquer is also a chemical bond and dope is a "lacquer". I just used the same waiting period I used for *dope*. I have not seen the 480S yet, but I will go to the paint store and see if it is sold around here (ban on auto lacquers in "bulk" in NC).

I can get quarts of Duplicolor Lacquer, but it is a synthetic (low VOC) lacquer

Big Bear

billbyles · « **Reply #16 on:** October 02, 2010, 04:56:52 PM »

Quote from: Steve Fitton on September 28, 2010, 01:27:38 PM

Ready to try 3608S here. Used sig thinner on my all sig dope finish on the new plane, and it acted awfully hot. Thinned 50/50, the final clear when shot caused the polar grey blocking coat to bleed through the white, making the plane look moldy in places. Also had blistering pop up where I went extra heavy with the clear, like over trim colours and lettering. The one good thing with the all sig is that the finish is mechanically bulletproof-I could probably mask with duct tape and not have any lifts or pulls.

Alternately, I may do the finish with Sig up to final clear, then shoot DuPont 480S clear to finish it off.

Hi Steve,

Of the butyrate thinners I use I have observed the following characteristics:
1. Sig thinner is the slowest drying of the three that I use.
2. Randolph is the next slowest drying butyrate thinner.
3. Certified brand is the fastest drying of the three, and is still quite a bit slower drying than lacquer thinner.

Because Sig is a relatively slow drying thinner I can spray on a little less material and it will still flow out to a glossy finish. I like Sig thinner a lot. Randolph is also an excellent medium drying thinner for all butyrate dopes. Certified butyrate thinner works well also, and is the fastest drying of the three.

Although many builders use lacquer thinner to thin butyrate dopes I do not. You can get away with using it because our models are a relatively small area to paint compared to a full-scale airplane, so the faster drying rate of the lacquer thinner doesn't matter as much. The cost of lacquer thinner has gotten right up there with the cost of Randolph or Certified thinners.

I think that the problem of the Sig thinner being "hot" & the bleed-through of the polar gray is caused by shooting too heavy a coat of the Sig material. I use Sig dopes & thinners regularly & don't have the problem of bleed-through. The best way to use butyrate dope is to thin it 50% as you mentioned and apply more coats rather than heavy ones.

You will find that DuPont 480s clear lacquer is one of the least fuel-resistant finishes you can use. It has a beautiful gloss as sprayed and is easy to polish to a fantastic gloss, but you have to be very careful to keep raw fuel & exhaust residue off of it. Tuned pipe engines, if you are careful while fueling them, work well with clear lacquer due to the minimal exhaust residue that gets on the airplane.

Steve Holt · « **Reply #17 on:** October 06, 2010, 11:43:32 AM »

Brodak has fairly recently released a new clear called "Crystal Clear" which does not cause yellowing of your white finish. Does anyone have any experience as to how fuel proof this clear is compared to the original?
Steve

Randy Powell · « **Reply #18 on:** October 06, 2010, 02:23:39 PM »

>>480S is the old 380S Lacquer, its just sold now as 480S and comes pre thinned<<

I don't know about the 480S, but 380S is only marginally fuel proof. You need to make sure you wipe the plane down immediately after a flight and don't spill any fuel on it.

Just understand that if you decide to use DuPont thinner with anything but DuPont lacquer, you're taking a chance. It may work OK or it may not. Using thinners that are formulated to work with the paint they are used in is the best policy for insuring that you get a consistent result. Lacquer is hard enough to shoot since it's more effected by conditions and contamination than urethane. Adding potential incompatibilities is just asking for it.

Steve Fitton · « **Reply #19 on:** October 06, 2010, 03:34:20 PM »

Quote from: Randy Powell on October 06, 2010, 02:23:39 PM

>>480S is the old 380S Lacquer, its just sold now as 480S and comes pre thinned<<

I don't know about the 480S, but 380S is only marginally fuel proof. You need to make sure you wipe the plane down immediately after a flight and don't spill any fuel on it.

Just understand that if you decide to use DuPont thinner with anything but DuPont lacquer, you're taking a chance. It may work OK or it may not. Using thinners that are formulated to work with the paint they are used in is the best policy for insuring that you get a consistent result. Lacquer is hard enough to shoot since it's more effected by conditions and contamination than urethane. Adding potential incompatibilities is just asking for it.

I understand there is a risk with using DuPont and Sig together, but my all Sig finish managed to fry itself pretty well without resorting to using any other brand products. My Sig thinner behaved like it was a *really hot* thinner, melting down to the primer and causing it to bleed through, and blistering the paint if you put on a wet coat. There is no way I can have a presentable plane if I continue to have that problem.

Bill Little · « **Reply #20 on:** October 07, 2010, 07:09:50 AM »

Quote from: Steve Fitton on October 06, 2010, 03:34:20 PM

I understand there is a risk with using DuPont and Sig together, but my all Sig finish managed to fry itself pretty well without resorting to using any other brand products. My Sig thinner behaved like it was a *really hot* thinner, melting down to the primer and causing it to bleed through, and blistering the paint if you put on a wet coat. There is no way I can have a presentable plane if I continue to have that problem.

Hi Steve,

I have only used 3608S thinner since I came back in the late '80s. Windy used to use only 3608S thinner and he had a 20 point plane with it. He was using Sig dope then since there was no Brodak dope yet. You should be perfectly fine with the 3608S. Ward-o uses 3602S sometimes since it is a bit better in high humidity. Brother Randy does a lot of experimenting with paints and has beautiful models, but I know he has the occasional problem with certain things but the 3608S will not be a problem in Sig Dope, or Dupont Lacquer, or PPG lacquer as far as that goes. I have used in in everything. The only problem I have EVER had was using too much Sig Retarder in clear once. It ate into the top coat and caused it to fade a bit on the bottom of a plane (and that was caused by getting in a hurry and putting it on too heavy).

My Geo Juno was painted almost 15 years ago using Sig Bright Red and 3608S, you have seen it, and there were no problems. In fact it was second to Windy at Flushing in Concours in 1997. Other than Aaron poking a couple holes in the wing, it still looks good.

Big Bear

Randy Powell · « **Reply #21 on:** October 07, 2010, 03:33:03 PM »

Hey Bill,

I know all kinds of guys that have used 3608s with various dopes. Usually works fine. I'm saying that if you use it with anything buy DuPont paint, you're taking a chance. You likely have a narrower envelop for mistakes.

But as always, if it's working for you....

Tim Wescott · « **Reply #22 on:** October 07, 2010, 03:45:57 PM »

Quote from: Steve Holt on October 06, 2010, 11:43:32 AM

Brodak has fairly recently released a new clear called "Crystal Clear" which does not cause yellowing of your white finish. Does anyone have any experience as to how fuel proof this clear is compared to the original?

No experience, but when I emailed Brodak to ask "what the heck is different between clear and crystal clear???" the response was that the regular old clear has some tint to it, and the crystal clear does not. If that's really the only difference, then I would expect the resistance to fuel would be the same -- but don't quote me on that.

Bill Little · « **Reply #23 on:** October 08, 2010, 09:17:59 PM »

Quote from: Randy Powell on October 07, 2010, 03:33:03 PM

Hey Bill,

I know all kinds of guys that have used 3608s with various dopes. Usually works fine. I'm saying that if you use it with anything buy DuPont paint, you're taking a chance. You likely have a narrower envelop for mistakes.

But as always, if it's working for you....

Hi Randy,

You do such intricate and beautiful work that you HAVE to be cautious when painting, that's a great thing.

A lot depends on the experience a person has in using certain paints, and combinations. Seeing Windy use 3608S in Sig dope (which I was using at the time) and getting 20 points for it, I figured I would try it since it was available locally and pretty cheap compared to dope thinner. I tested it in small amounts of other products, and it was fine. So I just have kept it going since it has worked. I generally spray all my products fairly thin and lightly which may be a real factor in no reactions occurring. About 21 years of usage is good enough for me.

The system of color/clear I liked th every best was Dupont Chromabase and Chromaclear. The base colors took so little amounts to cover, and the clear came out of the gun looking *wet*. I painted the entire Argus green with no more than 5 oz. of MIXED paint. And the three trim colors took no more than an ounce, mixed, each through the airbrush. A bit pricey, but a little bit goes a LONG way.

I was just yanking your chain a bit out of jealousy!! I cannot normally do all the masking and different colors you use, I get Adult ADHD.

Bill

Randy Powell · « **Reply #24 on:** October 09, 2010, 05:55:35 PM »

Bill,

I certainly have had my share of experimentation and tried all kinds of stuff. I've even got a plane that I used lacquer as a base, enamel colors and urethane top coat and it worked out beautifully. But it's not a way to do if you want consistent results. The best bet is to use materials that you know to be compatible (because the manufacturer says they are) and use the same thing from the ground up. I ran out of Certified thinner (using Certified dope) and changed over to Randolph's thinner for the remainder of the finish. Ended up with a bunch of crazing and blotches and it was a pain to sand all out and go again. You just never know.Even changing from one can of thinner to another from the same manufacturer can have an effect if they slightly changed the formulation and didn't tell you (had that happen too).

If you have a system that's working for you, keep at it. But if the materials are not matched, don't be surprised if under certain conditions you have problems. I've shot a lot of plane when the conditions are outside the recommended limits (like shooting catalyzed polyurethane in 40 degree weather). You can get away with it usually. You can cut the clear with urethane reducer to get it to flow out, but the manufacturer will tell you that they won't guarantee the results because one time in four, there will be a problem. It's not that it can't work, it's that there a reasonable chance that it won't. If the humidity is just a tiny bit high or there is a major change in temp while your shooting, it will go in the toilet (ask how I know).

Over the years, I've gotten to the point that I'm not all that interested in taking a chance on an airframe I've just spent months building so I use completely compatible materials as recommended by the manufacturer and do every thing I can to insure I'm shooting paint within the specs for that finishing material. Occasionally, things still go south anyway, but at least I'm taking as much chance out of the equations as I can.

But hey, you pays your money and takes your chances.