Author Topic: Mineral Spirits For Thinning Sig Dope? (Read 8869 times)

Chancey Chorney · « **on:** September 23, 2015, 08:23:12 PM »

Hi all, yet again. I am planning on doping an airframe this weekend, and had a quick question regarding thinning my Sig dope. I have a bottle of Sig Butyrate dope and was wondering about thinning it with mineral spirits. The plane(s) in question for now are profile sheet balsa 1/2a airplanes. I see many posts saying Lacquer thinner is ok to use to thin dope, but I had not seen anything regarding the use of mineral spirits. Reason being is that I have a bunch on hand as it is my thinner for spraying Tremclad paint as well as cleaning my spray gun. If I need to buy some, I will, but would just like to use what I have on hand. Thank you in advance for any and all help or ideas.

Randy Powell · « **Reply #1 on:** September 23, 2015, 08:51:07 PM »

I wouldn't.

Mark Scarborough · « **Reply #2 on:** September 23, 2015, 09:59:24 PM »

NO,,
and I strongly,, let me repeat,, STRONGLY reccomend against using hardware store lacquer thinner for dope,, it is way to fast to be effective and will lead to a long list of problems,,

now I know,, there will be someone who says,, yeah it works,, but I will NEVER use it as thinner to apply dope,, onlly use the thinner created for use in the product,, Please,,,

use the hardware store crap for cleaning up,,
and mineral spirits really isnt that good for cleaning spray guns with lacquer either,,

Bill Little · « **Reply #3 on:** September 23, 2015, 10:38:39 PM »

I agree 100% with Mark! No cheap lacquer thinner in dope. Get a gallon to clean your brushes and spray guns.

If you cannot find dope thinner and you HAVE to spray, get some Dupont 3608S thinner from the auto parts store. DO NOT USE THE DUPONT WITH THE SUFFIX "VS". Only the "S". Windy Urnowski one of the greatest model airplane painters used only the 3608S in his dope for years and there were no problems and the paint jobs have help up for 20+ years in some cases.

BIG Bear
RNMM/AMM

Mark Scarborough · « **Reply #4 on:** September 23, 2015, 11:56:16 PM »

Bill,,
I should be more carefull,, sometimes I come across a little strong in my responses,, I have just seen so many avoidable problems,, ( a LOT of them my own doing to be fair)
You are correct, I have heard of people having good success with that thinner,, I have never had occasion to try it myself,, of course that is a lot higher quality thinner than "rocket fuel" from Lowes or such,,

thanks for catching that omission

John Leidle · « **Reply #5 on:** September 24, 2015, 12:38:11 AM »

Mineral Spirits is paint thinner for use with Varnish & such put it in Dope I think it would ruin your afternoon.
John

Will Hinton · « **Reply #6 on:** September 24, 2015, 08:45:46 AM »

Quote from: John Leidle on September 24, 2015, 12:38:11 AM

Mineral Spirits is paint thinner for use with Varnish & such put it in Dope I think it would ruin your afternoon.
John

Not to mention your dope!!

Howard Rush · « **Reply #7 on:** September 24, 2015, 11:49:38 AM »

A real scientist would try it anyhow. (Well, a real scientist would have a chemical clue as to whether it would work before he tried.) Reminds me of diesel fuel in a rubber bladder tank. Everybody knows that won't work. Phillip Granderson tried it. It didn't work, of course, but it increased my respect for Phillip's scientific curiosity.

Chancey Chorney · « **Reply #8 on:** September 24, 2015, 02:42:47 PM »

Okey dokey. No mineral spirits for my planes it is. I will source out some quality lacquer thinner for this project then. Thanks for all the responses.

Bill Little · « **Reply #9 on:** September 24, 2015, 03:19:33 PM »

Quote from: Mark Scarborough on September 23, 2015, 11:56:16 PM

Bill,,
I should be more carefull,, sometimes I come across a little strong in my responses,, I have just seen so many avoidable problems,, ( a LOT of them my own doing to be fair)
You are correct, I have heard of people having good success with that thinner,, I have never had occasion to try it myself,, of course that is a lot higher quality thinner than "rocket fuel" from Lowes or such,,

thanks for catching that omission

Hi Mark,
I have never had a problem with your input. You definitely know what you are doing! Because of you, I use Randolph butyrate thinner exclusively, since I use Randolph, Sig and Brodak butyrate!

If I am out and in an emergency, I will use the Dupont.
Thanks for all you do!
Bill

Randy Powell · « **Reply #10 on:** September 24, 2015, 04:50:13 PM »

I've used 3608S with a variety of butryate lacquers. It generally works fine but the temp range tends to be a bit limited.

Allan Perret · « **Reply #11 on:** September 28, 2015, 03:55:14 PM »

You can get gallon of Duplicolor lacquer thinner from AutoZone/Pepboys. Should work OK if you cant get some SIG thinner in time. If you go this route use same thinner on subsequent color and clear coats.

Motorman · « **Reply #12 on:** September 28, 2015, 04:24:17 PM »

You guys can comb the hardware stores looking for an experiment if that floats your boat. I ordered 2 Qts. of thinner right from Sig. A little pricey but, so nice to have the good stuff when you need it.

MM

Larry Borden · « **Reply #13 on:** September 28, 2015, 04:34:02 PM »

Used 3608S for years, no prob.
If you can find an aircraft supply place, you can get gallons of dope thinner cheaper.

EddyR · « **Reply #14 on:** September 28, 2015, 04:48:55 PM »

Dupli Color thinner $17 gallon at auto parts stores it is just like the Dupont. Same drying time

Mineral spirits is for oil base paints.

billbyles · « **Reply #15 on:** September 29, 2015, 05:20:27 PM »

Quote from: Bill Little on September 23, 2015, 10:38:39 PM

I agree 100% with Mark! No cheap lacquer thinner in dope. Get a gallon to clean your brushes and spray guns.

If you cannot find dope thinner and you HAVE to spray, get some Dupont 3608S thinner from the auto parts store. DO NOT USE THE DUPONT WITH THE SUFFIX "VS". Only the "S". Windy Urnowski one of the greatest model airplane painters used only the 3608S in his dope for years and there were no problems and the paint jobs have help up for 20+ years in some cases.

BIG Bear
RNMM/AMM

The part number for the low VOC DuPont lacquer thinner is V3608S, not 3608VS. Small point but possibly confusing for someone who is not familiar with lacquer thinners.

billbyles · « **Reply #16 on:** September 30, 2015, 11:40:56 AM »

Quote from: Larry Borden on September 28, 2015, 04:34:02 PM

Used 3608S for years, no prob.
If you can find an aircraft supply place, you can get gallons of dope thinner cheaper.

I don't know about that...current price of a gallon of Randolph butyrate thinner is right at $42 per gallon. Still by far the best way to go for thinning butyrate dope.

EddyR · « **Reply #17 on:** September 30, 2015, 12:45:22 PM »

I used Dupli-color thinner and Randolph color start to finish on this just finished model. I have Dupont and Dupli-color and see no difference in drying speed. I do use Randolph retarder in all my clear and color. DC is still $18 gallon.

Tom Luciano · « **Reply #18 on:** September 30, 2015, 03:40:35 PM »

Hi Ed,

I'm curious about the duplicolor because I know others who used it and liked it. I went to purchase it(in a pinch) and the gallon can said it was 100% Acetone. Is this the same gallon can your using? I was a little scared to purchase thinking it would be too fast/hot. I ended up with Dupont 3602s. 42.00 a gallon

Thanks,
Tom

billbyles · « **Reply #19 on:** September 30, 2015, 06:51:46 PM »

Quote from: Tom Luciano on September 30, 2015, 03:40:35 PM

Hi Ed,

I'm curious about the duplicolor because I know others who used it and liked it. I went to purchase it(in a pinch) and the gallon can said it was 100% Acetone. Is this the same gallon can your using? I was a little scared to purchase thinking it would be too fast/hot. I ended up with Dupont 3602s. 42.00 a gallon

Thanks,
Tom

Hi Tom,

Acetone will dissolve the dope alright but dries way too fast to get good flow. DuPont 3602S is their slow drying lacquer thinner & would be way better than acetone. Acetone is good for cleaning your spray gun but not much else. The price of the 3602S at $42/gallon is about right. The only reason guys get away with using acetone to thin finishing dope at all is because our models are not very big with not much surface area. I still recommend using butyrate thinner for finishing by far.

Mark Scarborough · « **Reply #20 on:** September 30, 2015, 07:19:01 PM »

Quote from: billbyles on September 30, 2015, 11:40:56 AM

I don't know about that...current price of a gallon of Randolph butyrate thinner is right at $42 per gallon. Still by far the best way to go for thinning butyrate dope.

agreed

EddyR · « **Reply #21 on:** October 01, 2015, 11:54:31 AM »

Quote from: Tom Luciano on September 30, 2015, 03:40:35 PM

Hi Ed,

I'm curious about the duplicolor because I know others who used it and liked it. I went to purchase it(in a pinch) and the gallon can said it was 100% Acetone. Is this the same gallon can your using? I was a little scared to purchase thinking it would be too fast/hot. I ended up with Dupont 3602s. 42.00 a gallon

Thanks,
Tom

Tom you caught something I missed. The last time I bought four gallons of Dupli-Color thinner mid 2014 I got two of these ,see picture and two of the 100% acetone.
It was held for me and I did not check it. I did just check the local Advanced Auto and they do have the true Lacquer thinner at $16.99 gallon.

I guess I will go and get a few more gallons. I used retarder and it kept the drying time down. I was using the Acetone version on the last orange plane and I could not touch it for 30 minutes even to turn it. It took two hours to handle. Humidity was 15% that day. It smelled harsh like true lacquer thinner.
Dupli-Color must have changed there formula in 2014. The Acetone can has a yellow label on saying compliant formula.
I am glad you caught it.
Ed

Tom Luciano · « **Reply #22 on:** October 01, 2015, 01:28:36 PM »

Hi Ed,

Thanks for getting back to me. I figured something must have been array!

For the record guys, I had no intention of using Acetone that's why I asked Ed the question. Sorry for the confusion!

I agree to use the right product formulated for the job. Like I said i was in a pinch. Advance Auto 5 miles, Paint shop 30 miles, Aircraft Spruce 3 days

15% Humidity is to die for! I couldn't get my shop below 55% from August through the first week of September!

Finally got it to 52% and that was the ticket! 53% seems to be the cutoff from my experience. I went 3:1 3602s/Retarder and got good results.

Thanks,
Tom

Randy Powell · « **Reply #23 on:** October 01, 2015, 02:34:29 PM »

I just got dope and thinner from Spencer Aircraft (Randolph's all around). $16 a quart for clear non-taunting clear. $26 for a gallon of thinner. The color dope I got was slightly more expensive at $18 a quart.

billbyles · « **Reply #24 on:** October 01, 2015, 03:50:49 PM »

Quote from: Randy Powell on October 01, 2015, 02:34:29 PM

I just got dope and thinner from Spencer Aircraft (Randolph's all around). $16 a quart for clear non-taunting clear. $26 for a gallon of thinner. The color dope I got was slightly more expensive at $18 a quart.

Hi Randy,

You should get all of the $26/gallon Randolph butyrate thinner you can buy - that is only $3 more than the manufacturer (Consolidated Aircraft Coatings, Inc.) charges dealers for it (retail is $42.75/gallon.) The Randolph non-tautening butyrate clear is still about $18/quart, Randolph colors begin at about $18/quart for whites and go up from there.

Randy Powell · « **Reply #25 on:** October 01, 2015, 04:04:16 PM »

Maybe it's a loss leader, but that's what I paid for it. Nice people, too.

Gerald Arana · « **Reply #26 on:** October 01, 2015, 04:22:08 PM »

As I sit here reading all this "flap" about these various thinners, I got out a can of "Brodak" thinner and read the label. Can you guess what the "first" ingredient is? It's ACETONE!

If I am remembering correctly, the first ingredient listed on the label is the most (or highest %) contained in the product. Correct me if I'm wrong.

Keep on painting, Jerry

Chancey Chorney · « **Reply #27 on:** October 01, 2015, 09:19:00 PM »

Quote from: Gerald Arana on October 01, 2015, 04:22:08 PM

As I sit here reading all this "flap" about these various thinners, I got out a can of "Brodak" thinner and read the label. Can you guess what the "first" ingredient is? It's ACETONE!

If I am remembering correctly, the first ingredient listed on the label is the most (or highest %) contained in the product. Correct me if I'm wrong.

Keep on painting, Jerry

I second your thoughts on the first number being the highest quantity of the product.

Mark Scarborough · « **Reply #28 on:** October 01, 2015, 10:35:51 PM »

Quote from: Gerald Arana on October 01, 2015, 04:22:08 PM

As I sit here reading all this "flap" about these various thinners, I got out a can of "Brodak" thinner and read the label. Can you guess what the "first" ingredient is? It's ACETONE!

If I am remembering correctly, the first ingredient listed on the label is the most (or highest %) contained in the product. Correct me if I'm wrong.

Keep on painting, Jerry

your right, it has acetone in it,, but they dont tell you the percentage,, and its NOT pure acetone,, its the other stuff that makes it work,,

pay your money,, take your chances,, but for the record,, I have painted with laequer since 1979,, I will NEVER use cheap thinner,, except to clean my brushes,, and spray equipment,,

billbyles · « **Reply #29 on:** October 02, 2015, 01:08:30 PM »

Quote from: Gerald Arana on October 01, 2015, 04:22:08 PM

As I sit here reading all this "flap" about these various thinners, I got out a can of "Brodak" thinner and read the label. Can you guess what the "first" ingredient is? It's ACETONE!

If I am remembering correctly, the first ingredient listed on the label is the most (or highest %) contained in the product. Correct me if I'm wrong.

Keep on painting, Jerry

Jerry,

Looks like you thought you had a real "gotcha". The military specification for butyrate dope thinner is MIL-T-6906A which shows the components to be by weight: Ethyl Acetate 39.2% to 40.8%; Butyl Acetate 14.7% to 15.3%; Diacetone alcohol (Diacetone means the alcohol is acetone free) 9.8% to 10.2%; Methyl-Ethyl-Ketone 34.3% to 35.7%. This is for a normal relatively medium drying speed butyrate thinner such as Sig or Randolph. Faster drying thinners contain some acetone. And yes, there is quite a bit of MEK in the Mil Spec thinner, however MEK dries at about one third the rate of acetone.

Mark Scarborough's post on this subject is right on.

phil c · « **Reply #30 on:** October 21, 2015, 08:42:10 PM »

Quote from: billbyles on October 02, 2015, 01:08:30 PM

....Ethyl Acetate 39.2% to 40.8%; Butyl Acetate 14.7% to 15.3%; Diacetone alcohol (Diacetone means the alcohol is acetone free) 9.8% to 10.2%; Methyl-Ethyl-Ketone 34.3% to 35.7%....

Diacetone alcohol is an entirely different chemical than ether acetone or alcohol. Has nothing to do with blending alcohol and acetone. It's a less volatile solvent than acetone. Its supposed to give a glossier, harder finish to butyrate dope.

billbyles · « **Reply #31 on:** October 23, 2015, 01:12:30 PM »

Quote from: phil c on October 21, 2015, 08:42:10 PM

Diacetone alcohol is an entirely different chemical than ether acetone or alcohol. Has nothing to do with blending alcohol and acetone. It's a less volatile solvent than acetone. Its supposed to give a glossier, harder finish to butyrate dope.

"Has nothing to do with blending alcohol and acetone."

Isn't that pretty much what I said in my post above?