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Author Topic: Some thoughts on Thinners  (Read 650 times)

Offline kevin king

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Some thoughts on Thinners
« on: December 22, 2022, 11:33:23 AM »
So, i recently switched over to Randolph thinner and Dope. Prior to that i used sig dope and a fast drying hardware store Lacquer thinner. I've had some problems in the switch over i want to share. After doing a small repair on the elevator, which involved sanding and filling the defect with a small amount of glazing putty, I sealed it with a coat of clear. After it dried i sprayed the white. This caused the repair to look worse. My guess is the Randolph which is a hotter, slow drying thinner penetrated Through, around and underneath the repair and ruined all the previous steps in getting it flat and smooth. It seems to me there is a reason for 'Spot Repair thinner', which is a fast drying thinner. I also wonder if this is the reason Windy did not use Sig or Randolph thinner, but a cooler fast dry spot repair thinner called dupont 3608s. Any thoughts on this? 

Offline doug coursey

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Re: Some thoughts on Thinners
« Reply #1 on: December 22, 2022, 06:10:10 PM »
before Windy switched to Brodak completely he used the 3608 thinner.i think he used to use Sig dope before Brodak....
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Offline Dennis Toth

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Re: Some thoughts on Thinners
« Reply #2 on: December 23, 2022, 08:56:19 AM »
Kevin,
Randoph and Brodak thinner is basically the same. Windy did the development of the Brodak Butyrate paint line with Randoph. In some of his finishing tapes he indicated that this thinner gassed off much quicker than the Dupont 3608s. He could sand silver in a week and buff out clear in a week. The Sig thinner would take a month. With Butyrate dope the idea is that new coats penetrate and adhere to the coats below, but if the thinners are not compatible this could be reactions that are not good. 

I think the issue is the Randoph hitting the hardware store lacquer thinner cause the reaction. The hardware store thinners that I've used always caused issues for Butyrate dope, good for cleaning spray guns or brushes but not thinning dope. Sig, Randoph and Brodak thinners are all generally compatible, also Dupont 3608S the old formula.

How did you resolve the issue? Strip off the new material and go back to the hardware store brand?

Best,  DennisT

Online Brett Buck

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Re: Some thoughts on Thinners
« Reply #3 on: December 23, 2022, 10:33:26 AM »
So, i recently switched over to Randolph thinner and Dope. Prior to that i used sig dope and a fast drying hardware store Lacquer thinner. I've had some problems in the switch over i want to share. After doing a small repair on the elevator, which involved sanding and filling the defect with a small amount of glazing putty, I sealed it with a coat of clear. After it dried i sprayed the white. This caused the repair to look worse. My guess is the Randolph which is a hotter, slow drying thinner penetrated Through, around and underneath the repair and ruined all the previous steps in getting it flat and smooth. It seems to me there is a reason for 'Spot Repair thinner', which is a fast drying thinner. I also wonder if this is the reason Windy did not use Sig or Randolph thinner, but a cooler fast dry spot repair thinner called dupont 3608s. Any thoughts on this?

   Kevin, did you use Windy's technique of allowing the pigment to separate, then pouring off some of the clear?

      Brett

Offline kevin king

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Re: Some thoughts on Thinners
« Reply #4 on: December 24, 2022, 02:31:37 AM »
Brett, I cant remember if I poured off any clear from the silver

Offline wwwarbird

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Re: Some thoughts on Thinners
« Reply #5 on: December 24, 2022, 08:37:05 PM »

 Looks to be like it could have been sanded/feathered better prior to hitting it with the paint?
Narrowly averting disaster since 1964! 

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Offline kevin king

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Re: Some thoughts on Thinners
« Reply #6 on: December 24, 2022, 11:51:17 PM »
Looks to be like it could have been sanded/feathered better prior to hitting it with the paint?
The repair could not be felt by running your finger over it, prior to sealing it with clear. (1st picture) After shooting the white is the 2nd picture. It was pointed out the silkspan was not attached to the substrate, and add to that nitrate was used to attach the silkspan, add to that some CA for glueing the silkspan down and and some glazing compound, then add a hot slow drying thinner, the repair softens up and floats up as the thinner sinks down, I also put on a very wet coat making it worse. Should have sprayed lighter coats. All those things i now *think, was the reason for the failed repair. Thats my guess anyway. It is fixed now though. 40 years and still havent figured everything out.😂
« Last Edit: December 26, 2022, 01:18:53 PM by kevin king »

Offline YellowJacket

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Re: Some thoughts on Thinners
« Reply #7 on: January 29, 2023, 08:30:08 PM »
This is an older thread but hoping someone will answer.  I have always used Lacquer thinner from Home Depot for thinning my Sig dope and never had any trouble that I am aware.  However, a trained eye with more experience than I have could probably point out the flaws that I simply donít realize are there.

So, after reading so many say to use real butyrate thinner, has anyone experimented with Univair Butyrate thinner?  Their thinner is very reasonably priced but wanted to ask some experts on here about it before it was ordered.

Thoughts?

Greg

Offline kevin king

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Re: Some thoughts on Thinners
« Reply #8 on: January 31, 2023, 01:33:49 AM »
This is an older thread but hoping someone will answer.  I have always used Lacquer thinner from Home Depot for thinning my Sig dope and never had any trouble that I am aware.  However, a trained eye with more experience than I have could probably point out the flaws that I simply donít realize are there.

So, after reading so many say to use real butyrate thinner, has anyone experimented with Univair Butyrate thinner?  Their thinner is very reasonably priced but wanted to ask some experts on here about it before it was ordered.

Thoughts?


Greg
Greg, it seems that it is just their brand of a wash thinner, good enough for cleaning paint guns but not to be used in place of the recommended thinner for reducing dope to spraying consistency. In other words you can use it, but you are on your own if it doesn't work, I have also used cheap hardware store Lacquer thinner and had no problems. The reason i got fed up with it was because it dries so fast it was always trapping moisture. The other thing about that thinner you asked about is  it says its not recommended for Randolph dope. Thats 2 red flags. Best to use what the manufacture of the dope recomends. Maybe just buy a 55 gallon drum of this and split it up between your club members 😁👍

https://www.univair.com/categories/paint-dope-fabric/reducers-thinners.html

Offline Matt Colan

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Re: Some thoughts on Thinners
« Reply #9 on: January 31, 2023, 07:45:04 AM »
This is an older thread but hoping someone will answer.  I have always used Lacquer thinner from Home Depot for thinning my Sig dope and never had any trouble that I am aware.  However, a trained eye with more experience than I have could probably point out the flaws that I simply donít realize are there.

So, after reading so many say to use real butyrate thinner, has anyone experimented with Univair Butyrate thinner?  Their thinner is very reasonably priced but wanted to ask some experts on here about it before it was ordered.

Thoughts?

Greg

I have been using the Klean Strip lacquer thinner since 2018. Iíve finished four planes with that thinner and have had nothing but good luck with it. I have two more planes in the finishing process now and am continuing to use the Klean strip thinner. The only downside is itís a pretty hot thinner so it can blush pretty easily when it gets hot out. A little retarder fixes that
Matt Colan


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