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Author Topic: Silk dope coats  (Read 1950 times)

Offline Dennis Toth

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Silk dope coats
« on: August 27, 2018, 04:27:43 PM »
OK, making forward progress on the Barnstormer. Question I did the silk on the wing using the dry/CA method that Charles (Avaiojet) described to me. It worked great (simply said its like putting silk on as if it is MonoKote except that instead of using an iron to tack it down you use CA). With this method you give the frame 4 coats of clear then really pull the silk tight and add dots of CA starting at the high point, then the tip and pull the silk very tight as you work your way the rest of the frame. When you pull the silk tight there is very little relaxing of the silk as you put the clear on (first around the frame then the open  bays). I put on 2 coats of litecoat to secure the silk to the frame and one coat over the open bay followed by 3 coats of Supercoat to tighten it the last little bit.


My question is how many coats of the Supercoat should you put on before switching to lite coat to complete the fill of the weave?


Best,    DennisT

Offline Dave_Trible

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Re: Silk dope coats
« Reply #1 on: September 10, 2018, 04:35:23 PM »
Dennis I’d say stay with the tautening dope until the silk doesn’t bag or loosen any more with a fresh coat.  There is a good chance if you try the lite coat or non- tautening too soon and it bags, it may take a very long time for the silk to pull up again.  With full strength nitrate likely about four coats.  With the Sig butyrate is go about five- six coats.   This is why I cover silk wet.  The wet silk will stretch just a little more so when it dries it returns to its original state- not any tighter .  When you cover dry it MIGHT not pull all the way back to its original state with the first dope coat since it starts filling the open weave.  If it did turn out OK then you are pretty good with silk.

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Offline Shorts,David

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Re: Silk dope coats
« Reply #2 on: September 07, 2019, 03:12:38 PM »
Hi Dave, I'm in a similar boat, er, plane? I just posted about my problem. I I'd put the silk on wet and had the bays very tight. Now they are looking saggy. Is it too late to switch to supercote? It will it get tight eventually using lite Cote?

Offline Avaiojet

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Re: Silk dope coats
« Reply #3 on: September 07, 2019, 05:19:29 PM »
OK, making forward progress on the Barnstormer. Question I did the silk on the wing using the dry/CA method that Charles (Avaiojet) described to me. It worked great (simply said its like putting silk on as if it is MonoKote except that instead of using an iron to tack it down you use CA). With this method you give the frame 4 coats of clear then really pull the silk tight and add dots of CA starting at the high point, then the tip and pull the silk very tight as you work your way the rest of the frame. When you pull the silk tight there is very little relaxing of the silk as you put the clear on (first around the frame then the open  bays). I put on 2 coats of litecoat to secure the silk to the frame and one coat over the open bay followed by 3 coats of Supercoat to tighten it the last little bit.


My question is how many coats of the Supercoat should you put on before switching to lite coat to complete the fill of the weave?


Best,    DennisT

Den,

The amount of coats it takes to fill the weave depends on the mix and how tight the weave is.

Unlike Dave, I see no reason to apply silk wet, as I once did.
I see no reason to use nitrate either, as I never have.

A "method" used by one person may not be the same "method" used by another.
And the results can be equally as good.

Here's my, results, tight as a drum:


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Offline Randy Powell

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Re: Silk dope coats
« Reply #4 on: September 11, 2019, 02:51:10 PM »
Not how I do it, but if it works.....
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Offline Dennis Toth

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Re: Silk dope coats
« Reply #5 on: January 02, 2020, 09:26:27 AM »
OK, so I put on 2 base coats on the bare wood then attached the 6mm silk dry using the CA tack method as Charles describe to me (really works great, drum tight and can do it inside). Then applied 4 coats of thinned SIG taunting Supercoat clear. Wing is drum tight and weave is sealed but you can still see a little weave.

Question, I will be painting this ship (yellow base color) so in order to get the lightest substrate do I now add some Zinc Stearate to the next several clear coats or just straight non-taunting lite coat clear?

What have you guys been using as a block coat (we use to use silver or Dianna Cream)? I would like to avoid heavy primer if possible.

Best,   DennisT 

Offline Avaiojet

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Re: Silk dope coats
« Reply #6 on: January 02, 2020, 03:46:11 PM »
OK, so I put on 2 base coats on the bare wood then attached the 6mm silk dry using the CA tack method as Charles describe to me (really works great, drum tight and can do it inside). Then applied 4 coats of thinned SIG taunting Supercoat clear. Wing is drum tight and weave is sealed but you can still see a little weave.

Question, I will be painting this ship (yellow base color) so in order to get the lightest substrate do I now add some Zinc Stearate to the next several clear coats or just straight non-taunting lite coat clear?

What have you guys been using as a block coat (we use to use silver or Dianna Cream)? I would like to avoid heavy primer if possible.

Best,   DennisT

Dennis,

I put three coats on bare wood. I also sand it before applying silk.

I would apply another coat or two of dope pure, put nothing in it, not to thick and not to thin. Scratch this up lightly with 600, including the open bays, stay off the ribs.

I use 400 because it's quicker. Do you have a quality white lacquer primer?

Say yes.

Hit the thing with primer, heavy on the sheeted areas and really light on the open areas. Don't worry about dry build-up at walls, that is where the wing and fuselage meet and the stab also. EVERYTHING gets sanded. 600 or 400 is what I use.

Board sand all the wood areas and carefully sand the open areas. Did you say? "Spot putty." Look carefully for imperfections.

Don't even think about color until this is completed.

Hey! 6mm silk? I use the 5mm and it's offered in 8mm. Are you using Dharma's silk or have you gone rogue?

Charles
Trump Derangement Syndrome. TDS. 
Avaiojet Derangement Syndrome. ADS.
Amazing how ignorance can get in the way of the learning process.
If you're Trolled, you know you're doing something right.  Alpha Mike Foxtrot. "No one has ever made a difference by being like everyone else."  Marcus Cordeiro, The "Mark of Excellence," you will not be forgotten. "No amount of evidence will ever persuade an idiot."- Mark Twain. I look at the Forum as a place to contribute and make friends, some view it as a Realm where they could be King.   Proverb 11.9  "With his mouth the Godless destroys his neighbor..."  "Perhaps the greatest challenge in modeling is to build a competitive control line stunter that looks like a real airplane." David McCellan, 1980.


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