Best Practices: Nitrate and Butyrate From Al Lidberg

[freeflight]

How about a small survey? You should be able to make a response after every question.

Best Practices: Nitrate and Butyrate [If you respond, please preface your note with the words Nitrate or Butyrate – they do act differently!]

1. Do you start doping tissue, silk or polyspan with straight dope or non-tautening?

2. Do you switch to non-tautening after starting with straight?

3. How many coats do you apply?

4. How long do you wait between coats?

5. How long do you wait before applying masking tape for trim?

6. For masking, do you use regular tape, electrical tape, 3M blue car tape, something else?

7. How long do you wait before applying any kind of fuel proofer over dope – Fuller Plast, epoxy clear, catalyzed clear car paint, rattle can urethane varnish, other type?

8. Are you happy with the results of your doping process?

9. Other comments?

AL
A. A. Lidberg model plan service
AALmps@aol.com

[JIM MOSELEY]

Nitrate, only

1. Straight, on shrunk tissue – but thinned to 25% nitrate, 25% lacquer thinner, 50% nitrate thinner

2. No

3. As many as required to ‘fill’ tissue – maybe 3 on good Japanese, a half dozen on silk, etc.

4. Apply another coat as soon as previous looks dry … but then pin down panel for 12-24 hours, and proceed to next.

5. Only apply tissue trim, doped on after final coat

6. Regular tape if masking to spray colour on tips or fin(s)

7. I fuelproof when convenient – may be weeks after airplane is completed.

8. Yes

9. –

[Scott Lapraik]

Al, interesting questions. Since been away from the sport for 38 years I’m still in the dark ages. Nitrate dope wasn’t available when I last built planes, neither was butyrate lite! We just cut straight Butyrate 50% and hoped for the best. Hot fuel proofing was how good your coverage was with the Butyrate. Now I’m hearing/reading that there are over the counter hot fuel proofing like car clear paint, and spray polyurethanes. What is your preferrence.

Scottl0413
AMA881197
TTOMA
NFFS

[Bill Shailor]

I use 50% thinned Sig lite-coat to apply tissue. I don’t pre-dope structures except on built-up rubber fuselages. After tissue shrinks, I use 60-40 lite coat for doping. 60% thinner. Usually three coats. The tissue trim is added after the first two coats. I let the strutucture dry about three hours between coats. 3M blue tape for masking paint lines. For Polyspan, 2 coats is plenty.

[marauderbomber]

1) Fresh non-tautening Nitrate cut 50-50.

2) No.

3) 4 to a light sheen.

4) (15min.) 5min. in shade & 10 min. direct sun @ 70 deg. or above with low humidity. In AZ they call it “DRY HEAT”.

5) I don’t. I use color tissue for trim. Paint seems to be heavy.

6) N/A.

7) Minimum 3 days to allow the dope to gas out. Then correct any warps etc.

8)Yes.

9) You need to hold your tongue the right way to make this all work correctly.<>

[drake123]

I am back building an electric model after many decades off and at the stage of covering the model. Yesterday I went to one hobby shop asking about nitrate dope and was told “we don’t sell any of that stuff anymore”. Went to another and the one person never heard of dope. The other said I think we have a bottle of tissue shrinker. I probably should have asked here first , but I got it and it’s called “EZ Dope”. Water soluble , non odor, and all that safe stuff. My question is: has anyone used it and if so do you dilute it just like nitrate? Should it be sprayed?

Or should I just go online and get what I’ve used for 60 years? ie nitrate/butyrate

[George Reinhart]

Nitrate and butyrate plus thinners are available from A2Z in 1 qt. cans.
Mail order.
I also buy at an aicraft supply store in Ft. Worth.
You can also get whatever you want from Wickes or Aircraft Spruce.
Cheers!

[drake123]

Thanks Pete! Very helpful info. Will order tonight.
Drake

[Mike Schwartz]

This is a old trick from long ago. We used to add Knox gelatin to the water we used to tighten the jap tissue. This acted just like a filler coat on the tissue to help fill the pores in the tissue. This removed the need to add one moe coat of dope and saved some weight. You can use nitrate or butyrate dope over it with no problems. Let the tissue dry overnight before applying the dope and then put lite coats of dope until you are satisfied with the results. If appling tissue trim or letters just apply them as usual over the doped surface, no need to use the Knox gelatin on them. If you are unsure about this technique just make a test section up and try it yourself before covering your model itself.

Mike Schwartz

[drake123]

Wow! Never heard of that, but when I googled gelatin it makes sense. Thanks, I’ll try it

[Author]

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