Monokote over WBPU with Fiberglass - RC Groups
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Nov 06, 2017, 05:16 PM
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Monokote over WBPU with Fiberglass


So I have this large CL-415 I'm building and I had always wanted to do a test of whether or not WBPU and cloth would make a good waterproofer for UNDER a Monokote upper layer. This post is really just for information in case any one else has had this curiosity. The short answer is: No.

I applied my usual WBPU and light cloth covering over the entire fuse (I do this a lot and love the finish) and thought instead of painting it with my airbrush if I could add a heat shrink covering layer for dual waterproofing and smooth slick surface. I ironed on a section at high temp of ACTUAL monokote (not knock-off) to see what would happen. I left a corner unglued and waited 30 minutes. I then pulled the corner and noticed there was no adhesion between the WBPU and the covering adhesive. It peeled without any effort. So there you go, don't both. Paint it is.

Hope this saves someone the experiment!

Marc
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Nov 06, 2017, 06:11 PM
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Brian Allen's Avatar
Marc

Might try painting the glass with some Balsarite or similar and see if that improves the adhesion.

Brian

Veni Vidi Volavi

I came I saw I flew
Nov 06, 2017, 07:26 PM
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Soaringtuna, it's good to see someone's still experimenting!

Ditto on the Balsarite. I used that (or Mod Podge, Balsaloc, etc.) when ironing shrinkfilm over epoxied fiberglass center-section tape. Otherwise, it stuck about as well as a politician's promise...

CD

P.S. Yes, I'm tired of watching political ads on the TV!
Nov 06, 2017, 07:29 PM
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mrittinger's Avatar
It will stick to lacquer based auto primer used to fill the glass cloth weave, I've done it.
Nov 06, 2017, 08:40 PM
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St. Martin's Avatar
Quote:
Originally Posted by mrittinger
It will stick to lacquer based auto primer used to fill the glass cloth weave, I've done it.
Ditto

I have even covered fiberglass cowls & wheel pants w/no primer. But it worked better with. The cellulose in the primer is acting as a adhesive activated by the heat. I suspect that the WBU glassed surface is absorbing the adhesive from the monokote. Like brian says, you need an adhesive layer first. If you like using water based products, Gloss Mod Podge, Balsa-Loc, and even Tite bond yellow carpenters would work.

Fuzz
Nov 07, 2017, 09:42 AM
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Hey guys thanks for the info! I've used Balsarite quite a lot, but up here in Canada it's getting harder and harder to find... I will give those suggestions a shot! I was really just being lazy not wanting to break out all the painting gear if I could just cover it ... I've always wanted to give the mod Podge a go, St. Martin, do you use it as a light filler/sanding coat?
Nov 07, 2017, 10:27 AM
Big gov never Works
St. Martin's Avatar
I have used it thinned to attach silkspn over foam. I still do when I make wing/fuse fillets. Sometimes with a layer of .5oz glass under the silkspan. One of the things I learned about Mod Podge, is which type applies where. Matt should be used when ever sanding is required. It also works for laminating balsa/bass outlines. Sanding later is easy. When using it as a heat activated adhesive, gloss works best. You can even use the matt, thinned to seal the wood, then sand and use the adhesive gloss.

Another good trait of Mod Podge, is repeated coats get very hard. Altho, I never tried it, the product description says once hardened it can be wet sanded. I just dry sand with talc and it sands very well. The talc acts as a dry lubricant for the sand paper reducing clogging.

Try it..I think I was the first to tout it here, over ten yrs ago. And it spread like crazy. Alot of good ideas sprung up for it's use. Try it, you may find more applications. I think Glenn Lewis discovered it's iron on application.

Fuzz
Nov 07, 2017, 07:45 PM
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mrittinger's Avatar
For adhesion promoter, I've used watered down white glue, Deluxe Materials "Cover Grip", and Balsarite.....all have worked some form or another in varying applications.
I'm not one to paint an entire model with it...never saw the need on a balsa bird, but they do help on glass or ply surfaces...
Nov 09, 2017, 01:49 AM
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tspeer's Avatar
I wonder if Dap 25332 Weldwood Nonflammable Contact Cement would be a good base for iron-on coverings. I've read some things that lead me to believe it is heat activated, but it's not mentioned in this data sheet: http://www.buildsite.com/pdf/dap/DAP...ta-1383012.pdf.
Nov 09, 2017, 05:42 AM
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portablevcb's Avatar
Many contact cements will heat activate. Not sure if it is standard for all of them or not. The ones I used would need to be thinned.

Peter Rake 'taught' the use of thinned balsaloc or elmers white glue for attaching Litespan. Brush it on the back and treat it like any other adhesive backed film covering. But, they are not waterproof.

And, yes Fuzz, I still remember that first mention you made about Modge Podge all those years ago. I seem to remember it was when you were 'haunting' the aisles of a Walmart that you found it Was it when you were building that Earl Stahl Hurricane? And, no, after all these years I have still not tried it. May have to remedy that in the future.

charlie

PS Monokote over WBPU. I wonder if there is a layer of something in the finish that is hampering adhesion of the covering. Maybe if it was lightly sanded first then apply the covering?
Nov 09, 2017, 06:01 AM
Big gov never Works
St. Martin's Avatar
Hi charlie, hope you are well. And you are correct, it was Wal-Mart. IIRC, I was getting a bottle of Aleen's fabric glue, to attach canopies(same as RC-56), and I noticed the Mod-Podge puzzle sealer. I got a bottle of matt and gloss. Try it, you'll like it charlie. And I think it may have been the Hurricane.

Fuzz
Nov 09, 2017, 08:26 AM
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portablevcb's Avatar
Thanks Fuzz. Yep, doing well but not much building.
Nov 09, 2017, 07:31 PM
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mrittinger's Avatar
Here's the Kingcobra nose after it got crunched.
I repaired it, glassed it over, applied auto hi-build primer, and applied black Ultracote over the primer.....doesn't look bad, even for black
Nov 09, 2017, 10:01 PM
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Doesn't look bad by any yardstick.
Better than many New builds. Nicely Done.
Nov 09, 2017, 10:58 PM
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AntiArf's Avatar
High built auto primer works well over foam, first coated with a light coat of finishing resin. Several sanded coats makes a good paintable surface.


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