Using Poly-C resin

[Paul Williams]

I have been trying to make up my mind what to cover the P-47 with. I have gone away from film because I fancy a model that you don't poke your finger through whilst picking it up.
So glass fibre and paint. I have heard about this Poly C stuff from a friend who says its great to use has any body had experience with it. Is it durable, fuel resistant ect

http://www.poly-c.com/

[Craig Carr]

HI Paul,

 

Ive used Poly C in the past. It is easy to use but I did find some disadvantages. As its water based when put near balsa it can swell, and can in some cases (on thin sheeting for example) warp the structure. A club mate of mine ended up with a right disaster on his spitfire with warping etc

 

It is fuel resistant, however, It dosen't offer the same "ding" resistance as a traditional epoxy resin.

 

The trade off was suppoused to be that poly c is lighter than epoxy. However it will take about 8 -10 coats to fill the weave and as its water based it soaks into the structure and (especially if you start adding talc to the mix to help fill the weave as some do) the finish can end up just as heavy as an epoxy resin.

 

Ive since abandoned poly c completely and now use epoxy resin with hardly any problem whatsoever. The stuff I use is from fighter aces which is pretty much odourless and dosent leave any waxy deposit.  and the end result is a lot more ding proof

 

Fighter Aces and click moulding materails on the left

 

Hope this helps

 

Craig

Edited By Craig Carr on 26/02/2011 10:27:28

[Richard Wood]

Hi Paul,

Poly-C is often given the thumbs-up around here as an excellent

alternative to dope & resin.

Have a look here:

Poly-C

 

The FAQ's section on the Poly-C site you linked to has info on fuel

resistance etc.

I'm about to use the stuff for the first time on my latest job.

 

Cheers

 

 

[andy watson]

It's excellent stuff- really does do everything it says on the tin......erm plastic bottle. It is as easy to use as they claim. The only thing I would advise it to use it in a warm room- the drying time seemed to be much extended when I used it in the cool.

 

Some people have said that it is slightly rubbery compared to glassing- I think they have made a mistake. When it dries it does stay slightly soft for a while, but keeps drying and hardening.

 

 

[Tim Mackey]

to Poly-C

[Danny Fenton]

The warping of balsa puts me of to be honest.

 

I love the fighter Aces resin but its a bit awkward to mix as both parts come in a tin and have to be weighed to get the proportions right, I have bought some West systems Epoxy with the pumps, should be much easier if you just want a small amount.

 

Cheers

Danny

[r6dan]

West or SP systems make the best epoxy, I use it every day to build boats with, it will be lost cheeper than anything from a model shop too.

[andy watson]

just seal the balsa using sanding sealer, and there is no issue with warping

[Paul Williams]

Thanks guys it seems its down to personal opinion, PolyC or epoxy. My project is a 1/5 scale so I have nightmares about mixing all that epoxy. I have since found a previous thread which covers all in detail. My next question is although much thought has gone into obtaining a cheap water based varnish has anyone found a good sourse for the glass cloth ? The small packs offered by model shops are like gold leaf.

[Danny Fenton]

Hi Paul, with Epoxy don't mix too much in one go, it will get hot and go off to quick, hence me wanting to have an easy dispensing system. as you need some mix a bit more....

 

Glass cloth, Phil Clark does some nice stuff, as does Mike Woodhouse Free Flight supplies.

 

Good luck

D

Edited By Danny Fenton on 26/02/2011 19:03:27

[JOHN THOMPSON 5]

Hi Paul I pm you with some details

all the best JOHN

[r6dan]

If you get extra slow hardner for the epoxy you will have up to 3 hours open time with it, longer if you pour the epoxy into a roller tray so its spread over a bigger area.

[Glyn R]

Recently I tried to glass a veneer foam wing with Falcon Skincrylic. DON'T DO IT. It took ages to get the ripples out of the veneer so I could go back to Epoxy. I have glassed wings on my previous Acrowot but I thought the Acrylic route would be easier. WRONG

Using Zap finishing resin which is pretty thin I got a good finish. It takes 12 hours to harden but hey that's only 2 days for the wings. See above.

 

Skincrylic and similar products will be fine on the fuse or solid parts, NOT ON VENEER WINGS.

 

Edited By Glyn R on 27/02/2011 15:45:16

Edited By Glyn R on 27/02/2011 15:46:23

Edited By Glyn R on 27/02/2011 15:52:10

[Paul Williams]

I have to ask Glyn did you seal the wood first?

[TonyS]

Hi Paul,

It's so easy, I tend to glass virtually everything with Poly-C. Recently covered a Funjet Ultra on the underside, around the nose and leading edges of the wings - I won't always do this to my planes, just until I learn to land properly...I find it really easy to use but it does need a few coats to fill the weave an I suspect it's not a lot lighter than resin in the end. I use it as I can't stand the fumes with resin and I get through too many brushes (no matter how well I clean them they always set rock solid!)You MUST seal sheet balsa though first or you will warp your model - I have a trashed pair of Gloster G40 wings as testament to this!

T

[Chris Bott - Moderator]

Tony what do you seal the balsa with? Sanding sealer sanded down afterwards or something like that?

[Paul Williams]

Just when you think sorted another question pops up, there are different types of sanding sealer? Which one works guys. Acrylic or cellulose

[TonyS]

Excellent question. Can't remember. I think it was Solarfilm Clearcoat that I used just because I had some handy. Goes on well, needed a bit of a sand after as it lifted the grain ever so slightly. Might not have been the perfect product but it worked and gave a perfect result.

[Erfolg]

I have read this thread, with some interest.

 

I have not used Poly C, although I have used now about 4-5 WBV on models to-date.

 

Some of the varnishes are hard, some appear to be abrasion resistant. In my opinion I do not want an overly hard varnish, which can be brittle.

 

Back to the issues, To date I have not covered balsa sheet, in large unsupported areas. I have however covered small balsa assemblies. I have mainly covered light ply fuselages. I have not to-date had a warping issue.

 

I do not know if my approach is the same as others. I normally lightly coat the the surface to be covered. After drying, about 2-3 hours, I then cover with class cloth, still quite a light coat. After this has dried to touch dry I then put on a heavier coat.

 

This seems enough to fill lightweight cloth.

 

Unfortunately I have only one image using varnish although some is balsa, the sides ae ply, and the main objective was to get the model into the air quickly, as an experimental fling wing.

 

Discussions with Ronseal about the difference about trade products against DIY, seemed to indicate, that the trade want fast drying times, they also want good abrasion resistance, altogether with high adhesion properties with the wood substrate. The fast drying is not as critical with the DIY trade, but ease of application is highly desirable by those who lack experience and the levels of skill that come from frequent practise. Plus DIY users require lower quantities.

 

Unfortunately the toughest Ronseal product is not packaged in quantities that are viable for most DIY'ers. Although their WBV Hardglaze (if I have the name right) comes a close second apparently.

 

I personally have no trouble with WBV, and value the ease of usage and ease of cleaning, plus the lack of fumes/smells.

 

May be Poly C is better, but I believe that WBV in general are a match for resin systems which I have used.

 

[Paul Williams]

Sorry tp bring this up again, I have done various test pieces using Poly c with great success and I am now happy to go ahead and cover the Thunderbolt. I tried colouring the varnish without great success It still needed a top coat so defeated the objective.

Which brings me to another question I am using acrylic spray paint and wondered if I should varnish the finish to make it more fuel resistant? If so why not use the poly C as a top coat sprayed over? Anyone tried this

[andy watson]

You can use poly C as a fuel proofer, or as a varnish over a painted finish

[Paul Williams]

Help please, I have covered the elevators and I am quite impressed with the end results but I am struggling getting the cloth to stick around corners. Its taking ages to get it stuck down on the radius any suggestions? I thought about PVA to help matters

[Erfolg]

What ever resin you use, getting cloth to go around a sharp corner is not easily achieved, if possible.

 

MY experience suggests that in situations such as trailing edges, the cloth is not returned, but is allowed to overhang, then trimmed when at the green stage.

 

Other situations may require slitting and pleating.

 

In principal light weight simple weave cloths drape easier better than heavier , or twill types, which drape well. Chopped strand drape poorly.

[Paul Williams]

The trailing edge is not a problem I simply run a sanding block over the cloth and it leaves a nice straight cut, its wing tips and radius that are taking ages to get the cloth to stick I have tried slitting and it improves matters I just wondered if anyone had tried pva on the tricky bits.

Thanks for your help.

[Erfolg]

All I can suggest is that your cloth is heavier than i use and is much stiffer.

 

Some cloths did have a light starch covering to help handling until wetted out, when they would dissolve (starch. Could time be the issue, 30seconds or so?

 

Beyond that i have no suggestions, other that I would use masking tape as a temporary fastening, if desperate.