Glass Cloth and Poly C

[Greyhead]

Not a tutorial as such but I thought this was the best place to put the post.

Over the last many years I’ve used fibreglass cloth and resin for a multitude of jobs from moulding a complete glider fuselage to strengthening engine bays. One thing that all these jobs had in common was that they were awkward, messy and in the case of polyester resin also very smelly, in fact generally a pain in the ***!

I recently heard of a water-based system for “glassing” called Poly C so decided to give it a try and fully glass the wings and fuselage on my latest model. What a revelation, the whole process has been a pleasure and I would definitely recommend it. No point writing out a tutorial as the method is fully explained on the RC World web site.

One thing that caused me some concern was the amount of Poly C the first coat took, I thought I would run out way before completing the job, but subsequent coats were far more economical, so no need to worry.

 

[Glider Guider]

I am sure that a lot of modellers when visiting the shows have seen the short length of wing showing the four stages in glass covering a wing with epoxy resin. The results are very impressive to say the least and you go off with the glass cloth and resin thinking you are going to get a wing with a similar finish.

In my past days of competition glider guiding I did a lot of glassing, however using epoxy it is a thoroughly sticky messy process and the results are often disappointing with ‘fish eye’ (it looks like a fish’s eye – one on the fishmonger slab that is) and mysterious ‘air’ bubbles that appear over night, and only infrequently were all the elements in my favour and I achieved results like the show test piece.

I recently wanted to glass a model wing and decided to give Poly C a try as I had seen a model covered using Poly C and the results were impressive, but I was a little concerned about using a water based adhesive on balsa. As Grahame says it is far nicer to use than epoxy but I had a problem with some areas of the wing, where the veneer wasn’t properly bonded to the foam the veneer warped alarmingly but this disappeared over a few days as it dried out thoroughly. Giving the wing a few coats of sanding sealer as some pundit recommend made no difference.

In my case the model had three coats of Poly C which was sufficient as I was covering it with Solarspan so I can’t say how many coats are required to fully fill the weave and give a surface ready for painting.

 

[wonwinglo]

This sounds just too good to be true Dave,as one who just hates the icky sticky mess of fibreglass this sounds as if it is the answer,do you have a supplier please ?

And no smell I take it either ?

 

[Glider Guider]

There is a link on Grahame's article that takes you to the supplier. They are very good as they tell you when it is dispatched which is normally the same day.

To give an idea of coverage I used half a 500ml bottle giving a WOT4 the initial coat and two follow up coats.

 

[Greyhead]

Sorry I didn’t make it clear; RC World is the supplier of Poly C, the only one as far as I’m aware, as Dave says a very friendly and efficient firm to deal with. You guessed correctly Barry it has little or no smell!

 

[Greyhead]

Another point to be aware of is warping, Poly C is water based after all, and the instructions suggest that structures liable to warp should be pinned down whilst the Polc C dries.

I was so impressed with the results I'd got on the fuselage and wings that I decided to “glass the lot” and for some unknown reason one elevator warped. I didn’t pin it down as I covered both sides at the same time, wrapping the glass cloth around the LE, so thought it had no chance of warping!

It wasn’t until I came to assemble the tail unit that I realised that there was any warping. As I thought the situation was hopeless (as it would have been using epoxy/glass) and I’d have to make a new elevator I experimented to see if the warp could be removed. Nothing ventured anything gained!

I clamped the joined elevators to a length of aluminium angle to ensure they were straight and aligned then applied heat to both sides of the warped elevator using a heat shrink gun. When the clamps were removed the warp was gone!

By the way, this stuff really does go a long way; I’ve still got a small quantity left from a 500ml bottle after completely glassing an Acrowot and applying 10 coats of Poly C.