Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length.

[jarvo]

Hi Andy


This might seen daft but i usually put the seam domn the port side chine!!!!  I seem to hit the landing stage on that side!!!! As you have done tests using varnish, test the Wickes stuff the same way. Water based varnish come from somewere, posibly the company that makes Wickes also bottles Ezycote of Deluxe. Who knows???


Let me know what the result is. Wickes is a hell of a lot cheaper than Ezicote


Regards


Mark

[GrahamD]

I know its an old thread but.


PolyC is Ronseal XL Floorseal, its sold only in industrial quantities to the trade, and is 100% developed to not only seal wood, but also to harden the fibers in wood and to protect it.


The biggest use is on gymnasium floors and some shopping malls also have wooden floored areas where it is used.


PolyC should NEVER be applied to balsa or thin (<1/32") ply without priming it first as being water based it will warp.


How do I know this, I wrote the article in Model World that brought this alternative to epxoy coating to the model flying community 

[sigfortunata]

I am a newbie building my first boat ,balsa skinned with ply.  Having built planes and used tissue I decided to use this instead:


Fibreglass Surface Tissue 30gsm used with fibreglass - moulds - resin

£2.95 for a sq-mtr and I plan to use basic fibre glass resin and hardener £9.99 for 500ml. all from E-bay 

If I still need a finer topcoat I'll try Eze-coat or something similar as suggested here

[andymart]

Graham

What do you prime the wood with?

Thanks

Andy

[andymart]

In regards to the Wickes varnish, well to be perfectly honest I cant tell the difference between this and polyc. Both dry in similar time and both seems to have same hardness, that said though I also experimented with thinned pva and also thinned aliphatic glue both of which gave a harder but I suspect more brittle finish. None of them however come close to epoxy though which seems hard but resilient. The only trouble is I cant work with epoxy or cyano 

Graham pointed out that you need to prime the balsa, I noticed on youtube that polyc recommend you coat the balsa with a coat of polyc, let it dry and sand then cloth and polyc. Tried this with all products used so used wickes varnish as a primer followed by wickes varnish and cloth, so on so forth.

One thing I didn't try was sanding sealer, cloth and dope. But recall back in the day covering flying wing control line models with nylon and dope, this was a good finish and hardwearing, however shrinkage can be a problem. As stated originally cost and actually buying dope, nylon, thinners and sanding sealer is cost prohibitive and difficult in our area to get, most shops wont send by post either.

I have asked Graham to clarify what to prime wood with.

[GrahamD]

cellulose sanding sealer was the best solution that didnt warp wood when I was testing polyc


FYI I asked Ronseal when I was first testing their product (I only found out due to their chemical engineer also being a modeler, and had done some work on gliders using it) what if any end user alternatives were available and they insisted each product is engineered to do a specific job.


If it helps here is some info I did for Rcworld

[andymart]

Thanks Graham, however which takes me back full circle that I cant get cellulose dope to make sanding sealer (which is talc and dope for those who don't know) or sanding sealer, without paying exorbitant prices for shipping let alone the product.

I am sure you can appreciate that some people here will experiment with all sorts of products, personally I cant use epoxy or cyano and also have a reaction to some paints. I spoke to some member at my club yesterday, and in regards to painting balsa models some don't even bother with tissue, or fibreglass etc. they simply rub down paint with primer rubbing down then undercoat and enamels and their boats seem to last. Not sure I still go down this route though.

For those that want epoxy and fibreglass matting, non modelling place to get it much cheaper is http://www.easycomposites.co.uk/

[GrahamD]

I got mine from here > http://www.ebay.co.uk/itm/Bolgers-Cellulose-Sanding-Sealer-High-Build-Fast-Drying-Primer-For-Woodturning-/121700670960?var=&hash=item1c55ecddf0


£4.99 250ml + £2.50 p&p


Remember I was looking for a fast less nasty alternative to Epoxy (GF) covering aircraft that would be just as strong as epoxy when finished, but with the advantage of being non harmful and washes off in water. For a boat hull I would go for Polyc and heavy grade tissue. Applied neat on ply, but to a sealed surface first, like Balsa. Its really down to how the balsa (or very thin ply) is supported inside the hull, if the formers also have stringers then the balsa shouldnt be able to warp, unlike an open aircraft wing that is just wing ribs and 1/32" balsa sheeting.

[andymart]

Thanks for link, however costs again are starting to mount up. I would have to buy the sanding sealer then thinners to clean brushes. I have tried polyurethane varnish (oil based) as a sealer and then using this with fibreglass and it seems to be as good as other methods and probably the cheapest overall. I tend to use acrylic paint and am assuming acrylic will adhere to polyurethane varnish?

 

[inertia]

Andy
Buying cellulose thinners in modelling quantities is madness. Get a 5L can of Standard Thinners from your local motor car paint suppliers; it'll cost about 1/10th as much and lasts you ages. It's fine for thinning sanding sealer and dope and used as a general thinners and brush-cleaner. "Gun Wash" is even cheaper, I'm told.
DM

[andymart]

now that's interesting, good tip just had a look 5 litre of nitro cellulose thinner at  £10.99 at local motor factors. Also have just found cellulose sanding sealer 1 litre for £10.95. So don't understand why dope is so expensive is it not used by other industries? I know fireworks are manufactured using dope for instance but there are not many of them around where I can just go there and buy. 

[jarvo]

Hi Andy


Dont go to a motor factors look on line for car paint suppliers. Much cheaper again.


For sanding sealer, Try adding talc to the poly c, try it on a scrap piece of wood and leave to dry, should work!!!!


Mark

[andymart]

Thanks Mark

Trouble is I am in the middle of no where and very thin on the ground for car paint suppliers without driving 15 to 20 miles, but we do have a car factor close by.

I have tried a similar method to what you are describing for sanding sealer, I don't think it matters what medium you use as the talc is for filling the grain as long as the medium dries. I tend to find water based products never seem to dry that hard and seem to have a sort of very slightly rubbery feel to them. You can see what I mean if you use water based varnish, and then use a solvent based version, one never seems to be hard the other dries to a hard finish, the other thing I have noticed is water based products are permeable which allows the wood to move as doors in my house where this has been used swell up during colder months yet doors where solvent based was used don't move.

Anyway thanks one and all for your input, it is appreciated.  I will buy some PolyC along with other products, as I do have various models to finish.

[Stavros]

As a perfectly usable substitute for sanding sealer for wood I use car laquer apply 3 coats quick de nib of the wood and then 3 and rb down and prime with high build primer....it will seal and cover all the grain


Dave