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[anmo]

bigfella

Infact it has come to the stage in the drought that our State Govt has made the decision that we will be drinking our own sewerage

We have been doing that for years over hear, Its prob the reason for some of the posts.

Peter

I've often thought that, but maybe it's just the way some of the beer tastes down here in the south of England. I've just spent a week back home in Yorkshire, Theakstons Old Peculier, Timothy Taylor's, and best of all Kelham Island Pale Rider from Sheffield, magic in a glass.

[John W E]

hi all,  Kayem,

Lloyd's Standards and boats over 12 foot long bring back nightmares - to the extent of cutting a section out of a panel and being sent away for analysis & having the inspector stand over you while you laminate a test piece.

Another point, I know its a long while since I was in the industry - round about 1980s - anyway, polyester with wax added to it and other additives was called a Gellcoat whereas the surface that was in contact with the mould would harden and the opposite surface that was airborne would stay tacky to aid the bonding of lamination and layup resin did not have any wax in it.   Has this all changed now Kayem because of the new regulations on styrenes?  I certainly don't feel like going back into learning the industry - not for the amount of fibre glassing I do now.

Bluebird, wake up - too much mist first thing in the morning - you add Wax to gellcoat to make a flowcoat to repair defects in gellcoat - the wax floats to the surface of the gellcoat forming a barrier from the air allowing the gellcoat to harden - The surface of gellcoat which is exposed to air will not harden, it will just stay tacky.

now back to sleep Bluebird 

aye
john e
BLUEBIRD

[tigertiger]

bigfella

Infact it has come to the stage in the drought that our State Govt has made the decision that we will be drinking our own sewerage

We have been doing that for years over hear, Its prob the reason for some of the posts.

Peter

I've often thought that, but maybe it's just the way some of the beer tastes down here in the south of England. I've just spent a week back home in Yorkshire, Theakstons Old Peculier, Timothy Taylor's, and best of all Kelham Island Pale Rider from Sheffield, magic in a glass.

'Is the bottom falling out of your world? Drink Watneys and watch the world fall out of your bottom'

[FullLeatherJacket]

We used to have a local brew in Nottingham called Shipstones. It was very, VERY hoppy and it was said that you could spot a Shippoes drinker because he was the guy who took his btm for a pee every morning!
My top tipple is (Paul) Theakston's Black Sheep Special, but suit yourselves.

Ref using polyester resin, I've always followed the rule never to use it as a coating medium for the outside of wooden hulls. I prefer to buy a proper epoxy finishing system, as used by the model aircraft boys for covering wings. I buy a fresh pack every time from a large mail order model shop (to ensure it's as fresh stock as it can be) and then chuck away any left over. Having said that, I still prefer a dope-and-tissue finish for small wooden models.

Suit yourselves - it works for me.

[RickF]

I use that epoxy stuff too, FLJ, but only on the inside. I find it stiffens up the hull prior to rubbing down, as well as providing a nice, smooth, waterproof interior

Rick

[FullLeatherJacket]

Rick
I've not seen Z-Poxy Finishing Resin before. I've used Westbury Systems or SP 113, depending on what Gliders or Slough R/C have in stock. Might give it a try next time if it's thin enough to apply over lightweight glass cloth.
I use polyester resin or thinned polyurethane varnish inside wooden hulls - largely because they're cheaper than 'poxy. Goes to show there's no such thing as The Right Answer; just choose the one you prefer from those available!
FLJ

[cbr900]

Kayem,

Yoy have stated that if the resin has not gone off in a short period of time it will not, a friend who is a modeller applied resin to his yacht hull and keel and it was tacky for about a week and then it went off rock hard and smooth, it has been sanded and painted without a problem,   If as I suspect he has not mixed in enough hardner could this be the cause......



Roy

[RickF]

FLJ,

Z-Poxy is pretty viscous - I'd equate it to "squeezy-bottle" honey. I tend to mix it up and pour a good dollop in between stem and frame 1, spread it round, then allow it to run over to frame 2, and repeat until the whole of the inside is coated. Also needs thorough mixing, or patches remain tacky.

Rick

[Bunkerbarge]

After giving it a couple of days since I put the B&Q undercoat on I can now happily report that the resin seems to have finally hardened and I am unable to leave an imprint no matter how hard I press onto the surface.

It just goes to show that there are no hard and fast rules with these things and, as always, patience is the most significant strategy rather than rash and immediate reactions.

I actually left a small part of the original resin bare and, although it still has a stickiness it is most definately getting better so whether it was all as a result of not enough hardener or as a result of old stock I will never be sure.  In another part of the hull I also made a mix of the same resin to secure a fitting and made sure I put sufficient hardener in and whilst the resin did set hard the surface can still be imprinted by pressure from my fingers.

At the end of the day I can only thank Colin for his positive and supportive advice and encouragement which was particularly appreciated when enthusiasm was at it's lowest and all I could see was a lot of hard work ahead.

Once again I am reminded of how important it is to remain patient with our modelling and remember that normal accepted industry practise is not always the best course of action no matter how adamant it's advocates are.

Colin, very many thanks.

[Colin Bishop]

Glad your unorthodox solution seems to have worked Bunkerbarge. Sent you a PM. Looks like you've got away with it but we've all learned a little bit along the way.

[kayem]

It seems that a little further explanation is needed here. If polyester resin of any kind fails to harden or remains sticky for a long time, then what you are suffering from is undercure, so that’s what the various problems described in this thread amount to, no getting away from it. Undercure is a serious problem and it has several causes, low working temperatures, excessive moisture or humidity, insufficient catalyst, or materials that are past their use-by date. The least amount of medium reactivity catalyst that has to be added to laminating resin is 1%, and for gelcoat it’s 2% using good quality stuff that hasn’t been stored to too long. Just check on how much hardener you use, I’d bet that in many cases, it’s considerably less. Anything significantly under these amounts, and you’ll experience undercure, and yes, I’m ‘adamant’ about this, the stuff just doesn’t attain the hardness and other qualities that it should, and it never will. Apart perhaps from fibreglass hulls, most modelling applications of polyester resins don’t place great demands on the material, which means that it’s often possible to get away with something less than a 100% result, and if that meets your needs, then no problem at all. An analogy, say you have a fairly fast car, but you only ever use it to drive to the shops through 30mph limits. The wheels could be a mile out of balance, but you’d probably never know, and many modelling applications of polyester resins are like ‘driving to the shops’. If you can achieve whatever you want with a less than optimum result, if it’s good enough for you, then no problem, that's fine, but just don’t try to kid yourself that you have the best result possible. My experience of the reinforced plastics, GRP or fibreglass business is all pretty top level, I started on racing cars mostly F1, moved onto high performance road cars and large boats over 35 feet, and then moved to more racing cars and slightly smaller boats, and for quite a long time now, I’ve been running my own business. I’m not showing off, (trying not to anyway), but I’ve been fortunate enough to have many years experience of the top end of the GRP industry, but that’s just the way it is. I wouldn’t try to blind you lot with science, that’s usually the mark of an inadequate, but I’m not going to insult you by dumbing down any technical explanation either. Most of us on this forum have specialised knowledge of one or more of the techniques that we use to make our models, and that’s what’s so good about it. For example, electronics are a mystery to me, but there are several on the Mayhem forum whose advice I’m prepared to accept without question, it’s their area of expertise, they know what they’re talking about, so that’s great, tell me more. A wise man will always value experience in others.

[Colin Bishop]

Well that's fine Kayem and I don't doubt anything you say, you are undoubtably the expert. But at the end of the day Bunkerbarge seems to have sorted out his particular problem and got a result which meets his needs. And that is all he wanted when all is said and done. Hard to argue with that! 

[kayem]

.....But at the end of the day Bunkerbarge seems to have sorted out his particular problem and got a result which meets his needs. And that is all he wanted when all is said and done. Hard to argue with that! 

I think that's what I've just said.

[Colin Bishop]

Yes, it's in there somewhere...