Peel ply directly on the mold surface?

So t he answer is , its not easy to fit to compound curves. You have to cut strips.

Not a good option if you want to avoid those join lines.
On top of that, you get epoxy creep, oozing down between the strips,

I would rather sand the 'impurities" off than have to fair out a bunch of hard etched lines.

 

i am a great advocate for using peel ply where ever possible !!

aside from using in a mould its really good for all the inside of hulls and decks and saves a ton of sanding and grinding before flo coating , even doing repairs you can see straight away if the repair is the same level and the surrounding area , always used a 150mm wide strip over joins in cloth to make I smooth good surface to glass over . When bonding in bulkheads and stringers its heaven specially if the area will be flow coated or painted or the like . small moulding like insides of hatch's saves hours of work . it does not like to conform to shapes but done neatly and a few cuts and tucks and you can get it to lay over almost any surface .

apart from the surface it leaves when it ripped off its also a way of making sure there enough resin in a layup and if there's to much resin then the peel ply when its rolled will compress the glass layers and bring the surplus resin to the surface and through also to the edges of the area and out . with care and attention once you use it more and more and see the advantage's of using it your quality of workmanship cant help but improve that's for sure . all and any glassing is much better , you begin to take a pride in the finished articles inside appearance and with pride of workmanship improves so does satisfaction of having made a better job .

 

Those hard etched lines dont exist - because you doing it on a mold, so the outside surface becomes the same fairness as the mold surface. The laminate absorbs the thickness of the peel ply - about 0.1mm for each overlap of peel ply.

 

I would have to see that to believe it.

I would bet you get a small groove at every join.

 

At each overlap, the peel ply is a smooth as mold after demolding. Once you remove the peel ply, you get a recess in the laminate where the peel ply overlap was. This recess is equal to the width of the overlap and also equal to the thickness of 1 layer of peel ply - which is about 0.1mm.

After you apply your first coat of primer, you sand this back before apply your final coats etc - which removes the 0.1mm difference in height where the overlap was. In other words, there is no extra work invloved from it.

If you still need to see it to beleive it, cant say much more than come to my place and have a look, i do it all the time.... i have nothing to gain from lying about it on here...

 

This secondary bonding test seems to be contradictory to the adage that polyester won't bond to epoxy. On average here it bonds better to epoxy than to itself.

http://www.duflex.com.au/duflex2/professional/performance_data/secondary_bonding

 

In composites, there are so many myths... unfortunately there is so little time...

 

now you mixing up the information . it has never been stated poly wont stick to epoxy that I can ever recall over the past 3 year I been here ! it always been stated it doesn't stick very well and that is true !! as long as the surface is grounds and not smooth you can get a pretty good bond also remember to make the bond area bigger than you normally would helps as well .
There a big difference between wont bond and doesn't bond as well !!!



Choose your words more carefully !! and unless you have personal experience and have done this a few times yourself and you know first hand don't write misleading information!!
There's a really big difference between the actual truth and the truth we want others to see !!

 

If you want to get that technical with words and being precise in what you say, look to yourself as an example of someone who is not capable of presenting a simple idea in a reasonable amount of words in a coherent fashion.

Won't bond-doesn't bond as well... *******

Adage. Look it up. Enlighten yourself.

The adage is polyester won't bond to epoxy. The adage is polyester won't bond to epoxy as well. The implication is it is an inferior bond as compared to bonding to itself.

The test seems to show that that is ********, that polyester bonds better to epoxy than to polyester.

Here's the test results, interpret them however you want.

 

oops what did YOU say ???

theses are your words not mine (that polyester won't bond to epoxy)
For some one reading this means you can not put poly over epoxy . You wrote it I didn't !!

Poly will bond BUT how good is anyone's guess.

 

Yes, if someone only reads part of the directions and then goes with only that information, or if they have difficulties with comprehension in general, there could be problems.

So for anyone out there that might erroneously conclude by my use of the phrase 'polyester won't bond to epoxy' to mean that in fact polyester will not bond to epoxy, STOP WHAT YOU"RE DOING!!! and re-read all I posted!!!

As has been pointed out, the word 'adage' was used, which denotes

The words 'partially' and 'proverb' would subtly tend to modify the black or white, + or - , death sentence finality of 'won't', but I guess that subtle doesn't always work.

There is a key word in there though that I thought should be sufficient to make things clear, but as before, I mistakingly assumed abilities that don't necessarily exist.

'Contradictory'. Let me put in a few words that might explain what 'contradictory' might mean.

Exact opposite.

Myself, I thought what I posted was fairly clear and I still do. Not only did I imply that the proverb of poly bonding to epoxy might be wrong, but I pointed to the test as showing that poly stuck better to epoxy than to poly. If anyone got confused by it, you really need to STOP WHAT YOU"RE DOING, DROP YOUR HANDS TO YOUR SIDES AND BACK AWAY!!! You are a danger to yourself and others!!

OK, does that help, tunnels?
Do we know where to go to find the meaning of words when we don't know what they mean?
When it's anyone's guess, can controlled tests help?
Take a guess!!

(hint...up above was posted a reference http://www.duflex.com.au/duflex2/pro...ondary_bonding to a test http://www.duflex.com.au/duflex2/pro...ondary_bonding that was a little more precise http://www.duflex.com.au/duflex2/pro...ondary_bonding than anyone's guess. http://www.duflex.com.au/duflex2/pro...ondary_bonding Perhaps you could comment ON that.?? http://www.duflex.com.au/duflex2/pro...ondary_bonding Better yet, perhaps you could retrace back to my original question and explain how peel ply applied to a mold surface prevents pinholes. Preferably IN information and NOT in the FORM of '20 questions'??? :?::idea:

 

Its partly what you say but mostly how you say it !!

I have lived and worked with English as a second language for more than 25 years and because I some times have to rephrase and repeat some of what I say so a non English person can better understand !!,its made me rethink what I say and how I say it . One of the biggest problems is the English language in general ! every country speaks some form of English but there choice of words to make up sentence's is different . means the same just use different words .

 

oops pinholes where do they come from ??
have you really got up close and have a look at resin that's been catalysed ??? the reaction of the catalyst with the resin produces GAS so pinholes !!
Change the type of catalyst !!
change the ratio of your catalyst
use everything at a higher temperature so the viscosity is lower and bubbles rise to the surface easier .
wet out under the glass more and bring bubbles up through the glass fibres !
slower reactions give more time before gel takes place and more bubbles are able to dissipate

 

I never asked where pinholes come from or what causes them.

Last time as I hardly care anymore...How does applying peel ply to a waxed mold before laminating reduce pinholes?

 

problems are only problems if you think about them !dont think ,no problems !!!!

If you only know there's pinhole's all the time and never know or understand the cause you must be Chinese because thats how they think !!
and just keep repeating the same things over and over for ever.

one perfect example of Chinese thinking was the resin we were using always they promoted with cobalt always all the time .
one job we worked on we lost a great patch of the side of a 38 foot boat because it gelled and went off to quickly before it could be rolled out properly ,so I asked the question "why add so much cobalt "?? "
its what was always used" was the answer !! logical !
So I asked the supplier "why do we have to use cobalt in there resin and how much is the minimum do they advise for the summer with 40c degrees plus ?".
There reply "Its already promoted why are you using cobalt at all "?? answer "because we have always use it " . but why are you using it ?? "because we have always used it "!! " But why ??""
not one person in the place could give a logical reason why .
stopped using it and all the quick gel problems went away !

The pinhole problems could be the same scenario if you just accept that's what you get, then that's what you get and will never know the possible causes could . even the simple act of rolling glass slowly makes a huge difference to the extraction of air bubble out of the glass as well as the types of laminating rollers paddle roller and bristle roller being just two of the worst at breaking big bubbles into minuet sized bubble that are hardly seem until you look really really close !! peel ply on flat panels wet out and rolled out slowly is almost perfect , but if the surface is really bugging you then spray a quick coat of just resin over the mould surface and let it gel then a second coat and let it gell and go hard then glass over it first with resin rich tissue followed by 225 p matt csm then theres almost no pin holing what so ever any where .