fairing

[northerncat]

mark or jack have you got any photos of the finished product
sean

[Stevens 47]

mark or jack have you got any photos of the finished product
sean

Sean not yet I am just starting to fair my hull. Will post the deck photos when I get to that stage.

Jack

[Alan Wheeler]

Sorry guy's, I have been away out sailing again. Not that I can add much to the great info generated. But to Sean, rest easy about the curing issue.
Firstly, don't try and sand Epoxy untill it has cured enough. That could be much of the issue you are having if anything. It will just clog up the paper. Epoxy curing depends on the temperature. But at most of our working temps, 12hrs would probably be soonest you want to sand. If the night has been cool, then you may want even longer. 24hrs is no issue for a chemical bond to still occur. Infact, 48hrs is fine. Even fully cured, Epoxy has tremendouse adhesion ability and you would likely never have an adhesion problem anyway. The only issue you may ever have is if trying to adhere to an old Epoxy hull for a repair, in which you need to ensure a very good mechanical bond.
So what make Epoxy are you using. I take it it is one of the new colour coding Epoxies. It turns green when mixed properly?? This colour will most likely not change. It will stay green. The colour change is to signify a good mix.
If you want to speed up cure, a heat lamp (not tooo close) to the hull at night will help. Even better is to heat the workshop if it is possible. I see you are outside, so that won't be easily possible. Heat curing is done once the epoxy has had 48hrs. The temp is then raised to 50c. No higher than that. Even then, if it is pure epoxy/glass only, the hull has to remain over a mould to stop sagging and shifting. The temp softens the cure allowing chains that haven't linked to "find" each other and link up. Thus makign a higher percentage of chains makign a bond and thus raising the strength of the epoxy over all.

[cat man do]

Think you may have to go and do some more research there Wheels.

1] NC lives in Cairn's Australia, lack of heat is the least of his problem's, an airconditioned shed will be a better help to him.

2] As pointed out in post 18 from the West sysyem manual, there is only a limited time for a chemical bond. I have seen on more than one occassion the result's of lack of prep between layup's and bog job's.
One of them resulted in near loss of the vessel due to Amine Blush Contamination

3] Green relates to the various state of cure. When a laminate is firm, yet can still have a fingernail leave a mark when pushed in, it is said to be Green, therefore still OK to glass/bog onto.

While I have let it go off a bit longer than this you can start to run the risk of a compromise in the bond.

Dave

[northerncat]

i wish i needed a heat lamp, but most days under my temporary tent im hitting clost to 50 if not fifty with just the sun, makes epoxy go real quick and a large batch of epoxy is 50mls at this temp
it goes like smoke, still i dont have any problems compared to the poor beggars in darwin trying to build a boat, at least its cool and realtively low humidity 60%
sean

[Alan Wheeler]

Research is not the issue, it is the speak. Just an accent thing. It would also be helpful if the product in use was stated. I worked with many companies products and each have there own differences in products. West for instance have an ultra slow hardener which is what Sean should be using. But I can't advise him on that if I don't know what he is using. Maybe he already is. There are many other tips that can be used to enaid the slowing down of epoxy hardening and extending use time. All of what I have been trained in to advise commercial users. By the way, the Westsystems Comment about the "curing time" is NOT stating the next epoxy layer has to be laid on the previouse before 48hrs. Curing is still taking place and a chemical bond is still very achievable up untill 48hrs and even longer in some situations. I would also suggest that you are confusing curing time with quite different issues. As you did state, it is a case of poor surface prep.
wheels- dip.International/Epiglass coating technologies

[cat man do]

Thank's for editing my post there guy's.

I must have been mistaken, and I bow before the knowledge and powers of the mighty moderator.

Dave

[Whimsical]

Small note of caution on the west ultra slow hardener. I enquired with schioning about it for the summer over here, often around or over 40c. Very positive NO due to the reduced strength of the laminate. did look it up in the data sheets and it does show this. Probably ok for bog though.
Mike

[Alan Wheeler]

Dave who/what post has been edited??? No one has edited any post that I know of.
Now as for attitude, mate chill out. You don't need to be so condescending, belittling and patronising. All of which seem to be tones in your post toward me. Or am I greatly mistaken?
There are many there, OTHER THAN ME, that have a great deal of wisdom, a lot of experiance and are tremendous experts in their fields, (way more than I). I am not suggesting for one moment that I know more than anyone else, or even you for that matter. But I do know just a little about the epoxy systems, an maybe, just maybe some little snipet that I have learn't over the years could be valuable to someone else. Maybe, maybe not.

[Alan Wheeler]

Whimsical, no that is not correct info that has been given to you. The problem with ultra slow hardener (209) is that it takes much longer to reach the full strength point of cure. Ruffly twice as long as the other hardeners do. So if you have timber hunder high stress, eg, cold laminated, it needs to be secured mechanicaly for much longer than normal. Once fully cured, it is slightly down in some strength properties, but all in all, it is so close to not be of any issue. It does have a slight advantage of being a little more flexible, which in some joint applications can be a considerable advantage. It is also important to understand that the strength characteristics of Epoxies/hardeners are done with pure liquid. Or in other words, no added filling materials. Fillers and the ratio of them to epoxy, dramaticaly alter the epoxy strength characteristics.

[northerncat]

i am using fgi resin 180 with the ultra slow hardener
sean

[Alan Wheeler]

Arrr Nuplex's new baby. It's supposed to be very nice stuff. Certainly very well priced here in NZ. I haven't had the chance of personaly trying it yet, but I will be shortly. What I do know about it though, it doesn't have an Ultra slow hardener. The ES300 system is the only one with the ultra slow. (thats green in colour by the way;-)
This may help you. If you can find an old fridge, anything, as long as you can get the internal temp down to 15c, NO LESS,(although that has a fudge factor) then store the epoxy and hardener in there. Any colder will cause a possibility of it condensing moisture from the air. This cooler temp allows the viscosity to remain at very workable temp for mixing, but will help slow down the exothermic reaction once the two are mixed. If you can, get a large container that has plenty of cool water, even ice in it, that once you have mixed a batch, you can float the mixed batch (mixed in another container of course) in the cool water. This will also allow you more working time.
With the temperatures you have to work in, ensure the hull is not in direct sunlight so as the surface temp is kept as cool as possible. If the surface temp gets up high, the epoxy simply "melts" out of the filler and will pool at the surface interface below.
Ensure you are using the correct filler. The "Real" q-cells are actually a Glass ballon. It is hard to sand. I am still uncertain if you are just genericaly calling the filler qcell of if the filler is actually the real qcell. So to help me there, who's filler product are you using? Personaly I like usign the West system fillers. It is easy obtained for me here, and is a good product. I use 407 and 410 for fairing. BUT, you have to mix in 20-50% of 406 coloidial silica as a thixotropic so as two things happen. You can have a creamy consistancey and yet maintain the mix in a "point" consistancy. In other words, if you peak the mix, the little peak remains verticle. The 406 also holds the epoxy in suspention in the mix better. Especially as the heat increases.
I hope this helps.

[cat man do]

My appoligies to you Alan, as in no way was I meaning to offend.

My research comment was more for Sean's location than anything else, and I can keep making excuses for myself, but at the end of the day, I can be an arse at times. Sorry.

I did think my post had been altered, but it is possible I was mistaken, would'nt be the first time, and I never have a problem admitting it if I am.

Had a couple of day's away for a change, and feel marginaly rested now.

Bit of info on Q cels

Potters Industries Inc. - Polymers - Composites

Dave

[Alan Wheeler]

Thanks Dave. Have a Cold one for me.
Thanks for the link. I have not heard of that company, so will read up on it. Terminology is a major issue between countries. I think it would be impossible to do here, but in my maincarrer in Sound Eng. we made absolutly sure that everyone used the correct technical names and descriptions of things. Because we dealt with people all over the world in our jobs and often traveled all over the world in our jobs, it was essential that we all had the same technical language. It's amasing that for two countries so close together, that our languages are so different. Europe must be plain impossible.

[northerncat]

how do you get bog to go around tight radiuses smoothly, it just keeps dragging and im thinking of just waiting till im ready to high build open to ideas??

also how soon do you guys leave it to set before you start sanding and what is the longest you leave it before you consider it to be cocncrete
sean