Lamination process

I want to hand laminate my boat with polyster resin, mat and cloth. After laminated one layer should I should stop for some times (maybe one hour)-----my friend told me after I laminated one layer I should wait about one hour, or until the resin is not hot then I can laminate the next layer. He said there will be no print through in this way .
Is that right ?

 

or even tomorrow

 

If you not in hurry,wait a day.

 

We do all our mouldings in one go, even if it means overtime. Layer after layer going on whilst it is still wet and thus saving a lot of resin as the wet layer actually half wet the dry layer going on top. Also no de-lamination by having all layups go on as "one".

Never had heat problems either. I use about 1 - 1.5% MEKP mix with the resin, and only mix 500ml at a go (usually have a few containers ready awaiting the hardener) to prevent any wastage should the resin gel before used, and with 500ml, that very seldom happens.

 

It depends, frequently a skin coat is applied first and allowed to cure.

The skin coat may or may not be the same type of resin used in the rest of the laminate, this depends on how the product is going to be used. A high end resin may go down first and then a lower cost resin behind it.

The second reason is it is much easier to remove air from a thinner laminate, especially for a beginner. A great deal of care is taken to remove all the air from the first layer and its allowed to cure, the following layers are put on thicker to save time.

As far as how many layers can be applied at one time....it depends on the type of glass, the resin cure profile (some cure fast and hot, others slower and cooler), your experience, ambient temp, size of the part, etc. Some resins are so fast and hot that two layers would be the maximum, but we also have resins that can used to make a laminate up to 4" thick at one time.

If you're making a boat ( or any part on a mold) it is normally easier to apply a thinner first layer so air removal is easier, you allow it get hard, it could be one hour or the next day, then apply more glass as needed, this may be one more layer, or several.

 

2 small things to add:

MEKP curing agent is not just that. There are many types, some of which make for less heat, less shrinkage, etc. (and some even are not even MEKP but AAP, CMH, or mixtures)

The curing of the first layer seems to be very important for preventing print, so leave that layer to cure for several hours, and make sure it is a resin that cures thoroughly. (does create a bonding problem, however...)

 

I forgot the part question about the print.

Yes, putting on the initial layer and allowing it to cure will reduce the chance of print through.

Print also depends on the resin used, some resins shrink much more than others, the low shrink versions are used for good cosmetics. In this situation I'm sure you only have one resin to use, so the best method is to catalyze it at the upper end of it's range if possible, this results in the most thorough cure in a thin laminate. The more thoroughly cured it is the less print you'll get on the finished part.

You want the first layer cured to the point where it can resist the forces of the second laminate trying to distort it as it cures. A thick laminate will create more heat which results in more and uneven shrink.

As for bonding of the second layer, you have a good amount of time before bonding is an issue, even with DCDP bases and blends, laminating the next day isn’t an issue. Just don’t put it in the sun or allow the surface to become contaminated.


Different catalysts are available, but you may not be able to find them easily.

 

I agree with waikikin that you should wait until the next day if possible. Your friend basically suggested that you allow your first layer of 'glass to cure in order to prevent printthrough. Curing overnight is better than curing for just an hour.

Your first layer should be mat. There will be little glass threads sticking up here and there with hardened resin on them. When you lay on the next layer of mat, little air bubbles will appear at each of these sticky-uppy threads. To avoid this, give the hardened fiberglass a quick sanding with coarse sandpaper before adding your subsequent layers.

 

And for curing: if possible, you would like some promotor, like AADMA or similar, mixed in the resin. A good supplier should be able to tell you which peroxide and promotor you could use, and be able to supply that. I am surprised this material is so little available. For people in Europe I could send materials, overseas is a problem. I have all these materials available. (but personally am on holiday till August 24...). After that I will get a training for even more understanding, and learning about new fancy products for curing polyesters.

 

Readers !!

Having worked in a few differant countries over the years specially asian places hardly ever are materials such as resins, paints ,waxes etc etc compatable in any way with one and other !!!
When you check about the resin thats been suppied from Holland you find its casting resin for some sort of obsure application that you have never heard of and these guys are making boats from it .
Promotors that just get poured into the drum in a hap hassard fashion and a quick mix if you are lucky or a roll around the yard and a bumpy ride on the back of a delivery truck and when you start to use it theres Fast and slow patchs every where .
Catalysts that makes resin go off like greased lightening or the opposite and takes hours just to gel , by then the resin has drained out of the glass and one member of the staff sits with a mohair roller mopping it up from the bottom and putting it back at the top till it all finally gels .Mixing fast and slow catalysts in differant proportions to finally come up with somethings that you can work with in 36c and 89% to 98% humidity .
Then going to the other end of the spectrom Where you are told to use epoxys to skin a plug that never goes hard and stays like chewing gum even after 3 days Or epoxy crystalizes due to the cold and returns to a semi liquid when the day finally warms up .
Then got to use Vinylester resin that has to be promoted with a bottle of cobolt per 4 gallon tin and to find the each bottle has a differant quantity of cobolt in it ,so fast and slow brews appear and all this is is before breakfast !! The days never got any better !!
Point being what we take for granted day to day in one country is an impossability in other places . Its not a simple matter of getting on the phone and what you want it there on a courier in a hour .If you are able to locate what you want you have to order twice as much as whats needed because you order will get pilfered and 1/2 will mysteriously dissappear never to be seen again just for the hell of it !.
Grass roots laminating is beyond most peoples thinking and the frustrations are endless ,even after you have climbed over the mountain of obsticals to get to the other end and a beautiful boat sits on the floor , there are smiles of pride all round from the guys and gals you have worked with !!!.

 

Picturing this cracked me up.

 

This happened in two countries at differant ends of the scale of climates . First in Tahiti at + 35c and second in South Korea .
The resin we used in Korea came from France and laced with coupious amounts of styrene to keep the price down and make it into laminating resin in cold places , I bought a sample back to nz and gave it to a chemist friend . The resin in Tahiti was a casting resin and had little to no phxotrophic properties , bit like using infusion resin to laminate with .
This is grass roots laminating and when there is nothing else you make do with what you got !!. The point is it worked !!!!

 

hyboats,

If you are laminating the boat shown in your avatar, do it all at once, it is only a little fella and will not be all that thick anyhow. Tunnels has it right about different systems in different countriues, that was my game for 3.5 years too, but here in OZ land we are fairly stable.

Do not use poly gelcoat or tie layers though for the first few coats, they are crap...go vinylester.

 

I'm a little puzzled by the comments.

I don't think a boat the size of the one in the pic should be done in one step, especially by a beginner, It would be a disaster. Not sure what you meant by poly gel coat or tie coats, but VE gel coats weather terribly, they fade, turn yellow and chalk. The high end products are all polyester.

Doing it all at one time would most likely result in a great deal of air, localized shrink lines and a poor surface profile.

As far as using VE resin, that would be fine, most boats that size don't use it mainly because they don't spend long periods of time in the water, but it would be fine.

 

So you say that all these chemicals are sourced from different locations, and are not compatible? Why not source them from 1 single place, and have them suggest which chemicals to use? If you are willing to ship resin from Holland, then get the rest supplied by them as well! Although most chemicals (cobalt, MEKP, promotor) are very simple chemicals that should work well, after some initial testing.

You are kidding, right? For me it is very simple. If they drag me to their place to overview the laminating or infusion, then rules are simple, and they are my rules. Things need to be exact, need to be documented, and need to be done right. You need to instruct the workers on what you expect from them.

Perhaps a thixotropic resin would have been a good idea.... And the proper curing agent, which of course was tested.

Again, buy what you need, not what is cheap or readily available, or just happens to be around.

Again, if you do not know the product, at least test it! And cristalised epoxy should be heated up to about 60 degrees C to be fully usable again. Check geltimes after that.

Use scales. Resins are exact science, not "toss and hope" goo. I alsways recommend in percentages. I do not care for contents of bottles.