Hand layup on foam tips and tech

shizlenut · Apr 9, 2011

I am ready to begin the laminating procedure on my roof section. I am hoping for advice, tips and tricks to insure a great bond to my foam.

I will be using airex c70 foam laminated with 1708 and then a layer of 1.5 oz mat.

As I understand it, the steps go as such, please add anything I am missing.

Clean foam free of dust with vacuum and air

Apply thin resin layer

Saturate 1708

Apply 1708 mat down and sart working on with a laminating roller and brush
to work out bubbles

Saturate and apply 1.5 oz mat in same manner.
Wait for cure

I have heard some may cut the resin a little with acetone before pre coating the foam to thin it and allow resin to penetrate foam deeper. Is this a good idea or BS. Kind of scares me to get acetone in my resin.

How do I know I have the correct resin to glass ratio? Should I see a glossy layer of resin on top of the laminate or is that too much? Should I see it is fully saturated yet has the glass texture on the surface or is that too little.

In doing some testing I have noticed that while rolling laminate, the resin comes to surface looking very wet. When I stop rolling the glossy wet resin soaks back into the glass leaving a mat texture and a matte or flat, non glossy look. Is this indicating I have the correct glass to resin ratio or am I a little light on resin? How should my laminate look when it's got the correct ratio?

I have also read some people will purposely under saturated the next layer if they believe the first is over saturated and allow the second layer to absorb the excess resin. Is this smart, or does a novice run the risk of soaking up too much of the resin bonding the first layer to the foam?

If you have any tips or tricks to help me insure my hand layup on foam goes smoothly and last a long time please fill me in.

Thanks for your time.

I have heard of possibly

CatBuilder · Apr 9, 2011

Please read the replies to your post inline, in red

shizlenut said: ↑

I am ready to begin the laminating procedure on my roof section. I am hoping for advice, tips and tricks to insure a great bond to my foam.

I will be using airex c70 foam laminated with 1708 and then a layer of 1.5 oz mat.

As I understand it, the steps go as such, please add anything I am missing.

Clean foam free of dust with vacuum and air

Apply thin resin layer

Saturate 1708

Apply 1708 mat down and sart working on with a laminating roller and brush
to work out bubbles

Saturate and apply 1.5 oz mat in same manner.
Wait for cure

These steps are correct. I would add that you want to use a squeegee, in addition to the roller to work the bubbles out. It works the best. You need a plastic squeegee, not rubber... one made for squeegeeing epoxy.

I have heard some may cut the resin a little with acetone before pre coating the foam to thin it and allow resin to penetrate foam deeper. Is this a good idea or BS. Kind of scares me to get acetone in my resin.

Don't even consider it. You were talking to a retard (sorry for the politically incorrect word, but this board censors m o r o n as a word.) You cannot add anything but approved additives (microballoons, collodial silica, etc... ) to epoxy. Do not EVER think epoxy with acetone. The neat epoxy will bond perfectly to clean, dust free foam. Getting a good bond here is more about getting all the air bubbles out than anything.

How do I know I have the correct resin to glass ratio? Should I see a glossy layer of resin on top of the laminate or is that too much? Should I see it is fully saturated yet has the glass texture on the surface or is that too little.

The way to know it this: When the fiberglass changes from white to clear, you are properly wet out. Any excess resin above what it takes to change from white to clear is just that... excess. Just scrape the excess resin off with the squeegee while you are working out the air bubbles. You will be amazed at how easy this is once you try it... which reminds me: TRY IT!

Make up a small, 1ft square piece of foam and do an entire laminate on it before you do the real thing. It'll build your confidence without risking the project.

In doing some testing I have noticed that while rolling laminate, the resin comes to surface looking very wet. When I stop rolling the glossy wet resin soaks back into the glass leaving a mat texture and a matte or flat, non glossy look. Is this indicating I have the correct glass to resin ratio or am I a little light on resin? How should my laminate look when it's got the correct ratio?
That's about right. Again, it only has to be clear (see through), nothing else. All extra resin is just extra weight.

I have also read some people will purposely under saturated the next layer if they believe the first is over saturated and allow the second layer to absorb the excess resin. Is this smart, or does a novice run the risk of soaking up too much of the resin bonding the first layer to the foam?
Better to just get the technique down and get the right amount of resin on in the first place. Techniques like this are for people making mistakes. Make no mistakes and you'll be fine.

The real danger is over-saturation with resin. Once the glass goes clear, you are in good shape. Any excess resin beyond that will just add weight and reduce strength (so I'm told).

If you have any tips or tricks to help me insure my hand layup on foam goes smoothly and last a long time please fill me in.

The biggest thing is just to relax and develop a bit of a zen. Go to the bathroom, get a drink, eat, be ready to work until the layup is done. Have extra gloves and other gear within reach if you spill resin all over the place. It happens. Just keep at the project until you reach the end. Mix resin precisely and fully. Work your way from one side to the other, getting everything as perfect as you can. The resin will start setting up where you began , but will still be liquid where you are working. This "resin setting line" will follow you along the project. Just stay ahead of it. Maybe have someone else around you can ask for a hand if you need it.

Thanks for your time.

You'll do just fine. It's a lot easier than it sounds and comes out great!

I have heard of possibly
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Hand layup on foam tips and tech

shizlenut Junior Member

CatBuilder Previous Member

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