laursand's Canvas over Plywood

[mikeschn]

I've been experimenting with the bond of fiberglass to foam and titebond II to foam.

I've been able to peel of both rather easily. I've roughed up the surface with some 80 grit sandpaper... what else can I do to keep it sticking? Use GPW's perforating tool?

Mike...

[GPW]

Worth a try !!!

[Conedodger]

I've been experimenting with the bond of fiberglass to foam and titebond II to foam.

Mike...

When you say fiberglass are you meaning general purpose resin or epoxy resin?

In my tests GP resin eats the foam and epoxy resin sticks well and the only way i can get it off is to pull away foam, the bond does not fail but the foam does.

Old or wrongly mixed epoxy will not work.

TB2 is just a cross linked PVA, and cloth to foam peels off easily but then PVA is not supposed to stick to non-porous materials like foam as its not at all porous. Its only working due the large area its spread over and filling up of the holes in the foam.

[mikeschn]

Cone,

I am going to order some cloth and epoxy.

Would this 6 oz eglass stuff work?

http://www.uscomposites.com/cloth.html

Which epoxy resin do I need from this page?

http://www.uscomposites.com/epoxy.html

Thanks,

Mike...

[GPW]

Mike , 6oz. cloth looks Good !!! I'd use the SLOW hardener, it's summer (96F here right now) , and the slower the epoxy cures the stronger it is ...

Here's a trick ... when you do the edges with the overlap , once the cloth is wetted, lay some Saran Wrap over the seams and smooth that ... comes out like glass.. much smoother ...

[Conedodger]

Cone,

I am going to order some cloth and epoxy.

Would this 6 oz eglass stuff work?

http://www.uscomposites.com/cloth.html

Which epoxy resin do I need from this page?

http://www.uscomposites.com/epoxy.html

Thanks,

Mike...

The 6oz e glass will be fine, use 2 layers on any week points or stress joints. I have been told that the 7725 twill if very easy to work in the tight bits. You may well need to get a hard roller to get the air bubbles out.

The resin on the link is all the same, you just add more hardner to make it set faster or if its cool when laying up. Layup in the warm and GPW is right (as usual) that it will be stronger if it can cure slower.

When you have finished, if its still not up to your demanding standards coat it with coloured 2 part epoxy paint used for swimming pool repaints and it will be almost Bomb proof.

Oh, and take loads of pictures as the world is watching

Never heard of Saran Wrap in the UK, i remember a film with Sharon Stone.

Edit: Google is your friend, Saran Wrap = Cling Film, Cool idea GPW another thing for me to try. I have just had a look in our kitchen and all i can find is tin foil. My wife will think i have gone mad if i start buying cling film to wrap my camper.

[GPW]

QUOTE: "My wife will think I have gone mad ..." Not the first time I've been accused of that ... Wife thought I'd gone round the twist when I first proposed building yet another trailer ... You'd think after 37 years she'd be accustomed to it ...

[mikeschn]

Okay, I'll go with the 6 oz cloth, and probably the medium or fast epoxy.

G, my roller with spikes arrived today. It's really wicked! Those spikes are sharp.

I'll get some pics when I roll the foam... not this weekend, as we are out of town, but next weekend. This weekend we gotta celebrate fathers day!

Mike...

[GPW]

Mike , COOL ... careful with that tool .... easy to perforate fingers too ...

You SURE you want the Fast epoxy ??? Must be Cool where you are... ?

[mikeschn]

You SURE you want the Fast epoxy ??? Must be Cool where you are... ?

Well it's currently in the mid 70's.

But I am looking at set times and harden times...

Slow = # Set Time: 5-6 Hours
# Drying Time: 24-28 Hours

Medium = # Set Time: 3-4 Hours
# Drying Time: 8-10 Hours

Fast = # Set Time: 1-2 Hours
# Drying Time: 3-4 Hours

With the fast I can do one side in the morning, and in the afternoon flip it over and do the other side.

With the medium I could do one side on Saturday, and the other side on Sunday!!!

Mike...

[GPW]

Glad you have it all timed ... Down to 91F here right now ... Epoxy would set in no time .... GG foams in 10 min. Sweltering !!! Not even August ...

[Conedodger]

With the fast I can do one side in the morning, and in the afternoon flip it over and do the other side.

With the medium I could do one side on Saturday, and the other side on Sunday!!!

Mike...

If its any warmer it will cure faster, 1.5 hours sounds like a long time but thats a set time, you can knock off 20mins for mixing and from when you can no longer work it. Once it goes it will be impossible to work. If you get the mix wrong or need a pee you will be in trouble.

Dont try fast in full sun as it will cure before its mixed.

I did a pond repair with fast once and it was unworkable after a few minutes and once cured it went really hot and may well have melted foam

The longer set time the stronger and the more time you have to do a good job.

Remember its the amount of hardner you add and the higher the temp, the faster it gets

Best of luck

[Papi]

I've read all this with great interest, because I used to build model rockets and planes and dealing with the foam is similar. Polyester resin eats the foam, epoxy generally makes it super strong, GG "wood glue" takes forever to dry if it ever does, and the GG "pancake syrup" becomes like crystal and hard as a rock. What we commonly did in the model rocket days was take styrofoam or the pink foam, glue it into a chunk, and turn it in a wood lathe into a nose cone. When that was sanded smoth, we'd slather slow drying expoy on it and a layer of 1 oz fiberglass cloth. Repeat. Let dry and sand smooth. The resulting nose cone could withstand repeated launches past Mach 1.5 to upwards of 10K feet, with only minor scratches incurred on landing. The thrust of an M motor did not hurt it. So, no doubt a TD being towed at 65 mph will work well!

[GPW]

Papi , That's where I got my experience , with FFF Model planes , so we know this works on these SLOWER vehicles ...

[Papi]

I read somewhere about this stuff called "Styrospray 1000 Hard Coating" and thought it might be a good outer coating for a foamie. But after this, not too sure: http://youtu.be/50w-pzU9XK4

But it did seem they god somewhat good results in using it as a glue.