Fiberglass and resin really stick to foam??

[StrongFeather]

Timing and otherwise, this probably won't be of much benefit to you, Jimbo, but I'd like to invite you to check out my composite panel construction technique; viewtopic.php?f=21&t=71192
[edit: Corrected the link]

IF it works, it will have several advantages over other techniques, specifically with regards to finishing work required to obtain a class "A" finish. It certainly won't be everyone's cup of tea, but it might be right for others that read this thread.... IF I ever get the prototyping done and IF the technique works and IF I can make it work for a reasonable price. I don't want to hijack your thread, so I'm going to just stop here.


Steve

[GPW]

What’s a Class A finish ??? Like your car … ?

[StrongFeather]

What’s a Class A finish ??? Like your car … ?

Sorry, yes.


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[GPW]

SF, we discussed this a long time ago , and it was mentioned this was the most difficult , laborious , and time consuming finish you can put on foam ( compared to normal foam covering PMF and a weave finish ) … But I guess you read about that already eh ?

[tony.latham]

SF, we discussed this a long time ago , and it was mentioned this was the most difficult , laborious , and time consuming finish you can put on foam ( compared to normal foam covering PMF and a weave finish ) … But I guess you read about that already eh ?

He's cutting the labor and time out with his method.

T

[StrongFeather]

SF, we discussed this a long time ago , and it was mentioned this was the most difficult , laborious , and time consuming finish you can put on foam ( compared to normal foam covering PMF and a weave finish ) … But I guess you read about that already eh ?

Precisely why I'm working on the new technique, G

Jimbo, my apologies. Keep up the good work.

Steve

[GPW]

Sorry , didn’t mean to ruffle your feather … Must have missed it … can’t read everything … I wasn’t trying to “ cut you down” , just mentioning the intricacies of a “car Finish “ as we’ve experienced as a former "Car Painter" .. Apologies, we won’t interfere again …

[saywhatthat]

small glass.jpg (100.05 KiB) Viewed 2268 times

All fiberglass and foam in picture of a 100 year trailer using trailtop components . Poly DOSE not eat HR foam. will melt the white foam. When doing glass it is a waste of time to do the sand and fill. build from the outside in.

[theoldwizard1]

There are a lot of boats out there that a "foam" covered with epoxy and fiberglass. In most cases, the multiple layers of fiberglass provide the "structural" support. Watch this video. Note they are using "blue foam board" from a "big box store" https://youtu.be/OyKy-cDy6e8?t=79

In other cases, very expensive structural foam (Coosa Board) was used https://youtu.be/MY4Czpc8AXY?t=120

In both cases, these repairs were for STRUCTURAL members of the boat. Basically the steel frame under your foamy.

[tony.latham]

There are a lot of boats out there that a "foam" covered with epoxy and fiberglass.

He's using polyester resin. That's the issue.

T

[saywhatthat]

The attachment Picture 528.jpg is no longer available

If you use the right foam . poly will flex more than epoxy Don't have do as much fill and sand. Cost & labor is much less than epoxy . If you have something that will soak up water wood paper then epoxy is a must. But foam with added bite works great As the foam will not soak the resin up .Just had an gent that want to fight over this Said He seen on the web that it would melt foam . And I was playing him as a fool as he fingered a 1/2 built pod.
Now to piss of more .Yes you can use poly over Polystyrene the white foam say what. one can use Styro-Shield. but cost and time are very high. Are 2 are 3 coats of latex paint to seal the white foam .Then one layer at a time of poly.The heat from the cure will weaken the latex.[

[theoldwizard1]

There are a lot of boats out there that a "foam" covered with epoxy and fiberglass.

He's using polyester resin. That's the issue.

The first video they are clearly using epoxy https://youtu.be/OyKy-cDy6e8?t=176

Same with #2 https://youtu.be/MY4Czpc8AXY?t=360

[tony.latham]

There are a lot of boats out there that a "foam" covered with epoxy and fiberglass.

He's using polyester resin. That's the issue.

The first video they are clearly using epoxy https://youtu.be/OyKy-cDy6e8?t=176

Same with #2 https://youtu.be/MY4Czpc8AXY?t=360

Right. And I’ve done that with epoxy over foam. But this poster is discussing his use of polyester resin on poly foam.

T


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[dbhosttexas]

I am no expert in this, just in the learning stages myself, but check out youtube viddeos on fiberglass over foam. Polyester resin acts as a solvent and will melt white polystyrene foam (styrofoam), and from the videos I have seen, also XPS foam (pink insulation foam board). Polyiso foam such as R-Max is reportedly immune to this, but is more brittle than XPS.

If you want to go fiberglass over foam construction, and have the budget for it, it seems the best method is to use XPS foam, a fairly heavy fiberglass woven roving coth, and epoxy resin. The issue is the epoxy resin is about twice the cost of polyester fiberglass resin.

Using Amazon / Home Depot prices here we go...

PMF approach, canvas and gripper...
9x12 Canvas Drop Cloth https://amzn.to/2N7GDGk $19.95
5 gallon gripper primer. https://www.homedepot.com/p/PPG-Gripper ... /306920688 $108.00
XPS foam (pink foam) 1" x 4x8 https://www.homedepot.com/p/Owens-Corni ... /207179253 $19.98

Fiberglass cloth instead of canvas...
Simond's Fiberglass Woven Roving (18 Oz, Plain Weave) (50" x 36 ft. / 12 yd. Long) https://amzn.to/2Lp82kP $57.49

Epoxy resin option.
Clear Marine Epoxy Resin, 1.5 gal Kit https://amzn.to/34yojLY $89.99
XPS foam (pink foam) 1" x 4x8 https://www.homedepot.com/p/Owens-Corni ... /207179253 $19.98

Polyester resin option.
Polyester Fiberglass Laminating Resin ,Gallon with Hardener https://amzn.to/34AVq1z $44.99
Polyiso foam board. 1" x 4x8. https://www.homedepot.com/p/Thermasheat ... /100549260 $21.52.

[John61CT]

reasonable source
https://fiberglasssource.com/collections/epoxy-resin