Fiberglass Resin : What kind to use ?

[mylo]

Hey all,

I MUST be getting smarter as I get older. Instead of going head first into glassing my foam plug, I decided that I should try a test piece to make sure nothing strange was going to happen. In my test piece, my fiberglass resin "ate" the extruded foam. (THANK GOD !!....I tried this out first). Is there a certain resin I need to use ? ....do I need to prep my foam plug with something ? Right now, it's 99% covered witha thin layer of drywall mud (Kevin McLeod style) which according to my test piece, seemed to protect the foam.

The LAST thing I need is to wake up to a melted foam plug that I have a million hours into making. Obviously I'm doing something wrong. This is my first time handling fiber glass / resin.

Thanks in advance,

Mylo.

[anonymous]

Mylo,

Good god man . Polyester

Mylo,

Good god man . Polyester resin just loves to eat foam. So forget about that material for your process.

Get a 1 gallon kit of West Systems Epoxy. Most hobby shops or plastic supply stores will carry it. This will not eat your foam one bit.

Problem solved. Now go get em! Epoxy is the only way to go. You don't need to protect the foam at all. Just shape it and lay on your glass and epoxy.

Steve

[Guest]

Steve has given some good

Steve has given some good advice. However, if you don't fancy forking out for more materials, and I wouldn't personally, there's an easy solution.

You need to coat the foam with a barrier to stop the styrenes present in polyester resin from melting your foam.

This can be PVA (try the local DIY store) or an oil based paint.

Be liberal with your application and put more than one coat (two to three should be adequate).

This will do the trick.

[mylo]

Gents,

Thank you kindly.

Since I

Gents,

Thank you kindly.

Since I have about 5 gallons of this resin and another 5 gallons of oil based paint that I used to paint my garage floor with (seems like heavy duty stuff, amost a plastic), I think I'm going to try Sub's advice and paint the foam with this paint first. I'm assuming the paint won't eat the foam either ? .....where's my test piece ?

I'll put my wood / foam working books away and crack out my chemistry manuals I guess. Learning curve all the way. I'll be glad once I get some experience under my belt to shorten my build times. Half my time is spent trying to figure out how to do stuff.

Thanks again,

Mylo

[tmsmalley]

Jeff Jones uses this method

Jeff Jones uses this method with polyester resin. He lays down a bunch of coats of latex (water cleanup) paint on his foam before doing the glass.
Tim

[Guest]

If it's oil based, it

If it's oil based, it shouldn't harm the foam.

But do test on a piece of scrap first to be on the safe side.

Any solvent based paint will eat the foam, so car paint sprays are a no no.

Andy

[mylo]

Tim,

That is reassuring that

Tim,

That is reassuring that Jeff uses this resin on foam with a coat or two of paint. I've got a ton of this resin and paint......no West Systems Epoxy though.

Andy,

I painted my test piece with my garage floor paint. No damage, no eating, it looks like a go. I'm going to try using this resin now on top of my painted test piece and see how she goes. I learned a very valuable lesson doing this in terms of experimentation BEFORE application, particularly when you don't have a clue that you're doing. I'm so glad that I've gotten wiser over the years.


Mylo

[crazy ivan]

Mylo,

I've also had success using

Mylo,

I've also had success using clear polyurethane as a barrier for polyester resin. Following this up with several alternate coats of PVA and wax will insure good separation as well.

[mylo]

Crazy,

Great tip. Only thing

Crazy,

Great tip. Only thing is...........

What's Polyurathane ? Is it a paint of some sort ?

Is PVA = Polyurathane ? Wax...you mean rub a candle all over the thing ?


There, ...I believe I have made my complete lack of knowledge known.

The good thing is, I'm uneducated and not simply a moron.....I don't think.

Mylo.

[crazy ivan]

OK...

Polyurathane is similar to

OK...

Polyurathane is similar to varnish and is often used as a finish for wood floors. Should be available in any paint department at your local hardware store, home center, etc.

PVA: PolyVinyl Alcohol. This is a common parting agent used when molding with fiberglass. Available from fiberglass supply houses such as www.fibreglast.com, or any of a dozen others you can Google on the web. If there is a nearby boating center such as West Marine, they should carry it as well. It can be brushed or sprayed on.

Wax: Save your candles. The above mentioned suppliers also carry a special parting wax in paste form which is rubbed on. Never used it myself, but have had success with liquid car wax. I guess you could use a soft automotive paste wax too.

Looking at your build thread, you know how how to do your homework. Just keep on with the scrap testing before applying any glassing techniques to your finished plug and you will soon learn what works. You'll do fine.

[mylo]

Crazy,

It is this type

Crazy,

It is this type of education that I need.

Thanks.

Mylo.

[jeffrey j]

.....

hey Mylo,
I have done 5 hulls using foam and polyester resin. 3- 1/32nd type II's, 1- 1/24th type II, and a 1/24th type XXIII, I used "FIVE" thats "5" coats of laytex water clean up paint on the foam plugs to protect them. Once all the glass work is finished on the outside, cut and file everything out of the hull first, this will aid you when removing the foam, it will already have started to break up with all the file and drill work you have done cutting in all the limber flood holes.
I just ran across your build thread on your type VII yesterday, very, very, nice work. The type VII is my all time fav. u-boat and in MHO make the best looking model subs of all time.
Also , I used 5 layers of 5 oz fiberglass cloth , this way, the hull will be very strong and be able to support itself. Good luck, make sure to do this outside,,,,,,, sometimes even in the garage its not enough ventialtion,, make sure you have a warm day , and yes, your neighbors down the street will be able to smell this stuff once you get started...
sorry, one more thing, I had several soda cans marked and filled with resin before I started, this way I could do a can at a time by adding hardner to each can as I go. With this much resin, it will cook off fast and you won't have much working time with each batch, so don't mix it all at once......... Jeff Jones

[mylo]

Jeff,

Excellent advice.

I've done

Jeff,

Excellent advice.

I've done three coats of some pretty heavy duty oil based Urathane Enamel garage floor paint. The plug is hard as a rock.

I'm going to be casting hulls so....I'm actually building a plug and not the hull itself. Your "drill first, remove second" thing doesn't apply in this situation, but I hear what you are saying. A couple of my buddies are already wanting copies of this hull, might have a wolf pack on the go. I have yet to figure out the $$$ COST $$$ of that plan.

I'll be using your advice about making small batches of resin.

.....warm outside ?.....in Canada.....in November......ummmm....not going to happen. What if I stoke up my diesel heater in my garage real good ?


Thanks again,

Mylo

[jeffrey j]

...

hey Mylo,
Got ya, didn't realize your making copy's,, very cool. That is one neat model, awesome size, I have an 8' type IX uboat and also own a pickup truck just to move the subs in, again, very nice work. Jeff Jones

[mylo]

Jeff,

A type IIA is

Jeff,

A type IIA is definately on the "to do" list, I like those guys. Where did you get your plans ? I will do a IX as well some day, ....that one should be a good size at 1/25.....might need a long load permit.

I'm thinking about building a special little enclosed trailer, basically on the same kind of chassis as you see those motorcycle trailers on, just to haul my sub(s) / sub gear (including fins and mask for retrieval......as well as cyanide capsule in case I can't find it) in. Hook up 'n' go. When I get back, just park the whole unit in the garage up tight to the wall, like having it's own little drydock. Of course, the trailer would be like a mobile work station with a table that folds out and storage space for tools and such....for on scene fixes and the like. .....just a thought I've been toying with. I'll get the sub finished first, then think further about it.

I'd like to see what you have for plans, or where to get good plans for a type IIA or IX. My goal is to eventually have all three in 1/25 scale.

Mylo