Smoothcast Vs. Resin and Fiberglass

[The Ronin]

I was simply looking for a way to avoid odors and allow me to continue work on my build thru the colder months as the weather starts to change over here in North America soon. I guess I will look into non 3M branded stuff and see how well it works, but might still try smoothcast 65D as Beaker mentioned to see how it compares.

If you're looking for a low odor/less temp reactive method, go with epoxy resins instead of polyester resins. Epoxy resins usually have a 50/50 or 60/40 mix and don't cure funny with lower temps like poly resins do. I only use poly resins when I absolutely have to (IE: emergency day before the con, or fixing a racecar body AT the track) I haven't had the opportunity or need to play with urethane yet, so I can't comment on that.

 

[MattMunson]

Grenex, glad to be of help and thanks for the kind words! Show dat multipass when it's done!!! lol

If odor is your main concern, then yes go with epoxy stuff. I've also found polyester resins to be VERY temperature sensitive, so much so that without direct sunlight and warmth, it may not cure at all. Your mileage may vary. Never had that problem with epoxy.

I'd also recommend experimenting with the smooth on stuff the dude recommended above. ALSO, one thing I have consistently found with smooth-on is they have GREAT customer and tech support. Call them up, describe to them what you want (ie, a low odor product that you can brush on in layers, in cold weather) and they will point you in the right direction. Very knowledgeable staff over there.

 

[GhostMinion]

This has been a very helpful and informative thread, so far. I'd like to thank all of those who share with us good info and experience. It's good to know there's a real community SOMEWHERE on planet earth.

 

[Grenex]

West Systems as well as our EpoxAmite (same product category) are Epoxy systems, the Bondo is polyester system and Smooth Cast is a urethane system.
Polyester isn't particularly strong without cloth.... Smooth Cast 65D does a good job of sticking together without the delmaination issues.... but epoxies, yes, will bond to anything because they are.. well... EPOXIES!

Breaker: how does smooth cast 65D differ from the 300 product?

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[Kevin Gossett]

Here you go...

Smooth-Cast® 300, 300Q, 305, 310 Product Information | Smooth-On

Smooth-Cast® 45D & 60D/61D/65D Product Information | Smooth-On

 

[Bob McCormick]

I was simply looking for a way to avoid odors and allow me to continue work on my build thru the colder months as the weather starts to change over here in North America soon. I guess I will look into non 3M branded stuff and see how well it works, but might still try smoothcast 65D as Beaker mentioned to see how it compares.

Dirtsen has an interesting discussion in this thread about building indoors using an Acrylic resin and wood putty of all things. You might check that out. I've been following it because I'm interested in less toxic approaches I can use to build some costumes with my kids.

 

[Grenex]

Here you go...

Smooth-Cast® 300, 300Q, 305, 310 Product Information | Smooth-On

Smooth-Cast® 45D & 60D/61D/65D Product Information | Smooth-On

Thanks but the links seem to have almost the same description which is why I was looking to understand why the 65 version was preferred.

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[Beaker]

Smooth Cast 65D was originally developed for rotocasting, what that means is it has some very slight flex in thin sections (70D is considered a rigid plastic so the 65D is very close to rigid with some impact resistance) Because a very common application in rotocasting is to do multiple layers the Smooth Cast 65D was developed with this in mind...

 

[Grenex]

Smooth Cast 65D was originally developed for rotocasting, what that means is it has some very slight flex in thin sections (70D is considered a rigid plastic so the 65D is very close to rigid with some impact resistance) Because a very common application in rotocasting is to do multiple layers the Smooth Cast 65D was developed with this in mind...

Thanks Beaker!

 

[GhostMinion]

Is the 60D and 61D just as good? I like the sound of longer cure time. Also, I thought I had read that smoothcast was WAY less heavy than fiberglass. Is this true?

 

[Grenex]

Dirtsen has an interesting discussion in this thread about building indoors using an Acrylic resin and wood putty of all things. You might check that out. I've been following it because I'm interested in less toxic approaches I can use to build some costumes with my kids.

WOW! Acrylic resin and wood putty....and his example actually looks pretty damn good! Have you had a chance to try this yet Bob? I am wondering how hard it is to get clean cuts and folds in detailed areas with the laminated paper.

 

[sirciarly]

WOW! Acrylic resin and wood putty....and his example actually looks pretty damn good! Have you had a chance to try this yet Bob? I am wondering how hard it is to get clean cuts and folds in detailed areas with the laminated paper.

Really great news, this acrylic resin is no-toxic!!!wow now I must find in Italy..

i think that is ok

http://www.poolkemie.it/ra_stratificazione+B6Jkw9Mw__.0.html

or

http://www.poolkemie.it/fileadmin/schede/STPK ECORESIN Simil Ceramica.pdf

sorry for data sheet only in italian...

 

[Bob McCormick]

WOW! Acrylic resin and wood putty....and his example actually looks pretty damn good! Have you had a chance to try this yet Bob? I am wondering how hard it is to get clean cuts and folds in detailed areas with the laminated paper.

Not yet. I'd like to try it, although I think I'm going to either try coating the cardstock with a spray sealer or using foamies instead of the laminate.

 

[GhostMinion]

Smooth cast 300 sets up in under 10 minutes, depending on the thickness. If you're brushing it on, you might want to give it a little more time.

Here's the kicker though: smooth cast will not bond with itself as well as a fiberglassing resin like West Systems. It WILL bond to itself, just not as well. You will probably experience a degree of delamination when you are sanding it down.

Also, smooth cast mixes by volume, not weight.

In my opinion, for pepakura stuff, fiberglassing resin is a better choice, but NOT the cheapo stuff you get at home depot. Spend the extra money to get a marine grade resin, and some good cloth or matting. Whatever money you think you'll be saving by buying the cheap stuff, you will lose in the time you waste dealing with the stuff. Please trust me on this one! lol

So, having established that 3M resin is crap, what about the actual bondo body filler used on the outside of the project. Is it also crap, and if it is, what do you recommend to use instead?

Also, I'm still a little confused....smooth on is used on the inside (say a helmet for example), is that correct? In place of fiberglassing?

 

[Kevin Gossett]

Smooth On is a brand. They produce all kinds of products for molding, casting, etc. What is being discussed here is one of Smooth On's resin products. 65D is meant for rotocasting, so you can brush it on in thin layers inside your pep to strengthen it.

Bondo filler is "OK". It can be difficult to sand though. I prefer Evercoat Rage Gold, it sands much easier. It is a little more pricey, and not as readily available, but as Matt already mentioned, saving money on the cheap stuff doesn't always save you money in the end.

 

[Grenex]

I prefer Evercoat Rage Gold, it sands much easier. It is a little more pricey, and not as readily available, but as Matt already mentioned, saving money on the cheap stuff doesn't always save you money in the end.

Sanding the bondo was a pain. I wouldn't mind paying more for a product that is easier to sand. I will have to look for this stuff.

 

[MattMunson]

Kevin beat me to it, and I totally agree. Evercoat Rage Gold is great stuff, as is pretty much any product from Evercoat. Once I found evercoat again, I shed many tears over the years I wasted using bondo. It's just night and day. A clearly superior product.

I would say evercoat products are easier to sand. They don't gum up your files, rasps, and sandpaper the way bondo does. I've always found bondo to have a slight tack to it, which makes gumming up stuff convenient for it. lol. Evercoat also cures harder, in my experience.

There was a question earlier about brusing resin onto the inside OR outside of the pep model. That is a question for the pep thread, as I'm not sure. Materials questions, I gotcha covered. Pep process... not as much.

 

[Grenex]

Kevin beat me to it, and I totally agree. Evercoat Rage Gold is great stuff, as is pretty much any product from Evercoat. Once I found evercoat again, I shed many tears over the years I wasted using bondo. It's just night and day. A clearly superior product.

I would say evercoat products are easier to sand. They don't gum up your files, rasps, and sandpaper the way bondo does. I've always found bondo to have a slight tack to it, which makes gumming up stuff convenient for it. lol. Evercoat also cures harder, in my experience.

I found Evercoat Rage Gold in both Extremem #120 high performance and #105 Premium versions. Any recommendation of one over the other?

 

[GhostMinion]

Thanks Kevin and Matt!!! Good info to know. I'll be changing ALOT in the workshop, it would seem.

Here's a good question for you to crunch on: Why does EVERYTHING Home Depot/Lowes sell have to always be friggin' "D" grade!? :lol

 

[Kevin Gossett]

Big box stores don't need to carry higher end products to satisfy the weekend warriors. That is what specialty stores are for