thickening agent for polyester resin

KJM

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I'm going to need a fair amount of thickened resin and was wondering about using baby powder. Apparently talc is commonly used. Some say it absorbs water, others say its water repellant. I used amasil fumed silica and glass fibers so far but the fumed silica is expensive ($38 per gallon) and don't last very long. Talc instead of silica would be a lot cheaper. Also considering sawdust. I need it for making fillets along stringers and transom. Any thoughts?
 

jbcurt00

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Please don't start multiple topics about the same subject and avoid posting links to external sites, Utube included, in the inital post of a new topic

Merged.

W polyester resin avoid materials that could absorb water. Bondo (talc filler), talc, baby powder, wood flour, baking flour, wood chips, sawdust etc are all poor choices.

Suggest buying larger volumes of cabosil to get better price per unit/gallon, add microballoons and 1/4in milled fibers (can be made feom your scraps of 1708 & CSM.

Been thru WOGs transom stringers and deck replacement? Its all well covered.


Dont know specifically what that video is describing, but he says part and component a couple of times, so I highly doubt he's talking about use on a boat or regularly immersed in water parts...

Utube BoatWorks today. He knows boats.
 
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Scott Danforth

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$38 per gallon, is cheap

Avoid talc
 

kcassells

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yea baby powder absobs water. You want cabosil. Check uscomposit
 

KJM

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jbcurt00, not sure what you mean by multiple topics? Sorry about the youtube, i thought that was allowed, won't do it again. Yes i watch the boatworks today videos all the time, that guy is very informative. Scott, one gallon of that silica used up real quick, its so light and fluffy, not much substance to it. Would LOTS of glass fiber cut down on the amount of silica needed i wonder, or just make it really hard to work with? I suspected i'd get the negative replies on talc or sawdust and likely won't use them, but just for argument sake, if either ingredient is surrounded and soaked thru with resin which is waterproof then how does the water get into the cured mixture?
 

gm280

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First of all, exactly what are you trying to use the "thickened" polyester resin on? That will give us an idea what you are doing. Cabosil is the absolute best thickening agent for polyester...period! It is light because you want thickening, not weight. If you are mixing the polyester thick for filets or such, it works very well and can be sanded if you want. So depends what you are using the thickened polyester for...
 

Mad Props

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Agree with kcassells

Check uscomposites, you can get 4 gallons for under 30 bucks...
You can also get a 10lb bag for 67 bucks... I don't know how big a 10lb bag is, but its gotta be like the size of a minivan...That stuff is so light.
 

jbcurt00

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jbcurt00, not sure what you mean by multiple topics? Sorry about the youtube, i thought that was allowed, won't do it again

I merged the utube video you posted in its own topic, into this 1. It became the 2nd post in this topic.

Try embedding videos instead of linking them. Some cant access utube from work, not that anyone would ever surf boat stuff online while at work using both company computers and time.......

Specifically, links to other sites (any, not just utube) arent permitted in the 1st post in a topic.
 

gm280

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Agree with kcassells

Check uscomposites, you can get 4 gallons for under 30 bucks...
You can also get a 10lb bag for 67 bucks... I don't know how big a 10lb bag is, but its gotta be like the size of a minivan...That stuff is so light.

I have to equally wonder who would buy 10 pounds of Cabosil? I mean 10 pounds of lighter then feather material would be huge...US Composites is where I purchase all my fiberglass supplies and they have excellent products and service too!
 

racerone

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No such thing as " expensive " on a boat.------Just things that some of us can not afford.-------If you can't do it with the right materials the first time it get really expensive doing the same job over again !!
 

KJM

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No such thing as " expensive " on a boat.------Just things that some of us can not afford.-------If you can't do it with the right materials the first time it get really expensive doing the same job over again !!

Yeah i'm learning that, often the hard way. Silica it is then.
 

KJM

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KJM, check your PMs.

Yeah, i got that pm

Just going to bite the bullet and buy more silica tomorrow. I tried answering the PM but couldn't because of an advert that kept flashing on the screen!
 
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