as a general rule, epoxy sticks to anything, but not much sticks to epoxy
I see said the blind man to the crippled nudist who put his hands in his pockets & promptly walked away.
i would use a special type of substance for thickining epoxy, west system makes the cream coloured & then you have to add about 25% of some other stuff (i think aerosil but cant remember), yes using microballons makes it easier to sand, but this other stuff is much better. this is the proper way, because to microballons is like having lots of air bubbles in the epoxy, i think this would suck up a bit of water. or you could use talcom (?) powder, does the same thing.
I see said the blind man to the crippled nudist who put his hands in his pockets & promptly walked away.
i would suggest not using talcom. remember what the parents know( i hope to be on soon) this absorbs water, the microbaloons are micro( fibres) . they dont absorb water. a freind who is an enginner told me about them. he does this for real. i would think the proper way is the right way. and remember this is going out to everybody. young and old new guy to old guy. I am not saying robs idea is wrong. just that i would not use it. this is a good thread. so keep the information coming. i would like to keep on track. epoxy resin is what we all use. but do we need it. after all we are talking( in my case) and 1 meter long boat. the strengh. the polyester should do the job fine. what do you think? vinlyester in used on the big boats . just because they are BIG. do we have to scale it down?
cougar
long live the cup and cris dickson
I think you find there a different types and grades of Microballoons (colloidal silica I think is the posh name!) for either fairing or structural work, whatever its all good for models, as talc would be, I have seen it used!
I’ve never built a polyester model hull and I dont think I ever will, as to get down to the weight of an epoxy hull (even if it’s epoxy and glass rovings) a poly+csm laminate would be so thin it would be too easy to damage, and after all on a 1-2m boat the costs are not masively high.It does have to be said however polyester is easier to work with for those who have never laminated before, much less can go wrong.
Luff 'em & leave 'em.
Here’s what I use:
Wood: West System epoxy
Laminating: Aerospace Composites Products epoxy – wets out cloth, including kevlar, much better than West.
For gluing metal, wood, or lexan: hobby shop 5 min epoxy mixed with West System 404 filler to “peanut butter” consistency. Way back when the chemist for System Three used to post regularly to the Usenet boatbuilding group and he asserted that the 5 min stuff adhered better to metal. Warning: the filler turns 5 min epoxy into 1-2 min epoxy. The filler significantly increases the tensile strength of the bond.
Final epoxy coat, whether wood or laminating: mixed with West System 410 to “thick cream” consistency. Apply, and then “dry tip” with a dry sponge brush to smooth out. Note:
a cabinet scraper works much better than sandpaper for smoothing out epoxy.
For “bondo” type applications on epoxy, AquaMend epoxy putty (available at Home Depot) is simply terrific. The wood filler from the same company is equally good on wood.
A bit OT, but there is a new (to me at least) room temperature vulcanizing (RTV) silicone gasket material from Permatex called “Ultra Blue” that is great for sealing decks, etc. Has a moderate adhesive properties. Test on similar material to your project before use to see how well it does or doesn’t grip.
Hope this helps,
Earl
ok people
this may come as a shock . and should also help with the debate. polyester resin is very bad. for your health. you have to take precautions. I just came back from a clinic. there are reason which are personal<( a few mods and close friends know about this ) as to why i went there. I can no longer use poleyester reisn. the toxin that come off it , are very harmfull. they posted soem very large concern when told i use it. they told me only in the open should you use it. never indoors. appartenly the odour hangs around. and if you wear a mask and have a air purifirer. it will not work. now i have used polyester for over 20 years. and never even thought about it. but now in hind sight. i cant smell it. i can stick my face over the pot of resin. and no smell. the doctors seem to think it may hay hurt my sense of smell. personaly i just think i am use to it. SO to make things short. my wife is going to buy the resins from now on. and it will be epoxy. but what type is best for IOM and marbleheads. the iacc20 boats . we are stil experimenting on
cougar
long live the cup and cris dickson
Epoxy is bad for you as well .
Some are worse than others.
look for low blush expoxies with 2.1 ratios.
Some of the most popular epoxies that are regulary mentioned on this site are the worst offenders in this regard.
Doing some research and changing brands as enabled me to stay in the game.
Cheers
Brett
ok brett.
we need to know what epoxies are the good ones? i have been told to use the mgs brand. this was from a professional boat maker. now we all know we dont need that grade. what grade do we need? for our boat strength and our health? this thing with polyester though me for a loop. i never thought it could harm me that much. what resin is best to use?
back to my orignal question. just for different reasons
cougar
long live the cup and cris dickson
Like I said,look for low blush and low resin/hardner ratios.
You come from canada right? avoid the big name brand that comes from there.
Brett
at this stage, i wouldn’t bother building a rc boat by resin infusion, we just found out that it is lighter to do a hand lay up than to do a resin infusion… & iirc there was many more air bubbles in the resin infusioned part compareds to the hand layup
I see said the blind man to the crippled nudist who put his hands in his pockets & promptly walked away.