Fiberglass question
06-16-2002, 01:06 AM
#1
Fiberglass question
Can sanding resin be thinned slightly with acetone? I'm having trouble with the stuff going on (brushed) too thick, and hard to sand. I'd rather try one coat (on bare balsa) as a sealer, and the second coat as a filler...especially if it would be easier to sand, and give a better base for the primer.
Thanks for any help....Dave
Thanks for any help....Dave
06-16-2002, 10:01 PM
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Fiberglass question
Dave,
I assume you are talking about polyester. Yes, it can be thinned with acetone. I prefer not to thin it myself. Although, it depend on the brand of resin you have. In emergency cases, I have bought resin at Chief Auto or at Home Depot, that was much thicker than the resin I normally use. If you decide to thin it, don't thin it too much because it will have more of a tendancy to soak into the balsa. If you just want to seal the balsa, I would use laminating resin to do that. The sanding resin will have a waxy surface when it cures and the next coat will not stick as well. Just paint the laminating resin on as thin as possible, then put your filler coat of sanding resin over that.
Russ.
I assume you are talking about polyester. Yes, it can be thinned with acetone. I prefer not to thin it myself. Although, it depend on the brand of resin you have. In emergency cases, I have bought resin at Chief Auto or at Home Depot, that was much thicker than the resin I normally use. If you decide to thin it, don't thin it too much because it will have more of a tendancy to soak into the balsa. If you just want to seal the balsa, I would use laminating resin to do that. The sanding resin will have a waxy surface when it cures and the next coat will not stick as well. Just paint the laminating resin on as thin as possible, then put your filler coat of sanding resin over that.
Russ.
06-16-2002, 10:50 PM
#3
Fiberglass question
Russ....thank you for the input...but too late (ha ha).
I put the sanding resin on the bare balsa, and made a mess. I put it on full strength...and it ran and sagged...and I didn't mix the resin before i catylized it....so it had sticky areas...and oh-boy !
I don't what to tell you what happened when i started to sand the mess (you probably allready know).
That's why I wondered If the resin could be thinned somewhat...so as to use the first coat as a sealer, and the second as a filler.
On the wing tips and center section, it came out much better....and i was able to sand it ok...then primed, and painted with auto enamal...it came out pretty good.
But the mess i made on the fuse is a nightmare.
I'm finishing a Bridi "Big Dirty Birdy", and i was hoping...by painting the darn thing...It would look half-way decent.
I believe I'm finding out why they charge like $500. to paint a pylon plane....You'r lookin' at a weeks work...a lot of material...and a whole bunch of agravation.
Any help, and tips, are apreciated...Dave
I put the sanding resin on the bare balsa, and made a mess. I put it on full strength...and it ran and sagged...and I didn't mix the resin before i catylized it....so it had sticky areas...and oh-boy !
I don't what to tell you what happened when i started to sand the mess (you probably allready know).
That's why I wondered If the resin could be thinned somewhat...so as to use the first coat as a sealer, and the second as a filler.
On the wing tips and center section, it came out much better....and i was able to sand it ok...then primed, and painted with auto enamal...it came out pretty good.
But the mess i made on the fuse is a nightmare.
I'm finishing a Bridi "Big Dirty Birdy", and i was hoping...by painting the darn thing...It would look half-way decent.
I believe I'm finding out why they charge like $500. to paint a pylon plane....You'r lookin' at a weeks work...a lot of material...and a whole bunch of agravation.
Any help, and tips, are apreciated...Dave
06-17-2002, 02:13 AM
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Fiberglass question
Hmmm...
Well sorry to hear about that. I just reread you post and I think I misunderstood at first. So you catalyzed the resin, but you didn't shake up the can before you used it. Yes, the wax can separate from the resin so if you don't shake it up, you may end up with resin that remains somewhat tacky (not nesessarily sticky) like regular laminating resin and it will not be sandable. If this is the case, you can just try it again. Shake the can up to make sure the wax is mixed in and then paint another nice even coat over the fuse. You might want to try a small spot just as a test. It should be sandable when it cures.
Sometimes you will have problems with sanding resin staying tacky if the resin is old. I just ran into that very problem recently. If the resin you have is old, you might want to just get a fresh can and use that.
Russ.
Well sorry to hear about that. I just reread you post and I think I misunderstood at first. So you catalyzed the resin, but you didn't shake up the can before you used it. Yes, the wax can separate from the resin so if you don't shake it up, you may end up with resin that remains somewhat tacky (not nesessarily sticky) like regular laminating resin and it will not be sandable. If this is the case, you can just try it again. Shake the can up to make sure the wax is mixed in and then paint another nice even coat over the fuse. You might want to try a small spot just as a test. It should be sandable when it cures.
Sometimes you will have problems with sanding resin staying tacky if the resin is old. I just ran into that very problem recently. If the resin you have is old, you might want to just get a fresh can and use that.
Russ.
06-18-2002, 04:29 PM
#5
Fiberglass question
Russ....I had much better luck on the second coat. I bore down on it with some medium paper on a palm sander, and was able to get smooth. I mixed a batch (shaken, not stirred...ha ha ) and brushed it on full strength on some deep scratches, then I added a little acetone as to thin....and brushed the rest on.
It laid down much flatter. It seems that if the resin is thinned, it needs a little more catalyst... cause it didn't kick-off in the pot, like it had been doing. I still got a couple sticky spots, but I'm working them with the heat gun....and I think they'll cure.
Because I hadn't been shaking the can, and it's about half gone....I may have a "bad blend" left in the quart.I'm gonna do the rest of the fuse now...with a little more catalyst and hope for the best.
Thanks for the help...Dave
It laid down much flatter. It seems that if the resin is thinned, it needs a little more catalyst... cause it didn't kick-off in the pot, like it had been doing. I still got a couple sticky spots, but I'm working them with the heat gun....and I think they'll cure.
Because I hadn't been shaking the can, and it's about half gone....I may have a "bad blend" left in the quart.I'm gonna do the rest of the fuse now...with a little more catalyst and hope for the best.
Thanks for the help...Dave
06-18-2002, 08:39 PM
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Fiberglass question
Dave
What you need is Styrene Diluent. You can buy it from Hastings Chemical in Santa Monica. Mix it 2/3 polyester and 1/3 diluent and all your thick problems will go away. It makes glassing a real pleasure. 2 coats, both easily sanded and you are ready for primer.
What you need is Styrene Diluent. You can buy it from Hastings Chemical in Santa Monica. Mix it 2/3 polyester and 1/3 diluent and all your thick problems will go away. It makes glassing a real pleasure. 2 coats, both easily sanded and you are ready for primer.
06-18-2002, 09:51 PM
#7
Fiberglass question
djlyon....I wrote that info down...thanks.
The last coat I put on this morning was much better. It was hard to the touch after 3-4 hours, and has no sticky spots...so I think it's gonna be OK. Just as soon as I got the fuse covered, I brushed some in the engine area, and was putting some in the tank compartment, when it gelled in the pot.
Now I see how hard it is to put that resin on full strenght ...is the pits. I created alot of extra work (like sanding) that I could have done without.
The last coat I put on this morning was much better. It was hard to the touch after 3-4 hours, and has no sticky spots...so I think it's gonna be OK. Just as soon as I got the fuse covered, I brushed some in the engine area, and was putting some in the tank compartment, when it gelled in the pot.
Now I see how hard it is to put that resin on full strenght ...is the pits. I created alot of extra work (like sanding) that I could have done without.
