I thinck so too
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parrifin melts when sanding to give some lube and make it seem to sand better...
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Good tip! Thank you Dave!
Just wondering, would it be of benefit to say.......rub paraffin onto cured hotcoat and sand it then? Same effect as adding paraffin to unpolymerized resin? Worse? Better?
Retro, if I understood Dave correctly, he was saying it “seems” to sand better, but it doesn’t actually sand any better. Thus there would be no benefit to rubbing parafin onto your cured hotcoat before sanding.
Well guys, when i first started on swaylocks i had all kinds of whatiff questions to…
but i found the best way to learn was do… so as regards to your question about rubbing parrifin on the top of the hotcoat… go try it! but common sense tells me the wax in the pores if epoxy at anydepth would continue to lube as you go deeper…
and back to the origional thread questions about pintholes, im pretty sure #4 is right too, without seeing pics of what you have done i think your lam is pulled too dry…
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Thanks for a great explanation Dave. I suppose the same would be true of using DNA/Metho to thin epoxy.
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Can you thin epoxy with Metho ??????
I’ve not
tried it (yet!), but I know that several people on Swaylocks have talked
about thinning epoxy using De-Natured Alcohol (DNA), which according to
Wikipedia is what we in Oz call Methylated Spirits.
I have no doubt now that I sqeegeed the bottom lam too dry. For this 9 foot board I intially mixed 1100g of KK. It was not enough I eventually ended up using 1350g on the bottom. Since switching from PE to epoxy resin I have tended to be a bit frugal on quantities, trying to keep costs down, possibly from following the advice of others. Are the qualities given by Resin Research realistic for someone still getting to grips with eopxy? Maybe if I was more generous with the lams and the filler coats I would have less problems. Maybe I am still treating epoxy like PE?
That’s because the air under the surface of the hole has nowhere to go… so it stays there. The resin on top does not allow the air to escape. I’ve done the same thing around outgassing holes around boxes and plugs with EPS. You try to push the resin down into the hole, but it never really gets down in there. It just sort of caps it.
Which is good… it’s water tight.
As for xylene leaving microscopic holes at the molecular level… I don’t know because I’ve never tested it, and Dave knows more than me, but if I had to guess I’d say that it’s insignificant in terms of the context of the application. The ability to wet out better makes up for any weakening of the matrix from the evaporization of xylene, since you use very little.
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Thanks for a great explanation Dave. I suppose the same would be true of using DNA/Metho to thin epoxy.
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Can you thin epoxy with Metho ??????
[/quote]
I've not tried it (yet!), but I know that several people on Swaylocks have talked about thinning epoxy using De-Natured Alcohol (DNA), which according to Wikipedia is what we in Oz call Methylated Spirits.
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Thanks Paulr, Im in Oz too, I'll give the Metho a go, maybe about 5% of total volume to start. Im just looking for a smoother thinner last coat to cover some pinholes.
Does anyone know if the pinholes mean theres an opening in the waterproofing or are the pinholes just a cosmetic flaw ?
Hey ultimats
in Oz as well, The experience with pinholes i've had is that most of the time its cosmetic.. I did have one EPS board that had pinholes that leaked on the first surf.. but that was only one.. went through a "lightweight "stage- "trying to make the lightest board ever" and was taking way too much resin off the board.. had a few boards in this time which had pinholes, took away any additives and didnt squeeze out as much resin, problem fixed.. not too much heavier.
That sounds like a reasonable starting point. Let us know how you go, because I’m intending to try thinning the epoxy for the gloss coat on the two boards I’m just starting.
Cheers
Paul
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I'll give the Metho a go, maybe about 5% of total volume to start.
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That sounds like a reasonable starting point. Let us know how you go, because I'm intending to try thinning the epoxy for the gloss coat on the two boards I'm just starting.
Cheers
Paul
...No.....If you feel the need to "thin" the epoxy resin just add a little heat.
For example...it's 68 degrees F in the shop but it's 78 degrees outside....Put the resin and hardener and add F outside in the sun for about 30 min......I refuse to microwave my resin but a little Zap is better than solvent.....
Oh... it's so cold where you live...ok...keep your resin in the house where it's nice and warm....warm resin flows better.....
Ray
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Why is it ok to use Additive-F (xylene+parafin), but not DNA? Both are solvents, both aim to reduce the surface tension of the epoxy to make it flow and level better, both evaporate away.
I realise warmer temps make epoxy flow better (best gloss coat I’ve done was on a 40C day!), but I’m interested in exploring some of the other techniques used by people here.
From the man himslef:
Greg Loehr
"DNA won't effect EPS foam which is why we prefer it to Xylene. Xylene is fine under 3% but with DNA you can go to 5%+ without much problem. Most of the DNA in a laminate or hot coat will evaporate out during cure so it's not really much of a strength issue when used sparingly. Having said that, heat works better ... 10 - 15 seconds in a microwave, just the resin side before mixing, does a real nice job. BTW in my experience more bubbles can be introduced during laminating than during mixing. Be sure to follow general guidelines about overworking with the squeegee."
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Why is it ok to use Additive-F (xylene+parafin), but not DNA? Both are solvents, both aim to reduce the surface tension of the epoxy to make it flow and level better, both evaporate away.
I realise warmer temps make epoxy flow better (best gloss coat I've done was on a 40C day!), but I'm interested in exploring some of the other techniques used by people here.
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I did a thread on how to glass a surfboard with epoxy....I'm not a pro...I'm not a chemist....I do really nice glass jobs...ask around. I do nice glass jobs. Shop temp matters. So here's some numbers and other stuff....
The label on the One Quart can of Additive F says..."Surfacing agent for use with Resin Research Epoxies only. One ML per each ounce of hardener". Nothing about DNA or Xylene.
Over here at the Low Tech Lab we do a 2:1 mix with Resin Research....By volume... That would be 10 oz resin and 5 oz hardener. 1/2 cap full of Add F...that's about 2cc of F....if you read the label on the F we are using less than 1/2 of what they recomend. I don't think 2cc of add F is "thinning the resin". All of my friends that live "up north" swear that Add F causes problems......But my shop never goes below 65F when glassing.....And.......I gave step by step instructions. Don't glass when it's raining or snowing........
RR additive f is not xylene and wax. This keeps getting tossed around as a fact. You can make an epoxy ''surfacing agent'' with xylene and wax, but it's not going to be the same as add f.
The OP just drained his lam, and that is a never-ending disaster in poly or epoxy. Once you've done hc and sand you'll likely never get rid the problems.
Amen to that
From the MSDS at http://www.resinresearch.net/id7.html:
So additive-F is 85% Xylene. Fact. As for the 15% non volatile solids, who really knows but GL, but it does seem to fit the description of a wax of some kind.
BTW, perhaps this should be in a new thread, but we are not debating the cause of the original poster’s issue.
Cheers
Paul
In the interest of preventing the spread of bad information, I’ve edited this post…
Wasn’t there a thread a while back about RR turning pink? Didn’t someone, at some point, say it had something to do with using DNA to thin the resin? Turned out it didn’t… acetone… thanks paulr
It wasn’t DNA, but acetone that caused RR KK to turn pink:
http://www2.swaylocks.com/forums/kwik-kick-epoxy?page=23#comment-1376643
Search the archives, plenty of people have/are using DNA to thin epoxy. Like I said earlier, I haven’t tried it myself yet, but as I lack the luxuary of a dedicated glassing shed (I use tarps to seal off part of the otherwise open carport) and therefore can’t control the temperature, I am interested in exploring other techniques for getting a nice thin gloss coat.
Cheers
Paul