RR Epoxy with Fast Hardener Issues.

General Discussion
1

I just started using the fast hardener with the idea of cutting down my ‘flip’ time.

My original worries about possible difficulties in lamming under the ‘clock’ proved baseless.

However I have run into a couple of issues. The last two glosscoats that I have done have both had the same problems.

  1. I did pinlines on both of the boards. I followed the same procedure that I had done previously using the slow hardener. Taped off on sanded hotcoat, burnished tape, apply artists acrylic straight from tube( ala Harbour surfboards), and when it is dry (tried after a few hours and then overnight…same) sand the pinline with 220 grit paper until is is nice and smooth with no raised edges.

Everything done the same, and yet the glosscoat gets craters over the pinline. Spent at least a half hour baby sitting the recent coat, but still it ends up … far from smooth. I will go back and sand the board and then re-glosscoat it, but obviously I would like to find a way to not have to do this.

  1. On both of the glosscoats I have also gotten a few spots on the rails where it looks like the resin has ‘sagged’ while it was curing. Anyone ever seen this? Again, never had this with the slow hardener.

  2. The fish that I just finished is 6’ long. I used single 6oz. bottom and double 6 top for my glassing schedule. I have used the same on two other fishes… a 6’2" and a 6’4". When the board was lammed and hotcoated and I was getting ready to sand it, I gave it a bit of the 'squeeze test with my hand. No exessive pressure, just what I have done before and the lamination was much more compressible than before, I even left the littlest pressure dent from my thumb on the bottom. The small dent came out with sanding and glossing fortunately, but why the difference?

Does the fast hardener somehow change the stiffness of the epoxy? Using the 2000 modulus.

It would be nice to know if the properties of the epoxy will be quite different between hardeners as well as maybe some ways to work these issues out.

If I have to, I will use slow hardener for the glosscoats, especially pinlined ones, to get a better job. It would be nice to keep the short flip time though.

Thanks for any help.

Here are a couple of pics of the latest fish BTW.

2

Johan,

Nice board. Can’t help you with the other thing. Mike

3

Okay, here’s my take on what might have happened…

  1. The pinline procedure sounds good, and using Fast hardener is no problem. Be sure not to let the temp

where the board is below 80F until the board is finished- this is just a precaution. Letting the temp drop

between steps can potentially inhibit the cure.

I think your main culprit is contamination.

Is your paint the same type and brand as before?

Is your tape the exact same that you’ve used before? (tape adhesive can mess with epoxy)

Is your sandpaper the exact same? (‘stearated’ papers can really contaminate with a waxy material)

Is it possible to “wipe down” the pinline/surrounding area with denatured alcohol?

Did you do a ‘wipe down’ with some other material or paper towel or tape?

my instinct says it’s the sandpaper or the tape.

  1. Sagging glosses are a drag. Usually because the epoxy is left too thick when brushed on. Unlike polyester,

you can make epoxy coats extremely thin and they will still go to completion. Another reason for sags is

inhibited flow. What I mean is the gloss needs to flow in order to pull tight, like a drum head. If the tape

is not “wetted” the epoxy can “dam up” above the dry tape areas and a sag can start “up hill” from the area.

The tape should be fully wet all the way around the board- the skill here is to not wet the underside of the

board! If your tape is “waxy” and repels epoxy, you might not be able to wet the tape adequately.

I am starting to not like the tape…

  1. The glass job should be cured, it should cure much faster than a polyester one. If the temps dropped as

I stated above, then your glass job could be “soft” for some time, if not indefinitely. I cannot stress the

importance of maintaining ambient temps during the building process- esp with certain brands of epoxy…

I would be very interested to see if the slower hardener will make the problems go away, with all other

elements remaining the same… …this would imply unstable solvents present in Fast hardener, but I have

found problems outside of that for myself.

4

Aha! Now there are a few variables that I hadn’t put in the equation.

As for the pinlines, I bought some 1/2" tape from an automotive store, so yes, that could be the source of the problem there. I don’t think there is any way to wipe down the pinline. I have tried once with DNA, and it just smeared the acrylic. As for the sandpaper, it could be an issue as well. I bought some off the rack paper from a hardware store, where I think before I might have used some left over discs from my random orbital.

Now with the sags, I have used 3M’s 233+ tape for a while for it’s ‘chemical resistance’ (some of the painters tape would fall off after exposure to the epoxy) and maybe it could be the coating on top of it. It didn’t happen with the slow hardener, but I have noticed that the ‘ridge’ from the tape line is more pronounced… maybe with the slow hardener the epoxy had enough ‘liquid’ time so that the sag happened right at the tape. I will have to try some different tape, a good quality painters tape. Do you know of a brand name?

And lastly, which would probably be contributing to all of the problems, the temps are dropping here and the thermostat in the shop is not set that high (save some power bills) , the shop has been only at about 65 degrees. Obviously I will have to warm it up and keep it there for when I am doing epoxy work.

Thanks again for the info PlusOne! Your replies have always been very detailed and informative and very helpful.

Mahalo!

5

Johan,

Is the 3M 233+ the green stuff? 3M makes another tape available from automotive paint suppliers. Its Highland 2727. It is beige in color. I switched to this stuff after a discussion with a pro airbrusher who said that was what they went to when the beige 233 tape went to being green. Use it for glassing, airbrushing whatever. Someone else may chime in with more insight on this. I use RR fast for glossing so it will kick as as possible. When hot-coating or glossing epoxy is not very tolerant of any surface contamination as mentioned previously. Very sharp board BTW!

Dave_D

6

Yeah Dave, the green stuff is the 233+. I don’t know what the 1/2" stuff I got was. I will try and find the Highland 2727, there are a couple of auto places that I know of around here.

Thanks for the tip, and the comment.

7

I too have had the same problems with “fish eyes” over my acrylic paint on sanded hotcoats. I have solved it over pinlines by a light wetsand with a 800 grit paper followed by a complete wash with sunlight liquid dish washing soap, make sure to rinse it very well and don’t handle with bare hands at all after washing. On larger airbrush designs over a hotcoat i spray a clear coat of futures floor polish then scuff thouroughly (until the paint is complety dull) with a maroon Scotchbrite pad (Norton brand available from autobody stores) and follow up with a soap and water wash. Immediately befor glossing I wipe with denatured alchohol (avoiding painted areas as the alcohol dissolves paint).Nice boards by the way!

8

So the dishsoap didn’t affect the acrylic at all? No runs or smears?

Cool. Sounds like an easy fix.

Made the DNA mistake on my first pinline, one wipe and , whoa! not a good idea.

:slight_smile:

Thanks man.

9

Not a prob Johan, but…

65F is too cold. The stuff will harden but not really = Inferior product.

Not even a good idea to let the temp drop during any phase until completed and cured.

Ideal would be to work in 80 to 82F then place your work into a heat box or oven

(see our oven on our website) until you work on it again. Keep the box at about 80F.

Warning: on your second lam, DO NOT put the work into a warmer environment, as you

may blow the deck off or have other wierd blow outs. Slightly dropping temp is best,

like 82F lam room to 78F heat box.

You can make a heat box out of insulation sheets taped together and an oil type space

heater- figure it out. Use logic.

Have fun!

10

No, haven’t experienced any problems with dishsoap and acrylic (I use liquitex medium body thinned with future to spray). If you have any doubts, do a test panel first.

11

For what it’s worth from a backyard amateur (who’s been stoked on various formulations of epoxy boards since my dad (MIT chem engineering MS) quietly approved of my buying a Lite Wave board back in 86 )…Anyway, I’ve been using the Fiberglass Hawaii “House” epoxy with fast hardener all winter. After being severely bummed on how quick it kicked in the summer (temps in 80s+ and low humidity), it was a godsend this winter. I’m outside in the Santa Cruz mts (n facing slope under redwoods = cold/wet in winter, even in the drought we’re having)…and am getting nice lams with no blush, bubbles, etc. in 50 degree temps with 90+%humidity with the fast part b. All I did was take stuff inside at night or make sure it had a tarp over it (nice to keep the squirrel poop out anyway!). Microwave for 20seconds per 6-8 oz of part a helped a bit I’m sure and wrist wrenching stirring is mandatory (120 seconds or so for same volume. With spring here, the microwave is less important, but helps mixing…which is key. Hope this helps. Power to the backyard builders!