Epoxy coating problems

I need some help. I have been searching the archives, and applying what I read, but how on earth can I brush/spread on an epoxy coat (gloss, hotcoat or color work) without bubbles, some of which are as big as the layer is thick, making for pinhole/fisheye problems? I am using RR2000 and the fast hardener, and have tried various combinations of the following:

Additive F in 1cc and 2cc per oz hardener, as well as none at all

X-55 Accelerator in prescribed amount (1cc per ounce of mixed resin/hardener)

Denatured alcohol to thin the resin

Heating the resin before mixing

denatured alchohol wipe on board before coating

fans blowing across board while hardening

heating board outside before coating

foam vs bristle brushes vs plastic spreaders

slow vs fast brush speeds

soft vs harder brush pressure

I started with large separations, but using the above techniques, I can eliminate separations and I can sometimes reduce the amount of bubbles, but they are always present, and I cannot pin down the combination of things that will eliminate them. I glass in an air conditioned room (usually around 75 deg depending on how often the outside door is open), the humidity in my region is around 50%, and sometimes dusty, but I wipe down the board (with denatured alcohol) before taping off the rails and just before mixing the resin up.

I am new to board building, and shaping went very well, lamination was a breeze (I think, no bubbles under glass so far). I may have left the lams too dry, but I didn’t want the glass to float. I also may have moved the resin too much, as when I was removing the excess from the flats, it would sometimes come off on the squegee/spreader rather frothy. Hotcoats were the kicker for me, though.

Even on a cheater coat I tried after an hour after lam, I still got bubbles, and even if they were not felt at the surface after hardening, I could see them in the low spots of the weave between fibers. These very small bubbles were a constant regardless of whether or not a cheater coat was used on the lam to fill it in some. I usually just use the weight of the brush when brushing, unless I have to move resin to a dry area. Unfortunately, that is where the bubbles are worst, the dry areas that I brush the resin to after I pour it out. More brush passes just make the bubbles worse most of the time. I have tried ‘babysitting’ coats, but I just seem to make as many bubbles as I eliminate when I do this. The more I mess with it, the worse it gets, especially after the resin thickens some as it cures.

I cannot pin down the combination that will eliminate them, and there has to be a right way to do this. The archive has all sorts of praise for epoxy, as do I (it has been very easy to use so far), except for this problem. The only thing that bugs me is how some people boast that they can coat a board at an ounce of resin per foot, but then some of the fisheye posts say to coat thick (I imagine more than one ounce per foot) to avoid separations/bubbles. How can this be? Just different environmental conditions? Lots of advice, but also lots of money spent trying to follow the advice, guess it just goes with the territory when trying something new.

Other info: 2# Insulfoam EPS, sealed with Epoxy/Microballoons, 6 oz silane glass.

What do you guys think?

Thanks,

MM

wow dude

with all that testing you should be telling us everyting we need to know about epoxy

but what I think is you’re pulling the lam too dry, and your resin is draining into the foam, even though you sealed it (?)

what about bubbles from mixing, that stay bubular when you pour your resin on/

too much humidity?

good luck fixing it, let’s see the board

Yup, I think DF has it. Now, I’ve not used epoxy, but I’ve seen what I think is the same problem with a too-dry PE lam. If the lam has bubbles the hot coat won’t fill 'em, though it may cover them over, and allow a good finish coat, IF the hot coat totally covers the little bubbles, AND you don’t sand the hot coat down till the bubbles turn into craters. If the top of the bubble is sanded off (and it becomes a little pit crater) the finish resin won’t get into the pit and fill it. You’ve tried to do this by thinning and heating, but it isn’t working… stronger forces are at work than your efforts can overcome.

Soooo… I think that if your EPS sealing is well done, you’ll do better with a wetter lam. You’re using lightweight materials, so overall the result shouldn’t be overly heavy.

I like to have the lam adequately filled, which means for me that the resin has fully wetted the glass and filled in between the weave, but there is visible weave texture left. If you lam with less resin, in a perfect world you’d fill in the remaining visible weave with resin (and then some) anyway, so you’d net nearly the same amount of resin in the end. Endless pursuit of a 1:1 resin:glass weight ratio just won’t cut it, I don’t think, and still produce a smooth gloss finish. There will always be some loss to the blank, at least.

YMMV, of course, and others may chime it with their efforts and results. You have done well to explore the things you have, but I think in this situration you’re simply gonna need a wetter lam. Heck not having seen the steps, maybe your sealing simply isn’t quite enough… this would also be addressed by a wetter lam. Lotsa luck. With your level of effort you should be able to produce a very nice end product.

1:1 may be appropriate in pultruding operations, or many many layers, or if the surface finish isn’t critical. Just don’t obsess over it in this application.

Quote:

fans blowing across board while hardening

wow…i’m sorry…but that’s a new one on me

generally, we want still air while the hotcoat/gloss kicks…i won’t even let anyone open the door to the room when i’ve got a freshly coated board on the racks.

as for your problem, my epoxy hotcoat problems (dimples) was caused by just what DF mentioned…pulling the lam too dry. a cheater coat after the lam goes a long way. aside from that, just make sure everything is clean and that temp/humidity is within specs. use 2cc Additive F per ounce of hardener. add denatured alcohol to taste*. pour slowly…brush as you pour. long ways…then across…then one last time from nose to tail. then, walk away…and don’t go near it 'til it’s time to pull tape. voila…my recipe for epoxy hotcoat. enjoy.

  • do not actually taste the resin/hardener/additive f/denatured alcohol concoction, or any part thereof…it’s just an expression.

Thanks for the info folks. My digital camera won’t let me get photos smaller than 130k, so I can’t attach them (too large), unless there is another way I don’t know about.

I have done my testing on scrap pieces of foam (sealed and everything, just how I plan to do the real thing), and on a skimboard I cobbled up to try doing things with curves and non-horizontal surfaces on them. All color work is with the epoxy and pigment.

I have been pouring out the whole batch on the board/test pieces and moving the resin with the brush from wet to dry areas, then after all dry areas are gone, I do two 45 degree cross stroke passes and walkout per Mr Brucker’s DVD. Should epoxy be brushed differently than poly?

Soulstice, when you say brush as you pour, are you just following the pour with a brush (light to no pressure) to spread it as you go? I imagine that after the pour is when the longways and crossways passes happen, or is that all part of the pour?

Does the cheater coat go on the same way? How do you get resin to fill very small spaces like those in between the fibers of a lam that is too dry? Brush? Squeegee? A certain technique?

Sorry for the ignorance…

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Does the cheater coat go on the same way? How do you get resin to fill very small spaces like those in between the fibers of a lam that is too dry? Brush? Squeegee? A certain technique?

as you lam, use lighter pressure. remember, you’re just trying to saturate the cloth and lay it down smooth…NOT pull it dry. after you lam, as it’s started to thicken up, but not yet totally cured, i squeegee on a layer of resin using firm pressure…this is the cheater coat. then, after it’s all cured…hotcoat as usual.

Quote:

when you say brush as you pour, are you just following the pour with a brush (light to no pressure) to spread it as you go? I imagine that after the pour is when the longways and crossways passes happen, or is that all part of the pour?

yes…i follow the pour with the brush, but i use pretty firm pressure…enough to spread it across the length of the brush. you should pour out all the resin on your first lengthwise pass. then, cross-stroke to ensure everything’s covered. finally, take one smooth pass from nose to tail so everything’s all evened out. then…leave it alone! (that’s really the hardest part!!!).

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My digital camera won’t let me get photos smaller than 130k, so I can’t attach them (too large), unless there is another way I don’t know about.

the image needs to be resized. you can use a program like adobe photoshop. maybe even something like paint will work (i can’t say for sure)?? personally, i use windows powertoys image resizer. it’s a nifty little tool that adds a “resize image” option when you right-click on an image file. even at 640x480, the size of the file is reduced to about 30k. you can download it HERE.

On your camera issue, just go to http://www.photobucket.com, make yourself an account, and upload your photos there. It will automatically resize them, and then, when looking at your album there, look for the box that says “img”, copy the link there and paste it all into your post.

Thanks for the help with the image problems, and for clarification on the brush procedure. Here are the images:

Bottom and Top are the overall look of the thing. It is a sanded finish, as I was afraid to go any further and possibly sand through to weave.

Bubble is a pic of the tiny bubbles above the weave in the hotcoat, in the litttle depressions made by the weave pattern.

More pics on next post.

MM



Bubble Pin is a view of the tiny bubbles with some that were large enough that they became pinholes as I sanded into them.

Bubble topo is a view of the bubbles that occur near any topography, like the red color work, and in the red you can see some bubbles I sanded into to become small craters.

Hopefully the pics are good enough to see what I am talking about. Thanks for your advice and ideas. keep 'em coming. I’m currently away from home, but when I return I want to solve this problem.

MM


It looks to me like you either arent using enough pressure to wet out the glass or you arent being liberal enough with the epoxy when applying. The only place I use a brush is to apply epoxy where it looks like dry spots and getting the laps finished, everything else is dont with a sqweegy with good pressure. Another thing that I am going to start doing to make sure that I get no trapped micro bubbles under the cloth is first apply a thin layer of epoxy right on the foam. I dont use spackle or anything for that matter to seal my board. This fills in any imperfections and assures a solid bond. Then when I sqweegy on my cloth it brings out the bubbles, but if you seal youre board and make it super smooth first than you wouldnt have this problem as much as Ive had .

Howzit max, Not sure if this applies to epoxy but with poly resin you can get air bubbles if you leave to much resin on the board also. That is why glassing isn’t the easiest thing to do, it takes just the right amount of pressure when laminating to prevent those bubbles. Sounds like you are really thinking this problem over and in time you’ll figure out what is causing the problem,good luck.Aloha,Kokua

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Not sure if this applies to epoxy but with poly resin you can get air bubbles if you leave to much resin on the board also.

yep…goes for epoxy, too. if you leave too much resin in the lam, it will pool and the glass will pull away from the deck and float up on the excess resin.

I have three eps boards shaped ready for glassing and 3 gallons of Resin Research sitting in my workshop ready to use.

I have not glassed a board with epoxy yet.

The “problems” that you show in your photos are stuff that I would not even worry about. I see “pro” boards all the time with small bubbles ect. Why do you think so many “production” boards are sanded finish???

Your looking good and asking good questions… don’t wory about a few small flaws

Board #3 is going to be so awesome!!!

I really like the red spears on that deck ,got any more photos…

Ray

A thread about some proggys for resizing photos

http://www.swaylocks.com/forum/gforum.cgi?post=264225;search_string=kai%20irfanview;#264225

Max --------Stick with the Souljustice method and you will be fine. The cheater coat applied in a timely manner is the ticket. McDing

i also found that a 6 ounce weave harder to fill in a lam

and is more prone to pinhole

4 oz e glass is heaps easier to use and hotcoats are easier

so double 4 e would definately help

im finding if i dont filler coat “cheater” styles

i really need to sand the weave down a bit to get an even fillercoat

if i have pinhloes on a balsa skin its a disaster cuz the balsa goes dark and gets really soft

so im really careful

Glass when the temperature is dropping, doesn’t let the board breathe out while the epoxy is setting.

No wind, airflow around the board when glassing or coating.

Hope that helps a bit…

Thanks for the info folks. I will let you know how things go. Ray, here are some pics of the shaping process for the real board, haven’t glassed it yet. I used Excel to calculate my rail bands/bevels for me, you can see there are tons of markings on the board. I didn’t want to freehand it and screw it up. By mapping the rail bands like this, I only need 3 x-sections or so, and the computer tells me where to place my guide marks, and morphs the x-sections into one another for me. I use a linear function now to morph, so I have to modify the marks sometimes by hand to make them smooth curves. I then use 3/4" strapping tape to go on the marks, and I sand to the tape, so I don’t oversand. Works damn well, especially for people who do not trust themselves to sculpt from ‘the mind’s eye.’ (like me)

Here are the pics.

MM