Hey all - I’m in the process of building my second board. It’s shaped similarly to a minidriver. Overall I’m super excited with how the shape is looking.
I get a lot of inspiration from Almond Surfboards, so on Sunday I decided on a whim to try an epoxy foam stain using extra pigment left over from my last build. After pulling the tape I found some serious bleed through. I’m actually really stoked on the idea/pattern I came up with but the execution needs work. To be honest I kind of like that the board is a reflection of my learning curve.
I sealed the blank with a light layer of fast’nfinal and then sanded with 220 until almost all of the spackle was gone. She looked/felt great. I taped off with scotch tape and mixed a batch of RR epoxy with leftover teal pigment and some additive F. Put the stain on with a brush similarly to a hotcoat. My questions:
Would using better tape avoid this problem in the future? Is it just unavoidable? I used scotch general purpose masking tape - I feel like something higher quality may have stretched/conformed better to the eps irregularities. It was also pretty hot/humid that day so the epoxy was thin and the tape may have not bonded completely to the foam.
Does anyone do lighter 2 ounce fiberglass patches for colorwork (similar to a fabric inlay but with pigmented fiberglass instead)? I’ve been working exclusively with epoxy so far - I feel like lighter weight fiberglass stains might be an easy way to achieve cool colorwork.
Should I lightly sand the stain prior to lamination? Should I baste the edges similarly to a freelap? It’s been more than 24 hours since the foam stain so bonding may be an issue. I honestly don’t think it will be.
Somewhat unrelated - I weighed the blank prior to any foam stain and came up with 1395 grams (1.4kg). Using foam density of 2 pounds per cubic foot I calculated my board to be nearly 44 liters. According to boardcad it should be 35. I took a fair amount of foam out of the rails/deck/bottom so I’m pretty sure it’s much closer to 35 liters than 44. Has anyone weighed their boards and done density calcs to find their actual board volume? I’d be interested to find out if you guys are finding similar variances. For reference the board is 6’2" x 20.5 x 2.75. I considered cutting a small 1"x1"x1" block and weighing to find the true density but my scale doesn’t have the appropriate accuracy. It’s plausible I didn’t get an accurate weight off of my scale.
FYI - This board is for me. I’m not planning on shaping for anyone else until I build some skill/confidence. No loss if things aren’t perfect right now. Thanks everyone for reading and any help you may be able to provide!
Even then epoxy will WANT to bleed because it’s so thin
Never put additive f on a foamstain… you just thinned it even more.
You can use 2 ounce and dye it. But at that point just get a thin colored fabric.
Get better tape.
Weight and volume displacement are 2 completely separate things. I can shape my favorite HPSB and its 27.4l. It’s 27.4 whether I make it out of hot air balloon, a poly blank or concrete.
It’s the amount of space it takes up. Regardless of the core
Acqua is the pro. Always listen to him as I do. But since you didn’t limit this to pro glassers only (see other thread, ha), so here is my take. I’ve done both resin and acrylic stains. I much prefer acrylic on EPS. Much better color selections. Doesn’t delam. Tapes much easier. Use 3M 233 tape. If you do resin, you can mitigate the bleed by mixing a bit of clear resin and painting that on the tape line first, letting it cure just a bit, then come back with your colored resin. Which is a lot of trouble, but hey your time is free.
The acrylics on my avatar were done freehand, but I’ve done taped acrylics and been very happy.
Tape and smooth out with the end of a razor blade. Its tough with eps sometimes eps if it a lower density. I do foam stains and if they run I cover them with a pin line on the sanded hot coat. I have used posca pens with limited bleeds.
I haven’t tried pure acrylic foam stains. Are you just pouring the acrylic on the blank and then squeegee? Or just painting on? I have read the ratios for using acrylic on eps should be acrylic, water, future floor 1:1:1. Not sure of peoples thoughts on this.
Did you calculate the stringer in your weight to volume? They call it 2 lb. foam but it isn’t exactly 2, I think it’s 2.1. you could get a small piece of left over foam and find the exact weight to volume. (except they say that the beads are packed tighter on the outside and have a higher density) Like Aqua says best way is to measure displaced water if you have to know volume.
Surf it and see if it works.
You get to work on your painting skills some more to try to fix what you did so far. You can glass and then do lines on the hot coat to cover the bleed, it’s easier to get a hard line on finely sanded resin. But harder to not sand through the lines before finishing. Tape is cheap get the good stuff.
The board looks good other than the bleeds. For what you ended up with, I would have just painted it, I don’t think it would have looked any different, and paint is easier than working with resin. I only built one EPS board, spackled, and I found it kinda tricky too. Come to think of it, I shoulda just painted mine
Haha gtate good one I knew the answer on that one too but since I’m not an expert I wasn’t gonna tell.
Thank you so much! Stoked to get a response form a pro. My only comment is that while I agree weight and volume are two separate things, volume can definitely be calculated from weight if you know the density of your material. Density = Mass/Volume so you can arrive at the volume pretty easily by dividing your boards weight by it’s density. The difficulty seems to be (as pointed out below) quantifying stringer and glue density.
Once again - thank you so much for sharing your knowledge. I’ll get better tape and avoid additive F in foam stains in the future!
While I have your attention - when you glass do you leave the nose untucked? The nose of my first board gave me huuuuge issues when glassing (even with relief cuts). I noticed all of the boards at shops had what looked like cut off nose tips (maybe less than a half inch). I already sanded down my nose stringer thinking it would make folding the relief cuts a little easier but earlier today I found a video of a glasses tucking all the rails and leaving the nose tip untucked. After curing he went down and ground the extra cured fiberglass hanging off the nose flush giving him a perfect nose. Is this how the pros do it? Thanks again. Hope that made sense…
I’m not sure what I’m using to be honest haha. I used teal pigment sold by green light surf supply as they’re down the street from me. I’m not sure if it’s an acrylic or not - It certainly could be. I did it just like a hotcoat - mix in bucket, pour strategically, and spread with a brush. I got it all nice and level and left it alone to wet out.
Thanks - I think you’re right with the stringer. Glue probably doesn’t help either. I think it’d be interesting to record volume calculated via mass versus volume given by boardcad. I bet after a few we’d end up with a reliable coefficient we could use to better estimate true volume of a shaped board.
Thanks Huck - appreciate the complements! I’ve never done poly but I’m thinking I’m going to try a PU blank with epoxy resin next. I just don’t see the reason to learn poly resin aside from the beautiful artwork. Don’t get me wrong - I totally appreciate the beauty of it and the fact that it’s an important part of board building. I’d just rather hone my epoxy skills. It seems less toxic and maybe a little more friendly on the environment. I’m thinking of making some fin moulds to pour my extra epoxy into after each lam/hotcoat. I feel bad wasting all the resin and I bet I’d end up with a full set of fins after a few boards.
Everyone’s an expert compared to me at this point so all advice is welcome.
Thanks - I’ll consider that. Would you tape or freehand pinlines? Do you have to gloss coat over that? As much as I’d like to pretend I’ll do a gloss coat, i know I’m just going to surf her after a quick 5 minute sand job because I have no self control.
As the pros said, your biggest mistake was using crappy tape. Another one is to use a plastic spreader (squeegie) for your foam stain, rather than a brush. The spreader gives you more control and allows you to make a thinner, more uniform thickness coverage with the resin.
