I just found out after taking this surfboard out of its bag that i made for my gf, surfed only twice, had a big delam upon further inspection i see that the waterbased paint Montana WB had actually chewed in the foam or something but also while stripping the cloth i see thath it comes off with the color and its not really holding tight to the foam.
On top I dont an issue with delam bubbles but I guess it would be the same.
What course of action would you recommend?
Strip all the glass reshape to a smaller size like for a grom and reglass.
Reshape/fill only the bottom and seal.
Toss the board in the bin and start a new one.
I am going to use just resin tints from now on…
I just did and sold a full color board with the same paint, i am already waiting for the phone call… what should i do in that situation? New board no colour?
Glass actually comes off faily easy where there is paint, it’s as it’s not even holding to the EPS foam, and comes off clean with the paint. Like the resin glued to the paint and did not penetrate further in the foam.
I’ve only built one board & it was for my daughter but have s lot of experience with repairing boards. I built the board 15 years ago so things have likely changed. The giude I used for my one board said to rough up the blank before laminating to give it more “tooth”. I always wondered about painting blanks or coating them as the paint may not bond as well as your epoxy. And of course a good firm squeegy when glassing to get the glass tight against the blank. For coloring & grafics I’ve had good success with automotive finishes once i’m done with epoxy. I used to do body & paint on cars for a hobby so already had the equipment to spray paint. The advantage is if I do get any damage it is easy to blend repairs with left over paint The disadvantage is the paints are toxic & should be handled carefully. Was your epoxy fast setting? That could affect the bond if it didn’t have time to flow & penetrate. That’s 2 cents worth from an old guy with limited experience. I hope you can save it & look forward to seeing your progress & what you learn about what caused the trouble!
You probably sprayed the paint too think, you have good adhesion. It looks like you didn’t even spackle the blank. When the glass tears up the beads like that its pretty good lam. Also it might be the blank density, weather conditions you glassed in, and or glassing schedule…also don’t paint your stringer. Did you over sand and cause water intrusion in weave? So many questions.
Yes i guess i did spray too thick on that particular spot as you can clearly see that the foam was “dissolved” but the thing is that when i was glassing this was not the case.
Could it be possible for a later activation?
Water seeping in is possible but it was only 2 times in the water, i surfed it once and it was fine, then i find it with a huge air ballon so big that even the glass on the rails was cracked.
Why shouldn’t i paint the stringer?
The density i use if 23kg/m2 i know it’s on the low side but i was thinking i am going to make light boards and did not get the 28kg/m2… it bites me in the ass but i have a few more to go and practice on and then get a densier EPS block as i am hotwiring it out.
i am thinking of sanding it a bit, guess the nose rocker will increase, then fill in with qcell the gaps and redo and see what happens then.
glassing is aprox 2x5oz (180g/m2) on top and 1x on bottom.
This is why I asked.
Low density EPS contains enough air/gas to contract when cooled (negative pressure — sucking water through pinholes) and expand significantly when heated in the sun (increased internal pressure — delams). Basic Gas Law physics. For low density EPS, a vent plug is needed.
To be safe, without a vent, I would want 2 pcf EPS. Especially if you are cutting blanks from a block of generic EPS.
I’m a scientist. No disrespect intended about other inputs. Their comments are of value also.
Resinhead qualifies as a pro-builder IMO. He mentioned some other potential problems to consider beyond density.
you mentioned dissolved foam? did you use any solvent based paints or thinners? If so that would be the issue. EPS can only handle water based paint…and it has to be sprayed from a gun…those water based spray paints have propellant that have solvent in them. Also I only use premium art paints, Liquitex etc. They are a little more, but they have more titanium dioxide in the paint so you don’t have to pile up paint to get good coverage. Covering the stringer with paint is a no no because the adhesion will fail like 90% of the time. Around the stringer and under your back foot is where you really want a tight lamination. Well carry on and keep learning!
the Montana water based spray paint works pretty well on EPS foam. as people mentioned earlier, it is important to not spray to thick. Did you spackle the blank before painting it? and if so, how thick of a spackle layer did you leave on?
I had similar issues with liquitex from a can…like you mentioned there seems so be at least a little foam eating solvent in the can.
Interestingly the foam destruction only appeared after/while glassing, I guess if I had left the colour dry for a longer time it would have come out ok.
So here’s what I know / do. I primarily build only EPS boards since the fall of Clark foam in 2005…I never looked back.
I only use #2 foam, no more light weight stuff…no 1.5 lb After the shape is done I fill voids with Sherwin Williams light weight filler. I use filler on all my boards, it make a cosmetically perfect looking board. I sand the filler down to the tops of the EPS beads, there is no float coat over the eps. Use your compressor to blow off blank well. I spray all my boards, even white ones. I use a quality water based art paint, shot out of a top feed HVLP spray gun… I use the same compressor that blows off the dust (multi task machine) I make no more than 2 full passes of paint. I let the board dry at least 24 hrs in a dry room. Glass as usual
Montana water based should not melt foam. I’ve used it successfully, but I spackle before use (fast and final mixed with just a little water- pancake batter consistency). Let it dry. I sand that with 120 then paint.
I stopped using it because I always had a lot of paint left in the can but the propellant would run out. Now I just mix tempera and paint it by hand. You have to mix a lot of color because if you run out it can be hard to match exactly the color.
Like resin head I only use 2 lb and try to use the superfused. My next board I’m planning will use a Rusty 6-9. So no superfused.
Spackle is when you fill the voids in the EPS foam that are left from small beads missing, usually best is Lightweight finish spackle, it dries fast, some people use rich qcell mix with resin.
It is also called sealing the blank.
You do it prior to painting / glassing to get a good looking consistent finish.
You can also skip it if you dont care about some resin wells in the foam.
