I made my first board about 5 months ago. EPS blank, the ones you can get online and glue them up together with a wood stringer. Used Resin Research epoxy. I was just looking at the board today (havent used it in a while), and there is a slight indent along the stringer on the entire board, top and bottom. It’s not extreme looking, you can just feel that its slightly sunken right where the stringer is only. This was definitely not there before. It was flat and smooth. Any thoughts on what caused this and how to prevent in the future?
I glassed it in a 60 degree basement so cure temp is the only thing i can think of… Searched the archives and cant find anything on this. Thanks!
The stringer did not sink, the foam puffed up. Many reasons why. Heat is one, incomplete cure of the foam, is another. Sometimes both at the same time.
It’s fairly light wood. The board hasn’t been in any direct sunlight or warm areas. It’s winter and cold here in Massachusetts so if anything it’s been in colder than average temps. Sits in a room that can get in the 40s-50s
It’s hard to get a pic of it because its not super deep. Here you go. You can see the slight depression in the middle. Its’ like this along the entire stringer top and bottom.
I’ve had that happen numerous times on both eps and poly boards. Start out perfectly flat, but with time become ever so slightly depressed. More of a visual thing then something I could actually feel it was so slight. Also could tell by waxing the deck and see the wax not quite grabbing along the stringer.
my first thought was the same as the first response - the foam puffed, usually heat induced but there are other causes too, maybe even chemical?
I have patched dings with a chunk of foam then later the patched foam expands, have to sand down and reglass the patch.
I have had this occur over time (stringer area low) on a couple boards, I sanded and laid down a strip of glass along the stringer. I have also seen old boards where it is severe.
Awhile back someone posted about a stringer channel thinking it was a design element, and it was just the foam puffed around the stringer.
You say the board wasn’t subjected to heat since the cure so thats probably when it happened, and you just now noticed.
It was glassed at too low of a temperature. The air molecules were denser and trapped inside the blank. As you get into higher ambient temperatures. They will expand further. Seen boards you could roll a marble down those grooves.
Buy a vent or if green light still sells em a vented leash plug. To let that air balance.
You could also poke holes on both sides of the stringer get the board to 75-80 degrees for a few hours and then seal the holes.
So should boards be glassed in ambient temperature similar to the water temperature they will be surfed in?
I need to pay more attention to figure out how much the depressions on the side of stringers fluctuate with temperature.
I’ve only seen the shrinking on both sides of the stringers, and I thought it’s due to the foam shrinking with age, because it seems to affect badly beaten up old boards that have multiple ‘vents’ on both sides of the stringer!
on the deck side foam gets compressed from being ridden (foot wells) and will mash down so the stringer sits proud, causing the glass to crack along the stringer. Completely different from the stringer creating a low channel along its length.
[Quote=MrMik]So should boards be glassed in ambient temperature similar to the water temperature they will be surfed in?
[/quote]
Given that the OP is in MA, that would be impossible. Water temps range from high 30s in Winter to low 70s in Summer, depending on which part of the state you’re in. How you gonna decide that? Plus, the water temps are below glassing temp for nine months of the year, or more.
