I’ll try and dig out the photographs. A while back I played around with food colouring and epoxy (sad what I get up to!).
Tried a number of epoxies of different viscosities (yes a couple of infusion resins, they are really runny!) and temperatures. Warmed the foam as well. The idea was to see how far into the foam the different resins would soak. The food colouring (red) showed-up very nicely. The results were pretty predictable, thin resins on warm foam penetrate furthest! I’ll do it again with fluorescent dye in epoxy and take some pics.
I suppose the worry for the weight conscious is the possibility that too much resin will be adsorbed, but the way I surf these days, board weight is almost irrelevant, it’s getting to the water which seems to be the problem! Too much time spent fiddling around with experiments, I really must get out more.
At Max of swaylocks compsand révolution gorilla glue to glue prelam skins was commun, i do it with success on some boards. Bennie used to glue directly wood on eps with those pu foam glue, not a real sandwich but he have success with this build. Pu foam glue tend to rétract and stiffen with time ended with skin separation. Finaly epoxy works fine, possible to use flamingant epoxy.
The problem here is that my results do not include epoxy on un-sealed foam. While I do not think so, epoxy may bond better with the un-sealed foam than polycrylic sealer does.
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I have spare blue dow, and 2lb eps sitting around if you want to post up any other combinations you would like to test.
Cheers,
Jason
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As mentioned earlier, we still need unsealed vs. sealed comparisons. There is a wide range of variables to play with. It would be better for you to pick the combinations that interest you. I welcome any test data you are willing to collect and bring to the table.
Here are a few potential variables to combine for testing:
Dow (blue) vs. Owens-Corning (pink) foams: SAN + styrene vs. styrene, respectively = 2
Final sanding grits: 40, 60, 100, 150 (more?) = 4+
Sealed foam vs. unsealed foam = 2
Sanded sealer vs. un-sanded sealer (different grits too?) = 2
Sanded foam vs. unsanded foam = 2
Perforating rollers: Woodpecker vs. Carpet Seam Sealer = 2
XPS vs. EPS = 2
I am sure there are several more that I have omitted in the moment. Please use combinations that interest you.
For now, I am only testing four (4) treatments at a time with my quadrant panels. Carefully selecting the right variable combinations can eliminate the need for testing all variable combinations. For example, I want to look at perforation roller effects next:
Perforating rollers: Woodpecker vs. Carpet Seam Sealer = 2
Sealed vs. unsealed foam = 2
Sanded sealer vs. un-sanded sealer = 2
perforation before sealing vs. peforation after sealing = 2
potential sanding grits for final foam surface prep: 150, 100, 60, 40 = 4
I can think of a few more variables for “roller testing” alone but am ignoring them for the time being.
Please correct me if my ancient recollection about this calculation is wrong. If I remember my math correctly, the number of possible variable combinations/treatments for roller testing alone would be:
2 x 2 x 2 x 2 x 4 = 64
I only have 4 test patches in my next panel (limited by scraps) at the moment – a big panel would be cumbersome to laminate on an ironing board. So these are the first variables I will choose:
I have plenty of low-density, pink O-C XPS to work with = 1 variable (all treatments)
I will use 150 grit for final surface prep = 1 variable (all treatments)
Sealed foam vs. unsealed foam = 2 variables
Perforating rollers: Woodpecker vs. carpet seam roller = 2 variables
I will use the 150 grit to minimize sanding groove interference with perforation effects.
I think I can get a good idea overall about sealed vs. unsealed effects on this one and will have eliminated one surface grit to test.
I still want to the test the effects of peforations made before and after sealing – 2 more variables. Next round…
Please post any photos and data you have from previous XPS tests. I really like your dye testing work. BTW how did you get water-based food coloring to mix with epoxy?
An interesting coincidence, I was planning to color some polycrylic sealer with RIT fabric dye for use on EPS this weekend. My original thought was using the concrete sealer on EPS as a lightweight low viscosity sealer that would penetrate deeper into EPS than epoxy without adding a lot of weight. It would also prevent too much epoxy from soaking into the foam. But the main idea was to make the EPS more water tight in the event of dings – especially lower density EPS foam.
Next, I thought maybe adding dye to the sealer might be an interesting technique for coloring EPS foam, creating a unique mottling pattern with the styrene beads. Last weekend it suddenly ocurred to me that I could determine the degree of sealer penetration into EPS foam using the dyed sealer. Degrees of penetration could be controlled by application method (foam pad, nap roller, brush, etc.) and/or timed surface flooding of the EPS.
Ironically, it never occurred to me to use the dyed sealer on sanded/roughed XPS surfaces to observe penetration. I have a bottle of teal and a bottle of blue RIT dye. I can get one more round of testing from the first XPS panel now. More basic experiments. Love it…
Looking forward to seeing your test results. I really like your fluorescent dye idea.
Hi Stoneburner. I have built two stringer less boards using of the blue Dow (product code SMTG)… The foam has a density of 32kg/m3, compressive strength of 250kPa and is blown with HCFC’s. The first one I made some 10 years and it lasted until this year with no delamination at all, but unfortunately met it’s end (snapped clean in half) in decent sized Bells bowl some 6 months ago. Both were finished with 60 grit sandpaper and glassed with no other preparation. I live in a temperate climate zone (Australia’s South East) so heat isn’t too much of an issue, apart from summer time. I was a lot more thorough with removing excess resin when laminating the second board and have noticed a couple of dry spots on the rails eventually appear. Not sure if they have had a knock or two and a small separation has occurred or what. But the first board with the excess resin was pretty much bullet proof.
Hi stoneburner, in your math, you forget the fact that each test must be done several time to have some fiability, at least 10 time each with composits.
Your acrylic sealer is really lighter than you epoxy resin ? I do some work on waterprofing, strenghening, eps with sealer. I use many kind of foam and sealer, Finaly i have more consistant results with denser thighter foam, epoxy resin and “thick” lam. A thougher lam is essential to prevent open dings and water penetration is low with denser eps.
RDM, resin is the most important thing in surfboards…
Absolutely. For statistically valid comparisons, replication is needed to get a large enough sample size. My number does not include replication for statistical analyses.
My testing here is about feasibility and at this time is not replicated. Feasibility trials can be a good way to cull and select variables/treatments for further testing.
I am only speculating about the dried weight of a thin, single coat of concrete sealer. I am assuming a thin coat concrete sealer becomes lighter after application because drying (evaporation?) seems to be involved. At some point, I plan to weigh a piece of foam before and after sealing with polycrylic, but before lamination.
This is one of the “Other Tests” I did while working on the first XPS test panel.
Barry Snyder’s reptile heating pad method was the catalyst for this low budget resin warmer idea.
Upgraded low budget resin warmer:
In the winter I keep my house temperature in the mid to upper 60s F. I like to raise resin and hardener temperatures to between 75-85 F to insure thorough resin:hardener mixing. With the heating pad set on medium heat, the warmer raised resin/hardener temperatures and kept them between 82-83 F. I think the ceramic tile placed over the heating pad creates a surface with evenly disributed heat. I believe the EPS foam sheet significantly minimizes heat loss through the bottom of the box.
Upgrades:
9" x 12" ceramic tile ($1.80 @ Lowes)
Two pieces of EPS 1.0 pcf foam (scrap packing material), one under box & one on top
3, 1 lb dumbbells
6" x 11" aluminum tray salvaged from an old toaster oven
Previous equipment:
Beer case box (24, 12-oz bottles) corrugated cardboard
Heating pad (without automatic shut off)
9" x 13" cake pan
10" x 14" piece of cardboard under heating pad
Aluminum foil
Low Budget Resin Warmer in Use
Warmed epoxy resin and hardener
Resin warmer parts assembly
Heating pad covered by the 9" x 12" ceramic tile in the bottom of a beer-case corrugated cardboard box with some aluminum foil on the bottom and sides
6" x 11" toaster oven tray placed on top of the ceramic tile
Aluminum foil liner placed in the toaster oven tray
If there is lot of evaporation, your sealer may not be really water proof. No VOC Epoxy, 100% solid, is best for waterproofing eps. A not too fast fluid epoxy penetrate well in eps. Had some weight for sure but strengh too.
I liked your reptile heating pad concept the moment I saw it Barry.
My low budget unit is salvaged parts except for the ceramic tile and the aluminum foil. I do not know how much life is left in the (very old) muscle/joint heating pad – the high setting is dead, only low and medium remain. I may have to break down and spend $15 at Walmart for a replacement heating pad in the not too distant future.
With this last upgrade (lol), I decided I need to upgrade my heating box next. I have been keeping an eye out for a cheap styrofoam cooler/ice chest. Winter is the wrong season for that**…**
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I have got some more pictures that I need to compress. Glassing was delayed for panel 2. I forgot about curing/drying time for the secret sauce. Some complications popped up on the perforating roller panel.
Interesting you should mention that. The problems that popped up were related to uniformity and depth of perforations (first photo below), It was very difficicult to maintain even pressure across the whole carpet seam roller, getting half deep holes and half shallow holes. I had to over-perforate with the carpet seam roller: I feel like the holes were too deep which caused too much foam “crushing.” There is an obvious learning curve for the carpet seam roller – maybe Lavarat can offer some guidance.
I laminated the perforation test panel yesterday afternoon, I will peel the glass late tomorrow afternoon.
The Woodpecker perforator made smaller, nice clean deep holes and was much easier to control. Of course, I got a lot of practice with it perforating both sides of the first test panel before dying (photos below).
The experiments will continue**…**
**Second XPS test panel sanded first with 100 grit then perforated with Woodpecker (small holes) and Carpet Seam (larger holes) rollers -- left 2 quadrants are sealed with polycrilic concrete sealer after perforation; right 2 quadrants are unsealed.**
**The first XPS test panel with 60-150 grit re-sanded then dyed polycrylic sealer surfaces + re-sanded, Woodpecker Roller peforated, then dyed polycrylic sealer surfaces -- 4 oz of polycrylic sealer was dyed with 15 ml of dark green, liquid Rit Dye.**
It easy to see with the un-aided eye where the dye concentrated in deeper grooves. I did some cross-sections with a razor but not much was visible except the Woodpecker peforations (more photos later). The 60 grit seems to do as much tearing as it does grooving (at least with 1.3 pcf XPS).
The natural lighting late Christmas afternoon was good enough for some cross(X)-section photos of the dye panel. Dye penetration on the sanded surfaces is barely detectable to the un-aided eye on the 40-grit surface and "maybe" the 60-grit surface. The deep Woodpecker perforations stand out noticeably in contrast. The Woodpecker tines are approximately the thickness (maybe slightly thicker) of a single-edge razor blade and slice nicely into the foam surface.
Dyed 40-grit surfaces, Woodpecker tine perforations noticeable on bottom surface
(Some dyed grit grooves barely visible on top surface.)
**Dyed 60-grit surfaces, deep Woodpecker tine perforations noticeable on bottom surface**
(Some grit grooves visible on the top surface (maybe) in second picture?)
**Dyed 150-grit surfaces, most of the deep Woodpecker tine perforations noticeable on top surface**
I just did the peel test on the perforated XPS panel. There were obvious differences in peel pull resistance and the amount of foam pulled up, sealed vs. unsealed. Carpet vs. Woodpecker rollers too.
Much easier to cull combinations of test variables to look at now.
It is too late to shoot pictures now that the sun has set. I will save the write-up/observations and post them with the pictures**…**
