Laminating measurements

Does anyone have a nice simple table that i could use/print and have handy with the exact amount of resin that is required for laminating and hotcoating for boards and from 6’0" right up to 10’

Easy rule for Epoxy Resin, Laminate use 3x the length of your board, hotcoat use 2 the length of your board.

 

it really depends on your glassing skills. A pro glasser can glass a 6´2 standard shortboard with 14 oz (400cc) resin, I remember when I started glassing boards I used a lot, like 28 oz… (800cc), now I use 19-22 oz… 

It´s better to use more resin than less if you´re starting. 

It also depends on the area of the board. A 6’0 regular shortboard won’t need the same amount of resin like a 6’0 egg or a 6’0 minisimmons.

Just try your first one with more resin and write the amount down. Then you’ll have your own guideline how much you need for a board. From time to time you know it better how much you need.

There has to be a minimum value for blank type and size, cloth weight and number of layers. Different foams will suck up more or less resin. Newer builders could be a little more generous with their resin.

I just did the bottom of an 8’ 8" x 29" x 4.5" SUP using a combination of EPS and blue Dow XPS foam. I had about 4 inches of lap over to the top and used 2 layers of 6 oz with both layers going all the way up and around to the tape line. I didn’t want to run out of resin so I mixed up about 35 oz of mixed resin in 2 colors to get a swirled mix. It was just enough get the whole thing done with very little waste. Then I added about 9 oz of fill coat after about an hour. I used a yellow squeegee to push the resin down and around. There were quite a few pin holes that I filled in, so the lam was pretty dry.  

I’d love to see a set of numbers for this because I’ve always been too conservative (cheap) and didn’t have quite enough to get the laps completely wet out. I’ll do an 8’ x 21" x 3" EPS double 6 oz and only use about 18 oz of mixed resin, then wish I had about 4 more ounces to do a better job. I never use enough resin to have it pouring down the laps. I usually wet them out carefully wasting as little as possible.  

 

If you have a scale, cut your cloth to length - don't trim to outline yet - and weigh it.  The glass for a 9' board with double 6 should weigh out around 36 ounces depending on cloth width.  I would recommend multiplying this by 1.5 - 1.75 to arrive at your total resin+hardener weight.  That will give you room to wiggle and not worry too much about pin air or frothing from dragging resin all over the board.  

Once you trim the cloth to fit your outline, you will be mixing more than 1.5:1 resin to cloth ratio but some of that will get squeegeed off in the laminating process.

Guys with more boards under their belt can get away with less but even Sharkcountry mentions pin air and dry laps from a slightly short amount.  He used about a 1:1 ratio with his batch if my calcs are correct? 

This formula works for polyester or epoxy.  If using MEKP catalyzed poly it is nice to be able to work fast to beat the gel time.  There is going to be some waste but it beats F'ing up the whole board if you fiddle around too long and have the resin set up before you get your laps tucked. 

I've seen guys in professional glassing shops waste a lot of resin.  They all seem to just eyeball their resin amounts and allow for extra which usually gets poured on at the end to hit the laps and fill any pin holes.  The floors, their shoes and their aprons are literally piled high with resin.

 

There is an old technique in wetting laps that I used to use all of the time. You wet out the flat surface of the board and then flip the still dry laps up on it. The wet glass holds the folded up glass in place. next pour a bead of resin down the lap glass and it will wet out with the squeegee.When all the glass is wet grab it an pull down where its hanging again and you are ready to tuck it under. (no dry spots and very little waste).

     Kind of hard to explain and sounds tricky but it’s actually very easy to do. Used a lot in the days of double layers of 10 ounce glass. I will say that it pays to use the thin surgical type gloves as it is hard to grab the glass with thicker ones. Hell…the old time glassers didn’t even wear gloves.

 

“it really depends on your glassing skills. A pro glasser can glass a 6´2
standard shortboard with 14 oz (400cc) resin, I remember when I started
glassing boards I used a lot, like 28 oz… (800cc), now I use 19-22
oz…”

 

And for those of us in the metric system:

1 fluid ounce (US) = just under 30mL

I started using the same technique Cleanlines described several years ago, and it does save a lot of resin (epoxy or poly).  I use roofing paper on the floor, and I only change it every 6+ months instead of 3 or 4 when I did the “production” method for wetting laps as John mentioned.  When wetting the flipped up laps, the main problem is strings when you flip them back down.  This can be minimized by pulling off 2-3 rows of the horizontal weave after you trim.  Another advantage of this method is that the laps don’t get too wet (since you run over them lightly before flipping) so you don’t have to work them so much and create lots of other problems. 

Back to the original question, it’s really relative to your blank sealing and lamination technique as to how much resin is used.  When you’re a cheap bastard like me, it feels bad if there’s more than 1 oz left in the bucket.

Strings are a problem with flip up lap deal but I used to keep a pair of scissors hand to clip them before tucking under the lap. I like big fat 3"inch cutlaps on some boards and this method works great for that.

A guy here named Petey told me to lam with epoxy flipping up the laps to keep the quantity of resin down. The key is keeping the strings to a minimum. I do my laps full with 2 layers, so they both go over the rail and onto the other side for extra strength (no stringers in my boards). I’ve had some problems with the glass getting messy, so I don’t do that as much. I just use my hand under the lap, pull a little resin over, make sure the lap is wet and try not to have spilling. Strings are just as much a problem with this technique, but the 2 layers of glass stay flat and I don’t have problems with lumps from the bottom and top layer getting out of sync.

I’m thinking that I’d try it again but try to fold back one layer carefully then the next layer. Just not sure if I’d have enough time because it’s hot over here and the epoxy goes off quicker. Petey says to glass in an air conditioned room to have temperature control, but I don’t have that luxury. I’m also using XPS foam or a combination of XPS and EPS right now, and I’m trying to get it figured out. Petey says glassing XPS is more complicated and temperature sensitive.

John thanks for the info. Someone else I met told me a similar way, but he didn’t say anything about doing the calcs before cutting the glass. He made it simple, basically something like… the weight of glass being either 4 oz or 6 oz and then being so many feet/inches long and then taking into consideration the shape of the board cutting off so much glass would equal a certain number then you just make enough resin to match that. 

a simple way for me to wet my laps and saves a bit of resin is i will wet out the flats and squeegee them off, the take a clean bucket or cup or what ever you got with a 1 inch or 2 inch brush, you start in the middle of the board lift up the cloth with the cup then spread on the resin going towards the the nose then back to the middle and then towards the tail, you want a clean cup so it doesnt snag the cloth and fray it, once everything is wet squeegee away[img_assist|nid=1060009|title=wetting laps|desc=|link=none|align=left|width=239|height=161]

[img_assist|nid=1060010|title=wetting laps|desc=|link=none|align=left|width=247|height=167]

One of the greatest things about lammin w/epoxy is you can add to it…  so I end up making litttle tiny batches at the end to finish off the laps and make sure I’m not leaving any in the pot…  Never the less, I still get drips from the ends…  

I like to flip the laps up, and brush a coat on the rails too - I’m using mostly 2lb eps and I don’t fill every hole before hand, so the brushing helps.

Watch Carpers' video or Loehrs' for Epoxy.  Learn proper squeege technique and you won't have to open up the "flip your rails" can o' worms.  Flipping cloth up on the rails is just asking for a whole new set of problems and is an unecessary step.  It's all in proper squeege technique.