Im still a bit messy with my laminations. (on my 3rd board). I always have issues sanding down the ugly laps after alls said and done what with it being tacky. Usually wait a week too before sanding too try get it too cure. Any tips for making it easier too sand down the laps so I don’t use a couple of packs of sandpaper making it pretty. Couldn’t find much beyond glassing it better initially. (This is prior too the hot coat last time I just sort of sanded it and then hot coated it. That obviously sanded easy but was kinda pretty along the rails).
Welcome to the forum. What are using for resin and what is the temperature in your workspace? Are you doing free laps or cut laps?
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Clear freelaps and this ones fully laminated- so just cleaning up before I hotcoat. Im using pu and like 75ish degrees out. I always mix 1.5/2%. Its hard too touch. It just gums up the sandpaper when I use it.
With polyester resin you hot coat first and sand after. Polyester without styrene paaffine is not sandable. You can clean lightly bottom laps before top lam scrapping with a razor blade or a surform blade.
Real sanding lap before is an epoxy trick
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Like LeMat said, PE laminating resin can be hard to sand unless the surfacing agent (paraffin wax in styrene) has been added. I do epoxy and it’s all a matter of time and temp. Not enough temp and the resin stays soft for a long time and also waiting for the right level of cure to do cut laps (not too soft and not too hard).
Better sandpaper seems to work better than the cheap stuff and you need to swap it out once it’s used or gummed up or you’re wasting time and energy. If you use a rotary sander, the outer edge of sanding disks (the hook and loop ones are what I use) can be trimmed to fit smaller pads from 8 to 7 to 6 to 5 inches diameter (200-125mm by 25’s) for additional life.
what follows is based on my experience as an amateur shaper. it’ s only an opinion of what works for me.
other people might think or have diffrent opinions.
if something makes sense to me i try it, after all we are building not destroying.
a lot changed for me after watching this video.
Hello, if the resin has catalised good you wouldn’t have to wait more then 24 hours to sand and have no issues.
what is the resin you are using? (old?) (good quality)
Is the catalist fresh or old?
i use the machine in the photo ( has a very slow speed at force 1) to sand down the
laps and from one 125 mm sanding disc i can make tree pieces for the machine and that is more then enough.
i blow very well the sanding before moving on.
the better the cut of the laps the more clean the jobs.
i am a very big fan of eletric scissors for that efect.
when laping if there are lose threds try to cut them or make them stick to the lap, easier to sand down, other then if they stick on the foam.
try to wet as less foam as possible use the squegge runing kind of diagonal…watch that video or the ones from the swaylocks subscription.
cheers and good waves.
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If you do a good job on your free laps, you don’t have to sand or grind them until after the hot coat. Do a little research via the archives. The proper method for good free laps has been discussed on this site plenty. Sand them by hand using a hard block and 60# or a die grinder and a 50# Rolok disk. Use a hard plastic squeegee to get them to tuck hard and pull off excess resin. No strings or loose strands. Scissor cut those. You can also use a 3” cotton roller to tuck your rails. Mid rail to the nose. Mid rail to the tail. Sounds like you are not tucking a good lap and over sanding. If you do a good free lap; You will only need to sand around the cloth edge one trip lightly with a little extra on the relief cuts at the nose and tail. The part of the process you are attempting to do is only as good as the step before. Do a crummy lap and you’ll have trouble when you sand them.
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i think i haven’ t make my self clear when i refer to sanding or grinding laps when i say sand the lap ( i am refering to sanding the edge of the lap) the lap is of course clear laminated, gravity puled the resin down before laping and sticked clear and clean to the rail.
i use the machine mostly for the excess on the relif cuts of the nose and tail.
i do use a hard piece of wood for the edge.
now there are many ways to do a good lamination job and i am going to tell you one more, that for sure you never tried:
Put the glassing stand in a middle of an Half-pipe, now ride a unicycle blindfolded, while jugling 7 bananas and holding a squegee in your teeth, the rest is easy, when you are cruising trought the flat section of the pipe after performing the air just pass the squegge on the rails of the surfboard
cheers and good waves
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Damn, You figured out my “Secret” method. You left out the part about a banana up your wazoo though. Cheerio and good gravy.
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Ok seems a good funny tech, never think, i am not a funny guy, too much ingeneer background make me always think in the box, i should try …
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Unicycle on the half pipe would go crazy. Gotcha earlier on the just keeping it clean. Getting the excess resin out of the bottom of the laps is my next goal. Just need more practice really with that. Sprayed off all the foam particles with the water hose and weirdly found using water while sanding the lamination resin- kept it from gumming up the sandpaper.
A common trick is just to paste the laps (and fin area) with sanding resin with 2"-4" brush (depending on your level of brush control) wait for it to cure, and then sand just the lap areas. Then hotcoat the board as usual. If you’re using epoxy, you can “presand” the board, get it pretty much right and then hotcoat it- I’ve seen hotcoated boards look like glosses using these methods
Ill have too try that next time. If i can keep the coat after the rails thin it might even be closed too finished without excessive sanding.
The only real sanding I do on laps is the corners created at the nose and tail and very lightly along the edge just to remove any sharp edges that will snag the cloth. What little sanding I do of laminating resin is done with 40 or 60 grit. I will also use a scraper or a file depending on the situation and what tool is closest.
Yes scraper is a good tool with gummy resin
Scraper is one of my favorite tools. It does a very clean job and doesn’t make sanding dust. It can also be more precise than a sanding block for certain tasks. Particularly useful along tape lines.