Does anyone have any tips or hints on how to sand free laps without sanding over the airbrush job on the foam. On my last board, I needed to smooth the laps (from the bottom lamination onto the deck) but when I did so, I took off some of the paint job. Any help is appreciated.
Hi mate, yeah i’ve had the same problems.
What I can suggest is this:
1.) When pushing your laps over, push a little extra resin past the lap, and onto the foam. This acts as a slight protective layer for the exposed foam.
2.) If you do burn thru or gouge, repaint the foam before glassing again. I have taken off some paint by sanding too far, then left it, and put it on top of the fibreglass. This is a no no since it will never look the same color as it did on the foam, and also creates a purely visible level effect, where the paint seems to be above the foam… which it is…
3.) One thing to try if your not keen on pushing more resin, is to tape over the foam at the lap section you are sanding on… just another way to provide a protective barrier…
I haven’t gotten this 100% so I’m keen to see what other people say too…
Cheers
Ant
If your laps are not perfectly clean (and if you need to sand, I assume that they are not) you should first “baste” them with some laminating resin. This will make the transition between glass and foam less abrupt and fill in small cavities that might be a “bubble nest” when you laminate the deck. Once this basting has dried enough, hit the bigger bumps that you may have along the lap with a surform (clean blade!!! You don’t want shaping dust or worse to be in contact with sticky resin). Then glass the deck.
Balsa,
Can you elaborate a little more on the basting process? What do you use to apply the lam resin? How wide is the resin applied? Would this layer protect a fabric inlay?
Thanks.
a brush and only about an couple of inches along the lap line.
Use a clean 1", or 1 1/2" brush, and paint on a filler layer of lam resin extending onto the foam. Then, per Balsas comment, use a CLEAN sureform blade to take down the high spots. Just be careful.
I’m only repeating a trick I learnt here, so there must be a number of threads about “basting” in the archives.
Anyway, you apply resin with a small brush, like this:
Half on the lap, half on the foam. The part on the lap will fill every little hole, the part on foam will protect it (and the airbrush or cloth inlay) from “accidents” with the surform…
Of course, you still need to be very careful when sanding/surforming, but it does make things less tricky.
Sorry, Bill, you were faster…
Howzit balsa, I find the easiest way is just sqeegee the extra resin past the laps when wrapping the rails. This makes it a one step process with out having to go back and paint the resin on later. Better thanl etting it just drop to the floor. Aloha,Kokua
Aloha Kokua,
of course, it’s far better to do things right in the beginning. But this means that you’re good enough at it. I wish I were, but, unfortunately, I’m not yet… Sometimes everything goes fine, sometimes I have to fix a few things…
Thanks for all the good tips, guys! If you have something to add…keep 'em coming.
Do cutlaps (seal the paint with resin so the tape doesn’t pull paint off of the foam) and then press the cutlap edge down into the foam with a rolling pin while the laminate is still pliable. Either that or paint after laminating the hull.
Howzit Stevil, If you use some acrylic clear coat over the paint before taping off it should prevent the tape from pulling the paint off, but remember Murphys law. Since ir’s a painted board you don’t need to do a cut lap just free lap the lamination. Mostly cutlaps are used when doing pigment or tint lams.Aloha,Kokua
As a relatively unexperienced glasser I have found that I get far better results with a cutlap. Cutlaps are easy, and I’ve found after doing them regularly, they take less time for me then a free lap/ grinding.No risk of dirt/ sanding grit on your laps or pulling out foam beads when the edge of your disk catches on a lump of resin. I’ve found I save time down the road when sandind the hotcoat due to a nice even line where the glass is thicker.If you feel confident enough in your abilites to do a clean free lap and have a steady hand with a grinder then by all means this is the way to go. By the way Kokua, thanks for sharing your advice, most of the answers for my glassing dilemas can be found in your posts. Cheers.
The grinder/pad makes all the difference. Get a very stiff pad. I use 5" abrasive disks. They need to be:
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stiff
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perfectly flat
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balanced (no wobble)
Don’t use the very edge of the pad, but use the part of the disk a little in from the edge. Just don’t tilt the pad so far in that it hits the foam. You only need to take the tits off the lap and maybe feather it a tad. Don’t go overboard. Concentrate really hard on getting your laps very flat and clean when lamming, and you will barely need to grind at all. Also important when grinding, is don’t ever start pressing hard. Let the sandpaper do the work, keep the pad moving and use light pressure. 50 or 60 grit is good for green poly lam resin. Anything coarser shatters the lap, finer loads too fast. I’ve done literally tens of thousands of boards this way, and it’s the simplest way to do it, though it does take a very careful approach. Oh and don’t drink too much coffee beforehand. What others have said about spreading resin past the lap onto the foam is essential, too. Just make sure your lap is very wet and the resin still super fluid when you turn your lap and you should get nice overspread of resin past the cloth. I know what of I speak. Hope this helps.
“You only need to take the tits off the lap …”
… but…
here’s some tits I’d rather leave ON my lap …
…or anywhere else she wants to put them, really …I’m easy !
cheers mate
ben
